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  • 201. Laaksonen, J.
    et al.
    Kyrki, V.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Evaluation of feature representation and machine learning methods in grasp stability learning2010Inngår i: 2010 10th IEEE-RAS International Conference on Humanoid Robots, Humanoids 2010, 2010, s. 112-117Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses the problem of sensor-based grasping under uncertainty, specifically, the on-line estimation of grasp stability. We show that machine learning approaches can to some extent detect grasp stability from haptic pressure and finger joint information. Using data from both simulations and two real robotic hands, the paper compares different feature representations and machine learning methods to evaluate their performance in determining the grasp stability. A boosting classifier was found to perform the best of the methods tested.

  • 202. Larsson, Robin
    et al.
    Berge, Sten
    Bodin, Per
    Jönsson, Ulf T.
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Fuel efficient relative orbit control strategies for formation flying and rendezvous within PRISMA2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This article will outline the relative orbit control, including guidance and control tasks developed for the PRISMA technology in-orbit formation flying testbed mission. The focus is on real-time implementable solutions, working in arbitrary orbits (0 ≤ e < 1). The algorithms presented are based on linear Model Predictive Control(MPC). The computational heavy part of a MPC approach is usually to setup the matrices, associated with the linear program, if zero order hold discretization methods are used. This article introduces a different approach which uses the state transition matrices developed in [1], that accommodate steps of arbitrary length. This approach allows much larger time steps than the time varying dynamics would allow when zero order hold discretizing the dynamics. The computational complexity will instead depend on the number of state constraints and the number of allowed control inputs. These two factors can be designed to meet real-time execution requirements. The initial tests show that the expected ΔV consumption compares well to previous works in this area with only a small fraction of the computational load. To date, a version of the control algorithm for the Proximity Operations has been implemented and successfully demonstrated in real-time on flight representative hardware as a part of SSC's demonstration at the 6th International ESA Conference on Guidance, Navigation and Control Systems. The maximum processor load increase over one second was about 3%, on a Leon2 processor running at 32 MHz, with code not optimized for computational efficiency.

  • 203. Laskey, M.
    et al.
    Mahler, J.
    McCarthy, Z.
    Pokorny, F. T.
    Patil, S.
    Van Den Berg, J.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Abbeel, P.
    Goldberg, K.
    Multi-armed bandit models for 2D grasp planning with uncertainty2015Inngår i: IEEE International Conference on Automation Science and Engineering, IEEE conference proceedings, 2015, s. 572-579Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For applications such as warehouse order fulfillment, robot grasps must be robust to uncertainty arising from sensing, mechanics, and control. One way to achieve robustness is to evaluate the performance of candidate grasps by sampling perturbations in shape, pose, and gripper approach and to compute the probability of force closure for each candidate to identify a grasp with the highest expected quality. Since evaluating the quality of each grasp is computationally demanding, prior work has turned to cloud computing. To improve computational efficiency and to extend this work, we consider how Multi-Armed Bandit (MAB) models for optimizing decisions can be applied in this context. We formulate robust grasp planning as a MAB problem and evaluate convergence times towards an optimal grasp candidate using 100 object shapes from the Brown Vision 2D Lab Dataset with 1000 grasp candidates per object. We consider the case where shape uncertainty is represented as a Gaussian process implicit surface (GPIS) with Gaussian uncertainty in pose, gripper approach angle, and coefficient of friction. We find that Thompson Sampling and the Gittins index MAB methods converged to within 3% of the optimal grasp up to 10x faster than uniform allocation and 5x faster than iterative pruning.

  • 204. Lennvall, T.
    et al.
    Rizvanovic, L.
    Stoll, Pia
    KTH.
    Scheduling of electrical loads in home automation systems2015Inngår i: IEEE International Conference on Automation Science and Engineering, IEEE Computer Society, 2015, s. 1307-1312Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose a novel approach to schedule electric loads with the aim of reducing households' energy cost or CO2 emission with acceptable change in comfort. The approach involves both shifting households' electrical loads to times when the electricity prices or CO2 intensities are low, and reducing households' electrical loads at times when electricity prices or CO2 intensities are high. This approach assumes availability of day ahead hourly data of CO2 emissions and/or electricity cost from the external service provider. We categorize energy loads in two groups; constant and one-shot loads. Constant loads ensure environmental comfort for a consumer (e.g., heating, ventilation), while one-shot loads have a more dynamic nature (e.g., smart appliances, EV charging). Our approach is a best effort approach suitable for resource constrained embedded systems.

  • 205. Leong, Alex S.
    et al.
    Quevedo, Daniel E.
    Ahlen, Anders
    Johansson, Karl H.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    On Network Topology Reconfiguration for Remote State Estimation2016Inngår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 61, nr 12, s. 3842-3856Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we investigate network topology reconfiguration in wireless sensor networks for remote state estimation, where sensor observations are transmitted, possibly via intermediate sensors, to a central gateway/estimator. The time-varying wireless network environment is modelled by the notion of a network state process, which is a randomly time-varying semi-Markov chain and determines the packet reception probabilities of links at different times. For each network state, different network configurations can be used, which govern the network topology and routing of packets. The problem addressed is to determine the optimal network configuration to use in each network state, in order to minimize an expected error covariance measure. Computation of the expected error covariance cost function has a complexity of O(2(M Delta max)), where M is the number of sensors and Delta max is the maximum time between transitions of the semi-Markov chain. A sub-optimal method which minimizes the upper bound of the expected error covariance, that can be computed with a reduced complexity of O(2(M)), is proposed, which in many cases gives identical results to the optimal method. Conditions for estimator stability under both the optimal and suboptimal reconfiguration methods are derived using stochastic Lyapunov functions. Numerical results and comparisons with other low complexity approaches demonstrate the performance benefits of our approach.

  • 206. Li, W.
    et al.
    Christensen, Henrik
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Orebäck, Anders
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Chen, D.
    An architecture for indoor navigation2004Inngår i: Proceedings - IEEE International Conference on Robotics and Automation, 2004, nr 2, s. 1783-1788Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper is concerned with the design and implementation of a control architecture for a mobile robot that is to navigate in dynamic unknown indoor environments. It is based on the framework of Open Robot Control Software @ KTH, which is discussed and evaluated in this paper. As a hybrid architecture, it is decomposed into several basic components which can be classified as either deliberative or reactive. Each component can concurrently execute and communicate with another using unified communication interfaces. Scalability and portability and reusability are the goals of the design.

  • 207.
    Lindhé, M.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl H.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    USING ROBOT MOBILITY TO EXPLOIT MULTIPATH FADING2009Inngår i: IEEE wireless communications, ISSN 1536-1284, E-ISSN 1558-0687, Vol. 16, nr 1, s. 30-37Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Communication-aware motion control allows mobile networked robots to increase the average communication throughput. We exploit that in a multipath fading channel, robots can measure the SNR and adapt their motion to spend slightly more time at positions where the channel is good. Two new such cross-layer strategies are analyzed and evaluated: periodic stopping, where the stop duration is a function of the SNR, and controlled stopping, where the robot stops when the communication buffer is filling up. It is shown that the expected average channel capacity can be twice as high as when no cross-layer information is utilized. Experimental evaluation of the strategies confirms the theoretical results.

  • 208.
    Lindhé, Magnus
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Keviczky, Tamas
    TU Delft.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Multi-Robot Path Following with Visual Connectivity2011Inngår i: Conference Record: Asilomar Conference on Signals, Systems and Computers, IEEE , 2011, s. 1466-1471Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We consider a group of N robots moving through an obstacle field, where only robots that have a clear line of sight can communicate. When passing the obstacles, the group must coordinate its motion to remain connected. We propose using the path–velocity decomposition: Given obstacle-free paths that fulfill a higher-level goal, we propose a method to coordinate the robot motions along the paths so visual connectivity is maintained. The problem is shown to be equivalent to finding a path through an N-dimensional configuration space, avoiding unconnected configurations. We solve this problem with a rapidly exploring random tree algorithm and demonstrate by simulations how the solution time varies with the obstacle density.

  • 209.
    Lingelbach, Frank
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Path planning for mobile manipulation using probabilistic cell decomposition2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the field of autonomous robotics, manipulation planning is a problem of major significance. A very important component within a manipulation planner is a path planner that is able to connect two configurations by a feasible continuous path, provided that such a path exists. Recently, a new probabilistic path planning method, Probabilistic Cell Decomposition (PCD), has been shown to perform well for - amongst other problems - motion planning for a robotic manipulator. In this paper we investigate how the performance of the general method can be further unproved when used within the context of manipulation planning by incorporating knowledge of a specific manipulator. We propose pre-computation of a cell decomposition covering self-collision, adjustment of the cell splitting procedure to the articulated structure of the robot and tuning of distance metrics with respect to the robot. To evaluate the algorithms, we present simulations of a Puma 560 robot arm mounted on a Nomadic XR4000 mobile platform.

  • 210.
    Liu, Hongyi
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    An AR-based Worker Support System for Human-Robot Collaboration2017Inngår i: Procedia Manufacturing, ISSN 2351-9789, Vol. 11, s. 22-30Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In human-robot collaborative manufacturing, industrial robots would work alongside the human workers who jointly perform the assigned tasks. Recent researches revealed that recognised human motions could be used as input for industrial robots control. However, the information feedback channel from industrial robots to human workers is still limited. In response to the requirement, this research explores the potential of adopting augmented reality (AR) technologies in a worker support system for human-robot collaborative manufacturing. The robot commands and worker instructions can be virtually augmented for human workers intuitively and instantly. The designed AR-based worker support system is demonstrated by a case study.

  • 211.
    Liu, Hongyi
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Wang, Yuquan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Ji, Wei
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    A Context-Aware Safety System for Human-Robot Collaboration2018Inngår i: Procedia Manufacturing, Elsevier B.V. , 2018, s. 238-245Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recent advancements in human-robot collaboration have enabled humans and robots to work together in shared manufacturing environment. However, there still exist needs for a context-aware safety system that not only assures human safety but also provides system efficiency. In this paper, the authors present a context-aware safety system that provides safety and efficiency at the same time. The system can plan robotic paths that avoid colliding with humans while still reach target positions in time. Human poses can also be recognised by the system to further increase system efficiency. Different modules, algorithms, and interfaces are introduced in the paper to support the context-aware safety system for human-robot collaboration. A test case is demonstrated to validate the performance of the system. Finally, a summary and future research directions are given.

  • 212.
    Lotz, Max
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Depth Inclusion for Classification and Semantic Segmentation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The  majority  of  computer  vision  algorithms  only  use  RGB  images  to  make  inferencesabout  the  state  of  the  world.  With  the  increasing  availability  of  RGB-D  cameras  it  is  im-portant  to  examine  ways  to  effectively  fuse  this  extra  modality  for  increased  effective-ness.  This  paper  examines  how  depth  can  be  fused  into  CNNs  to  increase  accuracy  in  thetasks  of  classification  and  semantic  segmentation,  as  well  as  examining  how  this  depthshould  best  be  effectively  encoded  prior  to  inclusion  in  the  network.  Concatenating  depthas  a  fourth  image  channel  and  modifying  the  dimension  of  the  initial  layer  of  a  pretrainedCNN  is  initially  examined.  Creating  a  separate  duplicate  network  to  train  depth  on,  andfusing  both  networks  in  later  stages  is  shown  to  be  an  effective  technique  for  both  tasks.The  results  show  that  depth  concatenation  is  an  ineffective  strategy  as  it  clamps  the  ac-curacy  to  the  lower  accuracy  of  the  two  modalities,  whilst  late  fusion  can  improve  thetask  accuracy  beyond  that  of  just  the  RGB  trained  network  for  both  tasks.  It  is  also  foundthat  methods  such  as  HHA  encoding  which  revolve  around  calculating  geometric  prop-erties  of  the  depth,  such  as  surface  normals,  are  a  superior  encoding  method  than  sim-pler  colour  space  transformations  such  as  HSV.  This  only  holds  true  when  these  depthimages  are  normalised  over  the  maximum  depth  of  the  dataset  as  opposed  to  the  maxi-mum  depth  of  each  individual  image,  thus  retaining  geometric  consistency  between  im-ages.  The  reverse  holds  true  for  simpler  colour  space  transformations.

  • 213.
    Lundberg, Carl
    et al.
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Barck-Holst, Carl
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Folkesson, John
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    Christensen, Henrik I.
    KTH, Tidigare Institutioner, Numerisk analys och datalogi, NADA.
    PDA interface for a field robot2003Inngår i: Proc. of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS03), 2003, s. 2882-2888Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Operating robots in an outdoor setting poses interesting problems in terms of interaction. To interact with the robot there is a need for a flexible computer interface. In this paper a PDA-based (personal digital assistant, i.e. a handheld computer) approach to robot interaction is presented. The system is designed to allow non-expert users to utilise the robot for operation in an urban exploration setup. The basic design is outlined and a first set of experiments are reported.

  • 214.
    Lundberg, Carl
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Christensen, Henrik Iskov
    KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Evaluation of mapping with a tele-operated robot with video feedback2006Inngår i: Proc. IEEE Int. Workshop Robot Human Interact. Commun., 2006, s. 164-170Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This research has examined robot operators' abilities to gain situational awareness while performing teleoperation with video feedback. The research included a user study in which 20 test persons explored and drew a map of a corridor and several rooms, which they had not visited before. Half of the participants did the exploration and mapping using a teleoperated robot (IRobot PackBot) with video feedback but without being able to see or enter the exploration area themselves. The other half fulfilled the task manually by walking through the premises. The two groups were evaluated regarding time consumption and the rendered maps were evaluated concerning error rate and dimensional and logical accuracy. Dimensional accuracy describes the test person's ability to estimate and reproduce dimensions in the map. Logical accuracy refers to missed, added, misinterpreted, reversed and inconsistent objects or shapes in the depiction. The evaluation showed that fulfilling the task with the robot on average took 96% longer time and rendered 44% more errors than doing it without the robot. Robot users overestimated dimensions with an average of 16% while non-robot users made an average overestimation of 1%. Further, the robot users had a 69% larger standard deviation in their dimensional estimations and on average made 23% more logical errors during the test.

  • 215. Lundberg, I.
    et al.
    Björkman, Mårten
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Ögren, Petter
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Intrinsic camera and hand-eye calibration for a robot vision system using a point marker2015Inngår i: IEEE-RAS International Conference on Humanoid Robots, IEEE Computer Society, 2015, s. 59-66Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Accurate robot camera calibration is a requirement for vision guided robots to perform precision assembly tasks. In this paper, we address the problem of doing intrinsic camera and hand-eye calibration on a robot vision system using a single point marker. This removes the need for using bulky special purpose calibration objects, and also facilitates on line accuracy checking and re-calibration when needed, without altering the robots production environment. The proposed solution provides a calibration routine that produces high quality results on par with the robot accuracy and completes a calibration in 3 minutes without need of manual intervention. We also present a method for automatic testing of camera calibration accuracy. Results from experimental verification on the dual arm concept robot FRIDA are presented.

  • 216.
    Lundberg, Thomas
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Heimonen, Alexander
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    System Support for Cost Analysis2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The aim of this thesis was to analyze and evaluate possible matches betweeninvoices and assets from two different systems. This degree project was done incooperation with DGC, a network operator with an network stretching beyondthe borders of Sweden. The network solutions are provided through rentingthe copper and fiber connections (access services) from network owners andusing these to connect customers to their own network backbone. As a firststep towards a clearer overview of which customer pays for what, there was aneed to connect incomes generated from a paying customer with the outcomegenerated for renting an asset.  The approach taken to solve the problem involved analyzing the theory offuzzy logic and developing system support for matching using fuzzy logic ina .NET Windows Presentation Foundation application using the Model ViewViewModel design pattern.  The result became a fully functional implementation, integrated in an alreadyexisting tool called Oasis. This new tool allows users to quickly createpermanent mappings between invoices and assets.  This solution will decrease the time it would have taken to manually map theinvoices to the assets tremendously. This will make future steps in automatedcost analysis possible, giving the company a better overview of their financesand helping them to more easily find strange occurrences where an asset is beingrented without a customer paying for it, or vice versa.

  • 217.
    Lundell, Jens
    et al.
    Aalto Univ, Dept Elect Engn & Automat, Intelligent Robot Grp, Helsinki, Finland..
    Krug, Robert
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Schaffernicht, Erik
    Orebro Univ, AASS Res Ctr, Orebro, Sweden..
    Stoyanov, Todor
    Orebro Univ, AASS Res Ctr, Orebro, Sweden..
    Kyrki, Ville
    Aalto Univ, Dept Elect Engn & Automat, Intelligent Robot Grp, Helsinki, Finland..
    Safe-To-Explore State Spaces: Ensuring Safe Exploration in Policy Search with Hierarchical Task Optimization2018Inngår i: 2018 IEEE-RAS 18TH INTERNATIONAL CONFERENCE ON HUMANOID ROBOTS (HUMANOIDS) / [ed] Asfour, T, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 132-138Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Policy search reinforcement learning allows robots to acquire skills by themselves. However, the learning procedure is inherently unsafe as the robot has no a-priori way to predict the consequences of the exploratory actions it takes. Therefore, exploration can lead to collisions with the potential to harm the robot and/or the environment. In this work we address the safety aspect by constraining the exploration to happen in safe-to-explore state spaces. These are formed by decomposing target skills (e.g., grasping) into higher ranked sub-tasks (e.g., collision avoidance, joint limit avoidance) and lower ranked movement tasks (e.g., reaching). Sub-tasks are defined as concurrent controllers (policies) in different operational spaces together with associated Jacobians representing their joint-space mapping. Safety is ensured by only learning policies corresponding to lower ranked sub-tasks in the redundant null space of higher ranked ones. As a side benefit, learning in sub-manifolds of the state-space also facilitates sample efficiency. Reaching skills performed in simulation and grasping skills performed on a real robot validate the usefulness of the proposed approach.

  • 218. Lâiné, Mickäel
    et al.
    Cruciani, Silvia
    KTH.
    Palazzolo, Emanuele
    Britton, Nathan J.
    Cavarelli, Xavier
    Yoshida, Kazuya
    Navigation System for a Small Size Lunar Exploration Rover With a Monocular Omnidirectional Camera2016Inngår i: Proc. of SPIE Vol. 10011, 100111M, SPIE - International Society for Optical Engineering, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A lunar rover requires an accurate localisation system in order to operate in an uninhabited environment.However, every additional piece of equipment mounted on it drastically increases the overall cost of the mission.This paper reports a possible solution for a micro-rover using a sole monocular omnidirectional camera. Ourapproach relies on a combination of feature tracking and template matching for Visual Odometry. The resultsare afterwards re ned using a Graph-Based SLAM algorithm, which also provides a sparse reconstruction of theterrain. We tested the algorithm on a lunar rover prototype in a lunar analogue environment and the experimentsshow that the estimated trajectory is accurate and the combination with the template matching algorithm allowsan otherwise poor detection of spot turns.

  • 219.
    Madry, Marianna
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Ek, Carl Henrik
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Detry, Renaud
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Hang, Kaiyu
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Improving Generalization for 3D Object Categorization with Global Structure Histograms2012Inngår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on, IEEE conference proceedings, 2012, s. 1379-1386Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We propose a new object descriptor for three dimensional data named the Global Structure Histogram (GSH). The GSH encodes the structure of a local feature response on a coarse global scale, providing a beneficial trade-off between generalization and discrimination. Encoding the structural characteristics of an object allows us to retain low local variations while keeping the benefit of global representativeness. In an extensive experimental evaluation, we applied the framework to category-based object classification in realistic scenarios. We show results obtained by combining the GSH with several different local shape representations, and we demonstrate significant improvements to other state-of-the-art global descriptors.

  • 220.
    Madry, Marianna
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Song, Dan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Ek, Carl Henrik
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    "Robot, bring me something to drink from": object representation for transferring task specific grasps2013Inngår i: In IEEE International Conference on Robotics and Automation (ICRA 2012), Workshop on Semantic Perception, Mapping and Exploration (SPME),  St. Paul, MN, USA, May 13, 2012, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we present an approach for taskspecificobject representation which facilitates transfer of graspknowledge from a known object to a novel one. Our representation encompasses: (a) several visual object properties,(b) object functionality and (c) task constrains in order to provide a suitable goal-directed grasp. We compare various features describing complementary object attributes to evaluate the balance between the discrimination and generalization properties of the representation. The experimental setup is a scene containing multiple objects. Individual object hypotheses are first detected, categorized and then used as the input to a grasp reasoning system that encodes the task information. Our approach not only allows to find objects in a real world scene that afford a desired task, but also to generate and successfully transfer task-based grasp within and across object categories.

  • 221.
    Mahler, Jeffrey
    et al.
    Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94705 USA..
    Pokorny, Florian T.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Niyaz, Sherdil
    Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94705 USA..
    Goldberg, Ken
    Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94705 USA.;Univ Calif Berkeley, Dept Ind Engn & Operat Res, Berkeley, CA 94705 USA..
    Synthesis of Energy-Bounded Planar Caging Grasps Using Persistent Homology2018Inngår i: IEEE Transactions on Automation Science and Engineering, ISSN 1545-5955, E-ISSN 1558-3783, Vol. 15, nr 3, s. 908-918Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For applications such as manufacturing, caging grasps restrict object motion without requiring complete immobilization, providing a robust alternative to force-and form-closure grasps. Energy-bounded cages are a new class of caging grasps that relax the requirement of complete caging in the presence of external forces such as gravity or constant velocity pushing in the horizontal plane with Coulomb friction. We address the problem of synthesizing planar energy-bounded cages by identifying gripper and force-direction configurations that maximize the energy required for the object to escape. We present Energy-Bounded-Cage-Synthesis-2-D (EBCS-2-D), a sampling-based algorithm that uses persistent homology, a recently-developed multiscale approach for topological analysis, to efficiently compute candidate rigid configurations of obstacles that form energy-bounded cages of an object from an alpha-shape approximation to the configuration space. If a synthesized configuration has infinite escape energy then the object is completely caged. EBCS-2-D runs in O(s(3) + sn(2)) time, where s is the number of samples and n is the number of object and obstacle vertices, where typically n << s. We observe runtimes closer to O(s) for fixed n. We implement EBCS-2-D using the persistent homology algorithms toolbox and study performance on a set of seven planar objects and four gripper types. Experiments suggest that EBCS-2-D takes 2-3 min on a 6 core processor with 200 000 pose samples. We also confirm that an rapidly-exploring random tree* motion planner is unable to find escape paths with lower energy. Physical experiments on a five degree of freedom Zymark Zymate and ABB YuMi suggest that push grasps synthesized by EBCS-2-D are robust to perturbations. Data and code are available at http://berkeleyautomation.github.io/caging/.

  • 222.
    Manfredi, L
    et al.
    Institute for Medical Science and Technology (IMSaT), University of Dundee, Wilson House, 1 Wurzburg Loan, Dundee Medipark, Dundee DD2 1FD, UK.
    Assaf, T.
    Bristol Robotics Laboratory, Frenchay Campus, Bristol BS16 1QY, UK.
    Mintchev, S.
    The BioRobotics Institute, Scuola Superiore Sant’Anna (SSSA), Viale Rinaldo Piaggio 34, 56025 Pontedera (Pisa), Italy.
    Marrazza, S.
    The BioRobotics Institute, Scuola Superiore Sant’Anna (SSSA), Viale Rinaldo Piaggio 34, 56025 Pontedera (Pisa), Italy.
    Capantini, L.
    Department of Neuroscience, Nobel Institute for Neurophysiology, Karolinska Institutet.
    Orofino, S.
    The BioRobotics Institute, Scuola Superiore Sant’Anna (SSSA), Viale Rinaldo Piaggio 34, 56025 Pontedera (Pisa), Italy.
    Ascari, L.
    HENESIS srl, Viale dei Mille 108, 43125 Parma, Italy.
    Grillner, Sten
    Department of Neuroscience, Nobel Institute for Neurophysiology, Karolinska Institutet.
    Wallén, Peter
    Department of Neuroscience, Nobel Institute for Neurophysiology, Karolinska Institutet.
    Ekeberg, Örjan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsbiologi, CB.
    Stefanini, C.
    The BioRobotics Institute, Scuola Superiore Sant’Anna (SSSA), Viale Rinaldo Piaggio 34, 56025 Pontedera (Pisa), Italy.
    Dario, Paulo
    The BioRobotics Institute, Scuola Superiore Sant’Anna (SSSA), Viale Rinaldo Piaggio 34, 56025 Pontedera (Pisa), Italy.
    A bioinspired autonomous swimming robot as a tool for studying goal-directed locomotion2013Inngår i: Biological Cybernetics, ISSN 0340-1200, E-ISSN 1432-0770, Vol. 107, nr 5, s. 513-527Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The bioinspired approach has been key in combining the disciplines of robotics with neuroscience in an effective and promising fashion. Indeed, certain aspects in the field of neuroscience, such as goal-directed locomotion and behaviour selection, can be validated through robotic artefacts. In particular, swimming is a functionally important behaviour where neuromuscular structures, neural control architecture and operation can be replicated artificially following models from biology and neuroscience. In this article, we present a biomimetic system inspired by the lamprey, an early vertebrate that locomotes using anguilliform swimming. The artefact possesses extra- and proprioceptive sensory receptors, muscle-like actuation, distributed embedded control and a vision system. Experiments on optimised swimming and on goal-directed locomotion are reported, as well as the assessment of the performance of the system,which shows high energy efficiency and adaptive behaviour. While the focus is on providing a robotic platform for testing biological models, the reported system can also be of major relevance for the development of engineering system applications.

  • 223.
    Martí i Rabadán, Miquel
    KTH, Skolan för datavetenskap och kommunikation (CSC), Robotik, perception och lärande, RPL. Universitat Politècnica de Catalunya.
    Multitask Deep Learning models for real-time deployment in embedded systems2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Multitask Learning (MTL) was conceived as an approach to improve thegeneralization ability of machine learning models. When applied to neu-ral networks, multitask models take advantage of sharing resources forreducing the total inference time, memory footprint and model size. Wepropose MTL as a way to speed up deep learning models for applicationsin which multiple tasks need to be solved simultaneously, which is par-ticularly useful in embedded, real-time systems such as the ones foundin autonomous cars or UAVs.In order to study this approach, we apply MTL to a Computer Vi-sion problem in which both Object Detection and Semantic Segmenta-tion tasks are solved based on the Single Shot Multibox Detector andFully Convolutional Networks with skip connections respectively, usinga ResNet-50 as the base network. We train multitask models for twodifferent datasets, Pascal VOC, which is used to validate the decisionsmade, and a combination of datasets with aerial view images capturedfrom UAVs.Finally, we analyse the challenges that appear during the process of train-ing multitask networks and try to overcome them. However, these hinderthe capacity of our multitask models to reach the performance of the bestsingle-task models trained without the limitations imposed by applyingMTL. Nevertheless, multitask networks benefit from sharing resourcesand are 1.6x faster, lighter and use less memory compared to deployingthe single-task models in parallel, which turns essential when runningthem on a Jetson TX1 SoC as the parallel approach does not fit intomemory. We conclude that MTL has the potential to give superior per-formance as far as the object detection and semantic segmentation tasksare concerned in exchange of a more complex training process that re-quires overcoming challenges not present in the training of single-taskmodels.

  • 224.
    Martínez-Gómez, Jesus
    et al.
    University of Castilla-La Mancha.
    Caputo, Barbara
    University of Rome La Sapienza.
    Cazorla, Miguel
    University of Alicante.
    Christensen, Henrik I.
    University of California, San Diego.
    Fornoni, Marco
    Idiap Research Institute and EPFL.
    García-Varea, Ismael
    University of Castilla-La Mancha.
    Pronobis, Andrzej
    University of Washington, United States.
    Where Are We After Five Editions?: Robot Vision Challenge, a Competition that Evaluates Solutions for the Visual Place Classification Problem2015Inngår i: IEEE robotics & automation magazine, ISSN 1070-9932, E-ISSN 1558-223X, Vol. 22, nr 4, s. 147-156Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article describes the Robot Vision challenge, a competition that evaluates solutions for the visual place classification problem. Since its origin, this challenge has been proposed as a common benchmark where worldwide proposals are measured using a common overall score. Each new edition of the competition introduced novelties, both for the type of input data and sub-objectives of the challenge. All the techniques used by the participants have been gathered up and published to make it accessible for future developments. The legacy of the Robot Vision challenge includes data sets, benchmarking techniques, and a wide experience in the place classification research that is reflected in this article.

  • 225.
    Marzinotto, Alejandro
    KTH, Skolan för datavetenskap och kommunikation (CSC), Robotik, perception och lärande, RPL.
    Flexible Robot to Object Interactions Through Rigid and Deformable Cages2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In this thesis we study the problem of robotic interaction with objects from a flexible perspective that complements the rigid force-closure approach. In a flexible interaction the object is not firmly bound to the robot (immobilized), which leads to many interesting scenarios. We focus on the secure kind of flexible interactions, commonly referred to as caging grasps. In this context, the adjective secure implies that the object is not able to escape arbitrarily far away from the robot which is caging it. A cage is a secure flexible interaction because it does not immobilize the object, but restricts its motion to a finite set of possible configurations. We study cages in two novel scenarios for objects with holes: caging through multi-agent cooperation and through dual-arm knotting with a rope. From these two case studies, we were able to analyze the caging problem in a broader perspective leading to the definition of a hierarchical classification of flexible interactions and cages.

    In parallel to the geometric and physical problem of flexible interactions with objects, we study also the problem of discrete action scheduling through a novel control architecture called Behavior Trees (BTs). In this thesis we propose a formulation that unifies the competing BT philosophies into a single framework. We analyze how the mainstream BT formulations differ from each other, as well as their benefits and limitations. We also compare the plan representation capabilities of BTs with respect to the traditional approach of Controlled Hybrid Dynamical Systems (CHDSs). In this regard, we present bidirectional translation algorithms between such representations as well as the necessary and sufficient conditions for translation convergence. Lastly, we demonstrate our action scheduling BT architecture showcasing the aforementioned caging scenarios, as well as other examples that show how BTs can be interfaced with other high level planners.

  • 226.
    Marzinotto, Alejandro
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Stork, Johannes A.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Rope through Loop Insertion for Robotic Knotting: A Virtual Magnetic Field Formulation2016Rapport (Annet vitenskapelig)
    Abstract [en]

    Inserting an end of a rope through a loop is a common and important action that is required for creating most types of knots. To perform this action, we need to pass the end of the rope through an area that is enclosed by another segment of rope. As for all knotting actions, the robot must for this exercise control over a semi-compliant and flexible body whose complex 3d shape is difficult to perceive and follow. Additionally, the target loop often deforms during the insertion. We address this problem by defining a virtual magnetic field through the loop's interior and use the Biot Savart law to guide the robotic manipulator that holds the end of the rope. This approach directly defines, for any manipulator position, a motion vector that results in a path that passes through the loop. The motion vector is directly derived from the position of the loop and changes as soon as it moves or deforms. In simulation, we test the insertion action against dynamic loop deformation of different intensity. We also combine insertion with grasp and release actions, coordinated by a hybrid control system, to tie knots in simulation and with a NAO robot.

  • 227.
    Masud, Nauman
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL. Univ Gavle, Dept Elect Math & Sci, S-80176 Gavle, Sweden.
    Smith, Christian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Isaksson, Magnus
    Univ Gavle, Dept Elect Math & Sci, S-80176 Gavle, Sweden..
    Disturbance observer based dynamic load torque compensator for assistive exoskeletons2018Inngår i: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 54, s. 78-93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In assistive robotics applications, the human limb is attached intimately to the robotic exoskeleton. The coupled dynamics of the human-exoskeleton system are highly nonlinear and uncertain, and effectively appear as uncertain load-torques at the joint actuators of the exoskeleton. This uncertainty makes the application of standard computed torque techniques quite challenging. Furthermore, the need for safe human interaction severely limits the gear ratio of the actuators. With small gear ratios, the uncertain joint load-torques cannot be ignored and need to be effectively compensated. A novel disturbance observer based dynamic load-torque compensator is hereby proposed and analysed for the current controlled DC-drive actuators of the exoskeleton, to effectively compensate the said uncertain load-torques at the joint level. The feedforward dynamic load-torque compensator is proposed based on the higher order dynamic model of the current controlled DC-drive. The dynamic load-torque compensator based current controlled DC-drive is then combined with a tailored feedback disturbance observer to further improve the compensation performance in the presence of drive parametric uncertainty. The proposed compensator structure is shown both theoretically and practically to give significantly improved performance w.r.t disturbance observer compensator alone and classical static load-torque compensator, for rated load-torque frequencies up to 1.6 Hz, which is a typical joint frequency bound for normal daily activities for elderly. It is also shown theoretically that the proposed compensator achieves the improved performance with comparable reference current requirement for the current controlled DC-drive.

  • 228. Menghi, C.
    et al.
    García, S.
    Pelliccione, P.
    Tumova, Jana
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Poster: Towards multi-robot applications planning under uncertainty2018Inngår i: Proceedings of the 40th International Conference on Software Engineering: Companion Proceeedings, IEEE Computer Society, 2018, s. 438-439Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Novel robotic applications are no longer based on single robots. They rather require teams of robots that collaborate and interact to perform a desired mission. They must also be used in contexts in which only partial knowledge about the robots and their environment is present. To ensure mission achievement, robotic applications require the usage of planners that compute the set of actions the robots must perform. Current planning techniques are often based on centralized solutions and hence they do not scale when teams of robots are considered, they consider rather simple missions, and they do not work in partially known environments. To address these challenges, we present a planning solution that decomposes the team of robots into subclasses, considers complex high-level missions given in temporal logic, and at the same time works when only partial knowledge of the environment is available.

  • 229.
    Minnema Lindhé, Magnus
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Communication-Aware Motion Planning for Mobile Robots2012Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Mobile robots have found numerous applications in recent years, in areas such as consumer robotics, environmental monitoring, security and transportation. For information dissemination, multi-robot cooperation or operator intervention, reliable communications are important. The combination of communication constraints with other requirements in robotics, such as navigation and obstacle avoidance is called communication-aware motion planning. To facilitate integration, communication-aware methods should fit into traditional layered architectures of motion planning. This thesis contains two main contributions, applicable to such an architecture.

    The first contribution is to develop strategies for exploiting multipath fading while following a reference trajectory. By deviating from the reference, a robot can stop and communicate at positions with high signal strength, trading tracking performance for link quality. We formulate this problem in three different ways: First we maximize the link quality, subject to deterministic bounds on the tracking error. We control the velocity based on the position and channel quality. Second, we consider probabilistic tracking error bounds and develop a cascaded control architecture that performs time-triggered stopping while regulating the tracking error. Third, we formulate a hybrid optimal control problem, switching between standing still to communicate and driving to improve tracking. The resulting channel quality is analyzed and we perform extensive experiments to validate the communication model and compare the proposed methods to the nominal case of driving at constant velocity. The results show good agreement with the model and improvements of over 100% in the throughput when the channel quality is low.

    The second contribution is to plan velocities for a group of N robots, moving along pre-determined paths through an obstacle field. Robots can only communicate if they have an unobstructed line of sight, and the problem is to maintain connectivity while traversing the paths. This is mapped to motion planning in an N-dimensional configuration space. We propose and investigate two solutions, using a rapidly exploring random tree (RRT) and an exact method inspired by cell decomposition. The RRT method scales better with the problem size than the exact method, which has a worst-case time complexity that is exponential in the number of obstacles. But the randomization in the RRT method makes it difficult to set a timeout for the solver, which runs forever if a problem instance is unsolvable. The exact method, on the other hand, detects unsolvable problem instances in finite time.

    The thesis demonstrates, both in theory and experiments, that mobile robots can improve communications by planning trajectories that maintain visual connectivity, or by exploiting multipath fading when there is no line of sight. The proposed methods are well suited for integration in a layered motion planning architecture.

  • 230.
    Minnema Lindhé, Magnus
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Exploiting multipath fading with a mobile robot2013Inngår i: The international journal of robotics research, ISSN 0278-3649, E-ISSN 1741-3176, Vol. 32, nr 12, s. 1363-1380Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In indoor or urban applications, a moving robot with wireless communications will experience multipath fading. This causes rapid signal strength variations due to interfering reflections of the radio signal. By making short stops at positions with high signal-to-noise ratio (SNR), the robot can trade trajectory tracking accuracy for increased link quality. This represents a type of opportunistic communication-aware motion planning. We propose two novel strategies for improving the link capacity or throughput when either the robot has full knowledge of how the SNR varies along the trajectory, or when only the SNR distribution is known or can be estimated. In the latter case, this leads to an optimal stopping problem over a finite horizon. Both cases are analyzed for independent as well as correlated SNR samples, and a bounded maximum trajectory tracking error. We derive the resulting SNR distributions for the proposed strategies and use them to show how the expected capacity and throughput vary with the allowed tracking error. The results are confirmed by simulations and experiments. Experiments in six different locations validate the communication model and show that the proposed motion planning is robust to non-static fading and can yield throughput improvements of more than 100%.

  • 231.
    Mitsioni, Ioanna
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL. KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, Centrum för autonoma system, CAS.
    Karayiannidis, Yiannis
    Division of Systems and Control, Dept. of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Stork, Johannes A.
    Center for Applied Autonomous Sensor Systems (AASS), Örebro University, Örebro, Sweden.
    Kragic, Danica
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL. KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, Centrum för autonoma system, CAS.
    Data-Driven Model Predictive Control for the Contact-Rich Task of Food Cutting2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modelling of contact-rich tasks is challenging and cannot be entirely solved using classical control approaches due to the difficulty of constructing an analytic description of the contact dynamics. Additionally, in a manipulation task like food-cutting, purely learning-based methods such as Reinforcement Learning, require either a vast amount of data that is expensive to collect on a real robot, or a highly realistic simulation environment, which is currently not available. This paper presents a data-driven control approach that employs a recurrent neural network to model the dynamics for a Model Predictive Controller. We build upon earlier work limited to torque-controlled robots and redefine it for velocity controlled ones. We incorporate force/torque sensor measurements, reformulate and further extend the control problem formulation. We evaluate the performance on objects used for training, as well as on unknown objects, by means of the cutting rates achieved and demonstrate that the method can efficiently treat different cases with only one dynamic model. Finally we investigate the behavior of the system during force-critical instances of cutting and illustrate its adaptive behavior in difficult cases.

  • 232. Mitsunaga, Noriaki
    et al.
    Smith, Christian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Kanda, Takayuki
    Ishiguro, Hiroshi
    Hagita, Norihiro
    Adapting robot behavior for human-robot interaction2008Inngår i: IEEE Transactions on Robotics, ISSN 1552-3098, Vol. 24, nr 4, s. 911-916Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Human beings subconsciously adapt their behaviors to a communication partner in order to make interactions run smoothly. In human-robot interactions, not only the human but also the robot is expected to adapt to its partner. Thus, to facilitate human-robot interactions, a robot should be able to read subconscious comfort and discomfort signals from humans and adjust its behavior accordingly, just like a human would. However, most previous, research works expected the human to consciously give feedback, which might interfere with the aim of interaction. We propose an adaptation mechanism based on reinforcement learning that reads subconscious body signals from a human partner, and uses this information to adjust interaction distances, gaze meeting, and motion speed and timing in human-robot interactions. The mechanism uses gazing at the robot's face and human movement distance as subconscious body signals that indicate a human's comfort and discomfort. A pilot study with a humanoid robot that has ten interaction behaviors has been conducted. The study result of 12 subjects suggests that the proposed mechanism enables autonomous adaptation to individual preferences. Also, detailed discussion and conclusions are presented.

  • 233. Mitsunaga, Noriaki
    et al.
    Smith, Christian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Kanda, Takayuki
    Ishiguro, Hiroshi
    Hagita, Norihiro
    Robot Behavior Adaptation for Human-Robot Interaction based on Policy Gradient Reinforcement Learning2005Inngår i: 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005. (IROS 2005)., IEEE , 2005, s. 1594-1601Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose an adaptation mechanism for robot behaviors to make robot-human interactions run more smoothly. We propose such a mechanism based on reinforcement learning, which reads minute body signals from a human partner, and uses this information to adjust interaction distances, gaze-meeting, and motion speed and timing in human-robot interaction. We show that this enables autonomous adaptation to individual preferences by an experiment with twelve subjects.

  • 234. Mitsunaga, Noriaki
    et al.
    Smith, Christian
    KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA.
    Kanda, Takayuki
    Ishiguro, Hiroshi
    Hagita, Norihiro
    Robot Behavior Adaptation for Human-Robot Interaction based on Policy Gradient Reinforcement Learning2006Inngår i: Journal of the Robotics Society of Japan, ISSN 0289-1824, Vol. 24, nr 7, s. 820-829Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [ja]

    (Please note: The main body of this paper is written in Japanese) When humans interact in a social context, there are many factors apart from the actual communication that need to be considered. Previous studies in behavioral sciences have shown that there is a need for a certain amount of personal space and that different people tend to meet the gaze of others to different extents. For humans, this is mostly subconscious, but when two persons interact, there is an automatic adjustment of these factors to avoid discomfort. In this paper we propose an adaptation mechanism for robot behaviors to make human-robot interactions run more smoothly. We propose such a mechanism based on policy gradient reinforcement learning, that reads minute body signals from a human partner, and uses this information to adjust interaction distances, gaze meeting, and motion speed and timing in human-robot interaction. We show that this enables autonomous adaptation to individual preferences by the experiment with twelve subjects.

  • 235. Moberg, S.
    et al.
    Hanssen, Sven
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    A DAE approach to feedforward control of flexible manipulators2007Inngår i: 2007 IEEE International Conference on Robotics and Automation Conference, IEEE , 2007, s. 3439-3444Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work investigates feedforward control of elastic robot structures. A general serial link elastic robot model which can describe a modern industrial robot in a realistic way is presented. The feedforward control problem is discussed and a solution method for the inverse dynamics problem is proposed. This method involves solving a differential algebraic equation (DAE). A simulation example for an elastic two axis planar robot is also included and shows promising results.

  • 236.
    Mohammed, Abdullah
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Schmidt, B.
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Energy-Efficient Robot Configuration for Assembly2017Inngår i: Journal of manufacturing science and engineering, ISSN 1087-1357, E-ISSN 1528-8935, Vol. 139, nr 5, artikkel-id 051007Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimizing the energy consumption of robot movements has been one of the main focuses for most of today's robotic simulation software. This optimization is based on minimizing a robot's joint movements. In many cases, it does not take into consideration the dynamic features. Therefore, reducing energy consumption is still a challenging task and it involves studying the robot's kinematic and dynamic models together with application requirements. This research aims to minimize the robot energy consumption during assembly. Given a trajectory and based on the inverse kinematics and dynamics of a robot, a set of attainable configurations for the robot can be determined, perused by calculating the suitable forces and torques on the joints and links of the robot. The energy consumption is then calculated for each configuration and based on the assigned trajectory. The ones with the lowest energy consumption are selected. Given that the energyefficient robot configurations lead to reduced overall energy consumption, this approach becomes instrumental and can be embedded in energy-efficient robotic assembly.

  • 237.
    Mohammed, Abdullah
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Schmidt, B.
    Wang, Lihui
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Gao, L.
    Minimizing energy consumption for robot arm movement2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Robots are widely used in industry due to their efficiency and high performance. Many of them are operating in the manufacturing stage of the production line where the highest percentage of energy is consumed. Therefore, their energy consumption became a major focus for many robots manufacturers and academic research groups. Nevertheless, the optimization of that consumption is still a challenging task which requires a deep understanding of the robot's kinematic and dynamic behaviors. This paper proposes an approach to develop an optimization module using Matlab® to minimize the energy consumptions of the robot's movement. With the help of Denavit-Hartenberg notation, the approach starts first by solving the inverse kinematics of the robot to find a set of feasible joint configurations required to perform the task, solving the inverse kinematics is usually a challenging step which requires in-depth analyses of the robot. The module then solves the inverse dynamics of the robot to analyze the forces and torques applied on each joint and link in the robot. Furthermore, a calculation for the energy consumption is performed for each configuration. The final step of the process represents the optimization of the calculated configurations by choosing the one with the lowest power consumption and sends the results to the robot controller. Three case studies are used to evaluate the performance of the module. The experimental results demonstrate the developed module as a successful tool for energy efficient robot path planning. Further analyses for the results have been done by comparing them with the ones from commercial simulation software. The case studies show that the optimization of the location for the target path could reduce the energy consumption effectively.

  • 238.
    Morvan, Jérémy
    KTH, Skolan för datavetenskap och kommunikation (CSC).
    Understanding and communicating intentions in human-robot interaction2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis is about the collaboration and interaction between a robot and a human agent. The goal is to use the robot as a coworker, by implementing the premises of an interaction system that would make the interaction as natural as possible. This involves that the robot has a vision system that allows understanding of the intentions of the human. This thesis work is intended to be part of a larger project aimed at extending the competences of the programmable industrial robot, Baxter, made by Rethink Robotics. Due to the limited vision abilities of this robot, a Kinect camera is added on the top of its head. This thesis covers human gestures recognition through the Kinect data and robot reactions to these gestures through visual feedback and actions.

  • 239.
    Mosskull, Henrik
    KTH, Tidigare Institutioner, Signaler, sensorer och system. Bombardier Transportation, Sweden .
    Some issues on stabilization of an induction machine drive2004Inngår i: Proceedings of the IEEE Conference on Decision and Control, 2004, s. 4441-4446Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Stability problems due to interaction between the input filter and the voltage source inverter of an induction machine drive are revised. By incorporating properties of the input filter, previous work on stabilization is extended to increase the stability margins of the drive. The strategy is to assure a small phase shift of the inverter input admittance in a frequency region around the input filter resonance frequency. It is motivated why stabilization at zero torque is more critical with a low resonance frequency of the input filter compared to a high. This is a property known from practical experience. It is also shown how dynamic stabilization gains can be used to compensate for limited control bandwidth. This way the drive can be stabilized for very large powers.

  • 240.
    Mänttäri, Joonatan
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Folkesson, John
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Incorporating Uncertainty in Predicting Vehicle Maneuvers at Intersections With Complex Interactions2019Inngår i: 2019 IEEE Intelligent Vehicles Symposium (IV), IEEE, 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Highly automated driving systems are required to make robust decisions in many complex driving environments, such as urban intersections with high traffic. In order to make as informed and safe decisions as possible, it is necessary for the system to be able to predict the future maneuvers and positions of other traffic agents, as well as to provide information about the uncertainty in the prediction to the decision making module. While Bayesian approaches are a natural way of modeling uncertainty, recently deep learning-based methods have emerged to address this need as well. However, balancing the computational and system complexity, while also taking into account agent interactions and uncertainties, remains a difficult task. The work presented in this paper proposes a method of producing predictions of other traffic agents' trajectories in intersections with a singular Deep Learning module, while incorporating uncertainty and the interactions between traffic participants. The accuracy of the generated predictions is tested on a simulated intersection with a high level of interaction between agents, and different methods of incorporating uncertainty are compared. Preliminary results show that the CVAE-based method produces qualitatively and quantitatively better measurements of uncertainty and manage to more accurately assign probability to the future occupied space of traffic agents.

  • 241.
    Nassir, Cesar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Robotik, perception och lärande, RPL.
    Domain-Independent Moving Object Depth Estimation using Monocular Camera2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today automotive companies across the world strive to create vehicles with fully autonomous capabilities. There are many benefits of developing autonomous vehicles, such as reduced traffic congestion, increased safety and reduced pollution, etc. To be able to achieve that goal there are many challenges ahead, one of them is visual perception.

    Being able to estimate depth from a 2D image has been shown to be a key component for 3D recognition, reconstruction and segmentation. Being able to estimate depth in an image from a monocular camera is an ill-posed problem since there is ambiguity between the mapping from colour intensity and depth value. Depth estimation from stereo images has come far compared to monocular depth estimation and was initially what depth estimation relied on. However, being able to exploit monocular cues is necessary for scenarios when stereo depth estimation is not possible.

    We have presented a novel CNN network, BiNet which is inspired by ENet, to tackle depth estimation of moving objects using only a monocular camera in real-time. It performs better than ENet in the Cityscapes dataset while adding only a small overhead to the complexity.

  • 242.
    Nazem, Ali
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Kootstra, Geert
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Kragic, Danica
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Djurfeldt, Mikael
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Parallelldatorcentrum, PDC. KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsbiologi, CB.
    Interfacing a parallel simulation of a neuronal network to robotic hardware using MUSIC, with application to real-time figure-ground segregation.2011Inngår i: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 12, nr Suppl 1, s. 78-78Artikkel i tidsskrift (Fagfellevurdert)
  • 243.
    Neves, Pedro
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Ribeiro, Luis
    Dias-Ferreira, Joao
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Oliveira, Jose Barata
    Layout validation and re-configuration in Plug&Produce systems2016Inngår i: Assembly Automation, ISSN 0144-5154, E-ISSN 1758-4078, Vol. 36, nr 4, s. 412-428Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose - This paper aims to provide a method and decision support tool to enhance swift reconfiguration of Plug&Produce (P&P) systems in the presence of continuously changing production orders. Design/methodology/approach - The paper reviews different production scenarios and system design and configuration methods and more particularly specifies the need of decision support tools for P&P systems that integrate configuration and planning activities. This problem is then addressed by proposing a method that helps reduce the solution space of the reconfiguration problem and allows the timely selection of the most promising reconfiguration alternative. Findings - The proposed method was found to be helpful in reducing the reconfiguration alternatives that need to be considered and in selecting the most promising one for different orders. The advantages and limitations of this method are identified, and an illustrative test case of the approach is presented, corroborating the method applicability in the absence of large queues in the system. Originality/value - This paper addresses a less explored domain within the P&P systems research field, which is the system reconfiguration. It proposed a method to support system validation and reconfiguration jointly with an illustrative test case. This represents an original contribution to the P&P research field, and it can have impact in improving agility and decreasing the complexity of reconfiguration activities to cope with constantly changing production orders.

  • 244. Newman, P.
    et al.
    Christensen, Henrik Iskov
    KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA.
    Session overview simultaneous localisation and mapping2007Inngår i: Robotics Research: Results of the 12th International Symposium ISRR, Springer Berlin/Heidelberg, 2007, s. 187-189Konferansepaper (Fagfellevurdert)
  • 245. Ni, W.
    et al.
    Cheng, D.
    Hu, Xiaoming
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Minimum dwell time for stability and stabilization of switched linear systems2008Inngår i: Proc. World Congr. Intelligent Control Autom. WCICA, 2008, s. 4103-4108Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, the problem of minimum dwell time for the stability and stabilization of switched linear systems is considered. First, using the method of multiple Lyapunov functions, we obtain an estimate for the minimum dwell time(MDT), which assures the exponential stability of switched linear systems. Using the stability result obtained for free system, we then investigate the problem of MDT for stabilization of switched linear control system subject to input constraints. Under certain conditions the exponential stabilization can be achieved by using controls with restricted amplitudes as long as the switching laws satisfy the MDT time requirement. An illustrative example is presented to show the validity of the results.

  • 246.
    Niessen, Maria
    et al.
    Faculty of Mathematics and Natural Sciences, University of Groningen.
    Kootstra, Gert
    Faculty of Mathematics and Natural Sciences, University of Groningen.
    de Jong, Sjoerd
    Faculty of Mathematics and Natural Sciences, University of Groningen.
    Andringa, Tjeerd
    Faculty of Mathematics and Natural Sciences, University of Groningen.
    Expectancy-Based Robot Localization Through Context Evaluation2009Inngår i: Proceedings of the 2009 International Conference on Artificial Intelligence (ICAI 2009), CSREA Press , 2009, s. 371-377Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Agents that operate in a real-world environmenthave to process an abundance of information, which maybe ambiguous or noisy. We present a method inspired bycognitive research that keeps track of sensory information,and interprets it with knowledge of the context. We test thismodel on visual information from the real-world environmentof a mobile robot in order to improve its self-localization.We use a topological map to represent the environment,which is an abstract representation of distinct places andthe connections between them. Expectancies of the placeof the robot on the map are combined with evidence fromobservations to reach the best prediction of the next place ofthe robot. These expectancies make a place prediction morerobust to ambiguous and noisy observations. Results of themodel operating on data gathered by a mobile robot confirmthat context evaluation improves localization compared to adata-driven model.

  • 247.
    Nikou, Alexandros
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Tumova, Jana
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Dimarogonas, Dimos V.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Cooperative Task Planning of Multi-Agent Systems Under TimedTemporal Specifications2016Inngår i: Proceedings of the American Control Conference, 2016, s. 7104-7109Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper the problem of cooperative taskplanning of multi-agent systems when timed constraints areimposed to the system is investigated. We consider timedconstraints given by Metric Interval Temporal Logic (MITL).We propose a method for automatic control synthesis in a two-stage systematic procedure. With this method we guarantee thatall the agents satisfy their own individual task specifications aswell as that the team satisfies a team global task specification.

  • 248.
    Nikou, Alexandros
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Verginis, Christos
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Heshmati-alamdari, Shahab
    Dimarogonas, Dimos V.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    A Nonlinear Model Predictive Control scheme for cooperative manipulation with singularity and collision avoidance2017Inngår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017, IEEE conference proceedings, 2017, s. 707-712, artikkel-id 7984201Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses the problem of cooperative transportation of an object rigidly grasped by N robotic agents.In particular, we propose a Nonlinear Model Predictive Control(NMPC) scheme that guarantees the navigation of the object to a desired pose in a bounded workspace with obstacles, while complying with certain input saturations of the agents. Moreover, the proposed methodology ensures that the agents do not collide with each other or with the workspace obstacles as well as that they do not pass through singular configurations.The feasibility and convergence analysis of the NMPC are explicitly provided. Finally, simulation results illustrate the validity and efficiency of the proposed method.

  • 249.
    Ohnishi, Motoya
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Reglerteknik. Georgia Inst Technol, Georgia Robot & Intelligent Syst Lab, Atlanta, GA 30332 USA.;RIKEN, Ctr Adv Intelligence Project, Tokyo 1030027, Japan..
    Wang, Li
    Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA..
    Notomista, Gennaro
    Georgia Inst Technol, Sch Mech Engn, Atlanta, GA 30313 USA..
    Egerstedt, Magnus
    Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA..
    Barrier-Certified Adaptive Reinforcement Learning With Applications to Brushbot Navigation2019Inngår i: IEEE Transactions on robotics, ISSN 1552-3098, E-ISSN 1941-0468, Vol. 35, nr 5, s. 1186-1205Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a safe learning framework that employs an adaptive model learning algorithm together with barrier certificates for systems with possibly nonstationary agent dynamics. To extract the dynamic structure of the model, we use a sparse optimization technique. We use the learned model in combination with control barrier certificates that constrain policies (feedback controllers) in order to maintain safety, which refers to avoiding particular undesirable regions of the state space. Under certain conditions, recovery of safety in the sense of Lyapunov stability after violations of safety due to the nonstationarity is guaranteed. In addition, we reformulate an action-value function approximation to make any kernel-based nonlinear function estimation method applicable to our adaptive learning framework. Lastly, solutions to the barrier-certified policy optimization are guaranteed to be globally optimal, ensuring the greedy policy improvement under mild conditions. The resulting framework is validated via simulations of a quadrotor, which has previously been used under stationarity assumptions in the safe learnings literature, and is then tested on a real robot, the brushbot, whose dynamics is unknown, highly complex, and nonstationary.

  • 250.
    Pacchierotti, Elena
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA.
    Christensen, Henrik I.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk Analys och Datalogi, NADA.
    Jensfelt, Patric
    KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP.
    Design of an office-guide robot for social interaction studies2006Inngår i: 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, Vols 1-12, NEW YORK: IEEE , 2006, s. 4965-4970Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, the design of an office-guide robot for social interaction studies is presented. We are interested in studying the impact of passage behaviours in casual encounters. While the system offers assistance in locating the appropriate office that a visitor wants to reach, it is expected to engage in a passing behaviour to allow free passage for other persons that it may encounter. Through use of such an approach it is possible to study the effect of social interaction in a situation that is much more natural than out-of-context user studies. The system has been tested in an early evaluation phase when it worked for almost 7 hours. A total of 64 interactions with people were registered and 13 passage behaviors were performed to conclude that this framework can be successfully used for the evaluation of passing behaviors in natural contexts of operation.

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