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  • 251.
    Johansson, Karl H.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Barabanov, A.
    Astrom, K. J.
    Limit cycles with chattering in relay feedback systems1997Konferansepaper (Fagfellevurdert)
  • 252.
    Johansson, Karl H.
    et al.
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Barabanov, A. E.
    Astrom, K. J.
    Limit cycles with chattering in relay feedback systems2002Inngår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 47, nr 9, s. 1414-1423Artikkel i tidsskrift (Fagfellevurdert)
  • 253. Johansson, Karl H.
    et al.
    Horch, Alexander
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Wijk, Olle
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Hansson, Anders
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Teaching multivariable control using the Quadruple-Tank Process1999Inngår i: Proceedings of the 38th IEEE Conference on Decision and Control, 1999, IEEE , 1999, s. 807-812Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A multivariable laboratory process is presented together with its use in a graduate control course. The process is called the quadruple-tank process and demonstrates a multivariable level control problem. The multivariable zero dynamics of the system can be made both minimum phase and nonminimum phase by simply changing a valve. This makes the quadruple-tank process suitable for illustrating many concepts in linear and nonlinear multivariable control. In the paper some of these are described together with the basic setup of the process. Two computer exercises and one laboratory exercise have been developed as part of a course in multivariable and nonlinear control. These are detailed and some experience from the course is presented.

  • 254.
    Johansson, Karl H.
    et al.
    Department of EECS, University of California.
    Hägglund, Tore
    Department of Automatic Control, Lund University.
    Control structure design in process control systems2000Konferansepaper (Fagfellevurdert)
  • 255. Johansson, Karl H.
    et al.
    James, B.
    Bryant, G. F.
    Astrom, K. J.
    Multivariable controller tuning1998Inngår i: Proceedings of the American Control Conference, 1998, IEEE , 1998, s. 3514-3518Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The problem of tuning individual loops in a multivariable controller is investigated. It is shown how the performance of a specific loop relates to a row in the controller matrix. Several interpretations of this relation are given. An algorithm is also presented that estimates the model required for the tuning via a relay feedback experiment. The algorithm does not need any prior information about the system or the controller. The results are illustrated by an example.

  • 256. Johansson, Karl H.
    et al.
    Lygeros, J.
    Sastry, S.
    Egerstedt, Magnus
    Simulation of Zeno hybrid automata1999Inngår i: Proceedings of the 38th IEEE Conference on Decision and Control, 1999, IEEE , 1999, s. 3538-3543Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Zeno hybrid automata are hybrid systems that can exhibit infinitely many discrete transitions in a finite time interval. Such automata arise due to modeling simplifications and may deteriorate simulation efficiency and accuracy considerably. Some basic properties of Zeno hybrid automata are explored. Possible ways to extend a simulation beyond the Zeno time are suggested

  • 257.
    Johansson, Karl H.
    et al.
    Department of Automatic Control, Lund Institute of Technology.
    Nunes, J. L. R.
    Department of Informatics, University of Coimbra, Portugal.
    A multivariable laboratory process with an adjustable zero1998Inngår i: Proceedings of the American Control Conference, Philadelphia, Pennsylvania June 1998, AACC , 1998, s. 2045-2049Konferansepaper (Fagfellevurdert)
    Abstract [sv]

    A novel multivariable laboratory process that consists of four interconnected water tanks is presented. The linearized dynamics of the system have a multivariable zero that is possible to move along the real axis by changing a valve. The zero can be placed in both the left and the right half-plane. In this way the quadruple-tank process is ideal for illustrating many concepts in multivariable control, particularly performance limitations due to multivariable right half-plane zeros. Accurate models are derived from both physical and experimental data and multi-loop control is illustrated.

  • 258.
    Johansson, Karl H.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Pappas, George J.
    Tabuada, Paulo
    Tomlin, Claire J.
    Special Issue on Control of Cyber-Physical Systems2014Inngår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 59, nr 12, s. 3120-3121Artikkel i tidsskrift (Annet vitenskapelig)
  • 259.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Automation and vehicular applications of networked control2008Konferansepaper (Fagfellevurdert)
  • 260.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Book review of Relay Feedback by Wang et al2007Inngår i: Control Systems Magazine, ISSN 0272-1708, Vol. 27, nr 3, s. 101-103Artikkel i tidsskrift (Annet vitenskapelig)
  • 261.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Discussion on: "Stabilization of networked control system with time delays and data-packet losses"2007Inngår i: European Journal of Control, ISSN 0947-3580, E-ISSN 1435-5671, Vol. 13, nr 4, s. 353-355Artikkel i tidsskrift (Annet vitenskapelig)
  • 262.
    Johansson, Karl Henrik
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Hybrid control systems2004Inngår i: UNESCO Encyclopedia of Life Support Systems (EOLSS), Unesco, 2004Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Most practical control systems involve both analogue and logic components. Hybrid control system is a generic term for such systems, where the continuous and the discrete dynamics are interacting. These systems arise naturally in many applications of automatic control, for example when a physical plant is controlled by a finite set of controls. Hybrid systems is a recent and very active research area, which evolves from the foundations of control theory and computer science. The developed framework is suitable for the design of complex embedded and networked control systems, which are often hard to analyze with traditional tools. Here a brief introduction to hybrid control is presented and the EOLSS articles under hybrid control systems are put into context.

  • 263.
    Johansson, Karl Henrik
    Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA.
    The Quadruple-Tank Process-A multivariable laboratory process with an adjustable zero2000Inngår i: IEEE Transactions on Control Systems Technology, ISSN 1063-6536, E-ISSN 1558-0865, Vol. 8, nr 3, s. 456-465Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multivariable laboratory process that consists of four interconnected water tanks is presented. The linearized dynamics of the system have a multivariable zero that is possible to move along the real axis by changing a valve. The zero can be placed in both the left and the right half-plane. In this way the quadruple-tank process is ideal for illustrating many concepts in multivariable control, particularly performance limitations due to multivariable right half-plane zeros. The location and the direction of the zero have an appealing physical interpretation. Accurate models are derived from both physical and experimental data and decentralized control is demonstrated on the process.

  • 264.
    Johansson, Karl Henrik
    et al.
    University of California, Berkeley.
    Egerstedt, Magnus
    KTH.
    Lygeros, J.
    University of California, Berkeley.
    Sastry, S.
    University of California, Berkeley.
    On the regularization of Zeno hybrid automata1999Inngår i: Systems & control letters (Print), ISSN 0167-6911, E-ISSN 1872-7956, Vol. 38, nr 3, s. 141-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fundamental properties of hybrid automata, such as existence and uniqueness of executions, are studied. Particular attention is devoted to Zeno hybrid automata, which are hybrid automata that take infinitely many discrete transitions in finite time. It is shown that regularization techniques can be used to extend the Zeno executions of these automata to times beyond the Zeno time. Different types of regularization may, however, lead to different extensions. A water tank control problem and a bouncing ball system are used to illustrate the results.

  • 265.
    Johansson, Karl Henrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Lygeros, J.
    Sastry, S.
    Zhang, J.
    Hybrid automata: A formal paradigm for heterogeneous modeling2000Konferansepaper (Fagfellevurdert)
  • 266.
    Johansson, Karl Henrik
    et al.
    KTH, Tidigare Institutioner, Signaler, sensorer och system.
    Lygeros, John
    Sastry, Shankar
    Modeling of hybrid systems2004Inngår i: Encyclopedia of Life Support Systems (EOLSS), Theme 6.43: Control Systems, Robotics and Automation, Unesco, 2004Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The distinguishing characteristic of hybrid systems is the interaction between a continuous-time and a discrete-event component. By modeling these different components using differential equations and finite state automata, it is possible to represent a wide range of phenomena present in physical and technological systems. This paper illustrates hybrid dynamics by several simple examples. Some of these examples illustrate properties of hybrid systems not present in purely continuous or purely discrete systems, while others illustrate application domains such as vehicle control and real-time systems. A mathematical model called a hybrid automaton is then introduced, to show how hybrid dynamics can be formally analyzed.

  • 267. Johansson, Karl Henrik
    et al.
    Rantzer, A.
    Decentralized control of sequentially minimum phase systems1999Inngår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 44, nr 10, s. 1909-1913Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fundamental limitations in decentralized control of systems with multivariable zeros are considered. It is shown that arbitrary bandwidth can be obtained with a stable block-diagonal controller, if certain subsystems of the open-loop system fail to have zeros in the right half-plane and a high-frequency condition holds. Implications on control structure design and sequential loop-closuring methods are discussed.

  • 268. Johansson, Karl Henrik
    et al.
    Rantzer, A.
    Global analysis of third-order relay feedback systems1996Konferansepaper (Fagfellevurdert)
  • 269. Johansson, Karl Henrik
    et al.
    Rantzer, A.
    Multi-loop control of minimum phase processes1997Konferansepaper (Fagfellevurdert)
  • 270. Johansson, Karl Henrik
    et al.
    Rantzer, Anders
    Ås ström", Karl Johan
    Fast switches in relay feedback systems1999Inngår i: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 35, nr 4, s. 539-552Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Relays are common in automatic control systems. Even linear systems with relay feedback are, however, far from fully understood. New results are given about the behavior of these systems via a state-space approach. It is proved that there exist multiple fast switches if and only if the sign of the first nonvanishing Markov parameter of the linear system is positive. Fast switches are shown to occur as part of stable limit cycles. An analysis is developed for these limit cycles that illustrates how they can be predicted.

  • 271.
    Johansson, Karl Henrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Santucci, Fortunato
    On hybrid control problems in communication systems2005Inngår i: Proceedings of the 44th IEEE Conference on Decision and Control, and the European Control Conference 2005, IEEE , 2005, s. 5624-5629Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The importance of a strong research agenda on the convergence of communications and control has been emphasized by several researchers recently. The purpose of this paper is to evidence through concrete application examples how the envisioned synergy can actually be exploited. The focus is on control of wireless communication networks. In order to address in a rigorous and exhaustive way the complexity of interactions that usually arise in these systems, we try to devise how hybrid modelling may intrinsically provide a theoretical framework to formulate problems and provide partial solutions.

  • 272.
    Johansson, Karl Henrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Speranzon, Alberto
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Zampieri, S.
    On quantization and communication topologies in multi-vehicle rendezvous2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A rendezvous problem for a team of autonomous vehicles that is communicating through quantized channels is considered. Communication topologies and feedback control law are presented that solves the rendezvous problem in the sense that a meeting point for the vehicles is practically stabilized. In particular, it is shown that uniform quantizers can sometimes be replaced by logarithmic quantizers and thus reduce the need for communication bandwidth.

  • 273.
    Johansson, Karl Henrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Törngren, Martin
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Inbyggda styrsystem.
    Nielsen, Lars
    Linköping University.
    Vehicle Applications of Controller Area Network2005Inngår i: HANDBOOK OF NETWORKED AND EMBEDDED CONTROL SYSTEMS / [ed] Dimitrios Hristu-Varsakelis and William S. Levine, Springer, 2005, s. 741-765Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The Controller Area Network (CAN) is a serial bus communications protocol developed by Bosch in the early 1980s. It defines a standard for efficient and reliable communication between sensor, actuator, controller, and other nodes in real-time applications. CAN is the de facto standard in a large variety of networked embedded control systems. The early CAN development was mainly supported by the vehicle industry: CAN is found in a variety of passenger cars, trucks, boats, spacecraft, and other types of vehicles. The protocol is also widely used today in industrial automation and other areas of networked embedded control, with applications in diverse products such as production machinery, medical equipment, building automation, weaving machines, and wheelchairs.The purpose of this chapter is to give an introduction to CAN and some of its vehicle applications. The outline is as follows. Section 2 describes the CAN protocol, including its message formats and error handling. The section is concluded by a brief history of CAN. Examples of vehicle application architectures based on CAN are given in Section 3. A few specific control loops closed over CAN buses are discussed in Section 4. The paper is concluded with some perspectives in Section 5, where current research issues such as x-by-wire and standardized software architectures are considered. The examples are described in more detail in [14]. A detailed description of CAN is given in the textbook [6]. Another good resource for further information is the homepage of the organization CAN-in-Automation (CiA) [3]. The use of CAN as a basis for distributed control systems is discussed in [13].

  • 274. Jurado, I.
    et al.
    Quevedo, D. E.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Ahlén, A.
    Cooperative Dynamic MPC for Networked Control Systems2014Inngår i: Intelligent Systems, Control and Automation: Science and Engineering, ISSN 2213-8986, Vol. 69, s. 357-373Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work studies cooperative MPC for Networked Control Systems with multiple wireless nodes. Communication between nodes is affected by random packet dropouts. An algorithm is presented to decide at each time instant which nodes will calculate the control input and which will only relay data. The nodes chosen to calculate the control values solve a cooperative MPC by communicating with their neighbors. This algorithm makes the control architecture flexible by adapting it to the possible changes in the network conditions.

  • 275. Jurado, Isabel
    et al.
    Quevedo, Daniel E.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Ahlén, Anders
    Cooperative Dynamic MPC for NCSs2013Inngår i: Distributed MPC Made Easy / [ed] J. M. Maestre and R. R. Negenborn, Eds., Springer-Verlag New York, 2013Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This work studies cooperative MPC for Networked Control Systems with multiple wireless nodes. Communication between nodes is affected by random packet dropouts. An algorithm is presented to decide at each time instant which nodes will calculate the control input and which will only relay data. The nodes chosen to calculate the control values solve a cooperative MPC by communicating with their neighbors. This algorithm makes the control architecture flexible by adapting it to the possible changes in the network conditions.

  • 276.
    Karasalo, Maja
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Johansson, Linda-Maria
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Hu, Xiaoming
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Optimeringslära och systemteori.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Multi-robot terrain servoing with proximity sensors2005Inngår i: 2005 IEEE International Conference on Robotics and Automation (ICRA), 2005, s. 2791-2796Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The problem of coordinating a team of robots with heterogeneous sensing capabilities is studied in this paper. A control structure is proposed that combines terrain servoing for the leading robot with on-line formation planning and path following for the followers, while enabling obstacle avoidance for all the robots.

  • 277. Katsilieris, Fotios
    et al.
    Lindhé, Magnus
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Dimarogonas, Dimos V.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Ögren, Petter
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Demonstration of multi-robot search and secure2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We consider the search and secure problem, where intruders are to be detected in a bounded area without allowing them to escape. The problem is tackled by representing the area to be searched as a traversability graph, which is reduced to a tree graph by placing stationary robots to remove loops. The search of the remaining tree is performed using two strategies that represent different trade-offs between the needed search time and the number of robots. Proof of correctness is provided for these two strategies. The proposed algorithm was implemented and demonstrated as part of an outfield experiment involving a team of Rotundus spherical robots.

  • 278. Keviczky, Tamás
    et al.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    A study on distributed model predictive consensus2008Inngår i: Proceedings of the 17th IFAC World Congress, 2008, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate convergence properties of a proposed distributed model predictive control (DMPC) scheme, where agents negotiate to compute an optimal consensus point using an incremental subgradient method based on primal decomposition as described in Johansson et al. [2006, 2007]. The objective of the distributed control strategy is to agree upon and achieve an optimal common output value for a group of agents in the presence of constraints on the agent dynamics using local predictive controllers. Stability analysis using a receding horizon implementation of the distributed optimal consensus scheme is performed. Conditions are given under which convergence can be obtained even if the negotiations do not reach full consensus.

  • 279. Khan, U. A.
    et al.
    Korniienko, A.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    An H∞-based approach for robust sensor localization2016Inngår i: Proceedings of the IEEE Conference on Decision and Control, IEEE conference proceedings, 2016, s. 1719-1724Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we consider the problem of sensor localization, i.e., finding the positions of an arbitrary number of sensors located in a Euclidean space, ?m, given at least m+1 anchors with known locations. Assuming that each sensor knows pairwise distances in its neighborhood and that the sensors lie in the convex hull of the anchors, we provide a DIstributed LOCalization algorithm in Continuous-Time, named DILOCCT, that converges to the sensor locations. This representation is linear and is further decoupled in the coordinates. By adding a proportional controller in the feed-forward loop of each location estimator, we show that the convergence speed of DILOC-CT can be made arbitrarily fast. Since a large gain may result into unwanted transients especially in the presence of disturbance introduced, e.g., by communication noise in the network, we use H∞ theory to design local controllers that guarantee certain global performance while maintaining the desired steady-state. Simulations are provided to illustrate the concepts described in this paper.

  • 280. Khan, Usman A.
    et al.
    Korniienko, Anton
    Johansson, Karl H.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    An H-infinity-based approach for robust sensor localization2015Inngår i: 2015 54TH IEEE CONFERENCE ON DECISION AND CONTROL (CDC), Institute of Electrical and Electronics Engineers (IEEE), 2015, s. 1719-1724Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we consider the problem of sensor localization, i.e., finding the positions of an arbitrary number of sensors located in a Euclidean space, R-m, given at least m + 1 anchors with known locations. Assuming that each sensor knows pairwise distances in its neighborhood and that the sensors lie in the convex hull of the anchors, we provide a DIstributed LOCalization algorithm in Continuous-Time, named DILOC-CT, that converges to the sensor locations. This representation is linear and is further decoupled in the coordinates. By adding a proportional controller in the feed-forward loop of each location estimator, we show that the convergence speed of DILOC-CT can be made arbitrarily fast. Since a large gain may result into unwanted transients especially in the presence of disturbance introduced, e.g., by communication noise in the network, we use H-infinity theory to design local controllers that guarantee certain global performance while maintaining the desired steady-state. Simulations are provided to illustrate the concepts described in this paper.

  • 281.
    Kiener, Georg Alexander
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Lehmann, Daniel
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Actuator saturation and anti-windup compensation in event-triggered control2014Inngår i: Discrete event dynamic systems, ISSN 0924-6703, E-ISSN 1573-7594, Vol. 24, nr 2, s. 173-197Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Event-triggered control aims at reducing the communication load over the feedback link in networked control systems by sending information only if certain event conditions, which guarantee a desired control performance, are satisfied. This article investigates the consequences of actuator saturation on the behavior of the event-triggered control loop in terms of its stability and information exchange. Stability properties are derived using linear matrix inequalities (LMIs) which show how the stability of the event-triggered control loop depends on the selection of the event threshold. Moreover, it is shown that a lower bound on the minimum inter-event time exists being likewise affected by the event threshold. As actuator saturation might severely degrade the performance of the event-triggered closed-loop system, the scheme is extended by incorporating an anti-windup mechanism in order to overcome this problem. The results are illustrated by simulations and experiments.

  • 282. Kim, W.
    et al.
    Stankovic, M. S.
    Johansson, Karl H.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Kim, H. J.
    A distributed support vector machine learning over wireless sensor networks2015Inngår i: IEEE Transactions on Cybernetics, ISSN 2168-2267, E-ISSN 2168-2275, Vol. 45, nr 11, s. 2599-2611Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper is about fully-distributed support vectormachine (SVM) learning over wireless sensor networks. With theconcept of the geometric SVM, we propose to gossip the set ofextreme points of the convex hull of local data set with neighboringnodes. It has the advantages of a simple communicationmechanism and finite-time convergence to a common global solution.Furthermore, we analyze the scalability with respect to theamount of exchanged information and convergence time, witha specific emphasis on the small-world phenomenon. First, withthe proposed naive convex hull algorithm, the message lengthremains bounded as the number of nodes increases. Second, byutilizing a small-world network, we have an opportunity to drasticallyimprove the convergence performance with only a smallincrease in power consumption. These properties offer a greatadvantage when dealing with a large-scale network. Simulationand experimental results support the feasibility and effectivenessof the proposed gossip-based process and the analysis.

  • 283.
    Koller, Julian Phillip Johann
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Grossmann Colin, Alex
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Besselink, Bart
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Fuel-Efficient Control of Merging Maneuvers for Heavy-Duty Vehicle Platooning2015Inngår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, IEEE conference proceedings, 2015, s. 1702-1707Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The formation of groups of closely-spaced heavy-duty vehicles, known as platoons, reduces the overall aerodynamic drag and therefore leads to reduced fuel consumption and reduced greenhouse gas emissions. This paper focuses on the optimal control of merging maneuvers for the formation of a growing platoon. Hereto, the merging problem is formulated as a hybrid optimal control problem and an algorithm for the computation of optimal merging times and corresponding optimal vehicle trajectories is developed by exploiting an extension of Pontryagin's maximum principle. Moreover, a model predictive control approach on the basis of this algorithm is presented that makes the merging maneuvers robust to modelling uncertainties and external disturbances. The results are illustrated by evaluating a scenario involving three vehicles, which indicates fuel savings of up to 13% with respect to the vehicles driving alone.

  • 284.
    Larson, Jeffrey
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Kammer, Christoph
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Liang, Kuo-Yun
    Research and Developement, Scania CV AB.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Coordinated route optimization for heavy-duty vehicle platoons2013Inngår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, IEEE conference proceedings, 2013, s. 1196-1202Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Heavy-duty vehicles traveling in platoons consume fuel at a reduced rate. In this paper, we attempt to maximize this benefit by introducing local controllers throughout a road network to facilitate platoon formations with minimal information. By knowing a vehicle's position, speed, and destination, the local controller can quickly decide how its speed should be possibly adjusted to platoon with others in the near future. We solve this optimal control and routing problem exactly for small numbers of vehicles, and present a fast heuristic algorithm for real-time use. We then implement such a distributed control system through a large-scale simulation of the German autobahn road network containing thousands of vehicles. The simulation shows fuel savings from 1-9%, with savings exceeding 5% when only a few thousand vehicles participate in the system. We assume no vehicles will travel more than the time required for their shortest paths for the majority of the paper. We conclude the results by analyzing how a relaxation of this assumption can further reduce fuel use.

  • 285. Larson, Jeffrey
    et al.
    Liang, Kuo-Yun
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. Scania CV AB, Sweden .
    Johanson, Karl H.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    A Distributed Framework for Coordinated Heavy-Duty Vehicle Platooning2015Inngår i: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 16, nr 1, s. 419-429Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heavy-duty vehicles (HDVs) traveling in single file with small intervehicle distances experience reduced aerodynamic drag and, therefore, have improved fuel economy. In this paper, we attempt to maximize the amount of fuel saved by coordinating platoon formation using a distributed network of controllers. These virtual controllers, placed at major intersections in a road network, help coordinate the velocity of approaching vehicles so they arrive at the junction simultaneously and can therefore platoon. This control is initiated only if the cost of forming the platoon is smaller than the savings incurred from platooning. In a largescale simulation of the German Autobahn network, we observe that savings surpassing 5% when only a few thousand vehicles participate in the system. These results are corroborated by an analysis of real-world HDV data that show significant platooning opportunities currently exist, suggesting that a slightly invasive network of distributed controllers, such as the one proposed in this paper, can yield considerable savings.

  • 286.
    Larsson, Martin
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Lindberg, Jonas
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Lycke, Jens
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Hansson, Karl
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Khakulov, Aziz
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Ringh, Emil
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Svensson, Fredrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Tjernberg, Isak
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Alam, Assad
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Araujo, Jose
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Farokhi, Farhad
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Ghadimi, Euhanna
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Teixeira, Andre
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Dimarogonas, Dimos V.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Towards an Indoor Testbed for Mobile Networked Control Systems2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we consider the design of an indoor testbed composed of multiple aerial and ground unmanned vehicles for experimentation in Mobile Networked Control Systems. Taking several motivational aspects from both research and education into account, we propose an architecture to cope with the scale and mobility aspects of the overall system. Currently, the testbed is composed of several low-cost ARdrones quadrotors, small-scale heavy duty vehicles, wireless sensor nodes and a vision-based localization system. As an example, the automatic control of an ARdrone is shown.

  • 287. Lee, Seung Jae
    et al.
    Kim, Suseong
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Kim, H. Jin
    Robust Acceleration Control of a Hexarotor UAV with a Disturbance Observer2016Inngår i: 2016 IEEE 55th Conference on Decision and Control, CDC 2016, Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 4166-4171, artikkel-id 7798901Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents an acceleration control of a hexarotor unmanned aerial vehicle (UAV) in the earth fixed frame with a disturbance observer (DOB). Unlike conventional cascade control structures where the outer-loop position controller generates the desired attitude command, the position controller in this paper generates the desired acceleration command in X, V. Z axis of the earth-fixed frame. With acceleration control combined with DOB, the UAV could manage the lateral disturbance force that makes the trajectory tracking very challenging. This is a new concept compared with existing DOB-based UAV control approaches which aim to cancel the moment disturbance for precise attitude control. The small-gain theorem is used for stability analysis and Q-filter bandwidth design. Both simulation and actual experiment are shown to validate the performance of the proposed design.

  • 288.
    Lehmann, Daniel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Henriksson, Erik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Event-Triggered Model Predictive Control of Discrete-Time Linear Systems Subject to Disturbances2013Inngår i: 2013 European Control Conference (ECC), IEEE , 2013, s. 1156-1161Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents an approach to event-triggered model predictive control for discrete-time linear systems subject to input and state constraints as well as exogenous disturbances. Stability properties are derived by evaluating the difference between the event-triggered implementation and the conventional time-triggered scheme. It is shown that the event-triggered implementation, in stationarity, is able to keep the state in an explicitly computable set given by the disturbance bound and the event threshold. Simulation results underline the effectiveness of the proposed scheme in terms of reducing the communication and computational effort while guaranteeing a desired performance.

  • 289.
    Lehmann, Daniel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Event-triggered PI control subject to actuator saturation2012Inngår i: IFAC Proceedings Volumes (IFAC-PapersOnline) v2 Part 1, 2012, s. 430-435Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Event-triggered control aims at reducing the communication load over the feedback link in networked control systems by adapting the information exchange to the current needs. This paper firstly extends a common approach to event-triggered control by incorporating a PI controller and by showing the setpoint-tracking properties of the extended scheme. Second, it investigates the consequences of actuator saturation on the behavior of the event-triggered PI-control loop. Simulations show that the effect of actuator saturation depends on the selection of the event threshold which might even destabilize the closed-loop system due to integrator windup. Finally anti-windup techniques are discussed to overcome this problem.

  • 290.
    Lehmann, Daniel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Kiener, Georg Alexander
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Event-triggered PI control: Saturating actuators and anti-windup compensation2012Inngår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC), IEEE conference proceedings, 2012, s. 6566-6571Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Event-triggered control aims at reducing the communication load over the feedback link in networked control systems by adapting the information exchange to the current needs. This paper investigates the consequences of actuator saturation on the behavior of event-triggered PI control. Stability properties are derived using linear matrix inequalities (LMIs) which show how the stability of the event-triggered control loop depends on the selection of the event threshold. In order to overcome the potential performance degradation due to integrator windup caused by actuator saturation, the proposed scheme is extended by incorporating a static anti-windup mechanism. The results are illustrated by simulations.

  • 291.
    Lehmann, Daniel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Lunze, J.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Comparison between sampled-data control, deadband control and model-based event-triggered control2012Inngår i: 4th IFAC Conference on Analysis and Design of Hybrid Systems, IFAC , 2012, s. 7-12Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper investigates the stability as well as communication properties of sampleddata control and two event-triggered control schemes: deadband control and model-based eventtriggered control. After proposing a uniform representation, these schemes are compared by deriving approximation error bounds with respect to the behavior of the continuous-time statefeedback loop and by specifying lower bounds on the minimum inter-sampling times. The results show that, under the conditions derived in this paper, the model-based approach guarantees the best stability and communication properties which is also demonstrated by a numerical example.

  • 292. Leong, A. S.
    et al.
    Quevedo, D. E.
    Ahlén, A.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Network topology reconfiguration for state estimation over sensor networks with correlated packet drops2014Inngår i: IFAC Proceedings Volumes (IFAC-PapersOnline), IFAC Papers Online, 2014, s. 5532-5537Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper studies the problem of optimal network topology reconfiguration in sensor networks for state estimation. Multiple sensors make observations of a process, which are then transmitted, possibly via intermediate sensors, to a central gateway. Transmission over each link can experience packet drops. The time-varying wireless network environment is modelled by the notion of a network state as in Quevedo et al. (2013a). For each network state, different network configurations can be used, which govern the network topology and routing of packets. Switching between different configurations incurs a cost, in that unwanted links will need to be removed before the establishment of new links, leading to a transient time in which some links may not be available. The problem is to determine the optimal network configurations to use in each network state, in order to minimize an expected error covariance measure that takes into account the cost of reconfiguration. A simpler suboptimal method which minimizes the upper bound of the expected error is also proposed, which in numerical simulations gives essentially identical results to the optimal method.

  • 293. 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.

  • 294. Li, K.
    et al.
    Rojas, Cristian R.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Yang, T
    Hjalmarsson, Håkan
    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.
    Distributed Signal Recovery Via Piecewise Orthogonal Matching Pursuit and Finite-Time Consensus2014Inngår i: IEEE Explore, Institute of Electrical and Electronics Engineers (IEEE), 2014Konferansepaper (Fagfellevurdert)
  • 295.
    Li, Kezhi
    et al.
    Imperial College London, United Kingdom.
    Rojas, Cristian R.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Yang, Tao
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Hjalmarsson, Håkan
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Cong, S.
    Piecewise sparse signal recovery via piecewise orthogonal matching pursuit2016Inngår i: 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 4608-4612Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we consider the recovery of piecewise sparse signals from incomplete noisy measurements via a greedy algorithm. Here piecewise sparse means that the signal can be approximated in certain domain with known number of nonzero entries in each piece/segment. This paper makes a two-fold contribution to this problem: 1) formulating a piecewise sparse model in the framework of compressed sensing and providing the theoretical analysis of corresponding sensing matrices; 2) developing a greedy algorithm called piecewise orthogonal matching pursuit (POMP) for the recovery of piecewise sparse signals. Experimental simulations verify the effectiveness of the proposed algorithms.

  • 296. Liang, K. -Y
    et al.
    Martensson, Jonas
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    When is it fuel eficient for a heavy duty vehicle to catch up with a platoon?2013Inngår i: IFAC Proceedings Volumes (IFAC-PapersOnline), 2013, nr PART 1, s. 738-743Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Vehicle platooning has in recent years become an important research field for the vehicle industry. By establishing a platoon of heavy duty vehicles, the fuel consumption can be reduced for the follower vehicles due to the slipstream effect. However, as vehicles are scattered on the road driving by themselves, coordination amongst the vehicles is required. In this paper we study the problem of when it is beneficial for a heavy duty vehicle to drive faster in order to catch up and join a platoon. We derive a formula, based on at road and with no vehicle accelerations, to calculate if it is more fuel-eficient for a vehicle to drive faster and platoon or keep driving alone. Depending on the distance between the vehicles and the distance to the destination, the fuel savings vary. For a trip of 350 km, with a distance of 10km to the vehicle ahead, the fuel saving could be up to 7% if the follower vehicle decides to increase the speed from 80 km/h to 90 km/h in order to catch up and form a platoon, assuming an air drag reduction of 32% when platooning. Sensitivity analysis has shown that the speeds need to be relatively accurate in order to not give any false positive catch up decisions.

  • 297.
    Liang, Kuo-Yun
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. Scania CV AB, Sweden.
    Deng, Qichen
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Transportplanering, ekonomi och teknik.
    Mårtensson, Jonas
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Ma, Xiaoliang
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Transportplanering, ekonomi och teknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    The Influence of Traffic on Heavy-Duty Vehicle Platoon Formation2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Heavy-duty vehicle (HDV) platooning is a mean to significantly reduce the fuel consumption for the trailing vehicle. By driving close to the vehicle in front, the air drag is reduced tremendously. Due to each HDV being assigned with different transport missions, platoons will need to be frequently formed, merged, and split. Driving on the road requires interaction with surrounding traffic and road users, which will influence how well a platoon can be formed. In this paper, we study how traffic may affect a merging maneuver of two HDVs trying to form a platoon. We simulate this for different traffic densities and for different HDV speeds. Even on moderate traffic density, a platoon merge could be delayed with 20% compared to the ideal case with no traffic. 

  • 298.
    Liang, Kuo-Yun
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. Scania CV AB, Sweden.
    Mårtensson, Jonas
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Johansson, Karl H.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Experiments on Platoon Formation of Heavy Trucks in Traffic2016Inngår i: 2016 IEEE 19TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC), IEEE, 2016, s. 1813-1819Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Truck platooning is a means to significantly reduce the fuel consumption for the follower vehicle as the air drag is reduced when the inter-vehicle gap between the trucks is reduced. As each truck is assigned with different start and end locations, platoons will be frequently formed and split, while driving to their respective destinations. Additionally, the trucks are not the only ones driving on the road as there are other road users, which may influence how well a platoon can be formed. In this paper, an experimental study is conducted to investigate how traffic may affect a merging maneuver of two trucks trying to form a platoon on a public highway during rush hours. We obtained traffic data from Stockholm's motorway control system to determine the traffic condition for each testrun. Furthermore, we tried different truck speeds to study if it had any impacts on merge delay. Even in light traffic condition, a platoon merge could be delayed with over 10 % compared to the ideal case with the absence of traffic. This is partially caused by persistent drivers in which we encountered them in a fourth of the runs.

  • 299.
    Liang, Kuo-Yun
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. Scania CV AB, Sweden.
    Mårtensson, Jonas
    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.
    Fuel-Saving Potentials of Platooning Evaluated through Sparse Heavy-Duty Vehicle Position Data2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Vehicle platooning is important for heavy-duty vehicle manufacturers, due to the reduced aerodynamic drag for the follower vehicles, which gives an overall lower fuel consumption. Heavy-duty vehicle drivers are aware this fact and sometimes drive close to other heavy-duty vehicles. However, it is not currently well known how many vehicles are actually driving in such spontaneous platoons today. This paper studies the platooning rate of 1,800 heavy-duty vehicles by analyzing sparse vehicle position data from a region in Europe during one day. Map-matching and path-inference algorithms are used to determine which paths the vehicles took. The spontaneous platooning rate is found to be 1.2 %, which corresponds to a total fuel saving of 0.07% compared to if none of the vehicles were platooning. Furthermore, we introduce several virtual coordination schemes. We show that coordinations can increase the platooning rate and fuel saving with a factor of ten with minor adjustments from the current travel schedule. The platooning rate and fuel savings can be significantly greater if higher flexibility is allowed.

  • 300.
    Liang, Kuo-Yun
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Mårtensson, Jonas
    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.
    Heavy-Duty Vehicle Platoon Formation for Fuel Efficiency2016Inngår i: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 17, nr 4, s. 1051-1061Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heavy-duty vehicles driving close behind each other, also known as platooning, experience a reduced aerodynamic drag, which reduces the overall fuel consumption up to 20% for the trailing vehicle. However, due to each vehicle being assigned with different transport missions (with different origins, destinations, and delivery times), platoons should be formed, split, and merged along the highways, and vehicles have to drive solo sometimes. In this paper, we study how two or more scattered vehicles can cooperate to form platoons in a fuel-efficient manner. We show that when forming platoons on the fly on the same route and not considering rerouting, the road topography has a negligible effect on the coordination decision. With this, we then formulate an optimization problem when coordinating two vehicles to form a platoon. We propose a coordination algorithm to form platoons of several vehicles that coordinates neighboring vehicles pairwise. Through a simulation study with detailed vehicle models and real road topography, it is shown that our approach yields significant fuel savings.

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  • asciidoc
  • rtf