Tendon-driven continuum actuators (TDCAs) provide compliant and lifelike motion that is well suited for human–robot interaction, but their structural compliance and underactuation make them susceptible to undesired vibrations, particularly along unactuated axes under load. This work addresses vibration suppression in such systems by proposing a real-time control strategy for a two-degree-of-freedom TDCA-based soft robotic neck used in the HARU social robot, where yaw motion is unactuated and prone to oscillations due to eccentric loading. The proposed approach combines a current-based tendon pretensioning routine, baseline PID control of the actuated pitch and roll axes, and a novel Coupled Axis Indirect Vibration Suppression (CIVS) mechanism. CIVS exploits mechanical cross-axis coupling by using high-pass filtered yaw acceleration from an inertial sensor to generate transient tension modulations in the actuated tendons, thereby increasing effective damping of the unactuated yaw mode without introducing additional hardware or compromising compliance. A classical sliding mode control is also implemented as a nonlinear benchmark under identical hardware constraints. Experimental validation on the HARU neck under representative loading conditions demonstrates that the proposed method achieves substantial vibration attenuation. Compared to the baseline controller, CIVS reduces yaw angular range by approximately 53% and yaw acceleration area by over 60%, while preserving smooth, expressive motion. The results further show that CIVS outperforms the sliding mode controller in suppressing vibrations on the unactuated axis. These findings indicate that indirect, feedback-driven tendon modulation provides an effective and low-complexity solution for mitigating load-induced vibrations in underactuated soft robotic systems, making the approach particularly suitable for interactive applications where safety, compliance, and motion expressivity are critical.

Tactile sensors play a key role in human-machine interaction (HMI), providing essential tactile measurement capabilities for this field, where their performance directly determines the operational safety and haptic quality of HMI machines. When tactile sensors are applied to human or machine surfaces, their ability to fit comfortably and conform to the curves of the body is a significant challenge to address. Existing stretchable and flexible sensors show excellent adaptive conformability and accuracy. Yet, their fabrication methods usually rely on expensive and specialised equipment and are not accessible to many researchers from the interdisciplinary field of human-computer interaction to implement, customize and deploy. To address this problem, this paper proposes a stretchable pressure sensor of low-cost and fabrication complexity, drawing inspiration from the ancient paper-cutting art of Kirigami. The developed prototype is experimentally tested for its ability to conform to the human body, while being characterized by a high force-detection accuracy, with an average error of 4% in the range of 0 – 1000 g per cell), and the sampling electronics of it has demonstrated effective crosstalk elimination function. The proposed approach also serves as a methodology for rapid fabrication of flexible electronic devices, enabling high-precision continuous force monitoring across both preloaded (e.g., sitting/lying postures) and non-preloaded scenarios (e.g. contact detection).

To enable better human-machine and human-robot interaction in healthcare applications, there is a need to improve haptic devices, assistive and companion robots to touch humans in a way that can be perceived as comfortable, safe and trusting. Towards this vision, we developed a flexible, wearable matrix force-sensing garment capable of recording dynamic force behaviour of caring touch from four healthcare experts in their natural therapy environment, and enable the touch recipient to provide feedback on the perceived quality of the same touches. Instead of assuming particular touch gestures are caring, we explored the application of the sensing and analysing system to characterise a caring quality of touch across different gestures. We were able to characterise distinctive features for touch aimed for sensory aspects and for moving the body. Our findings demonstrate that caring touch is not limited to specific gestures or a single parameter but is rather characterised by how the touch is performed across multiple features, with deliberateness - the careful and smoothness in the increasing and decreasing of force, emerging as a shared characteristic of caring touch regardless of the specific gesture employed. The study also demonstrates the feasibility of using raw tactile sensor data to assess subjective touch quality.

In this chapter, we explore how new technologies and requirements affect current design methodologies for mechatronics. We investigate gaps and directions needed for the methodologies of tomorrow in view of trends affecting mechatronics and current state of the art. To fully reap the opportunities of mechatronics with advances in materials, sensors, additive manufacturing, AI, computing and communication, but also to handle new requirements and regulations, there is a need for new methodologies and architectures. We introduce the concept of “MechaOps” and related considerations that promise to assist in enhancing scalability, smartness, performance and sustainability for extended mechatronic products that collaborate with a smart infrastructure, humans and other mechatronic systems. MechaOps refers to the integration of the concepts of Mechatronics and DevOps. As opposed to DevOps in software engineering, MechaOps encompasses data gathering, upgrades/downgrades as well as reconfigurations considering both mechanics and/or software in a mechatronic product. With the life-cycle view implied by the MechaOps concept, it becomes essential to design for upgrading, downgrading, maintenance, reuse and refurbishment. The development of new methodologies requires overcoming disciplinary gaps, with specific considerations of novel architectures including digital twins, interactions with humans, other systems and a smart infrastructure, the role of AI in mechatronics, and in assuring trustworthiness and sustainability. We believe that new methodologies and architectures will initially be especially relevant for high-end systems, supporting the creation of adaptable and flexible mechatronics products and services with improved performance and reduced environmental footprint.

We present a qualitative study with five healthcare experts specialised in different types of touch practice to gain insight in how caring touch can be enacted. Through our analysis we focus on how to transfer this learning into design considerations towards enacting caring touch from technologies. Despite the rapidly growing expectation for and design interest in touch from technologies intending to enhance care and well-being, the knowledge on how to design caring touch is still fragmented. How caring touch is enacted in inter-personal touch is under-explored and such expertise from healthcare practitioners has not been engaged from the perspective of HCI design research. We propose designers to consider caring as an experiential quality instead of a division between instrumental types of touch and caring types. We recommend when designing for a caring quality in technology-initiated touch that designers create a progression of touch with dynamic sensitivity and adapt the materiality of actuating devices to the plural dimensions of the body’s textures.

This paper explores the model identification of a novel tendon-driven soft continuum actuator, intended as a functional joint for the social robot HARU. The actuator's design is customized for integration into HARU's eye joints, emphasizing safety in interactions with children, in accordance with UNICEF's 'Policy Guidance on AI for Children'. The performed experimental study assesses and compares the accuracy of various auto-regressive with exogenous inputs (ARX) modeling techniques - linear, nonlinear, and recursive - through motion data from dynamic experimental tests of the actuator under different orientations. The results provide insights into the efficiency of these modeling strategies in dynamic conditions with continuum actuators, thereby offering a basis for model selection in the integration of soft actuators into robotic systems for practical applications.

This paper focuses on the application of soft robotics in the area of social interaction, and presents a modular approach on the design of a soft robotic neck for integration with the social robot HARU. The proposed design incorporates soft robotics and additive manufacturing principles, enhancing safety through compliance for absorbing contacts with users or objects, while modularity allows for easy replacement or upgrade to meet HARU's specific application requirements. The paper discusses the conceptual design specifics of the soft robotic neck and provides an overview of the prototype development stages and its main functionalities.

Inter-human touch plays a vital role in social communication and bonding, maintaining physical and emotional well-being. Advances in robotics, alongside novel haptic technologies such as shape-changing interfaces, are leading to increasing opportunities for technologies to touch humans in different settings. This includes future touch-based interaction design to support remote and robot care, physical and mental well-being, social bonding, and novel sensory experience for the metaverse, entertainment and everyday life. However, the key to unlock these potentials depends on whether the technology can touch well, i.e. whether the felt quality, or experiential affordance matches the expectation for the intended use cases. In these applications, the touch function and its experiential affordances are two sides of the same coin and need to be investigated simultaneously. Currently we identify two main challenges. First, human touch is a highly complex matter to study and evaluate, with a wide range of variables impacting its experiential qualities, while authoring touch is laborious and demands cross-disciplinary expertise and skills. Second, these investigations are often conducted separately in different disciplines. In responding to this design issue, this one-day workshop aims to bring together scholars, designers and practitioners from diverse disciplines in order to initiate an experience-driven design paradigm, where the felt (somaesthetic) qualities, technical realisation, and ethical dimensions can be studied more holistically. Through a mixture of activities including presentations, hands-on interactions with haptic technologies samples, and group discussions, this workshop also aims to discuss principles, terminologies, methodologies, tools, opportunities, and challenges for such an experience-driven design paradigm, one that enables richer and more fine-grained technologies of touch.

This paper aims to provide a systematic review of the published results on design optimization techniques in the area of compliant and soft robots, with a focus on the manufacturing processes, actuation methods and application areas. The goal of this work is to provide a comprehensive view and categorization of recent efforts using optimization for improving the design paradigms of such robot technologies, while focusing on the popular methods of topology optimization and generative design. In addition, this paper provides insights into the technical and technological trends that could potentially steer this area towards widespread adoption in domestic and industrial settings.

This article presents a novel emotionally expressive robot platform targeting social engagement with children. This platform was implemented in accordance with UNICEF's policy guidance on artificial intelligence (AI) for children, focusing on factors such as safety, transparency, reliability and explainability. The robot prototype is presented from a design and development perspective, outlining all utilized electromechanical components that enable its 11 degrees-of-freedom and sensing functions. Preliminary evaluation results are provided in terms of dependability and expressiveness of basic emotions, thus demonstrating the robot's potential to facilitate trustworthy and secure interactions with children.