Joint Special Issue: Design and Control of Responsive Robots

Abstract

Robots are complex controlled dynamical systems interacting with their environment. Agile robotic systems have been penetrating almost all industrial sectors as the backbone for industrial automation, ranging from heavy duty manipulators to collaborative robots (cobots) and mobile platforms for logistics tasks. Currently, autonomous vehicles (e.g., cars, mobile delivery systems, drones, inspection, and maintenance) are entering the public sector, but also the use of surgical robots is becoming an integral part of medical treatments. In a foreseeable future, assistive robots for domestic use will become indispensable for caretaking and as exoskeletal devices providing physical support thus physically interacting with humans. Future robots need to be responsive; they must (inter)act safely, minimize the use of resources (energy, material, process-, development-, and commissioning-time), and adapt to variations in demands and environmental conditions.Advanced robotic systems are equipped with multimodal sensory systems, and are operated with model-based and model-free control schemes. Yet, the mechanical embodiment is the starting point of any robot design. Key to a reliable design and control of such robots are holistic design approaches embracing kinematic synthesis, dynamic analysis, control, sensory perception, and adaptability. Novel mechanical design principles, combining high-fidelity kinematic and dynamic models with data-driven methods, are applied along with model-free machine learning (ML) and artificial intelligence (AI) methods. The foundation is a synergetic combination of research in mechanism theory and dynamical systems and control.This joint special issue of the Journal of Mechanisms and Robotics (JMR) and the Journal of Computational and Nonlinear Dynamics (JCND) aims to bridge between these research fields and to bring together the latest research on robot kinematics and dynamics as well as intelligent control and data-driven methods for perception, planning, model identification, and control.This joint special issue is a collection of 13 papers published in JMR and 10 papers published in JCND, respectively. The papers published in JMR address several of the main research topics in robot design, namely, the design and control of agile and compliant robots intended for robust and safe interaction with its environment. The paper “Design, Calibration, and Control of Compliant Force-Sensing Gripping Pads for Humanoid Robots” introduces low-cost, light-weight, and compliant force-sensing gripping pads that enables smaller-sized humanoid robots to manipulate box-like objects. In “Dyno-Kinematic Leg Design for High Energy Robotic Locomotion,” technique for leg design for high energy robotic locomotion is presented that encodes desired dynamic features into the mechanical design. In the paper “Emerging Gaits for a Quadrupedal Template Model with Segmented Legs,” the gait stability of quadrupedal robots with articulated elastic legs is studied. The two papers “Stable Inverse Dynamics for Feedforward Control of Nonminimum-Phase Underactuated Systems” and “Experimental Safety Analysis of R-Min, an Underactuated Parallel Robot” deal with the operation of underactuated robots. In both papers, underactuation stems from the presence of compliant elements. Moreover, introducing compliance is becoming an important design approach which is the topic of the three papers “Kinetostatic Modeling of Continuum Delta Robot With Variable Curvature Continuum Joints,” “Design and Modeling Framework for DexTeR: Dexterous Continuum Tensegrity Manipulator,” and “Analysis of a Soft Bio-Inspired Active Actuation Model for the Design of Artificial Vocal Folds.” While the first two papers address the design of robots that make use of inherently flexible components, the last paper exploits the compliance to mimic a biological system. Mechanical compliance is also the crucial feature exploited in the two papers “Flexible Long-Reach Robotic Limbs