Special Section: Mechanisms and Robots for Safe Human–Robot Physical Interaction

Humans and robots are increasingly expected to coexist and interact in a number of industrial, medical, rehabilitation, and assisted-living environments. The physical proximity and interactions between humans and robots in these workplaces have created the need for ensuring human safety in these situations through a variety of design, sensing, and control approaches.This special section is focused primarily on solutions for achieving safe physical human–robot interaction and includes a collection of five papers from researchers on three continents. The papers generally address new methods for modeling and analysis of physical human–machine interaction, or methodologies and mechanism designs for achieving safe physical human–robot interaction. Topics span from theory to application and from modeling to hardware development.Two papers deal with modeling how humans regulate force and motion in physical tasks. Whereas one of these seeks to develop a framework describing how humans may develop an internal model of perturbing trajectories and modify stiffness accordingly; the other looks at shared human–machine tasks and investigates the relationship between trust and physical load sharing.Three papers have elements of hardware development, from surgical robots to hand exoskeletons to tensegrity manipulators. One paper details the development of a new spherical parallel manipulator architecture with a reconfigurability feature for improving kinematic performance in craniotomies. Another paper outlines a new hand exoskeleton design with a lightweight linkage and series-elastic actuator for force control. Finally, a tensegrity manipulator composed of two X-mechanisms suitable for lightweight, variable-stiffness interactions is presented.As a result of the significant efforts of authors who have submitted their work to this special section, and reviewers with providing valuable peer review, for which we are grateful, finally, we are very pleased to share with you this selection of papers that we hope you will find valuable and inspiring toward further research and achievements. Overall, this special section conveys the breadth of issues facing the mechanisms and robotics community in addressing the next generation of needs related to safe human–robot and human–machine interactions.Special thanks also go to Venkat N. Krovi, editor of the Journal of Mechanisms and Robotics, who supported a special section in this important research area, and to the journal’s administrative support team that made the special section possible.