Fuzzy coordinated control of contact constraint problem for robot system with compliant actuators

Abstract

A robot system would inevitably cause unpredictable collisions in an unknown or unstructured environment. In this paper, the controllability conditions of a general robot system with compliant actuators are proposed to judge and assess the contact constraints based on Port-based Hamiltonian. In order to satisfy the proposed controllability conditions, one fuzzy coordinated control method inspired from the pathfinding of a blind or normal person in dark environment is proposed to deal with the problem of contact constraint. This method achieves velocity-torque combined control without using force or vision sensors compared with conventional methods. Finally, the experiments validate the feasibility of the controllability conditions to deal with contact constraint problems. The results show that the fuzzy coordinated controller can work more efficiently and effectively to detect and respond to contact constraints compared with the proposed proportional control.

Flexible Bio-tensegrity Manipulator with Multi-degree of Freedom and Variable Structure

“…Traditional robot combined with elastic/compliant actuator [27,28] is another recipes to obtain structural compliance. The advantages of elastic/compliant actuator is that series elastic actuators [27] and variable stiffness actuators [28] combine the elastic element or compliant mechanism with conventional stiffness actuators to regulate energy transmission [29], to improve energy efficiency, and to achieve safety physical interaction. Ham and Sugar et al surveyed the various elastic actuators with passive adjustable compliance and controllable stiffness for robotic applications [28].…”