Influence Vectors Control for Robots Using Cellular-Like Binary Actuators

Abstract

Robots using cellular-like redundant binary actuators could outmatch electric-gearmotor robotic systems in terms of reliability, force-to-weight ratio, and cost. This paper presents a robust fault-tolerant control scheme that is designed to meet the control challenges that are encountered by such robots, i.e., discrete actuator inputs, complex system modeling, and cross-coupling between actuators. In the proposed scheme, a desired vectorial system output, such as a position or a force, is commanded by recruiting actuators based on their influence vectors on the output. No analytical model of the system is needed; influence vectors are identified experimentally by sequentially activating each actuator. For position control tasks, the controller uses a probabilistic approach and a genetic algorithm to determine an optimal combination of actuators to recruit. For motion control tasks, the controller uses a sliding mode approach and independent recruiting decision for each actuator. Experimental results on a four degrees of freedom binary manipulator with 20 actuators confirm the method’s effectiveness and its ability to tolerate massive perturbations and numerous actuator failures.