Position and force control of a robot by means of round-belt twist-actuation generating contraction forces

Abstract

This paper introduces a novel robotic joint mechanism composed of antagonistically twisted round-belt actuator, which has multiple small-diameter round-belts in antagonistic location around the joint. This joint mechanism is developed by emulating muscle structure of human upper limbs, and can be activated by twisting each round-belt that is made of polyurethane materials. Especially, this paper shows position and force control by means of the proposed twisted round-belt actuators with traditional P/PI controllers. We clearly demonstrate that contact force on tip of the robot is able to follow desired sinusoidal trajectory with no errors by means of straightforward algorithm on the basis of voltage-controlled robot hardware. Through these experiments, we explain intrinsic characteristics of twisted round-belt actuator system and advantages of the structure in control performance.