Backlash-free motion control of robotic manipulators driven by tensegrity motor networks

Abstract

Tensegrity robots with backlash free motion control functionality are considered. Without introducing any link-to-link motors, the proposed system achieves controllability by a motorized-pulley tendon actuation network. Due to the mechanical coupling between two motorized-tendons and two robotic manipulators, the proposed actuation system maintains a surjective mapping from the space of admissible tendon forces to the space of singularity-free maneuvers of the individual serial-chain manipulators (provided the links remain non-contacting). For this new class of snake-like robots, a position-feedback motion control law is developed that minimizes the maximum motor torque while ensuring that the tendons do not go slack at any point along a given robot trajectory. Numerical simulations illustrate the method and demonstrate tensegrity's superior maneuvering and backlash avoidance capabilities