Velocity-free task-space regulator for robot manipulators with external disturbances
Haiwen Wu, Bayu Jayawardhana, Dabo Xu
TL;DR
This work addresses robust task-space regulation of robot manipulators subjected to external sinusoidal disturbances generated by a linear exosystem. It introduces both a full-state and a velocity-free controller that fuse the internal model principle with passivity-based output feedback, offering asymptotic regulation error convergence and complete disturbance rejection without relying on velocity measurements. The controllers rely on parallel internal models to counteract disturbance channels $d_1$ (actuator disturbances) and $d_2$ (end-effector disturbances) and leverage Lyapunov–LaSalle arguments to guarantee stability under a full-rank Jacobian. Simulation on a two-link planar manipulator demonstrates effective disturbance rejection and practical performance, including saturation-aware variants that curb peak control effort while preserving convergence.
Abstract
This paper addresses the problem of task-space robust regulation of robot manipulators subject to external disturbances. A velocity-free control law is proposed by combining the internal model principle and the passivity-based output-feedback control approach. The resulting controller not only ensures asymptotic convergence of the regulation error but also rejects unwanted external sinusoidal disturbances. The potential of the proposed method lies in its simplicity, intuitiveness, and straightforward gain selection criteria for the synthesis of multi-joint robot manipulator control systems.