Passivity-Based Motion and Force Tracking Control for Constrained Elastic Joint Robots

Abstract

In the past, several motion and force controls were successfully implemented on rigid-joint robots with constraints. With the invention of mechanically compliant robots, the focus on designing controllers for elastic joint robots with constraints is increasing, especially involving the complexity of the joint elasticity in control. Aiming to bridge the gap between the control schemes of rigid-and elastic-joint robots, this letter presents a controller consisting of a PD+ task-space tracking and integral force control, while the intrinsic inertial and elastic properties of the system are fully preserved. We provide a passivity analysis and prove uniform asymptotic stability of the equilibrium. Simulations on a planar two-armed benchmark system with constraints validate the proposed control law.

Finite-Time Nonlinear H∞ Control of Robot Manipulators With Prescribed Performance

“…Robotic systems are inherently nonlinear and often face uncertainties and disturbances during a mission, which inevitably leads to known challenges in their control design. To provide accurate tracking performance of robot manipulators under realistic conditions, numerous classical control strategies have been explored, including robust control, [1] adaptive control [2], passivitybased control [3], variable structure control [4], backstepping control [5], PID control [6], observer-based control [7], just to name a few. More recently, finite-time control strategies have been introduced that can result in a quick transient response, improved steady-state accuracy, as well as guaranteed finite-time convergence [8], [9].…”