Dedicated Nonlinear Control of Robot Manipulators in the Presence of External Vibration and Uncertain Payload

TL;DR

This paper develops two nonlinear control strategies for robot manipulators operating under external vibrations and uncertain payloads, ensuring stability and improved tracking despite disturbances.

Contribution

It introduces two novel control approaches that account for nonlinear uncertainties from vibrations and payload variations in robot manipulators.

Findings

Both controllers guarantee stability via Lyapunov analysis.

Simulation results confirm effective disturbance rejection and accurate tracking.

Controllers demonstrate trade-offs between accuracy and control effort.

Abstract

Robot manipulators are often tasked with working in environments with vibrations and are subject to load uncertainty. Providing an accurate tracking control design with implementable torque input for these robots is a complex topic. This paper presents two approaches to solve this problem. The approaches consider joint space tracking control design in the presence of nonlinear uncertain torques caused by external vibration and payload variation. The properties of the uncertain torques are used in both approaches. The first approach is based on the boundedness property, while the second approach considers the differentiability and boundedness together. The controllers derived from each approach differ from the perspectives of accuracy, control effort, and disturbance properties. A Lyapunov-based analysis is utilized to guarantee the stability of the control design in each case. Simulation results validate the approaches and demonstrate the performance of the controllers. The derived controllers show stable results at the cost of the mentioned properties.