Adaptive robust control of a four-cable-driven parallel robot

Abstract

This present study introduces an adaptive control strategy for four-cable robots. An adaptive sliding mode control to overcome the uncertainties of the system as well as avoidance of estimating an upper bound of the system uncertainties is presented. The proposed controller is designed based on the Lyapunov stability theory. Therefore, it ensures the stability of the closed-loop system and makes the tracking error converge to zero. In this robot, the cables can only pull the end-effector but not push it; therefore, we present a simple mathematical solution to design a positive tension controller for the cable suspended robot with redundant cables. The properties of the proposed method such as high performance tracking, disturbance rejection and insensitivity to parameter variations are demonstrated by simulation.