UDE-based Robust Control of Robot Manipulator Using Dual Quaternion

Abstract

In this paper, a dual quaternion based uncertainty and disturbance estimator (UDE) controller is proposed for a redundant robot manipulator. By employing dual quaternion, the geometric parameters (including position, orientation, velocity and acceleration) of robot manipulator motion are accurately represented without singularity. Then, the dynamics model of a 7-DOF redundant manipulator is established in dual quaternion space, which can describe the coupling effect between translation and rotation. The tracking error is also defined to guarantee that the posture of the end-effector can converge to the desired trajectory. With twist error dynamics, the UDE control framework is developed. This framework can improve the robust trajectory performance in the case of nonlinearity, model uncertainty and external disturbance. The dual equilibrium problem is also handled with the introduction of the parameter s <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</inf> , which represents the symbolic function of the dual quaternion error real part. Finally, the tracking performance and robustness of the proposed controller are validated by numerical simulations.