DYNAMIC MODELLING USING SCREW THEORY AND NONLINEAR SLIDING MODE CONTROL OF SERIAL ROBOT

摘要

This paper presents a novel method towards the dynamic modelling of serial robot by combining screw theory and Kane's equations, which can simplify the dynamic analysis of the system, reduce the workload of calculation and make the process smooth. The kinematic pair screw and body Jacobian of rigid body have been introduced. Then a novel partial velocity and partial velocity twist matrix according to screw theory are given respectively. In the following, the Kane's dynamic equations based on screw theory of serial robot have been deduced. To verify the convenience of the proposed method, an example of the dynamic modelling is illustrated. After that, a nonlinear robust sliding mode controller is designed to promote the tracking performance with considering system uncertainties and modelling errors. To enlarge the small error and avoid the accumulation of large error, a new nonlinear integral slide surface is proposed, along with a saturation function instead of switch function to eliminate the chattering. Then the stability analysis of the proposed sliding mode controller for the system is performed by using Lyapunov stability theory. Finally, comparative experiments are given to demonstrate the effectiveness and robustness of the proposed approach.