Vibration Control of a High-Speed Parallel Robot Using Discrete Variable Structure Control Methodology

Abstract A discrete variable structure control methodology is presented to suppress vibration of high-speed flexible parallel robot. The elastic dynamic model of the flexible robot is built by using the finite element method and experimental modal testing. Considering uncertain external disturbances and measurement noise, and uncertain parameters of the system, we can utilize invariance of the sliding mode of variable structure control in order to eliminate these adverse influences. The discrete variable structure control strategy is employed to construct the vibration robust controller which enables the flexible robot to be zero state so that the system states are away from the equilibrium one due to external disturbances and uncertain parameters. The discrete Kalman filter is constructed to as state estimator because the state variables cannot be directly measured. The first four natural frequencies and damping ratio are obtained by using experimental modal testing, and the correctness of theoretical model is verified. The experimental vibration control system is constructed and experimental validation of the controller is carried out using dSPACE real-time control system and MATLAB/Simulink tool. The experimental results showed that the proposed controller can effectively alleviate the vibration response of the high-speed flexible robot.