Dynamic modeling and terminal sliding mode control of a 3-DOF redundantly actuated parallel platform

An improved 3-degrees-of-freedom (DOF) redundantly actuated parallel platform (RAPP) has been designed to adjust the pose of heavy-loaded and large-scaled equipment. This paper presents the dynamic modeling and controller designing of the 3-DOF parallel mechanism. According to the specific structure and characteristics, the proposed mechanism is considered as a multibody system, whose dynamic model is formulated via Lagrange's Equations. On the foundation of dynamics analysis, a control strategy based on the terminal sliding mode is presented to achieve precise motion tracking control. The simulation results indicate that the designed controller not only makes an improvement on the trajectory tracking ability, but also enhances the robustness under constantly changing parameters and disturbance. Experiments are also conducted on the pose adjustment prototype system to validate the RAPP's performance and assess the control method.