Research On Posture And Vibration Control Of 6-DOF Parallel Platform Driven By Pneumatic Muscles

Aiming at the application requirements of the new technology experiment of underground auxiliary transportation equipment and the safe driving training of operators,this thesis takes the six-degree-of-freedom parallel platform driven by pneumatic muscles as the research object,aiming at improving the position and attitude control accuracy of the parallel platform and realizing vibration control.By combining theoretical analysis with experimental verification,the direct / indirect adaptive robust control strategy and the calculation torque vibration control method based on task space are studied.The main contents of this thesis are as follows.(1)The background and significance of this topic are expounded.The development and application status of six-degree-of-freedom parallel platform are summarized.The current situation of pneumatic muscles driven parallel platform at home and abroad and the development status of parallel platform in the field of driving simulation are introduced in detail.(2)A six-degree-of-freedom parallel platform driven by pneumatic muscles is designed,and its components are selected.Then,the design of pneumatic servo drive system and measurement and control system of parallel platform is completed.Finally,in order to facilitate the research of control algorithm,the construction of experimental platform based on rapid control prototype is completed.(3)Based on the six-degree-of-freedom parallel platform,the posture representation method of the motion platform is firstly established,and the inverse solution of the parallel platform is obtained by analytic method.The forward kinematics solution of the parallel platform is obtained by Newton-Raphson iterative algorithm.Secondly,the mathematical model between the speed and acceleration of the pneumatic muscle and the speed and acceleration of the motion platform is established.Then the dynamic model of a single pneumatic muscle is established,and the mathematical model of the parallel platform in the joint space is derived.Finally,the parallel platform driven by pneumatic muscle is simplified,and the dynamic model of the parallel platform is established by using Newton-Euler principle.(4)Firstly,the control strategy of parallel platform based on joint space is studied.The posture control of the motion platform is transformed into the length control of a single pneumatic muscle,and a direct / indirect adaptive robust controller based on pneumatic muscle is designed.Then,the performance of the controller is verified by experiments.The results show that the maximum error of the controller doesn’t exceed2.2 mm when tracking 30 mm sinusoidal trajectory,and the mean square error of the tracking error is only 0.8384 mm,which is 64 % higher than that of the traditional adaptive robust control.Finally,the multi-degree-of-freedom hybrid control and interference test experiments prove that the designed adaptive robust control has good dynamic trajectory tracking performance and anti-interference ability.(5)Aiming at the experimental noise of the six-degree-of-freedom parallel platform,the extended Kalman filter(EKF)algorithm is used to filter the velocity and acceleration of a single pneumatic muscle,and the velocity and acceleration of the sixdegree-of-freedom parallel platform are synthesized.Secondly,a vibration controller based on calculated torque is designed in the workspace,and the stability of the controller is proved theoretically.Finally,based on the controller,the experiment is designed to realize the vibration control of the pneumatic muscle driven parallel platform under single degree of freedom and multi degree of freedom.Finally,the main work and conclusions of the thesis are summarized,and the future is prospected.