The Development Of Electro-hydraulic Servo Parallel Mechanism Motion Control System Based On Compactrio

Parallel mechanism has wide applications in mechanical manufacture and motion simulation because its carrying capacity is stronger,bigger rigidity and the cumulative error is smaller compared with serial mechanism.With the development of information and virtual instrument technology,how to intelligent control and real-time monitor the parallel mechanism has become a hot topic.This paper set the 3-UPS/S parallel platform as the object and develop a set of motion control system based on the NI CompactRIO embedded controller,which will give full play to the advantages of virtual instrument technology.The concrete research content is as follows:The kinematics reverse solution of 3-UPS/S parallel platform is established,which provides the theoretical foundation to the position control.Then I calculated the match of the hydraulic cylinder and servo valve and finally complete the hydraulic system.In order to accurately control the position of parallel platform,the hydraulic cylinder is closed loop position controlled by reasonable sensors.I completed the CompactRIO control system hardware configuration based on the selected sensors.This paper will introduce the CompactRIO control program written procedures in LabVIEW programming environment and complete the development of the control program.In the hydraulic cylinder closed-loop control,I established the transfer function model of non-symmetrical hydraulic servo-system and studied its particularity.Aimed at the deficiency of the traditional PID control in this model,I designed an improved speed-feedforward control,and found the mathematical expression based on experiments.Finally the feasibility of this algorithm is verified in simulation and experiments.At last,I developed of a wireless motion control program for the parallel mechanism by using the network communication ability of Compact RIO.In this program,people operate ipad to transfer position information to the controller using UDP protocol and the parallel platform can track the ipad’s position.