| With the continuous development and wide application of six-degree-of-freedom platform technology and computer technology,six-degree-of-freedom parallel mechanisms are widely used in driving simulators,medical equipment,Ship simulator and many other fields.The six-degree-of-freedom motion platform involves many professional fields such as mechanical structure,hydraulic design,electrical control,and computer simulation.In this thesis,the electro-hydraulic servo system of the 6-UCU parallel motion platform(where 6 is six degrees of freedom,C is the cylinder pair,and U is the Hooke hinge)is the research object,and the 6-UCU parallel motion platform is modeled and analyzed.The focus is on the design of the platform control system and its experimental research.First of all,this thesis has completed the structural analysis of the 6-UCU parallel motion platform,related analysis of its structural composition,and the calculation of its degrees of freedom.The kinematics analysis of the platform is mainly carried out on the derivation of the positive and negative solutions of the position,and the related analysis of the inverse velocity solutions.By using the Lagrangian method,a dynamic model of the6-UCU platform system is established.Because the six-degree-of-freedom mechanism inverse solution theory is simpler and more suitable for solving practical engineering problems,this thesis focuses on the kinematics inverse solution theory and applies the kinematics theory to the control system.Secondly,for the existing 6-UCU electro-hydraulic servo system PID control has a certain deviation and a certain hysteresis,an auto disturbance rejection controller is given.First,by establishing a single hydraulic servo actuator mathematical model,according to the established mathematical model,the transition process of the auto disturbance rejection controller,the expanded state observer,the nonlinear combination and the disturbance compensation link are designed respectively.Finally,the control strategy of the electro-hydraulic servo system of the motion platform is simulated and verified.Finally,the 6-UCU electro-hydraulic servo control system is designed and implemented and experimental research is carried out.Completed the design of the main controller module,command input module,D/A conversion module,flutter signal module,power amplifier module and feedback input module.The anti-interference of the servo controller was studied,and the software and Hardware anti-jamming measures.The software uses first-order lag filtering and moving average filtering methods to process the signal,and the hardware uses RC filter circuits and decoupling capacitors to filter out high-frequency noise interference.Through motion simulation and motion following experiments,the feasibility of the control algorithm of the electro-hydraulic servo control system is verified. |
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