The Force Adaptive Control And Vibration Characteristics Analysis Of Multi-point Servo Pneumatic Supporting

This paper focuses on the pneumatic servo supporting device used in the thinwalled parts mirror milling of the spacecraft.Due to the special size and weak rigidity,thin-walled parts are easily deformed and vibrate under cutting force,which seriously affects the machining accuracy.Based on the mirror milling requirements,the pneumatic supporting device and pneumatic control system are proposed in this paper.The support head has multi point support with variable stiffness,which not only ensures the support stiffness,but also achieves the self-adaptive shape support.Multi point support increases the effective support area and avoids the high control precision requirement.For analyzing the performance of pneumatic support device,a mathematical model of pneumatic support system is established,and the dynamic characteristics of pneumatic support system are analyzed with cylinder friction and breathing hole damping.Based on the dynamic cylinder support force,an air spring model is established to achieve the variable stiffness support,and the following performance of the pneumatic support system for cutting force is simulated and verified.The pneumatic system model with simplified boundary conditions establishes thin-walled support equivalent vibration model,with the vibration coupling analysis to classify the main moving form,and analysis the forced vibration with the theory and Simulation,finally combining the isolation to determine the support pressure range theoretically.For faster and more accurate support pressure,the paper combines neural network with the conventional PID,the proportion,integration and differential in neural network realizes parallel computation,which improves the response speed of the pressure;with the weight automatic adjustment,the PID control parameters of achieves self-adaptive and self-tuning,compared with the conventional PID and neural network PID,the neural neuron PID proves its better control performance.For verifying the theoretical support pressure and the control performance,a pneumatic control system was built and verified its performance.Finally,the effectiveness of supporting pressure on vibration control was verified in experiments.