Variable Gain Cross Coupling Contour Control For Cam Grinding

Key components are the core links in the manufacture and play the role of support and guarantee to the construction machinery industry. In recent years, in order to satisfy the requirements of higher machining accuracy of the key components, the application of contour error compensation control in the field of computer numerical control(CNC) machine tools gradually becomes a research hotspot. In the process of cam grinding, speed optimization is generally the way to inhibit the big error. After speed optimization, in order to meet the requirements of high accuracy, contour error compensation method is adopted to inhibit the small error at the same time. The cam contour error directly reflects the cam contour accuracy. This thesis is just to improve the cam contour accuracy and study the cam contour error compensation control methods in the foundation of speed optimization. This thesis designs the variable gain cross coupling compensation control model of the cam contour error, and presents effective contour error compensation control methods. The cam contour error is chosen to be controlled effectively, so as to improve the cam contour machining accuracy.The cross coupling cam contour error compensation control model is composed of three parts: the contour error mathematics model, the coupling controller with parameter set-up, and the distribution method of the error compensation value. The three parts are deeply studied in turn.Firstly the space geometric vectorization modeling method is used to establish the mathematics model of the cam contour error, and the effectiveness of the cross coupling cam contour error compensation control strategy is verified in the MATLAB as well as the effectiveness of the established cam contour error mathematics model.Secondly the parameters adaptive setting control algorithm of the cross coupling controller is designed. The parameter setting method directly determines the cam contour error compensation control performance. Under the premise of using proportion error distribution method, three different cross coupling controller parameter setting methods are designed in turn. The cross coupling controller based on BP neural network is designed intensively, the outputs of the BP neural network output layer are chosen to be the three cross coupling controller PID control parameters, and the weight coefficients of each layers in the BP neural network are corrected to realize the adaptive adjustment of PID control parameters. The effectiveness of the cross coupling control parameters adaptive setting algorithm is verified in MATLAB, and the better cam contour error compensation control performance is produced compared to the other parameter setting methods at the same time.Finally the variable gain error distribution cam contour error compensation control method is proposed. Under the trend of that proportion error distribution method is widely used in the field of the cross coupling contour control at present, the arbitrary proportion variable gain error distribution method is deeply studied in this paper. And BP Neural Network Technique is used in error distribution method to realize the arbitrary proportion variable gain error distribution control method. The outputs of the BP neural network output layer are chosen to be the distribution weight coefficients of cam rotating axis and grinding wheel feeding axis, and the weight coefficients of each layers in the BP neural network are corrected to realize the arbitrary proportion variable gain error distribution. The effectiveness of arbitrary proportion variable gain error distribution method is verified in MATLAB, and the best cam contour error compensation control performance is produced compared to the same gain error distribution and the proportion variable gain error distribution at the same time. The arbitrary proportion variable gain error distribution method proposed in this paper offers a new scheme to solve the cross coupling contour control problem.This thesis designs the variable gain cross coupling compensation control model of the cam contour error, and presents effective contour error compensation control methods, besides the simulation experiments are carried out to verify the feasibility and effectiveness of the control strategies one by one. However, how to ensure the stability of the closed loop system in theory for the control strategies proposed in this paper still needs to be perfect.