Research On High-Precision High-speed High-frequency Linear Motor Control Method

The main content of this paper is researh on derivative controller and control method of linear servo system of large ship piston turning machine. Turning system servoed by linear motor correctly meets the need of precision structure processing on large workpieces.In the first chapter, The shortcomings of traditional CNC are analyzed, and points out the key point of the project is adopting derivative structure. The application status of linear servo system at home and abroad is reviewed, and the current linear motor drive control method is summarized. The scope of application of the main control method is pointed out, and the research direction of adaptive control method based on robust stability is established for linear servo motor of derivative lathe.In the second chapter, it studied the current mainstream control thought, and described some of the basic control structures suitable for motion control, highly summarized the basic concepts of various control methods:feedforward thinking and feedback thinking. The control law derived from the following two kinds of thought is:compensation according to the model, approach by error. It points out that the former is suitable for modeling system control, and the latter is suitable for non modeling control. According to the linear servo motor, the integrated control structure of adaptive feedforward and robust stability is determined.In the third chapter, it mainly studies the feed forward adaptive method, and our major innovations have been made in the method. First of all, it study and implement the self turring method of feedforward parameters, and put forward differental ahead RLS with forgetting factor. The relation formula between the calculation step and the order is derived. Differential ahead identification can reduce the amount of 70% addition and multiplication, and effication of identification is greatly improved. Secondly, Relationship of vector error and the parameters is deeply studied, and it points out that the vector error and parameters of the speed feedforward and acceleration feedforward parameters in a wide range is monotonic.The optimal scheme P and PI based on the vector error using the monotonic relationship is designed. The dSPACE physical system is adopted in validation test. It compared the pros and cons of the two strategies. The experimental results show that the method can find the optimal feed forward parameters in the case of stable inner loop, and the control parameters can be adjusted according to the relationship between the parameters and the system characteristics. The method has one order error convergence speed, low dependence on modle, and stability is easy to be kept. Thirdly, the recursive forgetting factor least square method is applied to the on-line extraction of vector error. The experiment is designed and the feasibility of the method is verified.In the fourth part, the derivative controller hardware design principle and auxiliary debugging software design are introduced.The corresponding hardware interface design scheme is listed. The innovative design of the external bus addressing quadrature encoder expansion circuit saves I/O port; and the newly design of the output signal line switch serial port multiplexing circuit meets the requirements. It also designs the high precision DA interface.The auxiliary debugging software design based on LabVIEW is briefly described. The hardware system and software system are used in the field debugging. When the bandwidth is 20Hz and the frequency is 5Hz, the tracking precision is less than±6 micronmetter, which can reach the domestic advanced level.The fifth chapter summarizes the research achievements and the deficiency of the current work, and puts forward the suggestions for improvement.