| In order to improve the reliability of CNC machine tools,firstly,need to improve the reliability of its key functional components.The electric spindle is one of the key functional components that affect the reliability of CNC machine tools,The prerequisite for improving the reliability of the electric spindle is to obtain the reliability data.Reliability data of the electric spindle can be obtained through reliability field test or reliability bench test,considering the high reliability and high test cost of the electric spindle,carrying out the reliability bench test in the laboratory is one of the effective measures to obtain the reliability data of the electric spindle.Developed an electric spindle reliability test bench with the ability to simulate real working conditions,carrying out reliability tests that can reflect real working conditions,it can quickly trigger the failure of the electric spindle and find the design insufficient,so that the reliability can be improved and the reliability level can be improved.Piezoelectric ceramic loading system has the advantages of high control precision,high loading frequency,fast response,large loading force and strong output stability.It is an effective means of external force loading on the electric spindle.Therefore,the development of electric spindle piezoelectric ceramic loading control system has great engineering significance.The electric spindle of machine tools was the research object in this paper,by analyzing the real working conditions,the mathematical model of PZT loading system was established and the PZT loading control system was designed.Based on the analysis of the control system,a new design method of neuron adaptive PID controller was proposed,and the control simulation of system was completed by combining the controller model.The PZT loading control system of electric spindle was developed based on Lab VIEW,and the reliability test was carried out.Through test analysis,this control system has higher loading accuracy than the traditional PID control system.The main contents of this paper are as follows:1.The overall design of the PZT loading control system.Force analysis for electric spindle reliability test bed,analysis for software and hardware of control system,and the overall scheme of the PZT loading control system was obtained.The selection and function of the control system's hardware was discussed.2.Mathematical modeling of the PZT loading control system.The PZT,servo amplifier,pressure sensor's mathematical modeling were established,the transfer function of control system was obtained by the modeling,the state space method was used to described and discretized the control system.Judge the system stability through Bode diagram based on Lab VIEW.3.Control strategy research and system simulation of PZT loading control system.the principle of PID control and basic theory of BP neural network were studied,and neuron adaptive PID control algorithm was determined as the core algorithm of PTZ loading control system.The controller was designed and was analyzed for simulation based on Lab VIEW.4.Software development and test verification of PZT loading system.The software structure of loading system was designed,whose function and program code were given.Electric spindle reliability test was carried out to verify the control effect of the control system.The PZT loading control system developed in this paper can load the spindle steadily,control stably,accurately and easily.It provided technical support for electric spindle reliability test for simulating the real working conditions,and had higher engineering application value. |
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