Study On The Influence Of Electromagnetic Parameters Of Dynamic Spindle On Its Dynamic Output Performance

The dynamic output performance of high-speed spindle is directly related to the high-speed machining precision and efficiency,and control technology is the prerequisite for high dynamic performance output.However,no matter what kind of control technology,it cannot get rid of the dependence of the electromagnetic parameters(stator resistance,rotor resistance,stator inductance,rotor inductance and mutual inductance).The electromagnetic parameters will change,from the initial value due to the operating conditions changing of the spindle,which seriously reduces the dynamic output performance of the spindle.In this paper,the influence of electromagnetic parameters of electric spindle on its dynamic output performance is proposed based on the above discussion.The evaluation parameters of high-speed spindle operating quality are spindle speed and torque.Then,based on the different control methods of the electric spindle,the influence of the time-varying characteristics of the electromagnetic parameters on its dynamic output performance is analyzed.Comparing their running quality through the evaluation parameters,it is found that although the electromagnetic parameters of time-varying characteristics have a greater impact on the vector control.But judging from the integrated control performance,it is still an excellent high-performance control method.So the vector control is chosen as the spindle control system in the paper.The main content is as follows:First of all,the influence of electromagnetic parameters time-varying characteristics on the magnetic field orientation and the dynamic output performance of vector control is analyzed.It is found that the time variation of each electromagnetic parameter can cause the magnetic field orientation to be destroyed which can reduce the dynamic output performance of the electric spindle.In particular,the fluctuation of the rotor time constant caused by rotor resistance or rotor inductance can also lead to the attenuation of the control system,which can reduce the response speed of the control system and seriously affect he dynamic output performance.Secondly,it is pointed out that the off-line identification can only provide the initial or steady-state value of the electromagnetic parameters.But it cannot meet the system dynamic control requirements.The shortcomings of the ordinary least squares and the weighted least squares are analyzed.And the weighted recursive least squares recognition scheme isproposed.The least squares form of the electromagnetic parameters is deduced and discretized.Thirdly,three conditions of the spindle no-load,constant load and time-varying load are designed.Based on MATLAB / Simulink software,the vector control system simulation with electromagnetic parameter identification is carried out.Based on the high speed numerical control machine with a normal vector control spindle,the high-speed milling experiments are carried out.The results of electromagnetic parameter identification are analyzed.The dynamic output performance of the simulation and the experiment is compared and analyzed.The results show that the identification scheme can effectively solve the problem that the dynamic output performance of the spindle is reduced caused by the time-varying characteristics of the electromagnetic parameters.