Research On The Dynamic Measure And Compensation System Of Position Errors Of X-Y Table

With the development of high exact machining technology, people have advanced more and more high request for the machining precision of machine tool. Moreover the orientation precision of machine tool is one of the mostly factors which affect its machining precision, so that how to advance tool position precision expediently and practicality is an import task which is studied in every respect now. Especially for the open loop and the half closed loop numerical control system, because the exist of the open loop tache, position precision improved more is limited. For this kind of machine tools their orientation precision mostly lies on the control precision of electric motor and the machining precision of cutting feed screw rod, along with the infection of friction and hot distortion of the guideway fit and screw rod fit and so on. This study task improves tool's position precision mostly through the dynamic measure and compensate of screw rod cumulated error, sequentially to satisfy people with more and more high machining precision of numerical control machine tool.First of all we summarize the study status in quo and up to the minute development of the control arithmetic of electric motor inside and outside country, as well as the relational study of the dynamic measure and compensation of screw rod error in this text. The control precision of electric motor affects the dynamic measure of screw rod cumulated error greatly. The general PID control , because of its simple principle,convenience,robustness, has been used in the industry process control widely, and acquire upstanding apply effect. But it is the same with linearity system only, and that the practice industry produce process is provided with non-linearity,time-varying nondeterminacy, difficult to constitute accurate math model, the perfect control result can't reach under the routine PID control. Modern times control theories , such as fuzzy control,NN control and so on, still locate in simulation stage, adjusting on lie and realizing high degree of accuracy control with difficulty. This text uses integral separate PID control arithmetic to improve inhere PID control arithmetic, it can not only removes steady error, but also improves systemic respond velocity, minishes overshoot. So systemic control precision is improved effectually. The experiment validate this means can minish the overshoot and surge of X-Y table effectually.The cumulation error of screw rod is the primary factor which affects the position error of the X-Y table. If want to minish its effect on the position precision ,we must measure its value firstly. Now high exact long grating linear is the dynamic measure apparatus in common use. But because of the factors such as installation and so on, the parallel error exists in the measure process. Because the laser vibration measurer is provided with dynamic respondent quickly,less parallel error, so this task uses the laser vibration measurer in stead of the long grating linear to measure and analyse the cumulation error of screw rod. Based on this, we use the feedforward compensatory means to minish the cumulation error of screw rod, improve the position precision of the table. The experiment validate this means can measure the cumulation error of screw rod well and truly, so that the error can be compensated accurately, and the position precision of the table can be improved.