Development Of Reliability Test Bench For Towing Torque Loading Of Motorized Spindle Based On Fuzzy PI Algorithm

After years of development,China's CNC machine tool technology has grasped the nettle and occupied a place in the middle and low-end market.However,advanced CNC machine tool technology is still monopolized by foreign countries,curbing the development of China's manufacturing industry.In order to break through foreign technical blockade,in addition to focusing on the improvement of processing performance,we also need to keep a watchful eye on the reliability of the whole CNC machine tool.Even with high processing accuracy,the reliability is too low to be widely used in real production.Motorized spindle as an important core component of CNC machine tool,its reliability straight impacts the reliability of the complete machine.As the precondition of all reliability research,it is very important to obtain reliability experimental data.It is more sensible to abandon the inefficient way of collecting experimental data in the field and adopt a more efficient bench test.Therefore,it has an important meaning to build a reliability test platform for motorized spindle.In this paper,based on the principle of towing,two identical motorized spindles were used to build a reliability test platform,and the control strategy of motorized spindles direct torque control was emphatically studied.By introducing SVPWM technology and fuzzy algorithm,the torque fluctuation in traditional direct torque control was effectively suppressed,so that the test platform could obtain a better loading effect.The major research paper is as follows:Firstly,the structure and principle of motorized spindle are analyzed.Establish its mathematical model in different coordinate systems.It lays a theoretical grounding for the pursuant research of direct torque control.Secondly,DTC is adopted as the control strategy in this paper,and its principle is introduced.The reason why the traditional DTC produces big torque fluctuation is analyzed.In order to settle the matter of big torque fluctuation,this paper introduces SVPWM technology which can control the time of voltage vector to substitute the traditional switching list,and PI controller substitutes hysteresis controller,so that the torque fluctuation has been to advantage suppressed.Thirdly,in order to improve the capability of PI controller,realize online setting and further suppress torque fluctuation,a fuzzy algorithm is introduced in this paper.According to the principle of PID self-tuning and the real demands,a set of fuzzy rule bases is constructed.And the fuzzy PI controller based on the rule base is used to replace the PI controller on the torque ring.The simulation results make real that the improved DTC has less torque fluctuation.Finally,the physical platform of motorized spindle towing test rig is built.Combined with the principle of drag and energy conversion,the energy change of motorized spindle under different states was analyzed,and a more energy saving loading scheme was finally selected.The mechanical and electrical part of the physical platform was established by the use of related instruments and equipment,and the related software platform is complete with the help of Labview software and embedded FPGA chip c RIO.Relevant experiments are carried out to verify that the test platform can realize torque loading and the fuzzy PI algorithm can suppress the torque fluctuation.In this paper,the development of motorized spindle for towing test platform not only can realize static load,also can achieve a certain frequency of the sinusoidal loading,and the torque ripple is less.Compared with the traditional dynamometer to simulate the loading torque,the test platform uses two motorized spindles to simulate each other's load,which is equivalent to carrying out reliability tests on both meanwhile.It means that more reliability test data can be obtained in the same time and the time of reliability test can be availably contracted.Therefore,the motorized spindle test platform developed in this paper has great practical significance in improving the reliability of motorized spindle.