The Research Of One Motion Control System Of Brushless DC Motor Based On DSP

This paper sets out from the control motor and control algorithm to improve the performance of drive unit of motion control system. By the analysis of the performance of control motor which is always used in motion control system, the excellent brushless DC motor (named as BLDCM) is selected as the actuator and the high performance/cost ratio TMS320LF2407A chip of motion control is selected as the controller. On the basis of mathematics model of BLDCM and control method realized by DSP, a two-loop control system based on DSP is developed and the control codes is programmed.By the analysis of the advantages and disadvantages between PID and Fuzzy control algorithm, a kind of piecewise continuous Fuzzy-PID intelligence control algorithm with feedforward control is designed. This algorithm combines the advantages of Fuzzy control, PID control, intelligent weight function and feedforward control, which need not ascertain the membership function of fuzzy variable and the table of control rules. Though the calculation time of this algorithm is as much as that of PID algorithm, the performance is superior to that of integral separation PID and general Fuzzy control with intelligent weight function. This intelligence control algorithm is applied to the control of velocity-loop in the two-loop control system. According to the characteristic of the speed instruction of motion controller, a series of experiments are accomplished to prove the validity of this algorithm.Additionally, in order to improve the resolution of instruction signal, the sourced absolute circuit which is often used in electrician and measure field is improved and it's disadvantage has been overcome. A kind of pretreatment interface circuit of DSP's A/D conversion is designed. This circuit is used as the signal interface between the upper motion controller and BLDCM control system. With the "excess sampling" technique of DSP, this circuit expands the sampling windows and increases the accuracy of sampling and control.Experiment results proved that the BLDCM control system designed in this paper can fleetly respond to and track the instruction signals, has higher precision of control and track. It has practicality in the field of engineering.