Research On The Subdivided Driving Of Step-Motor Realized By FPGA

Step-motor is a kind of electromechanical component that is driven in step angle or line displacement by electric pulse signal. Because of having the advantage of easy open-loop control and no accumulating error, step-motor is being applied widely in many fields. In order to meet the requirement of high-precision orientation and moving smoothness, subdivision driving of stepper-motor is adopted.The thesis analyses the electromagnetic restricted relation of two-phase hybrid step-motor and sets up its mathematics models. After that the thesis presents the subdivided control method. A method of step-motor subdivided technology realized by single chip and Field Programmable Gate Array(FPGA). By using single chip, speed and direction are set up. The step pulse changed by FPGA which forms step voltage signal realized any subdivided technology of step- motor. The step-motor 256 subdivision controllers about the PWM module, the speed control module, digital comparison module and so on have been achieved with VHDL language programming.The chip XC2S15 is selected to be the design carrier and VHDL is the development tools in this research. The pulse distributor is designed and PWM waveform data are written in the ROM of the FPGA(XC2S15). And then, check the table to realize the alterable subdivided. Finally, the multi-ply subdivided system of several step-motors is achieved.Using FPGA has resolved the problem of I/O not enough in single chip because FPGA has many I/O which can be defined by user.Adopting FPGA, the system doesn't need linking an exterior D/A converter, and will simplify the complexity of circuit of the system and improve its ability to resist EMI. It has the characteristics of structure succinctness, high precision control and the widespread application prospect.