Control method of electronic cam based on DSP and FPGA

WEI Jun-chao， ZHANG Guo-yuan， CHEN Yao， YAN Xiu-tian
（School of Mechanical Engineering， Northwestern Polytechnical University， Xi'an 710072， China）

Abstract： Aiming at the requirements of integrating the electronic cam function into the DSP and FPGA-based controller card and reducing the burden of the DSP，an open-loop electronic cam control method based on the DSP and FPGA was presented. In this method，the discretion sub-range characterized by equal acceleration motion was used as the basic cam control element，and the assignment of the control system was functionally divided into the DSP and FPGA modules. The DSP as the master processor，was used to plan the trajectory of the electronic cam，send sub-range motion orders to the FPGA，inquire about the motion execution information about sub-ranges，and make the cam execution and other tasks of the control card well coordinated. The FPGA as the coprocessor，was used to fulfill the sub-range motion execution and related interface functions. In the FPGA's cam module，two cascaded DDA algorithm blocks were used for producing driving pulses. The simulation result shows that the frequency of the pulse train in the subrange changes smoothly，and the field application results indicate that the speed of the subrange changes smoothly，the speeds between two adjacent subranges are continuous，and the control system runs stably.
Key words： electronic cam； field programmable gate array（FPGA）； digital siginal processor（DSP）； digital differeatial analyzer（DDA）