The Design And Research Of Stand-alone Embedded Motion Controller Based On STM32and FreeRTOS

The motion control system is widely used in industrial processes. With the developmentof manufacturing industry, the motion controller demand is increasing constantly. At present,the most of the domestic motion controller products are based on PCI bus, and require adedicated PC to constitute the control system. The motion controller which uses a dedicatedchip, the versatility is poor. Most of device manufacturing equipments need both motioncontrol and sequential logic control, but only high-end PLC product has a motion controlmodule, which is costly.In response to these issues, with the motion controller distributed network developmenttrend, this paper designed a stand-alone motion controller which is based on the real-timeoperating system FreeRTOS and takes STM32F107as the core. It could connect with the PCthrough USB, CAN, RS232, and run under the supervision of the PC. At the same time, itcould support the embedded HMI with touch screen to run independently. It integrates PLCprocess logic control and motion control functions, and has good versatility.The main contents of this article are as follows:1. Considering the development status and the basic principles of motion controltechnology, the hardware architecture based on the STM32F107and FPGA is fixed byanalysis. Circuits of the hardware modules are designed.2. The embedded real-time operating system kernel FreeRTOS was ported toSTM32F107. The verification and performance test experiments were done. The results showthat the FreeRTOS transplant is successful and its performance meets applicationrequirements. On this basis, defined various functional tasks, and designed the program ofeach module. Reasonable distributed bus motion controller software architecture is designed.The interpolation cycle time of just4ms is able to meet most applications. μC/GUI has beenported to FreeRTOS to solve the problem of human-machine interaction.3. According to the characteristics of the information exchange between upper and lowercomputer, a reliable and efficient data communication protocol is developed and a hostcomputer application test software is written using VC++. WDM device driver model isresearched, and a USB device driver is written for USB communication between PC and motion controller.4. The hardware and software co-debugging experiment of Motion controller has beendone. The motion controller was applied to the vertical CNC rotary table machine. Accordingto application requirements, the HMI was designed. Results of the application experimentshow that hardware and software of the motion controller with comprehensive function arereasonable, and it has both motion control and sequence logic control functions, and theperformance meets application requirements.