Design and test of drive and control system for electric wheeled mobile car

Abstract: Electric wheeled mobile car plays an important role in agricultural production, but when the mobile car's loads or road conditions change, the drive motor controller of the existing wheeled mobile car is difficult to control the motor efficiently and in real time, leading to difficulties in modularization and productization. Therefore, on the basis of the architecture developed in laboratory, a system for driving and controlling the motor of the car was developed, and a master-slave control system structure based on the main control chip STM32F103RCT6 and the underlying motor control chip ATMEGA48PA was proposed. In this paper, the drive control system included a control board and six driver boards, and master-slave electric wheel drive control system, steering drive control systems, overload and undervoltage alarm circuit of four-wheel drive moving car were designed. Following the transmission speed signal, the signal and various control signals of the host machine or hand control board changed with speed that was solved by the main control chip, and then the speed of the 4 brushless DC motor and the cornor of the 2 DC motor were controlled, allowing the car to achieve driving, steering, translation, rotation and braking. The control system used the main control MCU STM32F103RCT6 to calculate the mathematical model of the car and got the respective speed of the four driving wheels for the torque distribution of the drive motor, and then controlled the speed of the four in-wheel motors, the angle of the two steering motors and two breaking motors. Through the control of the motors, the car could be kept straight road, cornering, parallel displacement and rotation. The commutation mode of the BLDC motor driver control system was controlled by MCU ATmega48PA. The control system used the driver chip IR2113 to control the MOSFET, and calculated the pulse signal of the motor's internal hall sensor for the speed detection of the brushless DC motor, and the over current protection circuit was based on the amplifier LM358. The system used the kinematic strategy, that was, when car turned left, turning into a left turn signal acquisition angle on the left side of the wheel, the gathering speed signal was set to the left of the wheel speed; when car turned right, turning into a right turn signal acquisition angle on the right side of the wheel, the gathering speed signal was set to the right side of the wheel speed. According to the equations of motion car, the angle and the other side of the wheel speed signal was calculated. The drive control system has achieved a four-wheel drive and four-wheel independent electronic differential, and has initially achieved the distribution of torque; under the effect of the control system, the four-wheel car can run smoothly and reliably, and can run with a load in the cement pavement, dry dirt roads, slopes and meadows, which basically meets the demand for car transport and operations at the facility agriculture. A series of experimental results show that, the brushless DC motor drive control system has stable performance, reliable data communications, open source, modular controllers. The developed control system of four-wheel car has achieved the four electronic differential and torque distribution, and has realized effective control of car's four-wheel drive moves. The car with stable and reliable system performance and better load performance, can meet the needs of agricultural transportation and agricultural operations, reduce people's physical labor, and improve production efficiency.