Speed and Direction Control of Two In-wheel BLDC Motors for the Self-Driving Surveillance Robot

This paper presents a design and control of the self-driving surveillance robot which is driven by two in-wheel BLDC(Brushless DC) motors. The detailed design of the self-driving surveillance robot and improved control scheme are presented in this paper. For the improved speed and motion control performance, the sensorless speed estimation is adopted for the actual speed detection. In the low-speed region, the continuous estimated speed can improve the speed control performance due to the extremely slow response of the actual feedback of hall sensor. The moving direction of the designed robot is calculated by the rotating positions of two in-wheel motors. Then, the direction is revised by the estimated direction by IMU(Inertial Measurement Unit) sensor. In order to compensate the heading angle error of the robot, the compensating term of moving angle based on the actual rotating positions of each in-wheel BLDC motor and the compensating term of angle error make revised speed reference to adjust the error. The proposed design and the control scheme are verified by the practical test of the manufactured robot, and shows the advanced control performance during self-driving.