Novel Curving Control Scheme of Rail-Type Monitoring Robot System Using Two BLDC Motors and IMU Sensor

This paper presents a novel arbitrary curved path control scheme to reduce the unbalance load between traction motors and position error at the designed rail-guided surveillance system. The designed rail-guided surveillance system is controlled by the two BLAC(Brushless AC) motors based on the internal hall position sensor without any external rail position sensors. Because of the arbitrarily curved guide rail, the traction loads of the inner and outer motor become different due to the mechanical friction of the inner side. Furthermore, the position error also increases. In order to reduce the unbalance load and improve the driving performance at the arbitrarily curved guide rail, the differential of estimated heading angle from IMU(Inertia Measurement Unit) is used to calculate the difference moving length between the inner and outer side motors. At every 2ms sampling period, the compensated moving length references of the inner and outer side motor are updated according to the change of the estimated heading angle. The compensated moving length references control the moving speeds of the inner and outer motor to improve the curved driving performance. In the practical experimental verification, the proposed control scheme shows advanced driving and excellent position control performance for the designed rail-guided surveillance robot.