A design and control of rail mover with a hall sensor based BLDC motor

Abstract

This paper presents a design and control of the rail mover system for the security system of the wide area. The rail mover is driven by the geared BLDC(Brushless DC) motor on the rail surface. The position of the rail mover body has to be controlled at the correct position during the running on the rail surface. In this paper, the BLDC motor with hall sensor is used to control of the position. Because the speed estimation from the hall sensor is not accurate in the low speed region, the accurate position control is very difficult. Furthermore, the actual position and the motor position are not same due to the slip effect on the rail surface and driving roller. In order to overcome these problems, an accurate micro-angle control scheme in the low speed range and slip compensator are proposed in this paper. The proposed micro-angle control scheme uses the reference angle from the reference speed with the torque angle compensation. The advanced rotating flux in the low speed region to keep the actual position is based on the reference speed and angle. But the actual rotor position and speed are used to control the motor speed in the normal speed range. The two sensors which are attached to the side of the mover are used to compensate the slip error during the forward and backward moving. The virtual position is derived by the slip error which is calculated by the side sensor of the body can reduce the actual error of the rail. The proposed control scheme and designed mover are verified by experiments of the manufactured rail mover system.