Brushless DC Motor Control System Used For The Medical Electric Bed

This paper is based on a production developing project taken by the institute.The hardware and software of the system is designed and BLDCM control system is simulated with fuzzy control method. As the research project the brushless DC motor(BLDCM) for driving the medical electric bed is used to control two motors.As the main controller , special integrated circuits MC33035 produced by MOTORALA is used in this designed system. The circuits construction is simpfied greatly, and the cost of the system is reduced. On the basis of analyzing internal structure and its function of MC33035,the hardware of the system is designed. The control circuit ,the detection circuit of Hall position sensors signal design,MC33039 speed feedback circuit and the overcurrent detection and protection circuit are also given. The Unit 80C51MC is also used to realize a function of position memory of the electric bed. The anti-disturbance steps are used in the design of hardware circuit, which makes the system work safely and reliably.In this dissertation, software design is finished to realize the position memory function. The controller drives the electric bed to start and stop, up and down. It also makes the electric bed have 4 memory potions and functions of locking poison and reposition. One interface of man-machine conversation is offered by remote control. This interface is designed to be simple and convenient for users.The effective means to design fuzzy logic controller are introduced when control rules are certain or uncertain with fuzzy logic toolbox and S-function of MATLAB. The corresponding fuzzy logic control system is designed and simulated with SIMULINK.In the end of this dissertation, the control system of BLDCM is tested. The experiments show that the system of BLDCM has good performance and stability.