Two-dimension Motion Control System In Medical Instrument

In this thesis, a method of developing two-dimension motion controller for step motor based on micro-controller has been expatiated on systematically. A sample of such a controller has been made and tested strictly through practical operation. It has reached its design requirements. The controller can easily control each axis to work independently or cooperatively. The step motor can run smoothly, locate accurately, do the same work well and not lose steps, because the control software uses automatic accelerating and decelerating control design.The content of this text is as follows: (1) Research the circuit driver of the step motor. (2) Design the system control method. (3) Design the hardware system. It contains how to choose the micro-controller and design the serial communication. (4) Design the software system. The control part of the system consists of AT89S52 micro-controller and two PMM8713 chips, the micro-controller communicates with computer based on RS-485 standard, and PMM8713 produces control signals to make the corresponding stepper motor run correctly. In the drive part, to get constant current, we choose UC3842 to give out impulse driving signal, which can switch on and off the driving power tube, to make the step motors run according the required track and speed. The control software is composed of PC software and micro-controller software. The PC control software is written by Visual Basic program language and it has good using interface. The micro-controller software is written by assembly language. The source motion control program code is transmitted to RAM of micro-controller through serial port of PC. The micro-controller has three main functions. The first is receiving data or instructions from PC. The second is executing the instructions. The last is transmitting related hint message to PC.The motion controller has the following characters:1. Without the high-speed impulse generator, the motion controller adopts the inner clock to produce the drive impulse. The function is achieved by software so that it reduced the cost;2. In the hardware designing, a lot of standard and module circuits are used in the design. Thereby the success probability and flexibility are greatly improved;3. The circuits and chips which are powerful, integrated, general and bought conveniently are choosed. This kind of motion controller has the features of simple hardware structure, low cost and powerful function. So it has wide application prospect.