Development Of Macro/Micro Stage Control System Based On Voice Coil Motor

With the development of science and technology, in the area of ultra-precision machining, bio-engineering, microelectronics engineering, nano-science and technology and so on, there is an increasing demand for drive feed technology:to achieve precise positioning in large stroke. Currently, macro/micro combined dual drive technology is an effective strategy to achieve large stroke, high-precision motion control.Voice coil motor is a new type of direct drive motor based on Ampere force. It can avoid the disadvantages such as gap and so on in the transmission link. In addition, it has the advantage of high acceleration, high speed, high response, small size, good force characteristics and so on in theory. Therefore, the voice coil motor is suitable for the motion system requiring high-acceleration, high-speed, high-frequency and high-precision positioning.In this paper, the macro/micro dual drive technology and the voice coil motor are combined, and some applied research are made around macro/micro stage. The macro moving stage is controlled by the multi-axis motion controller Clipper designed and manufactured by Delta Tau in this paper. While Clipper maintains low-cost and integration, it also provides a powerful control performance. Clipper can use analog or pulse to control motors. In order to control motors, the hardware circuit should be first connected, then relevant variables should be set and motion program should be written. If necessary, PLC program is also to be written. Furthermore, the PC software is developed using VC++to easily control the macro moving stage by calling C++functions supplied by Delta Tau.Macro moving stage is a high-speed and high-precision motion system, and grating displacement sensor is utilized for position detection. However, high-speed and high-precision both make the frequency of pulse generated by the grating displacement sensor increase. In order to achieve data acquisition near the target point of the macro moving stage, TMS320F2812is used. The date collected by the TMS320F2812which is the number of up-downs of pulses needs to be translated into actual displacement. Therefore, the data acquisition program is written continually using VC++, in which the basic functions such as data conversion, data graphical display, data text export and so on are achieved.ADAMS has a powerful simulation and optimization function. The equivalent model of the micro moving stage is established in ADMAS, and the simulation and optimization of PID parameters of the micro moving stage are achieved by combining control system with mechanical system, which makes the micro moving stage to acheieve rapid start and stop while meeting the accuracy condition. In this paper, the micro moving stage is driven by the voice coil motor, and TMS320F2812’s event managers bring great convenience to the control of motors. In addition, when the mirco moving stage performs high-speed motion along with the macro moving stage, encoder feedback signal will lose steps through the terminal board. Therefore, TMS320F2812is used as the controller to send PWM/direction signal to Copley drive, then the voice coil motor is controlled.