Research On Double-side Permanent Magnet Linear DC Motor With A Magneto-Rheological Damper

Linear motors have a wide application future in precision equipments. Compared to the brush DC rotary motors, linear DC motors (LDM) needn't commutate while driving in a direction, and with simple and linear electromagnetic force model, LDM is more suitable for high speed and precision driven occasions. Combined the traditional linear DC motor with the characteristics of magnetic circuits in CT equipment, we developed a new type double-side permanent magnet LDM. The electromagnetic field in the gaps was analyzed and tested here, which was proved consistent with the FEA.Driven by electromagnetic force directly and lack of damped chain, sudden changes in acceleration and external disturbances transmit to linear motor without attenuation, which will prolong the transition, cause vibratory and overshoot, and limit the precisions. In this paper we studied a Magneto-Rheological damper (MRD), which was used to enhance the stability. We explored the preparation of Magneto-Rheological fluid with fluidized bed and optimized the structure of Magneto-Rheological damper with ANSYS optimum design and simulated the forward dynamic model with BP neural Network trained by Levenberg-Marquardt algorithm to solve the nonlinear dynamic models.A testing platform integrated with LDM and Magneto-Rheological damper above was designed here and controlled by a double closed loop speed servo digital control system designed by the indirect engineering methods. The control system was constructed here and its hardware and program were also discussed on details. The parameters related to the control system were tested to determine the transfer functions before experiments. The current closed loops of the coil of the LDM and the damper were designed with digital PID and fuzzy algorithms, and the experiments contrast showed that the fuzzy controller was more robust and fewer ripples in the output of controller and current of coils than the PID controller, but the PID controller was faster. A finite state machine in Verilog quadrupled the frequency of the raster output signals, which was used to detect the position and speed of the mover to make a closed loop. A PI controller with a differential negative speed feedback was applied into the speed closed loop to eliminate the overshoot.Some theoretical and practical achievements were obtained through deeply researching the operating principle, mathematical model, control algorithm and strategy, design and implementation of the servo control system, which made a foundation for the further research and development.