Design and analysis of a linear motor drive system for machine tooling

The mathematical model of the linear motor was developed using mass, resistance, inductance, flux density, back e.m.f., and length of the control coil as its parameters.

The controllers were designed for the linear motor tool control system using position and velocity feedback loops. Two methods of compensation techniques were used during the course of this work to satisfy system requirements. The performance of the system was judged by the surface finished products and the minimum position error signal. The compensation technique used the Bode diagram, the phase diagram, the step response, and the closed loop response of the system. The analytic compensation technique was based on the high value of the velocity error constant and the ratio of pole (zero) to zero (pole) of the compensator (α ≤ 15). Whereas in the experimental compensation technique approximate values of RC components of the compensation were selected first and later tuned to achieve minimum position error signal. The analytic design was developed after the experimentally obtained compensation was working well.

The final compensation of the linear motor system obtained by these two different techniques was simulated on the computer using the Continuous System Modeling Program. The results achieved by the computer simulation of different techniques were compared for overall system performance. Finally, the experimentally determined compensation was installed on the linear motor control system.