Printed Circuit Motor Feed Drives for a C.N.C. Lathe
This paper summarizes the characteristics and performance of the feed drive servos on an Adaptively-Controlled CNC lathe. After a brief resume of the reasons for using printed motors, the main components of the servo are briefly described. This is followed by a description of how the controlling computer was used to perform tests and record results on the servos.
Step, ramp and frequency responses are given and show that the servos have a natural undamped frequency of about 37 rad/sec when operated with a position loop gain of 1.12mm/min/micron; also, rapid traverse rate can be reached in 0.1 sec. from standstill. The frequency responses and circular contouring test show that a very close degree of matching between the feed drives can be obtained from their ramp response. Results indicate that the printed motor servo is rather limited in the torque available for drilling operations, but ways around this problem are given. Finally the significance of the results and operating considerations are discussed.
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