METHOD OF AND A DEVICE FOR REDUCING THE INFLUENCE OF BACKLASH IN THE DRIVE OF A MACHINE TOOL

摘要

1450078 Automatic control of speed G LUCHERINI 31 Dec 1973 [29 Dec 1972] 60295/73 Heading G3R In a system wherein a machine tool is driven by two motors each with a feedback speed control using a tachometric dynamo. When the detected torque on one motor approaches zero, speed control of both motors is maintained using the dynamo associated with the other motor. Each speed feedback includes a bias so that the two motors do not approach zero torque simultaneously, and the system is said to eliminate backlash in the machine tool drive. As shown, motors 1, 2 with stabilized field currents, have associated dynamos 6, 7 and circuits 15, 16 that calculate the torque on each motor from the sensed motor speed and armature current. A bi-stable circuit 14 switches the speed control to one dynamo when the calculated torque on the other motor approaches zero. The output of the bi-stable switch is compared with a speed reference 19 to control the armature currents in the motors using amplifier 12.