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Digital Velocity Servomechanism

IP.com Disclosure Number: IPCOM000075114D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Dobransky, RP: AUTHOR [+2]

Abstract

This digital velocity servomechanism reversibly controls the initial acceleration and the subsequent steady state running velocity of motor 1, in accordance with distance-traveled feedback provided by digital tachometer 2.

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Digital Velocity Servomechanism

This digital velocity servomechanism reversibly controls the initial acceleration and the subsequent steady state running velocity of motor 1, in accordance with distance-traveled feedback provided by digital tachometer 2.

The previous cycle of operation of the motor sets acceleration latch 3. A signal is then supplied on conductor 4 which indicates to motor control logic network 5 that the next occurrence of a GO command on conductor 6 will necessitate an acceleration interval, during which the motor will be brought from rest to 90% of its desired running velocity. The desired direction of motor rotation is indicated by a command received on conductors 7 or 8. With network 5 set to the accelerate mode, the motor receives steady state energization, by way of motor driver network 9 and power supply 10 until the motor velocity reaches 90% of its desired running velocity.

The actual motor velocity is determined by measuring the time it takes for the motor to travel a given distance. The time factor is supplied by oscillator 11, and the distance factor is supplied by the tachometer 2.

During acceleration, each output pulse from the tachometer sets latch 12, enables AND gate 13, and causes master counter 14 to increment upward from an initial reset state. So long as the motor velocity is below 90% of the desired running velocity, counter 14 reaches a high-order count Y and resets latch 12 before the next tachometer pulse occurs. When th...