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Servo System With Constant Acceleration

IP.com Disclosure Number: IPCOM000073844D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Schmitt, SA: AUTHOR

Abstract

This system which provides constant acceleration to produce a constant force on inertial loads has three basic parts: a digital-to-analog converter 2, a circuit to form a voltage ramp during speed changes, and a rate servo. The digital-to-analog converter consists of a number of computer-controlled input sources wherein, during normal operation, one current source is always on and the remainder are off.

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Servo System With Constant Acceleration

This system which provides constant acceleration to produce a constant force on inertial loads has three basic parts: a digital-to-analog converter 2, a circuit to form a voltage ramp during speed changes, and a rate servo. The digital-to-analog converter consists of a number of computer-controlled input sources wherein, during normal operation, one current source is always on and the remainder are off.

The output voltage 3 from digital-to-analog converter 2 is delivered to a circuit which produces a voltage ramp whenever the converter voltage changes. This circuit includes a differential amplifier 4, a controlled current source Q2 and a fixed current source Q1. There is a 100% feedback from output 5 to amplifier input 6 so that normally the output and input voltages are equal. Current source Q1 is adjusted to deliver half the current delivered by controlled current source Q2. When the input voltage changes in a positive direction, the output of differential amplifier 4 saturates at a negative voltage turning on Q2. Q2 delivers a current I and Q1 delivers a current -I/2. Therefore, capacitor 7 is charged by a current I/2 producing a linearly increasing output. When the output voltage equals the input voltage the current delivered by Q2 is reduced to I/2 by differential amplifier 4. When the input voltage 3 changed in a negative direction, the output of differential amplifier 4 saturates at a positive voltage turning off Q2....