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Servo apparatus for an automatic speed control of vehicles

  • US 4,389,990 A
  • Filed: 09/24/1981
  • Issued: 06/28/1983
  • Est. Priority Date: 09/23/1981
  • Status: Expired due to Fees
First Claim
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1. Servo apparatus for automatic control of an engine throttle in accordance with an error signal, comprising:

  • an electric motor, adapted to have a direct linkage on its shaft which is connectable to a vehicle engine throttle to open the throttle against a biasing force by shaft rotation in one direction, and to release the throttle by rotation in the other direction;

    a sampling circuit for sampling stable motor back emf values;

    a pulsed waveform signal generator having its output connected to drive the motor, and an input for a control signal in accordance with which the pulsed waveform signal is variable to vary the motor torque in the direction of rotation of throttle opening;

    a control unit having its output connected to the generator control signal input, and having an error signal input, and a further input connected to receive values from the sampling circuit, the unit being adapted to vary the pulsed waveform signal to rotate the shaft in accordance with the error signal and open the throttle in a controlled manner, to use the sampling circuit input in addition to the error signal to vary the pulsed waveform signal to allow the shaft to rotate and release the throttle under the biasing force, and, to maintain the motor in a stalled condition.

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