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Multiple loop control system

  • US 4,542,679 A
  • Filed: 12/15/1983
  • Issued: 09/24/1985
  • Est. Priority Date: 02/17/1981
  • Status: Expired due to Term
First Claim
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1. A multiple loop control system providing a single composite output, comprising:

  • a plurality of actuators, each actuator receiving at least two separate control signals and generating an output interconnected with the output of all other actuators in the plurality to provide a single composite output;

    a plurality of control loops, at least one connected to each of said actuators, each control loop responsive to an individual input signal and generating one of said control signals to one of the actuators;

    failure monitoring means connected to each of said actuators and the control loops to monitor the operation thereof, said failure monitoring means including means responsive to a monitor signal from each actuator, and means responsive to the monitor signal from one actuator having a difference from the monitor signals for the other actuators above a first threshold level to generate a disengage signal to one of the actuators for a failure condition, said failure monitoring means further including means for detecting a hard-type failure and inert-type failure and means for generating the disengage signal at a lower threshold level for an inert-type failure than for a hard-type failure; and

    said failure monitoring means further including means connected to each of said plurality of control loops for isolating each of said plurality of control loops from each other.

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