CONTROL WHEEL STEERING SYSTEM FOR AIRCRAFT AUTOMATIC PILOTS

• US 3,807,666 A
• Filed: 06/11/1973
• Issued: 04/30/1974
• Est. Priority Date: 06/11/1973
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Bernard T. Devlin
• Inventors: Devlin, Bernard T.
• Primary Examiner(s): Blix, Trygve M.
• Assistant Examiner(s): Kunin, Stephen G.
• Application Number:
  US05/369,018
• Time in Patent Office: 323 Days
• Field of Search: 235/150.2 244/77M,77V,77SE,77D,77E,83E 318/563-564,584-585,591
• US Class Current: 244/194
• CPC Class Codes: G05D 1/0077 using redundant signals or controls
• CPC Class Codes: G05D 1/0808 specially adapted for aircraft

Abstract

Aircraft control wheel steering (cws) apparatus having a pair of force sensors coupled to the pilot control wheel for providing redundant command signals to respective independent cws control channels operatively associated with a single axis of the aircraft. Each control channel operates in a synchronizing mode to cancel the applied input command signal until both command signals exceed a predetermined threshold level and thereafter the command signals are applied to the aircraft control surface actuators through the autopilot integrator. Upon reaching a predetermined maneuver limit signal level in either channel, or upon reduction of the control wheel force to a level below the threshold, the command signals are decoupled from the autopilot integrator and both cws control channels revert to the synchronizing mode of operation.

Claims

1. An aircraft flight control system including first and second redundant control channels, said system being selectively operable in an autopilot mode or a pilot control wheEl steering (cws) mode for controlling an aircraft about one of its axes where pilot commands are provided by force sensors coupled with the pilot'"'"''"'"'s control wheel, each sensor being associated with a respective control channel and wherein each control channel comprises synchronizer means coupled to the related control wheel sensor and operable in the autopilot mode to cancel the sensor output signal until the output signals of both sensors reach a predetermined threshold level, detent detector means for detecting the predetermined threshold level of the related control wheel sensor output signal to provide a signal indicative of the detected threshold, and gate means responsive to the simultaneous existence of detected threshold indicative signals in both channels for providing a mode switching signal to switch both channels from the autopilot mode to the cws mode and disengage said synchronizer means which thereafter remains clamped at the level of the control wheel sensor signal applied thereto at the instant of synchronizer disengagement whereby further increases of each control wheel sensor output signal are coupled through the associated flight control system channel to control the aircraft control surface actuators in accordance therewith.

2. The system of claim 1 wherein each synchronizer means comprises summing means having one input connected to receive said force signal and another input, high gain integrator means having its input connected to the output of said summing means and having its output connected to said other input of said summing means, and switch means responsive to said mode switching signal for interrupting said integrator input connection, whereby said integrator output is clamped at the level of said force signal existing at the instant of mode switching.

3. The system of claim 1 wherein each control channel further includes maneuver limit detector means responsive to the simultaneous existence of a signal in the related control channel representative of a predetermined aircraft attitude limit and a signal of the related control wheel sensor representative of a corresponding attitude sense, under a condition of detent detector threshold indicative signals existing in both channels, for providing an inhibit signal to terminate operation of said gate means whereby the related synchronizer means is re-engaged and the respective control channels are switched back to the autopilot mode.

4. The system of claim 3 wherein each synchronizer means comprises summing means having one input connected to receive said force signal and another input, high gain integrator means having its input connected to the output of said summing means and having its output connected to said other input of said summing means, and switch means responsive to said mode switching signal for interrupting said integrator input connection, whereby said integrator output is clamped at the level of said force signal existing at the instant of mode switching.

5. The system of claim 3 wherein the means responsive to the simultaneous existence of detected threshold indicative signals in both channels includes an inhibitor means having a data input terminal for receiving the detent detected threshold indicative signal and an inhibit input terminal for receiving the maneuver limit detector inhibit signal, and an AND circuit coupled to receive the inhibitor output signal of both control channels for providing the mode switching signal.

6. The system of claim 5 wherein each control channel further includes an OR circuit coupled intermediate the related inhibitor output and the input of the AND circuit of both channels, and means for supplying a respective control channel disengage signal to each OR circuit.

7. THe system of claim 6 wherein each synchronizer means comprises summing means having one input connected to receive said force signal and another input, high gain integrator means having its input connecTed to the output of said summing means and having its output connected to said other input of said summing means, and switch means responsive to said mode switching signal for interrupting said integrator input connection, whereby said integrator output is clamped at the level of said force signal existing at the instant of mode switching.

8. The system of claim 1 wherein each control channel comprises integrator means for receiving the cws command signals and providing an output surface command signal to the autopilot actuators whereby the aircraft attitude rate is proportional to the cws force input signals.

9. The system of claim 8 wherein each control channel includes a lead network coupling said force sensor signal to the input of the integrator means for compensating for inherent lag of the response of the aircraft to the pilot input and assuring that the output of the integrator means is closely representative of the instantaneous aircraft attitude.

10. The system of claim 9 wherein each control channel further includes maneuver limit detector means responsive to the simultaneous existence of a signal in the related control channel representative of a predetermined aircraft attitude command limit and a signal of the related control wheel sensor representative of a corresponding attitude command sense, under a condition of detent detector threshold indicative signals existing in both channels, for providing an inhibit signal to terminate the operation of said gate means whereby the related synchronizer means is re-engaged and the respective control channels are switched back to the autopilot mode.