MULTIPLE CHANNEL REDUNDANT CONTROL SYSTEM

• US 3,665,809 A
• Filed: 08/19/1970
• Issued: 05/30/1972
• Est. Priority Date: 08/19/1970
• Status: Expired due to Term

• Current Assignee: Chevron Research Company (Chevron Corp.)
• Original Assignee: Charles A. Kubilos, Colin Graham Walker, Edmond Michael Traczyk, Edward John Leadbeater, Ralph Fredrick Darlington
• Inventors: Kubilos, Charles A., Walker, Colin Graham, Leadbeater, Edward John, Darlington, Ralph Fredrick, Traczyk, Edmond Michael
• Primary Examiner(s): Maslousky, Paul E.
• Application Number:
  US05/065,104
• Time in Patent Office: 650 Days
• Field of Search: 91/363A
• US Class Current: 91/363.00A
• CPC Class Codes: B64C 13/505 having duplication or stand-by provisions
• CPC Class Codes: F15B 20/00 Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
• CPC Class Codes: F15B 2211/3058 having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode directional control valves having a regenerative position F15B2211/3133; directional control valves having a floating position F15B2211/3127
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6336 representing a state of the output member, e.g. position, speed or acceleration
• CPC Class Codes: F15B 2211/862 the abnormal condition being electric or electronic failure
• CPC Class Codes: F15B 2211/863 the abnormal condition being a hydraulic or pneumatic failure
• CPC Class Codes: F15B 2211/87 Detection of failures
• CPC Class Codes: F15B 2211/8752 Emergency operation mode, e.g. fail-safe operation mode
• CPC Class Codes: F15B 2211/8757 using redundant components or assemblies
• CPC Class Codes: G05B 11/01 electric
• CPC Class Codes: G05B 9/03 with multiple-channel loop, i.e. redundant control systems
• CPC Class Codes: G05D 1/0077 using redundant signals or controls

Abstract

A multiple channel redundant electro-hydraulic servo system for controlling an aircraft guidance element. This system is redundant so that upon failure of one or more channels of the system, the remaining active channels still maintain control of the guidance element with a minimum of transient shift during shutdown of the failed channel.

Claims

1. A multiple channel servo system comprising a plurality of separate servo control channels, each channel having an input path to receive an electrical command input signal and a hydraulic actuator having a displaceable output element to produce a displacement output in response to a command signal produced in the channel, each channel also having means to feed back an electrical channel feedback signal from the displaceable output element to the input path to cancel out the control signal when the required channel output has been produced, the system including a device coupled to the output element of all the channels and having an output member to produce a system displacement output dependent upon the sum of the force outputs of all the channel output elements, the improvements which comprises a failure detect means in each channel operative to hydraulically disconnect a failed channel from the system, said failure detect means including a jet pipe electro-hydraulic bypass valve operative to shut down a failed channel when an error exceeds a preset limit.

2. The multiple channel servo system of claim 1 in which the failure detect means is responsiVe to either a slow drift failure of the channel or a fast hard over failure of the channel.

3. The multiple channel servo system of claim 1 in which the failure detect means is responsive to a small magnitude slow drift error signal or a large magnitude fast hard over signal to hydraulically disconnect the failed channel from the system.

4. In a multiple channel servo system of the type having a plurality of separate redundant force summed servo channels, each channel having a source of an input command electrical signal and a hydraulic output actuator movable in response to the electrical input command signal and means for producing an electrical position feedback signal in response to movement of the actuator, the improvement which comprises means for detecting a failed channel when the force on the channel exceeds some predetermined value in relation to the other operative channel, and disconnect means responsive to said failure detect means for hydraulically disconnecting the actuator of the failed channel from the system and for connecting it in a closed hydraulic loop so that it follows the operative channel without affecting operation of the operative channel, said disconnect means including an electro-hydraulic jet pipe valve.

5. The multiple channel servo system of claim 4 wherein the failed channel detect means includes means to compare the force on each channel against the average force of the multiple channels and to actuate a disconnect valve in response to the force on the channel exceeding the average force by a predetermined value.

6. The multiple channel servo system of 4 in which the failure detect means is responsive to either a slow drift failure of the channel or a fast hard over failure of the channel.

7. The multiple channel servo system of claim 4 in which the failure detect means is responsive to a small magnitude slow drift error signal or a large magnitude fast hard over signal to hydraulically disconnect the failed channel from the system.

8. In a multiple channel servo system of the type having a plurality of separate redundant force summed servo channels, each channel having a source of an input command electrical signal, an hydraulic output actuator movable in response to the electrical command signal and means for producing an electrical position feedback signal in response to movement of the actuator, each channel further having means to disconnect the actuator of the channel from the system upon failure of the channel, the improvement wherein the failed channel disconnect means is responsive to both sudden hard over large magnitude force error signals and more prolonged smaller magnitude drift error signals to disconnect the actuator of the failed channel from the system, said disconnect means including a lag lead amplifier circuit operative to integrate input signals and generate an output force error signal the amplitude of which is a function of time.

9. The multiple channel servo system of claim 8 wherein the disconnect means is operable to actuate a hydraulic valve which disconnects the actuator of the failed channel from the system.

10. In a multiple channel servo system of the type having a plurality of separate redundant force summed servo channels, each channel having a source of an input command electrical signal, an hydraulic output actuator movable in response to the electrical command signal and means for producing an electrical position feedback signal in response to movement of the actuator, means for generating an average force signal having a characteristic representative of the average magnitude of force on all operative channels, means for comparing the force of each channel with the force of the average channel and for generating a synchronizer feedback signal having a characteristic representative of the difference between the force on the channel and the average force on all the channels, means for utilizing both the position feedback signal and the foRce error synchronizer feedback signal to control movement of the actuator in response to the command signal, and failure detect means including a jet pipe electrohydraulic bypass valve operable upon the synchronizer feedback signal exceeding some preset value to disconnect a failed channel from the system.

11. The multiple channel servo system of claim 10 in which the algebraic sum of the synchronizer feedback signals of all operative channels is zero.

12. The multiple channel servo system of claim 10 in which the failure detect means is responsive to both a small magnitude slow drift synchronizer signal or a large magnitude fast hard over synchronizer signal.