Flight control system employing three controllers operating a dual actuator
First Claim
1. A hydraulic flight control system comprising:
- a tandem hydraulic actuator having an actuating rod connected to a pair of pistons mounted in respective first and second cylinders;
first and second electrohydraulic servovalves controlling the flow of hydraulic fluid into and out of said first and second hydraulic cylinders, respectively, each of said electrohydraulic servovalves being controlled by a pair of actuating coils;
first, second and third controller means receiving a flight control signal, said first controller means having a control channel that is capable of providing an output to one actuating coil of said first electrohydraulic servovalve for operating said first electrohydraulic servovalve, said second controller means having a control channel that is capable of providing an output to one actuating coil of said second electrohydraulic servovalve for operating said second electrohydraulic servovalve, said third control having first and second control channels that are capable of providing respective outputs to the other actuating coils of said first and second electrohydraulic servovalves for operating either or both of said electrohydraulic servovalves; and
monitor and control logic means for monitoring the performance of said controller means, electrohydraulic servovalves and actuator, said monitor and control logic means selectively enabling said controller means so that each of said electrohydraulic servovalves is operated by only one controller means at a time and, in the event of a malfunction in the performance of one electrohydraulic servovalve or controller means driving said electrohydraulic servovalve, enabling the other controller means connected to said electrohydraulic servovalve.
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Accused Products
Abstract
An aircraft flight control system for use with a dual or tandem hydraulic actuator coupled to a flight control surface through an actuating rod. Each half of the tandem actuator is controlled by a respective electrohydraulic servovalve. Each electrohydraulic servovalve is controlled by signals applied to either of two actuating coils. Control signals are applied to the actuating coils from three controllers. The control signals are generated as a function of the difference between the flight control signal and a feedback signal indicative of the position of the actuating rod. Each electrohydraulic servovalve includes a pair of linear variable differential transformers generating feedback signals indicative of the position of the valve stem in each electrohydraulic servovalve. The valve feedback signals are compared to each other and to reference signals corresponding to the expected value of such feedback signals in order to detect and identify malfunctions in the flight control system. In one embodiment, the electrohydraulic servovalves are controlled by two channels of a primary controller in normal operation. In the event of a malfunction, control is transferred to one of two secondary controllers. In another embodiment, the electrohydraulic servovalves are controlled by respective primary controllers, with control being transferred to one of two channels of a secondary controller in the event of a malfunction.
72 Citations
21 Claims
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1. A hydraulic flight control system comprising:
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a tandem hydraulic actuator having an actuating rod connected to a pair of pistons mounted in respective first and second cylinders; first and second electrohydraulic servovalves controlling the flow of hydraulic fluid into and out of said first and second hydraulic cylinders, respectively, each of said electrohydraulic servovalves being controlled by a pair of actuating coils; first, second and third controller means receiving a flight control signal, said first controller means having a control channel that is capable of providing an output to one actuating coil of said first electrohydraulic servovalve for operating said first electrohydraulic servovalve, said second controller means having a control channel that is capable of providing an output to one actuating coil of said second electrohydraulic servovalve for operating said second electrohydraulic servovalve, said third control having first and second control channels that are capable of providing respective outputs to the other actuating coils of said first and second electrohydraulic servovalves for operating either or both of said electrohydraulic servovalves; and monitor and control logic means for monitoring the performance of said controller means, electrohydraulic servovalves and actuator, said monitor and control logic means selectively enabling said controller means so that each of said electrohydraulic servovalves is operated by only one controller means at a time and, in the event of a malfunction in the performance of one electrohydraulic servovalve or controller means driving said electrohydraulic servovalve, enabling the other controller means connected to said electrohydraulic servovalve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In an aircraft having at least one flight control surface and a flight control computer generating flight control commands from manual control inputs, an improved flight control system comprising:
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a tandem hydraulic actuator having an actuating rod connected to a pair of pistons mounted in respective first and second cylinders, said actuating rod being connected to one of sad flight control surfaces; first and second electrohydraulic servovalves controlling the flow of hydraulic fluid into and out of said first and second hydraulic cylinders, respectively, each of said electrohydraulic servovalves being controlled by a pair of actuating coils, said electrohydraulic servovalves each having a pair of valve operation sensors generating respective valve feedback signals indicative of the operation of said valves; four actuator rod position sensors generating respective actuator rod position signals indicative of the position of said actuating rod; primary controller means generating first and second control signals through respective first and second control channels as a function of said flight control signal and respective actuator rod position signals from two actuator rod position sensors, said first and second control channels being connected to one actuating coil of said first and second electrohydraulic valves, respectively; first secondary controller means selectively generating a third control signal as a function of said flight control signal and an actuator rod position signal from a respective actuator rod position sensor, said first secondary controller being connected to the other actuating coil of said first electrohydraulic servovalve; second secondary controller means selectively generating a fourth control signal as a function of said flight control signal and an actuator rod position signal from a respective actuator rod position sensor, said secondary controller being connected to the other actuating coil of said second electrohydraulic servovalve; and monitor and control means receiving said valve feedback signals, said monitor and control means comparing the valve feedback signals from each electrohydraulic servovalve to a respective reference signal corresponding to the expected valve feedback signal resulting from said flight control signal and, in the event that a valve feedback signal does not correspond to a respective reference signal, enabling the first or second secondary controller that is connected to the electrohydraulic servovalve that is generating the valve feedback signal that does not correspond to its respective reference signal. - View Dependent Claims (16, 17)
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18. In an aircraft having at least one flight control surface and a flight control computer generating flight control signals from manual control inputs, an improved flight control system comprising:
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a tandem hydraulic actuator having an actuating rod connected to a pair of pistons mounted in respect to first and second cylinders, said actuating rod being connected to said flight control surface; first and second electrohydraulic servovalves controlling the flow of hydraulic fluid into and out of said first and second hydraulic cylinders, respectively, each of said electrohydraulic servovalves being controlled by a pair of actuating coils, said electrohydraulic servovalves each having a pair of valve operation sensors generating respective valve feedback signals indicative of the operation of said valves; four actuator rod position sensors generating respective actuator rod position signals indicative of the position of said actuating rods; first primary controller means generating a first control signal as a function of said flight control signal and a respective actuator rod position from an actuating rod position sensor, said first primary controller means being connected to one actuator coil of said first electrohydraulic servovalve; second primary controller means generating a second control signal as a function of said flight control signal and a respective actuator rod position signal from an actuating rod position sensor, said second primary controller means being connected to one actuating coil of said second electrohydraulic servovalve; secondary controller means selectively generating third and fourth control signals with respect to first and second control channels as a function of said flight control signal and respective actuator rod position signals from two actuator rod position sensors, said first and second control channels being connected to one actuating coil of said first and second electrohydraulic servovalves, respectively; and monitor and control means receiving said valve feedback signals, said monitor and control means comparing the valve feedback signal from each electrohydraulic servovalve to a respective reference signal corresponding to the expected valve feedback signal resulting from said flight control signal and, in the event that a valve feedback signal does not correspond to a respective reference signal, enabling the first or second control channel of said secondary controller that is connected to the electrohydraulic servovalve generating the valve feedback signal that does not correspond to its respective reference signal. - View Dependent Claims (19, 20, 21)
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Specification