Multiple channel redundant control system

Claim 2

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.

Claim 3

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.

Claim 4

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.

Claim 5

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.

Claim 6

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.

Claim 7

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.

Claim 8

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.

Claim 9

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.

Claim 10

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.

Claim 11

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.

Claim 12

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.

Claim 13

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.

Claim 14

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.

Claim 15

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.

Claim 16

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

Claim 17

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.