Controller for a dual servo system
First Claim
1. In a dual servo system for driving a controlled element with mechanically coupled first and second servos in response to a pair of control signals separately applied thereto, said servos cooperating with a sensing means for providing a signal signifying on operating parameter associated with at least one of said servos, a controller comprising:
- first digital processing means connected to said first and second servos for simultaneously driving them by providing to each a corresponding one of said control signals, said first digital processing means being operable to measure the responsiveness of said servos to said first digital processing means to provide a self-checking indication; and
second digital processing means connected to said first digital processing means for measuring the responsiveness of said servos to said first digital processing means to provide an independent indication of failure of said responsiveness, said independent indication being provided by at least one signal comparison, examining the signal of said sensing means but neither of said control signals.
1 Assignment
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Accused Products
Abstract
A controller (FIGS. 1, 2) is provided in a dual servo system that drives a controlled element (22) with mechanically coupled first and second servos (24 and 44). This controller has a first (10, 110, 112) and second (14, 108, 114) digital process subsystem. The first digital processing subsystem can simultaneously drive the first and second servos. This first processing subsystem is operable to measure the responsiveness of the servos to the first processing subsystem and provide a self-checking indication. The second digital processing subsystem measures the responsiveness of these servos to the first digital processing subsystem and can provide an independent indication of failure. The foregoing can be extended to multiple channels for controlling independent multiple elements such as aircraft control surfaces. Preferably, two different types of computers (10, 14; 108, 110, 112, 114) with different programs can be employed to control three control channels. Since the system can provide self-checking and independent checking of its operation, the likelihood of "multi-axis hardover" is reduced.
40 Citations
24 Claims
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1. In a dual servo system for driving a controlled element with mechanically coupled first and second servos in response to a pair of control signals separately applied thereto, said servos cooperating with a sensing means for providing a signal signifying on operating parameter associated with at least one of said servos, a controller comprising:
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first digital processing means connected to said first and second servos for simultaneously driving them by providing to each a corresponding one of said control signals, said first digital processing means being operable to measure the responsiveness of said servos to said first digital processing means to provide a self-checking indication; and second digital processing means connected to said first digital processing means for measuring the responsiveness of said servos to said first digital processing means to provide an independent indication of failure of said responsiveness, said independent indication being provided by at least one signal comparison, examining the signal of said sensing means but neither of said control signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. In a dual channel system having a first and second pair of cooperating servos for driving first and second independent controlled elements, respectively, said servos being operable in response to control signals applied thereto, at least one of said servos cooperating with a sensing means, said sensing means being operable to provide a signal signifying an operating parameter associated with said at least one of said servos, a controller, including apparatus for avoiding undetected multiple channel failures comprising:
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first digital processing means for simultaneously driving said first pair of servos and for simultaneously driving said second pair of servos, by providing to each of the servos a corresponding one of the control signals, said first and second controlled elements being driven independently; and second digital processing means connected to said first digital processing means and arranged to perform a sequence of programming steps differing from that of said first digital processing means to reduce the probability of their simultaneous failure, said second digital processing means being operable to monitor said first digital processing means to provide an independent indication of its failure, said independent indication being provided by a signal comparison examining the signal of said sensing means but none of said control signals. - View Dependent Claims (21, 22)
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23. A method for controlling mechanically coupled dual servos, comprising the steps of:
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simultaneously driving said servos with one digital device; monitoring said one digital device with another digital device having a different program; and comparing and equalizing the output torques of each servo with said one device but not the other. - View Dependent Claims (24)
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Specification