Patent US4260580A successfully refreshed from Google Patents.
Patent US4741159A successfully refreshed from Google Patents.
US4741159A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power transmission
Assignee: Vickers Inc
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Filing: 1986-12-22
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Granted: 1988-05-03
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Expires: 2006-12-22
Abstract
Abstract An electrohydraulic servo system which includes a plurality of pressure compensated flow control servo valves for feeding hydraulic fluid from a variable displacement pump to associated actuators and loads. A closed-loop velocity-control servo system is coupled to each servo valve, and is responsive to velocity command inputs from an operator and to feedback signals from the respective loads for providing flow control signals to the respective servo valves. A pump controller receives the valve flow control signals, derives associated valve flow rates from predetermined functional characteristics of the pressure compensated valves, and obtains a total flow demand as a function of the sum of the indicated individual valve flow rates. A pump displacement command is derived as a combined function of total flow demand and pump speed to accommodate volumetric inefficiencies which vary with speed, and the displacement command signal is fed to a pump displacement servo control loop for controlling pump output. Displacement command is limited as a function of power available at the engine coupled to the pump to prevent engine stall.
Inventors
- 👤 Rajamouli Gunda
- 👤 Michael R. McCarty
- 👤 Melvin A. Rode
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:51
CPC Classifications
F; F15; F15B; F15B19/00; F15B19/002; G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/414; G05B2219/00; G05B2219/30; G05B2219/33; G05B2219/33337; G05B2219/41; G05B2219/41309
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
211 words
An electrohydraulic servo system which includes, in combination, a pressure compensated flow control servo valve for proportionally variably feeding hydraulic fluid to a load at a flow rate which is a predetermined proportional function of an electronic valve control signal, a variable output pump for coupling to a source of motive power to feed hydraulic fluid under pressure from a source to said servo valve, pump control means for controlling output of said pump, and an electronic servo control coupled to said valve and including means for receiving a first signal indicative of motion desired at the load, means for receiving a second signal indicative of actuation motion at the load and means for generating said valve control signal to said valve as a function of a difference between said first and second signals, said valve control signal being indicative of fluid flow velocity at said valve required to obtain said desired motion at the load, characterized in that said pump control means comprises: means for receiving said valve control signal, means for providing a signal indicative of fluid flow rate at said valve as said predetermined function of said valve control signal, and means for providing an output control signal to said pump as a function of said flow-indicative signal.
Claim 2
Dependent Claim
211 words
An electrohydraulic servo system which includes, in combination, a pressure compensated flow control servo valve for proportionally variably feeding hydraulic fluid to a load at a flow rate which is a predetermined proportional function of an electronic valve control signal, a variable output pump for coupling to a source of motive power to feed hydraulic fluid under pressure from a source to said servo valve, pump control means for controlling output of said pump, and an electronic servo control coupled to said valve and including means for receiving a first signal indicative of motion desired at the load, means for receiving a second signal indicative of actuation motion at the load and means for generating said valve control signal to said valve as a function of a difference between said first and second signals, said valve control signal being indicative of fluid flow velocity at said valve required to obtain said desired motion at the load, characterized in that said pump control means comprises: means for receiving said valve control signal, means for providing a signal indicative of fluid flow rate at said valve as said predetermined function of said valve control signal, and means for providing an output control signal to said pump as a function of said flow-indicative signal.
Claim 3
Dependent Claim
35 words
The system set forth in claim 1 wherein said means for providing said flow-indicative signal comprises first look-up table means relating flow rate to valve command signal at said predetermined function associated with said valve.
Claim 4
Dependent Claim
55 words
The system set forth in claim 1 further comprising means for sensing speed of motive input power to said pump and providing a corresponding speed signal, and wherein said pump control means comprises means for providing said output control signal to said pump as a combined function of said flow-indicative signal and said speed signal.
Claim 5
Dependent Claim
49 words
The system set forth in claim 1 wherein said source of motive power comprises an engine, and wherein said pump control means further comprises means responsive to throttle commands to said engine for limiting said output control signal to said pump to a level below overload on said engine.
Claim 6
Dependent Claim
104 words
The system set forth in claim 1 comprising a plurality of said pressure compensated flow control servo valves for variably feeding hydraulic fluid to a corresponding plurality of loads at flow rates which are predetermined functions of corresponding valve control signals, and wherein said pump control means comprises means for receiving all of said valve control signals, means for providing a plurality of signals indicative of fluid flow rates at said valves as corresponding said predetermined functions of said plurality of valve control signals, and means for controlling output of said pump as a function of a sum of said plurality of flow-indicative signals.
Claim 7
Dependent Claim
148 words
An electrohydraulic servo system which includes a pressure compensated flow control servo valve for variably feeding hydraulic fluid to a load at a flow rate which is a predetermined function of an electronic valve control signal, a variable output pump for coupling to a source of motive power to feed hydraulic fluid under pressure from a source to said servo valve, and pump control means for controlling output of said pump, characterized in that said pump control means comprises: means for receiving said valve control signal, means for providing a signal indicative of fluid flow rate at said valve as said predetermined function of said valve control signal, means for sensing speed of motive input power to said pump and providing a corresponding speed signal, and means for providing an output control signal to said pump as a combined function of said flow-indicative signal and said speed signal.
Claim 8
Dependent Claim
148 words
An electrohydraulic servo system which includes a pressure compensated flow control servo valve for variably feeding hydraulic fluid to a load at a flow rate which is a predetermined function of an electronic valve control signal, a variable output pump for coupling to a source of motive power to feed hydraulic fluid under pressure from a source to said servo valve, and pump control means for controlling output of said pump, characterized in that said pump control means comprises: means for receiving said valve control signal, means for providing a signal indicative of fluid flow rate at said valve as said predetermined function of said valve control signal, means for sensing speed of motive input power to said pump and providing a corresponding speed signal, and means for providing an output control signal to said pump as a combined function of said flow-indicative signal and said speed signal.
Claim 9
Dependent Claim
50 words
The system as set forth in claim 6 wherein said pump control means comprises for providing said output control signal as a function of the relationship b*Qc/N, where Qc is said flow-indicative signal, N is said speed signal, and b is a constant selected as a function of speed N.
Claim 10
Dependent Claim
35 words
The system set forth in claim 7 wherein said output control signal providing means comprises look-up table means relating said output control signal to said flow-indicative signal as differing predetermined functions of said speed signal.
Claim 11
Dependent Claim
148 words
An electrohydraulic servo system which includes a pressure compensated flow control servo valve for variably feeding hydraulic fluid to a load at a flow rate which is a predetermined function of an electronic valve control signal, a variable output pump for coupling to an engine to feed hydraulic fluid under pressure from a source to said servo valve, and pump control means for controlling output of said pump, characterized in that said pump control means comprises: means for receiving said valve control signal, means for providing a signal indicative of fluid flow rate at said valve as said predetermined function of said valve control signal, means for providing an output control signal to said pump as a function of said flow-indicative signal, and means responsive to throttle commands to said engine for limiting said output control signal to said pump to a level below overload on said engine.
Claim 12
Dependent Claim
148 words
An electrohydraulic servo system which includes a pressure compensated flow control servo valve for variably feeding hydraulic fluid to a load at a flow rate which is a predetermined function of an electronic valve control signal, a variable output pump for coupling to an engine to feed hydraulic fluid under pressure from a source to said servo valve, and pump control means for controlling output of said pump, characterized in that said pump control means comprises: means for receiving said valve control signal, means for providing a signal indicative of fluid flow rate at said valve as said predetermined function of said valve control signal, means for providing an output control signal to said pump as a function of said flow-indicative signal, and means responsive to throttle commands to said engine for limiting said output control signal to said pump to a level below overload on said engine.
Claim 13
Dependent Claim
78 words
The system set forth in claim 9 wherein said throttle command-responsive means comprises means responsive to the engine throttle for providing a signal indicative of desired engine speed set by said throttle, means for sensing speed of motive input power to said pump and providing a corresponding pump speed signal, means for comparing said desired-speed signal with said pump-speed signal, and means for limiting said output control signal where said pump-speed signal is less than said desired-speed signal.
Claim 14
Dependent Claim
153 words
An electrohydraulic servo system comprising a valve for variably feeding hydraulic fluid to a load at a flow rate which varies as a function of electronic valve control signals to said valve, an engine including a throttle for selectively setting desired speed at said engine, a variable output pump coupled to said engine for feeding fluid under pressure from a source to said valve, and pump control means for controlling output of said pump comprising means responsive to said engine throttle for providing a signal indicative of desired engine speed set by said throttle, means for sensing speed of said pump and providing a corresponding pump speed signal, means for comparing said desired-speed signal with said pump-speed signal, means responsive to said valve control signal for providing a pump output control signal to said pump, and means for limiting said output control signal where said pump-speed signal is less than said desired-speed signal.
Claim 15
Dependent Claim
153 words
An electrohydraulic servo system comprising a valve for variably feeding hydraulic fluid to a load at a flow rate which varies as a function of electronic valve control signals to said valve, an engine including a throttle for selectively setting desired speed at said engine, a variable output pump coupled to said engine for feeding fluid under pressure from a source to said valve, and pump control means for controlling output of said pump comprising means responsive to said engine throttle for providing a signal indicative of desired engine speed set by said throttle, means for sensing speed of said pump and providing a corresponding pump speed signal, means for comparing said desired-speed signal with said pump-speed signal, means responsive to said valve control signal for providing a pump output control signal to said pump, and means for limiting said output control signal where said pump-speed signal is less than said desired-speed signal.
Claim 16
Dependent Claim
31 words
The system set forth in claim 11 further comprising means for scaling each of said first signals as a function of a ratio between said first and second pump control signals.
Claim 17
Dependent Claim
224 words
An electrohydraulic servo system comprising a plurality of pressure compensated flow control valves for variably feeding hydraulic fluid to a corresponding plurality of loads at fluid flow rates which vary as individual predetermined functions of electrical control signals to said valves, an electronic serve control coupled to each of said valves and including means or receiving a first signal indicative of motion desired at the corresponding load, means for receiving a second signal indicative of actual motion at said corresponding load, and means for generating a valve control signal to said valve as a function of a difference between said first and second signals, each said valve control signal being indicative of fluid flow velocity at the corresponding said valve required to obtain said desired motion at the associated load, a pump for coupling to a source of motive power variably to feed hydraulic fluid under pressure from a fluid source to said plurality of valves, and pump control means comprising means for receiving said valve control signals from each said electronic servo control, means for providing a signal indicative of fluid flow rate at each said valve as said predetermined function of the corresponding said valve control signal, and means for controlling output fluid flow from said pump to said valves as a function of a sum of said fluid flow rate-indicative signals.
Claim 18
Dependent Claim
224 words
An electrohydraulic servo system comprising a plurality of pressure compensated flow control valves for variably feeding hydraulic fluid to a corresponding plurality of loads at fluid flow rates which vary as individual predetermined functions of electrical control signals to said valves, an electronic serve control coupled to each of said valves and including means or receiving a first signal indicative of motion desired at the corresponding load, means for receiving a second signal indicative of actual motion at said corresponding load, and means for generating a valve control signal to said valve as a function of a difference between said first and second signals, each said valve control signal being indicative of fluid flow velocity at the corresponding said valve required to obtain said desired motion at the associated load, a pump for coupling to a source of motive power variably to feed hydraulic fluid under pressure from a fluid source to said plurality of valves, and pump control means comprising means for receiving said valve control signals from each said electronic servo control, means for providing a signal indicative of fluid flow rate at each said valve as said predetermined function of the corresponding said valve control signal, and means for controlling output fluid flow from said pump to said valves as a function of a sum of said fluid flow rate-indicative signals.
Claim 19
Dependent Claim
59 words
The system set forth in claim 13 comprising means for sensing speed of motive input power to said pump and providing a corresponding speed signal, and wherein said output fluid-controlling means comprises means for providing a flow control signal to said pump as a combined function of said sum of said fluid flow rate-indicative signals and said speed signal.
Claim 20
Dependent Claim
57 words
The system set forth in claim 14 wherein said output fluid-controlling means comprises means for providing said fluid control signal as a function of the relationship b*Qc/N, where Qc is said sum of said fluid flow rate-indicative signals, N is said speed signal, and b is a constant which varies as a predetermined function of speed N.
Claim 21
Dependent Claim
33 words
The system set forth in claim 14 wherein said flow control signal-providing means comprises a look-up table relating said flow control signal to said sum as differing predetermined functions of said speed signal.
Claim 22
Dependent Claim
49 words
The system set forth in claim 14 wherein said source of motive power comprises an engine, and wherein said pump control means further comprises means responsive to throttle commands to said engine for limiting said output control signal to said pump to a level below overload on said engine.
Claim 23
Dependent Claim
78 words
The system set forth in claim 17 wherein said throttle command-responsive means comprises means responsive to the engine throttle for providing a signal indicative of desired engine speed set by said throttle, means for sensing speed of motive input power to said pump and providing a corresponding pump speed signal, means for comparing said desired-speed signal with said pump-speed signal, and means for limiting said output control signal where said pump-speed signal is less than said desired-speed signal.
Claim 24
Dependent Claim
83 words
The system set forth in claim 18 wherein said means for providing said flow control signal to said pump comprises means for providing a first pump control signal as a function of said rate-indicative signals; and wherein said output-limiting means comprises means for providing a second pump control signal as a function of a difference between said desired-speed signal and pump speed signal, and means for controlling said pump as a function of the lesser of said first and second pump control signals.
Claim 25
Dependent Claim
31 words
The system set forth in claim 19 further comprising means for scaling each of said first signals as a function of a ratio between said first and second pump control signals.
Claim 26
Dependent Claim
26 words
The system set forth in claim 19 wherein said output-limiting means further comprises means for selectively clamping rate of change of said second pump control signal.
Claim 27
Dependent Claim
83 words
The system set forth in claim 21 wherein said means for providing said flow control signal to said pump comprises means for providing a first pump control signal as a function of said rate-indicative signals; and wherein said output-limiting means comprises means for providing a second pump control signal as a function of a difference between said desired-speed signal and pump speed signal, and means for controlling said pump as a function of the lesser of said first and second pump control signals.
Claim 28
Dependent Claim
25 words
The system set forth in claim 22 wherein said output-limiting means further comprises means for selectively clamping rate of change of said pump control signal.
Claim 29
Dependent Claim
139 words
An electrohydraulic servo system which includes a plurality of pressure compensated flow control servo valves for variably feeding hydraulic fluid to a corresponding plurality of loads at flow rates which are predetermined functions of corresponding electronic valve control signals, a variable output pump for coupling to a source of motive power to feed hydraulic fluid under pressure from a source to said servo valves, and pump control means for controlling output of said pump, characterized in that said pump control means comprises: means for receiving all of said valve control signals, means for providing a plurality of signals indicative of fluid flow rates at said valves as corresponding said predetermined functions of said valve control signals, and means for providing an output control signal to said pump as a function of a sum of said plurality of flow-indicative signals.
Claim 30
Dependent Claim
139 words
An electrohydraulic servo system which includes a plurality of pressure compensated flow control servo valves for variably feeding hydraulic fluid to a corresponding plurality of loads at flow rates which are predetermined functions of corresponding electronic valve control signals, a variable output pump for coupling to a source of motive power to feed hydraulic fluid under pressure from a source to said servo valves, and pump control means for controlling output of said pump, characterized in that said pump control means comprises: means for receiving all of said valve control signals, means for providing a plurality of signals indicative of fluid flow rates at said valves as corresponding said predetermined functions of said valve control signals, and means for providing an output control signal to said pump as a function of a sum of said plurality of flow-indicative signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |