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US 4,625,622 AGranted
Power transmission
AssigneeVickers, Incorporated
InventorsRajamouli Gunda, Melvin A. Rode
Life of this patent
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AssigneeVickers, Incorporated
InventorsRajamouli Gunda, Melvin A. Rode
Estimating the term…
A system and method for pulse-width modulation of multiple solenoid-operated valves in an electrohydraulic servo system employing a microprocessor-based digital controller. Solenoid-energization pulse widths are identified by comparison of operator command input signals to feedback signals responsive to actual motion at the actuators and loads. During each modulation period, all solenoids are initially selectively simultaneously energized as a function of binary information stored in an energization control register, and the shortest energization pulse duration is identified. After a delay corresponding to such shortest duration, during which the microprocessor may perform other control functions, the solenoids associated with such shortest duration are selectively de-energized as a function of binary information stored in a de-energization control register. The next-shortest duration is then identified, and the process again delays for a time equal to the difference between such next-shortest duration and the previous duration. The process of identifying pulse durations of increasing length and correspondingly deenergizing the solenoids continues until all pulse durations have been accommodated or until the modulation period terminates, at which point the entire control process rebegins.
A fluid servo system comprising first and second solenoid valve actuators for variably actuating respective first and second loads, first and second sensing means respectively coupled to said actuators and loads to provide corresponding first and second sensor signals respectively indicative of actuation at said actuators and loads, means for receiving first and second input command signals, and digital control means for providing first and second pulse-width modulated signals to said first and second solenoid valve actuators as respective functions of differences between said first and second sensor signals and the corresponding said first and second command signals, said digital control means comprising
In an electrohydraulic servo system which includes a plurality of hydraulic actuators coupled to associated valves, said valves being operated by a plurality of electrical solenoid meeans, and means for directing pulse-width modulated control signals to each of said solenoid means for controlling operation of the associated said valves and actuators, a method of pulse-width modulating all of said solenoid means employing a single timer comprising the steps of:
Dependencies are inferred from the claim text.