The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 1988
Filed:
Dec. 22, 1986
Rajamouli Gunda, Rochester, MI (US);
Michael R McCarty, Troy, MI (US);
Melvin A Rode, West Bloomfield, MI (US);
Vickers, Incorporated, Troy, MI (US);
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.