Electro-hydrostatic actuator deceleration rate control system
AssigneeParker-Hannifin Corporation
InventorsRalf Gomm, Bjorn Eriksson
Life of this patent
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Abstract
Presented is a system and method to control hydraulic fluid flow, more specifically throttle hydraulic fluid flow, to achieve actuator deceleration rates greater than the maximum deceleration rate of an electrically driven pump. Electric machines and electric machine inverters generally have a maximum torque and current limit beyond which they cannot be operated at. To decelerate a large inertia load for example, high electric machine torque and inverter current are required to provide the braking torque, opposing the fluid flow and pressure generated by the load and hydraulic system.
Claims20
A hydraulic system comprising:
- a controller connected to an operator interface;
- a first load holding valve operatively connected to the controller;
- a pump operable in a first direction for supplying pressurized fluid through the first load holding valve, the pump operatively connected to the controller;
- wherein the controller is configured to receive a requested actuator deceleration, to compare the requested actuator deceleration with a predetermined threshold, and to control the first load holding valve to close, causing actuator deceleration equal to the requested actuator deceleration, if it is determined that the requested deceleration is above the predetermined threshold, and to control the pump to cause actuator deceleration equal to the requested actuator deceleration if it is determined that the requested deceleration is not above the predetermined threshold.
A method of controlling deceleration of an actuator in a hydraulic system, the method comprising the steps of:
- receiving a requested deceleration rate of an actuator;
- comparing the requested deceleration rate with a predetermined threshold;
- generating a control signal to close a first load holding valve, causing an actuator deceleration rate equal to the requested deceleration rate if the requested deceleration rate is greater than the predetermined threshold, and generating a control signal to operate an electrically driven pump, causing an actuator deceleration rate equal to the requested rate if the requested deceleration rate is not greater than the predetermined threshold.
Dependencies are inferred from the claim text.