Hydraulic actuator with a frequency dependent relative pressure ratio
AssigneeClearMotion, Inc.
InventorsJoseph Thomas Belter, Graham A. Dowie, Marco Giovanardi, Brian Alexander Selden
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Abstract
Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.
Claims13
A hydraulic actuator comprising:
- a hydraulic cylinder that includes a first chamber and a second chamber;
- a hydraulic pump, with a first port and a second port, capable of generating a pressure differential between the first chamber and the second chamber;
- a first gas charged accumulator;
- a second gas charged accumulator;
- a first fluid flow path fluidically connecting the first port to the first chamber;
- a second fluid flow path fluidically connecting the first gas charged accumulator to the first fluid flow path;
- a third fluid flow path fluidically connecting the second port to the second chamber;
- a fourth fluid flow path fluidically connecting the second gas charged accumulator to the third fluid flow path;
- and
- a hydraulic restriction arranged along the second flow path, wherein the hydraulic restriction is configured and positioned to modify a compliance of the first flow path relative to the third flow path, as a function of a frequency of an oscillating input.
A method of operating a hydraulic actuator with a dynamically variable motion ratio, operationally interposed between a vehicle body and a wheel assembly of a vehicle, wherein the actuator includes a piston, attached to a piston rod, slidably received in a hydraulic cylinder and dividing the hydraulic cylinder into a first chamber and a second chamber, and wherein the hydraulic actuator is exposed to an oscillating input at a frequency above and below a threshold frequency, the method comprising:
- with a hydraulic restriction, modifying a compliance of a first chamber side flow path relative to a second chamber side flow path, wherein the first chamber side flow path allows fluid exchange between the first chamber and a first port of a hydraulic pump, wherein the second chamber side flow path allows fluid exchange between the second chamber and a second port of the hydraulic pump;
- and
- inducing a change in the motion ratio of the actuator as a function of the frequency of the oscillating input relative to a threshold frequency, wherein the threshold frequency is a wheel hop frequency of a wheel associated with the wheel assembly.
Dependencies are inferred from the claim text.