Active suspension component degradation determination
AssigneeZoox, Inc.
InventorsJohannes Edren, James W. Fash, Ahditya Melkote, Sharath Kumar Thirupathyswamy
Life of this patent
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Abstract
This disclosure describes techniques for determining a state of a pressurized chamber of a suspension of a vehicle, wherein the pressurized chamber comprises a hydraulic fluid chamber and a gas chamber separated by a piston. The state is determined by varying a pressure in the hydraulic fluid chamber and determining a knee point in a change of pressure in the hydraulic fluid chamber. The knee point indicates that the separator has been bottomed out. The pressure in the knee point may be used to determine a state of the suspension system.
Claims20
A system comprising:
- a plurality of springs, wherein each spring couples a chassis of a vehicle to a respective wheel of the vehicle, and wherein each spring comprises a hydraulic fluid chamber and a gas chamber separated by a movable separator, wherein the plurality of springs includes:
- a first spring including a first hydraulic fluid chamber and a first gas chamber, and
- a second spring including a second hydraulic fluid chamber;
- the system further comprising:
- one or more processors;
- and
- one or more non-transitory computer-readable media storing instructions executable by the one or more processors, wherein the instructions, when executed, cause the system to perform operations comprising:
- gradually reducing the pressure in the first hydraulic fluid chamber while maintaining the pressure in the second hydraulic fluid chamber,
- receiving, over a period of time, sensor data indicating pressure in the first hydraulic fluid chamber,
- determining, based at least in part on the sensor data, a knee point in a change of pressure in the first hydraulic fluid chamber during the period of time, the knee point being indicative of a change from a predominantly compressible operating regime to a predominantly incompressible operating regime of the spring,
- determining, based at least in part on a pressure in the knee point and a predetermined volume of the first gas chamber, an amount of gas present in the first gas chamber,
- comparing the amount of gas with a predetermined value,
- determining, based at least in part on the comparison, a state of the first spring, and
- controlling the vehicle based at least in part on the state of the first spring.
A method comprising:
- receiving, over a period of time, sensor data indicating a pressure in a pressurized chamber of a suspension system of a vehicle, the pressurized chamber comprising a hydraulic fluid chamber and a gas chamber separated by a movable separator;
- varying the pressure in the hydraulic fluid chamber;
- determining, based at least in part on the sensor data, a knee point in a change of pressure in the hydraulic fluid chamber during the period of time, the knee point being indicative of a change between a predominantly compressible operating regime and a predominantly incompressible operating regime of the pressurized chamber;
- determining, based at least in part on a pressure in the knee point, a state of the suspension system;
- and
- performing, based at least in part on the state of the suspension system, an action associated with the vehicle.
One or more non-transitory computer-readable media storing instructions executable by one or more processors, wherein the instructions, when executed, cause the one or more processors to perform operations comprising:
- receiving, over a period of time, sensor data indicating a pressure in a pressurized chamber of a suspension system of a vehicle, the pressurized chamber comprising a hydraulic fluid chamber and a gas chamber separated by a movable separator;
- varying the pressure in the hydraulic fluid chamber;
- determining, based at least in part on the sensor data, a knee point in a change of pressure in the hydraulic fluid chamber during the period of time, the knee point being indicative of a change between a predominantly compressible operating regime and a predominantly incompressible operating regime of the pressurized chamber;
- determining, based at least in part on a pressure in the knee point, a state of the suspension system;
- and
- performing, based at least in part on the state of the suspension system, an action associated with the vehicle.
Dependencies are inferred from the claim text.