Steering angle calibration
AssigneeMotional AD LLC
InventorsOmar Al Assad, Francesco Seccamonte
Life of this patent
Estimating the term…
Abstract
Among other things, techniques are described for steering angle calibration. An autonomous vehicle receives a steering angle measurement and a yaw rate measurement, and estimates a steering angle offset using the steering angle measurement, the yaw rate measurement, and a wheel base of the autonomous vehicle. An estimated yaw rate is determined based on a yaw rate model, the steering angle measurement and the estimated steering angle offset. The yaw rate measurement and the estimated yaw rate are compared and an action is initiated on the autonomous vehicle in response to the comparing.
Claims27
A method comprising:
- receiving, using a processing circuit of an autonomous vehicle (AV), a steering angle measurement;
- receiving, using the processing circuit, a yaw rate measurement, wherein the steering angle measurement and the yaw rate measurement are taken when a set of operating conditions is met, wherein the set of operating conditions includes a forward speed of the AV less than a threshold value and presence of one or more road surface conditions,
- estimating, using the processing circuit, a steering angle offset based on the steering angle measurement, the yaw rate measurement, and a wheel base of the AV;
- determining, using the processing circuit, an estimated yaw rate equal to
- V
- x
- L
-
- tan
-
- (
- δ
- m
- +
- δ
- ˆ
- o
- )
- where Vx is a forward speed of the AV, L is the wheel base of the AV, δm is the measured steering angle, and {circumflex over (δ)}o is the estimated steering angle offset;
- and
- operating, using a control circuit, the AV based on the estimated yaw rate.
A steering angle calibration system for an autonomous vehicle (AV), the system comprising:
- a steering angle sensor;
- a yaw rate sensor;
- one or more processing circuits;
- one or more non-transitory storage media storing instructions which, when executed by the one or more processing circuits, cause performance of operations comprising:
- receiving a steering angle measurement from the steering angle sensor;
- receiving a yaw rate measurement from the yaw rate sensor, wherein the steering angle measurement and the yaw rate measurement are taken when a wheel base angle of a wheel of the AV is less than a wheel base angle threshold value;
- estimating a steering angle offset based on the steering angle measurement, the yaw rate measurement and a wheel base of the AV;
- determining an estimated yaw rate, the estimated yaw rate equal to
- V
- x
- L
-
- tan
-
- (
- δ
- m
- +
- δ
- ˆ
- o
- )
- where Vx is a forward speed of the AV, L is the wheel base of the AV, δm is a measured steering angle based on the steering angle measurement, and {circumflex over (δ)}o is the estimated steering angle offset;
- comparing the yaw rate measurement and the estimated yaw rate;
- and
- initiating an action on the AV based on a result of the comparing.
A non-transitory, computer-readable storage medium having instructions stored thereon, that when executed by one or more processors of an autonomous vehicle (AV), cause the one or more processors to perform operations comprising:
- receiving a steering angle measurement;
- receiving a yaw rate measurement, wherein the steering angle measurement and the yaw rate measurement are taken when a wheel base angle of a wheel of the AV is less than a wheel base angle threshold value;
- estimating a steering angle offset based on the steering angle measurement, the yaw rate measurement, and a wheel base of the AV;
- determining an estimated yaw rate equal to
- V
- x
- L
-
- tan
-
- (
- δ
- m
- +
- δ
- ˆ
- o
- )
- where Vx is a forward speed of the AV, L is the wheel base of the AV, δm is a measured steering angle based on the steering angle measurement, and {circumflex over (δ)}o is the estimated steering angle offset;
- and
- operating the AV based on the estimated yaw rate.
Dependencies are inferred from the claim text.