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GoogleGranted patentCars & transportInterest 6/10

Waymo patents self-driving car system that adjusts steering when wheels slip

This patent describes a method for autonomous vehicles to detect when a wheel is slipping by comparing its actual speed to the speed the computer expects it to be. If a wheel slips, the system adjusts the steering of other wheels to keep the car on its intended path and estimates how slippery the road is to guide future driving decisions.

Why it mattersThis helps self-driving cars maintain control and safety on wet or icy roads where tires might lose grip.

In the filing’s own words

The disclosure relates to assessing and responding to wheel slippage and estimating road friction for a road surface. For instance, a vehicle may be controlled in an autonomous driving mode in order to follow a trajectory. A wheel of the vehicle may be determined to be slipping such that the vehicle has limited steering control. In response to determining that the wheel is slipping, steering of one or more wheels may be controlled in order to orient the one or more wheels towards the trajectory in order to allow the vehicle to proceed towards the trajectory when the wheel is no longer slipping. In addition, the road friction may be estimated based on the determination that the wheel is slipping. The vehicle may be controlled in the autonomous driving mode based on the estimated road friction.

What exactly they claim (claim 1)

1. A method of controlling a vehicle operating in an autonomous driving mode in response to wheel slippage, the method comprising: receiving, by one or more processors of an autonomous driving computing system, a measured rotational wheel speed of each wheel of a plurality of wheels of the vehicle while operating in the autonomous driving mode; for each wheel of the plurality of wheels, determining, by the one or more processors of the autonomous driving computing system, an expected rotational wheel speed for that wheel, wherein the expected rotational wheel speed is determined based on actuation commands sent by the one or more processors to one or more systems of the vehicle; for each wheel of the plurality of wheels, comparing, by the one or more processors of the autonomous driving computing system, the measured rotational wheel speed for that wheel to the expected rotational wheel speed for that wheel to determine a difference between the measured rotational wheel speed for that wheel and the expected rotational wheel speed for that wheel; and when the difference for one or more wheels of the plurality of wheels meets a threshold, controlling, by the one or more processors of the autonomous driving system, the vehicle in the autonomous driving mode to change trajectory along a route to a destination.

Facts

Company
Google (Waymo LLC)
Official title
Road friction and wheel slippage assessment for autonomous vehicles
Patent number
US12728862B2
Application number
18200616
Filed
May 23, 2023
Granted
Sep 8, 2026
Inventors
3
Claims
20

Classified under

B60W 30/18172 Operations & transportB60W 10/20 Operations & transportB62D 6/003 Operations & transportG05D 1/0223 Physics & computingG05D 1/0276 Physics & computingB60W 2520/06 Operations & transport
Read the full filing (official PDF) ↗ Open in the Patent Tracker

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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.