System and method of estimating vehicle speed

Patent metadata

Field	Value
Publication number	US-2024118305-A1
Application number	US-202318376792-A
Country	US
Kind code	A1
Filing date	Oct 4, 2023
Priority date	Oct 4, 2022
Publication date	Apr 11, 2024
Grant date	—

Abstract

A method to estimate the longitudinal vehicle speed is disclosed. The method can be digitally implemented to process speeds of all wheels and longitudinal acceleration of the vehicle to estimate the vehicle speed.

First claim

What is claimed is:

1 . A system for estimating a speed of a vehicle comprising a plurality of wheels, the system comprising:
a first subsystem configured to receive a steering angle, dimensions of the vehicle, wheel speeds and tire radii of the plurality of wheels and determine compensated wheel speeds of the plurality of wheels; a second subsystem configured to receive moment of inertia of the plurality of wheels, estimated torque of one or more motors of the vehicle, a weight of the vehicle, the wheel speeds and tire radii of the plurality of wheels, and output an estimated vehicle acceleration; a third subsystem in communication with the second subsystem and configured to receive the estimated vehicle acceleration from the second subsystem, the third subsystem further configured to predict a current speed of the vehicle based on the estimated vehicle acceleration and a previous vehicle speed; and a fourth subsystem in communication with the first subsystem, the second subsystem, and the third subsystem, the fourth subsystem configured to estimate the speed of the vehicle based on either the compensated wheel speeds or the predicted vehicle speed.

2 . The system of claim 1 , wherein the first subsystem is configured to determine compensated wheel speeds of the plurality of wheels by multiplying a rotating speed of each of the plurality of wheels by the tire radius of the wheel to calculate a linear speed of each wheel and determine the compensated wheel speeds based on the linear speeds of the plurality of wheels, an average angle of two of the plurality of wheels, a width of the vehicle, and a wheelbase of the vehicle.

3 . The system of claim 1 , wherein the second subsystem is further configured to calculate a total driving force produced by the one or more motors, remove from the total driving force a total wheel acceleration force, a total road load, and a gravity-induced force to output the estimated vehicle acceleration.

4 . The system of claim 1 , wherein the second subsystem comprises:
a first module configured to calculate a total torque and force used to increase a rotating speed of the plurality of wheels; a second module configured to calculate the total driving force produced by the one or more motors; a third module configured to calculate a total road load; a fourth module configured to receive the estimated vehicle acceleration from the second subsystem, compare it with an actual vehicle acceleration computed based on estimated vehicle speed, and estimate a road grade based on a difference between the estimated vehicle acceleration and the actual vehicle acceleration.

5 . The system of claim 4 , wherein the total road load comprises a tire load and a drag load.

6 . The system of claim 4 , wherein the first module is configured to calculate the total torque and force based on the wheel speeds, moments of inertia, and radii of the wheels.

7 . The system of claim 4 , wherein the fourth module is configured to estimate the road grade in response to receiving a signal from the fourth subsystem.

8 . The system of claim 7 , wherein the fourth module is configured to use the latest estimate of the road grade as the road grade in the absence of the signal from the fourth subsystem.

9 . The system of claim 1 , wherein the third subsystem is configured to use an average acceleration since last step as estimated by the second subsystem and a vehicle speed in the last step to predict a current vehicle speed.

10 . The system of claim 1 , wherein the fourth subsystem is configured to evaluate a speed of each wheel and determine if the speed of each wheel should be included in a calculation of the vehicle speed.

11 . The system of claim 10 , wherein the fourth subsystem is configured to override a range check of wheel speeds and consider all wheel speed readings as valid if friction brakes are detected to be engaged.

12 . The system of claim 11 , wherein the friction brakes are detected to be engaged either by a driver's press of the brake pedal or by an electronic stability program.

13 . The system of claim 10 , wherein the fourth subsystem includes in the calculation of vehicle speed an achieved friction brake torque reported if the achieved friction brake torque is accurate.

14 . A method of estimating a speed of a vehicle comprising a plurality of wheels, the method comprising:
receiving a steering angle, dimensions of the vehicle, wheel speeds and tire radii of the plurality of wheels and determining compensated wheel speeds of the plurality of wheels; receiving moment of inertia of the plurality of wheels, estimated torque of one or more motors of the vehicle, a weight of the vehicle, the wheel speeds and tire radii of the plurality of wheels, and outputting an estimated vehicle acceleration; predicting a current speed of the vehicle based on the estimated vehicle acceleration and a previous vehicle speed; and estimating the speed of the vehicle based on either the compensated wheel speeds or the predicted vehicle speed.

15 . The method of claim 14 , further comprising:
determining compensated wheel speeds of the plurality of wheels by multiplying a rotating speed of each of the plurality of wheels by the tire radius of the wheel to calculate a linear speed of each wheel; and determining the compensated wheel speeds based on the linear speeds of the plurality of wheels, an average angle of two of the plurality of wheels, a width of the vehicle, and a wheelbase of the vehicle.

16 . The method of claim 14 , further comprising calculating a total driving force produced by the one or more motors; and
removing from the total driving force a total wheel acceleration force, a total road load, and a gravity-induced force to output the estimated vehicle acceleration.

17 . The method of claim 14 , further comprising:
calculating a total torque and force used to increase a rotating speed of the plurality of wheels; calculating the total driving force produced by the one or more motors; calculating a total road load; comparing the estimated vehicle acceleration with an actual vehicle acceleration computed based on estimated vehicle speed; and estimating a road grade based on a difference between the estimated vehicle acceleration and the actual vehicle acceleration.

18 . The method of claim 14 , further comprising calculating the total torque and force based on the wheel speeds, moments of inertia, and radii of the wheels.

19 . The method of claim 14 , further comprising evaluating a speed of each wheel and determining if the speed of each wheel should be included in a calculation of the vehicle speed; and
overriding a range check of wheel speeds and considering all wheel speed readings as valid if friction brakes are detected to be engaged.

20 . A non-transitory computer-readable storage medium storing instructions for causing a processor to perform a method of estimating a speed of a vehicle comprising a plurality of wheels, the method comprising:
receiving a steering angle, dimensions of the vehicle, wheel speeds and tire radii of the plurality of wheels and determining compensated wheel speeds of the plurality of wheels; receiving moment of inertia of the plurality of wheels, estimated torque of one or more motors of the vehicle, a weight of the vehicle, the wheel speeds and tire radii of the plurality of wheels, and outputting an estimated vehicle acceleration; predicting a current speed of the vehicle based on the estimated vehicle acceleration and a

Assignees

• Faraday&Future Inc

Inventors

• Ziaieinejad Saleh
• Niu Geng

Classifications

• B60W2510/1005

  Transmission ratio engaged · CPC title

• B60W2530/10

  Weight · CPC title

• B60W2530/201

  Dimensions of vehicle · CPC title

• B60W2520/06

  Direction of travel · CPC title

• B60W2530/20

  Tyre data · CPC title