System and method of estimating vehicle speed

Patent metadata

Field	Value
Publication number	US-2024116518-A1
Application number	US-202318376786-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 is 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 longitudinal acceleration from an inertial measurement unit of the vehicle, remove gravity-induced acceleration term from the longitudinal acceleration, 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 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.

3 . The system of claim 1 , wherein the second subsystem is further configured to calculate a gravity-induced acceleration term.

4 . The system of claim 3 , wherein the second subsystem is further configured to estimate a road grade by comparing the estimated vehicle acceleration with an actual vehicle acceleration computed based on the estimated speed of the vehicle.

5 . The system of claim 4 , wherein the second subsystem is further configured to estimate the road grade in response to receiving an activate road grade estimator signal from the fourth subsystem.

6 . The system of claim 5 , wherein the second subsystem is further configured to use a previous estimate of the road grade as the estimated road grade if no activate road grade estimator signal is received.

7 . The system of claim 1 , wherein the fourth subsystem is further configured to evaluate the compensated speed of each wheel and determine if the compensated speed should be used in calculating the speed of the vehicle.

8 . The system of claim 7 , wherein the compensated wheel speed of a wheel is used in calculating the speed of the vehicle if the compensated wheel speed is within a range; and wherein the predicted current speed of the vehicle replaces the compensated wheel speed in calculating the speed of the vehicle if the compensated wheel speed of a wheel is outside of the range.

9 . The system of claim 7 , wherein the fourth subsystem is further configured to determine whether to send an activate road grade estimator signal to the second subsystem.

10 . A method of estimating a speed of a vehicle comprising a plurality of wheels, the method comprising:
obtaining a steering angle, dimensions of the vehicle, wheel speeds and tire radii of the plurality of wheels; determining compensated wheel speeds of the plurality of wheels based on the steering angle, dimensions of the vehicle, and the wheel speeds and tire radii of the plurality of wheels; receiving longitudinal acceleration from an inertial measurement unit of the vehicle; outputting an estimated vehicle acceleration based on the longitudinal 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 current speed of the vehicle.

11 . The method of claim 10 , further comprising removing gravity-induced acceleration term from the longitudinal acceleration prior to outputting the estimated vehicle acceleration;

12 . The method of claim 10 , wherein determining the compensated wheel speeds of the plurality of wheels comprising 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.

13 . The method of claim 10 , further comprising calculating a gravity-induced acceleration term.

14 . The method of claim 13 , further comprising estimating a road grade by comparing the estimated vehicle acceleration with an actual vehicle acceleration computed based on the estimated speed of the vehicle.

15 . The method of claim 14 , wherein estimating the road grade is in response to receiving an activate road grade estimator signal.

16 . The method of claim 15 , further comprising using a previous estimate of the road grade as the estimated road grade if no activate road grade estimator signal is received.

17 . The method of claim 10 , further comprising evaluating the compensated speed of each wheel and determining if the compensated speed should be used in calculating the speed of the vehicle.

18 . The method of claim 17 , wherein the compensated wheel speed of a wheel is used in calculating the speed of the vehicle if the compensated wheel speed is within a range; and wherein the predicted current speed of the vehicle replaces the compensated wheel speed in calculating the speed of the vehicle if the compensated wheel speed of a wheel is outside of the range.

19 . The method of claim 17 , further comprising determining whether to send an activate road grade estimator signal.

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:
obtaining a steering angle, dimensions of the vehicle, wheel speeds and tire radii of the plurality of wheels; determining compensated wheel speeds of the plurality of wheels based on the steering angle, dimensions of the vehicle, and the wheel speeds and tire radii of the plurality of wheels; receiving longitudinal acceleration from an inertial measurement unit of the vehicle; outputting an estimated vehicle acceleration based on the longitudinal 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 current speed of the vehicle.

Assignees

• Faraday&Future Inc

Inventors

• Ziaieinejad Saleh
• Niu Geng

Classifications

• B60W2520/105

  Longitudinal acceleration · CPC title

• B60W2520/06

  Direction of travel · CPC title

• B60W2530/201

  Dimensions of vehicle · CPC title

• B60W2530/20

  Tyre data · CPC title

• B60W2520/28

  Wheel speed · CPC title