Method and apparatus for determining lateral velocity of a vehicle

• US 6,477,480 B1
• Filed: 11/15/2000
• Issued: 11/05/2002
• Est. Priority Date: 11/15/2000
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Tseng, Hongtei Eric, Hrovat, Davorin David
• Primary Examiner(s): Hilten, John S.
• Assistant Examiner(s): SUN, XIUQIN
• Application Number:
  US09/713,712
• Time in Patent Office: 720 Days
• Field of Search: 701/1, 701/70, 701/72, 701/41, 701/36, 180/140, 180/141, 180/412, 303/146, 303/139, 364/426.01
• US Class Current: 702/142
• CPC Class Codes: B60T 2210/22 Banked curves
• CPC Class Codes: B60T 2250/04 Vehicle reference speed; Vehicle body speed
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 40/109 Lateral acceleration

Abstract

A method and apparatus for determining lateral velocity of a vehicle (10) uses a controller (16) having a lateral velocity estimator (18) therein. A vehicle speed determination circuit (20) is used to determine the vehicle speed which is coupled to the controller (16). A yaw rate sensor (26) is used to generate a yaw rate signal, a lateral acceleration signal (28) is used to generate a lateral acceleration signal, and a roll angle sensor (30) is used to generate a roll angle signal that are each coupled to controller (16). The controller (16) measures an unbiased lateral velocity derivative and determines a fictitious lateral velocity estimation using the unbiased lateral velocity derivative. Using the fictitious error to drive a model based adaptive observer, an accurate lateral velocity determination may he made in spite of model uncertainties and measurement noise.

Claims

1. A method of determining lateral velocity of a vehicle comprising the steps of:

determining an unbiased lateral velocity derivative;

creating a fictitious lateral velocity estimation error in response to the unbiased lateral velocity derivative; and

,

determining a lateral velocity by feeding the fictitious lateral velocity estimation error into an adaptive sliding mode observer.

2. A method as recited in claim 1 wherein prior to the step of feeding, filtering the fictitious lateral velocity estimation error.

3. A method as recited in claim 2 wherein the step of filtering comprises the step of high pass filtering the lateral velocity estimation error.

4. A method as recited in claim 1 wherein the step of creating a fictitious lateral velocity estimation error comprises the step of integrating the difference of the unbiased lateral velocity derivative and an estimated lateral velocity derivative.

5. A method as recited in claim 1 wherein the step of creating a fictitious lateral velocity estimation error comprises the step of integrating the difference of the unbiased lateral velocity derivative, an estimated lateral velocity derivative, and the product of a forgetting factor multiplied by a previous fictitious lateral velocity estimation error.

6. A method as recited in claim 1 wherein the step of creating a fictitious lateral velocity estimation error comprises the step of high-pass filtering the integration of the difference of the unbiased lateral velocity derivative and an estimated lateral velocity derivative.

7. A method as recited in claim 1 wherein the step of measuring an unbiased lateral velocity derivative comprises the steps of obtaining the unbiased lateral velocity derivative by the formula:

8. A method as recited in claim 7 wherein the roll angle is based on lateral acceleration and determined by the formula:

$\frac{<br><br>}{<br><br>t}<br><br>\left[\begin{array}{c}\mathrm{\phi <br><br>}\\ \mathrm{\phi <br><br>}\end{array}\right]=\left[\begin{array}{cc}0& 1\\ -k& -c\end{array}\right]<br><br>\left[\begin{array}{c}\mathrm{\phi <br><br>}\\ \mathrm{\phi <br><br>}\end{array}\right]+\left[\begin{array}{c}0\\ h\end{array}\right]·<br><br>a_y.$

9. A method as recited in claim 7 wherein the roll angle is estimated based on a lateral acceleration signal.

10. A method of determining lateral velocity of a vehicle comprising the steps of:

measuring an unbiased lateral velocity derivative;

determining a fictitious lateral velocity estimation by integrating an error of an estimated lateral velocity derivative and,

feeding the fictitious lateral velocity estimation error into an adaptive observer to obtain a lateral velocity of the vehicle.

11. A method as recited in claim 10 wherein the step of determining comprises determining a fictitious lateral velocity estimation by integrating an error of an estimated lateral velocity derivative with a forgetting factor to ensure the fictitious error tends-to zero at steady state.

12. A method as recited in claim 10 wherein the step of determining a lateral velocity using an observer is a function of vehicle speed, steering angle and yaw rate.

13. An apparatus for determining lateral velocity of an automotive vehicle comprising:

a vehicle speed sensor for generating a vehicle speed signal;

a roll angle sensor for generating a roll angle signal;

a yaw rate sensor for generating a yaw rate signal;

a lateral acceleration sensor for sensing lateral acceleration; and

,

a controller for determining an ‘

unbiased’

lateral velocity derivative as function of the lateral acceleration signal, the yaw rate signal, the vehicle speed signal, and the roll angle signal, and determining a fictitious lateral velocity estimation error as a function of the estimated lateral velocity derivative, the ‘

unbiased’

lateral velocity derivative, and a forgetting factor, and obtaining a lateral velocity of the vehicle therefrom.

14. An apparatus as recited in claim 13 wherein the step of obtaining lateral velocity is a function of vehicle speed, steering angle, and yaw rate.