System for determining side slip angle

• US 5,711,023 A
• Filed: 06/07/1995
• Issued: 01/20/1998
• Est. Priority Date: 11/25/1994
• Status: Expired due to Term

• Current Assignee: ITT Automotive Europe GmbH (Xylem, Inc.)
• Original Assignee: ITT Automotive Europe GmbH (Xylem, Inc.)
• Inventors: Eckert, Alfred, Lammen, Benno
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/477,583
• Time in Patent Office: 958 Days
• Field of Search: 364/426.01, 364/426.02, 364/426.03, 364/426.027, 364/426.016, 303/139, 303/140, 303/146, 303/147, 303/148, 303/150, 303/155, 303/167, 303/186, 303/189, 180/197
• US Class Current: 701/70
• CPC Class Codes: B60G 2400/1042 using at least two sensors
• CPC Class Codes: B60T 2210/12 Friction
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 2270/313 with less than three sensors (yaw rate, steering angle, lateral acceleration)
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2422/95 Measuring the same parameter at multiple locations of the vehicle
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/20 Sideslip angle
• CPC Class Codes: B60W 2720/14 Yaw
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 40/064 Degree of grip

Abstract

A system for controlling the yaw rate of a vehicle is provided. The system includes a facility for measuring the yaw rate, the lateral acceleration and the reference velocity of the vehicle. The velocity of the side slip angle of the vehicle is determined according to the equation: ##EQU1## where β is the velocity of the side slip angle, a_trans is the lateral acceleration, ν is the reference velocity, γ is the yaw rate, ν is the time derivative of the reference velocity, and β is a side slip angle. The velocity of the side slip angle determining mechanism includes a mechanism for setting the value of the time derivative of the reference velocity to zero, and a mechanism for determining the side slip angle by integrating the velocity of the side slip angle.

Claims

1. In a vehicle which has a yaw rate, a lateral acceleration, and a reference velocity, a system for determining a side slip angle, comprising:

means for measuring the yaw rate, the lateral acceleration and the reference velocity;

means for determining a velocity of the side slip angle of the vehicle according to the equation;

##EQU33## wherein β

is the velocity of the side slip angle, a_trans is the lateral acceleration, ν

is the reference velocity, Ψ

is the yaw rate, ν

is the time derivative of the reference velocity, and β

is the side slip angle; and

means for determining the side slip angle by integrating the velocity of the side slip angle.

2. A system according to claim 1, wherein the velocity of the side slip angle is kinematically determined, and the vehicle has a steering angle, further comprising:

means for multiplying the kinematically determined velocity of the side slip angle by a factor k, to form a weighted kinematically determined velocity of the side slip angle, where k is an integer between 0 and 1;

observer vehicle model means for calculating an observer model velocity of the side slip angle based on the steering angle of the vehicle;

means for multiplying the observer model velocity of the side slip angle by a factor (1-k) to form a weighted observer model velocity of the side slip angle;

means for adding the weighted kinematically determined velocity of the side slip angle and the weighted observer model velocity of the side slip angle to form a sum; and

means for integrating the sum to form an estimated side slip angle.

3. A system according to claim 2, wherein the observer vehicle model means include means for applying a correction to the observer model velocity of the side slip angle based on the measured yaw rate.

4. A system according to claim 3, further comprising yaw moment control means responsive to the estimated velocity of the side slip angle for determining an additional yawing moment that is applied to the vehicle.

5. A system according to claim 1, wherein the means for determining the velocity of the side slip angle includes means for setting the value of the time derivative of the reference velocity to zero.

6. In a yaw moment control system for improving the driving behavior of an automotive vehicle tending to oversteering or understeering, the vehicle having means for determining a reference velocity value and a plurality of sensors for generating signals representing lateral acceleration of the vehicle, a steering angle of the vehicle and a measured yaw rate of the vehicle, apparatus for generating an estimated velocity of the side slip angle of the vehicle, comprising:

observer model means for generating a value representing an observer model velocity of the side slip angle and a yaw acceleration rate value based on the reference velocity value, the signal representing the steering angle, an estimated side slip angle value and a feedback signal;

means for forming the feedback signal based on the yaw acceleration rate value and the signal representing the measured yaw rate;

kinematic determination means for generating the estimated velocity of the side slip angle based on the reference velocity value, the estimated side slip angle value, and the signals representing the lateral acceleration and the measured yaw rate; and

means for forming the estimated side slip angle value based on the values of the observer model velocity of the side slip angle and the estimated velocity of the side slip angle.

7. A system according to claim 6, wherein the estimated side slip angle forming means include:

means for multiplying the estimated velocity of the side slip angle by a factor k, to form a weighted kinematically determined velocity of the side slip angle, where k is an integer between 0 and 1;

means for multiplying the observer model velocity of the side slip angle by a factor (1-k) to form a weighted observer model velocity of the side slip angle;

means for adding the weighted kinematically determined velocity of the side slip angle and the weighted observer model velocity of the side slip angle for form the estimated velocity of the side slip angle.

8. Apparatus according to claim 7, wherein the kinematic determination means determine the estimated velocity of the side slip angle of the vehicle according to the equation:

##EQU34## wherein β

is the estimated velocity of the side slip angle, a_trans is the lateral acceleration, ν

is the reference velocity, Ψ

is the yaw rate, ν

is the time derivative of the reference velocity, and β

is the estimated side slip angle value.

9. Apparatus according to claim 8, wherein the velocity of the side slip angle determining means include means for setting the value of the time derivative of the reference velocity to zero.

10. In a device for controlling the yawing moment of a vehicle having a sensor system for determining information on the yaw rate, the lateral acceleration and the velocity of the center of gravity of the vehicle, the improvement comprising:

means for determining the current velocity of the side slip angle of the vehicle kinematically by means of the equation ##EQU35## based on the information provided by the sensor system, wherein the factor ν

equals zero under certain circumstances, and

means for determining the side slip angle by the integration of the velocity of the side slip angle.

11. A device in accordance with claim 10, further comprising:

means for multiplying the kinematically determined velocity of the side slip angle by a factor k, 0<

k<

1;

means for multiplying, by a weighting factor (1-k), a value for the current velocity of the side slip angle, which was obtained at least partially via an observer vehicle model;

means for adding the values thus weighted; and

means for integrating the value of the velocity of the side slip angle thus obtained into an estimated value of the current side slip angle.

12. Device in accordance with claim 11, wherein the value of the velocity of the side slip angle is first corrected with respect to the measured yaw rate prior to the weighting.

13. Device in accordance with claim 12, wherein the determined value of the yaw rate is sent to a yaw moment control law unit, which uses this value as the basis for the calculation of an additional yawing moment M_G to be applied to the vehicle.