# US 5,711,023 A · System for determining side slip angle

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- Number: US 5,711,023 A
- Document ID: US5711023A
- Status: Granted
- Kind: A
- Application number: 08/477,583
- Filed: 1995-06-07
- Granted: 1998-01-20
- Earliest claimed: 1994-11-25
- Assignees: ITT Automotive Europe GmbH
- Inventors: Alfred Eckert; Benno Lammen
- Web page: https://patentgrep.com/patent/US5711023A

## CPC

- B60T 8/17551: {determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters}
- 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)
- B60W 10/184: with wheel brakes
- B60W 30/02: Control of vehicle driving stability
- B60W 40/064: Degree of grip
- B60G 2400/1042: using at least two sensors
- B60T 2210/12: Friction
- B60T 2230/02: Side slip angle, attitude angle, floating angle, drift angle
- B60T 2270/313: with less than three sensors (yaw rate, steering angle, lateral acceleration)
- B60W 2422/95: Measuring the same parameter at multiple locations of the vehicle
- B60W 2520/125: Lateral acceleration
- B60W 2520/14: Yaw
- B60W 2520/20: Sideslip angle
- B60W 2720/14: Yaw
- B60W 2720/30: Wheel torque
- B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00})

## 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 .beta. is the velocity of the side slip angle, a.sub.trans is the lateral acceleration, .nu. is the reference velocity, .gamma. is the yaw rate, .nu. is the time derivative of the reference velocity, and .beta. 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

### Claim 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 .beta. is the velocity of the side slip angle, a.sub.trans is the lateral acceleration, .nu. is the reference velocity, .PSI. is the yaw rate, .nu. is the time derivative of the reference velocity, and .beta. is the side slip angle; and
means for determining the side slip angle by integrating the velocity of the side slip angle.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

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.

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 1)

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.

### Claim 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.

### Claim 7 (depends on 6)

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.

### Claim 8 (depends on 7)

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 .beta. is the estimated velocity of the side slip angle, a.sub.trans is the lateral acceleration, .nu. is the reference velocity, .PSI. is the yaw rate, .nu. is the time derivative of the reference velocity, and .beta. is the estimated side slip angle value.

### Claim 9 (depends on 8)

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.

### Claim 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 .nu. equals zero under certain circumstances, and
means for determining the side slip angle by the integration of the velocity of the side slip angle.

### Claim 11 (depends on 10)

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.

### Claim 12 (depends on 11)

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.

### Claim 13 (depends on 12)

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.sub.G to be applied to the vehicle.