# US 5,345,385 A · Method for detecting driving situation with respect to vehicle yaw behavior

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- Number: US 5,345,385 A
- Document ID: US5345385A
- Status: Granted
- Kind: A
- Application number: 07/907,109
- Filed: 1992-07-01
- Granted: 1994-09-06
- Earliest claimed: 1991-07-13
- Assignees: Mercedes-Benz AG
- Inventors: Adam Zomotor; Walter Klinkner; Erich Schindler; Frank-Werner Mohn; Thomas Wohland
- Web page: https://patentgrep.com/patent/US5345385A

## CPC

- B62D 6/00: Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00)
- 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)
- G05D 1/0891: {specially adapted for land vehicles}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- 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
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES

## Abstract

A method detects the driving situation with respect to the yaw behavior of the vehicle, in which a desired value of the vehicle yaw angle rate .mu..sub.des is derived in a computer unit from measured values (such as vehicle speed, steering wheel angle), and at least one sensor signal is supplied to the computer unit from which the actual value of the vehicle yaw angle rate .mu..sub.act is derived. The difference between the desired value of the yaw angle rate .mu..sub.des and the actual value of the yaw angle rate .mu..sub.act is formed in the computer unit. The actual value of the yaw angle rate .mu..sub.act is subtracted from the desired value of the yaw angle rate .mu..sub.des, and at least one output signal is generated in and emitted by the computer unit from this difference. The output signal represents the detected driving situation with respect to the yaw behavior of the vehicle. The magnitude of the time derivative of the difference is used to derive whether there is a tendency towards an increasingly critical driving situation.

## Claims

### Claim 1

A method for detecting an undesired yaw behavior of a vehicle, which behavior produces instability, comprising the steps of forming a desired value of the vehicle yaw angle rate .mu..sub.des in a computer unit from values measured by sensors on the vehicle, supplying to the computer unit at least one sensor signal to form an actual value of the vehicle yaw angle rate .mu..sub.act, determining in the computer unit any difference between the desired value of the yaw angle rate .mu..sub.des and the actual value of the yaw angle rate .mu..sub.act, by subtracting the actual value of the yaw angle rate .mu..sub.act from the desired value of the yaw angle rate .mu..sub.des, forming a time derivative of the difference in the computer unit, and generating at least one output signal in the computer unit, said at least one output signal representing the detected undesired yaw behavior of the vehicle and is used to permit intervention in a control system of the vehicle to one of increase understeering handling and to reduce oversteering handling, wherein a first part of said at least one output signal is generated in the computer unit as a function of the difference, said first part being representative of understeering or oversteering handling of the vehicle, and a second part of the output signal is generated in the computer unit as a function of the time derivative of the difference, said second part being representative of an instability increase or decrease in the handling of the vehicle.

### Claim 2 (depends on 1)

The method according to claim 1, wherein a variable MULT is determined in the computer unit by multiplying the difference by the mathematical sign of the yaw angle rate .mu..sub.act, and generating an output signal representative of said understeering handling of the vehicle when the variable MULT is less than zero and an output signal which represents said oversteering handling of the vehicle when the variable MULT is greater than zero.

### Claim 3 (depends on 2)

The method according to claim 2, wherein a variable DIFF is determined in the computer unit by multiplying the time derivative of the difference by the mathematical sign of the yaw angle rate .mu..sub.act and generating by the mathematical sign of the variable MULT, and an output signal representative of an increase in vehicle instability when the variable DIFF is greater than zero and an output signal representative of an instability decrease when the variable DIFF is less than zero.

### Claim 4 (depends on 2)

The method according to claim 2, wherein an output signal representative of the order of magnitude of the understeering or oversteering handling is generated in the computer unit as a function of the value of the variable MULT.

### Claim 5 (depends on 3)

The method according to claim 3, wherein an output signal representative of the order of magnitude of the instability increase or instability decrease is generated in the computer unit as a function of the value of the variable DIFF.

### Claim 6 (depends on 1)

The method according to claim 1, wherein a warning device, arranged to be monitored by a vehicle driver, is operable as a function of said at least one output signal.

### Claim 7 (depends on 6)

The method according to claim 6, wherein an output signal representative of a tendency towards an increasingly critical driving situation, is generated in the computer unit when the magnitude of the time derivative of the difference exceeds a threshold value.

### Claim 8 (depends on 6)

The method according to claim 6, wherein a variable MULT is determined in the computer unit by multiplying the difference by the mathematical sign of the yaw angle rate .mu..sub.act, and generating an output signal representative of said understeering handling of the vehicle when the variable MULT is less than zero and an output signal representative of said oversteering handling of the vehicle when the variable MULT is greater than zero.

### Claim 9 (depends on 8)

The method according to claim 8, wherein a variable DIFF is determined in the computer unit by multiplying the time derivative of the difference by the mathematical sign of the yaw angle rate .mu..sub.act and by the mathematical sign of the variable MULT, and generating an output signal representative of an instability increase when the variable DIFF is greater than zero and an output signal representative of an instability decrease when the variable DIFF is less than zero.

### Claim 10 (depends on 9)

The method according to claim 9, wherein an output signal representative of the order of magnitude of the instability increase or instability decrease is generated in the computer unit as a function of the value of the variable DIFF.

### Claim 11 (depends on 3)

The method according to claim 3, wherein an intervention into at least one of the steering and braking of individual wheels of the vehicle occurs as a function of said at least one output signal.

### Claim 12 (depends on 11)

The method according to claim 11, wherein an output signal representative of the order of magnitude of the instability increase or instability decrease is generated in the computer unit as a function of the value of the variable DIFF.