# US 2010/0168977 A1 · Vehicle motion control apparatus

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- Number: US 2010/0168977 A1
- Document ID: US20100168977A1
- Status: Published application
- Kind: A1
- Application number: 12/654,485
- Filed: 2009-12-22
- Published: 2010-07-01
- Earliest claimed: 2008-12-25
- Assignees: Fuji Jukogyo Kabushiki Kaisha
- Inventors: Koji Matsuno
- Web page: https://patentgrep.com/patent/US20100168977A1

## CPC

- B60W 30/00: Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W 50/0098: {Details of control systems ensuring comfort, safety or stability not otherwise provided for}
- B60W 2520/30: Wheel torque
- B60W 2720/125: Lateral acceleration
- B60W 2720/14: Yaw
- B60W 2720/30: Wheel torque
- 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

## Abstract

A front/rear driving/braking force control unit 30 calculates driving/braking forces of front and rear axles that minimize energy loss realizing a target steering characteristic as first front/rear driving/braking forces Fxfte, Fxrte and calculates driving/braking forces of the front and rear axles that realize the target steering characteristic and maximize the sum of maximum tire lateral forces of the front and rear axles as second front/rear driving/braking forces Fxftp, Fxrtp. Then, the front/rear driving/braking force control unit 30 sets a grip margin Mg based on the tire lateral force Fyf, Fyr of the front and rear shafts which is calculated based on lateral acceleration (d2y/dt2), and road information (road μ), calculates target driving/braking forces Fxft, Fxrt of the front and rear axles according to the grip margin Mg based on the first front/rear driving/braking forces Fxfte, Fxrte and the second front/rear driving/braking forces Fxftp, Fxrtp, and outputs the target driving/braking forces Fxft, Fxrt to a driving/braking force control unit 20.

## Claims

### Claim 1

A vehicle motion control apparatus comprising:
a maximum tire lateral force calculator configured to calculate maximum tire lateral forces of front and rear axles considering a nonlinearity with respect to front-rear load shift and influence of a friction circle according to driving/braking forces of the front and rear axles and road surface information;
a first front/rear driving/braking force calculator configured to calculate the driving/braking forces of the front and rear axles that minimize an energy loss realizing a target steering characteristic as first front/rear driving/braking forces based on the driving/braking forces of the front and rear axles and the maximum tire lateral forces of the front and rear axles;
a second front/rear driving/braking force calculator configured to calculate driving/braking forces of the front and rear axles that realize the target steering characteristic and maximize sum of the maximum tire lateral forces of the front and rear axles as second front/rear driving/braking forces based on the driving/braking forces of the front and rear axles and the maximum tire lateral forces of the front and rear axles;
a grip margin calculator configured to calculate a margin of grip of the front and rear wheels as a grip margin based on a travel condition of the vehicle; and
a target driving/braking force calculator configured to calculate target driving/braking forces of the front and rear axles based on the first front/rear driving/braking forces and the second front/rear driving/braking forces, according to the grip margin.

### Claim 2 (depends on 1)

The vehicle motion control apparatus according to claim 1, wherein
the first front/rear driving/braking force calculator is configured to calculate a square sum of the driving/braking forces of the front and rear axles and a steering characteristic with respect to the maximum tire lateral forces of the front and rear axles and calculate the first front/rear driving/braking forces by correcting the driving/braking forces of the front and rear axles based on the calculation result.

### Claim 3 (depends on 1)

The vehicle motion control apparatus according to claim 1, wherein
the second front/rear driving/braking force calculator is configured to calculate a sum of the maximum tire lateral forces of the front and rear axles and a steering characteristic with respect to the maximum tire lateral forces of the front and rear axles and calculate the second front/rear driving/braking forces by correcting the driving/braking forces of the front and rear axles based on the calculation result.

### Claim 4 (depends on 1)

The vehicle motion control apparatus according to claim 1, wherein
the grip margin calculator is configured to set the grip margin based on the tire lateral forces of the front and rear axles that are calculated based on road information and lateral acceleration.

### Claim 5 (depends on 1)

The vehicle motion control apparatus according to claim 1, wherein
the target driving/braking force calculator is configured to increase the ratio of the second front/rear driving/braking forces as the margin of grip of front and rear wheels reduces.

### Claim 6 (depends on 1)

The vehicle motion control apparatus according to claim 1, wherein
the target driving/braking force calculator is configured to increase the ratio of the first front/rear driving/braking forces as the margin of grip of front and rear wheels increases.

### Claim 7 (depends on 1)

The vehicle motion control apparatus according to claim 1, wherein
the target driving/braking force calculator is configured to set the target driving/braking forces of the front and rear axles smaller as the margin of grip of front and rear wheels increases.