Vehicle control system

• US 20080249689A1
• Filed: 04/02/2008
• Published: 10/09/2008
• Est. Priority Date: 04/03/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Sawada, Mamoru, Matsumoto, Toshiki
• Granted Patent: US 7,970,516 B2
• Time in Patent Office: Days
• US Class Current: 701/48
• CPC Class Codes: B60C 99/006 Computer aided tyre design or simulation
• CPC Class Codes: B60T 2260/08 Coordination of integrated systems
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/173 Eliminating or reducing the effect of unwanted signals, e.g. due to vibrations or electrical noise
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2050/0036 Multiple-track, 3D multi-body vehicle model, e.g. combination of models for vehicle sub-units
• CPC Class Codes: B60W 30/025 related to comfort of drivers or passengers
• CPC Class Codes: B60W 30/04 related to roll-over prevention
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06

Abstract

A vehicle control system estimates the vibration states of tires by using a vehicle vibration model that is separated into a vehicle body vibration model, a chassis vibration model, and a tire vibration model with high precision. The tire vibration model in the vehicle vibration model is formed of a rear wheel tire vibration model, a front wheel tire vibration model, and a virtual coupling element vibration model that virtually couples the rear wheel tire vibration model and the front wheel tire vibration model. Influence of the vibration state that is conducted between the front wheel tires and the rear wheel tires is considered while the tire vibration model and the chassis vibration model are separated from each other, thereby making it possible to estimate the vibrations that occur in the front wheel tires and the rear wheel tires.

Claims

1. A vehicle control system comprising:

a control unit that stores a vehicle vibration model that is separated into a vehicle body vibration model, a chassis vibration model, and a tire vibration model to estimate vibration states at respective portions of a vehicle; and

an operation device controllable by the control unit and operative to change a motion state of the vehicle,

wherein the control unit receives an input parameter to be input to the vehicle vibration model, calculates estimate vibration states of the respective portions of the vehicle, and calculates control quantities according to the vibration states to control the operation device, and

wherein the tire vibration model in the vehicle vibration model includes vibration models of front wheel tires, rear wheel tires and a virtual coupling element that virtually couples the front wheel tires and the rear wheel tires with each other.

2. The vehicle control system according to claim 1, wherein:

the virtual coupling element includes a spring element and a damper element which are arranged in parallel.

3. The vehicle control system according to claim 1, wherein:

the tire vibration model is configured such that a first virtual coupling element couples a front right wheel tire and a rear left wheel tire, which are diagonally positioned in the vehicle, and a second virtual coupling element couples a front left wheel tire and a rear right wheel tire.

4. The vehicle control system according to claim 1, wherein:

the tire vibration model calculates the estimated vibration state of the front and rear wheel tires in a longitudinal direction of the vehicle; and

the control unit estimates and calculates the vibration state of the front wheel tires, the vibration state of the rear wheel tires, and the vibration state of the virtual coupling element, respectively, individually calculates the control quantities for suppressing the respective vibrations, and individually controls the operation device based on the control quantities that are calculated.

5. The vehicle control system according to claim 4, wherein:

the control unit calculates the control quantities so that the vibrations of the front wheel tires, the vibrations of the rear wheel tires, and the vibrations of the virtual coupling element approach zero, respectively, or calculates the control quantities so that vibrations are made, and calculates the total control quantity from the respectively calculated control quantities.

6. The vehicle control system according to claim 5, wherein:

the control unit calculates, in calculating the control quantities so that the vibrations of the front wheel tires, the vibrations of the rear wheel tires, and the vibrations of the virtual coupling element are conducted, the control quantities for conducting the vibrations, the control quantities for making the vibrations approach zero and then inverts signs of the control quantities.

7. The vehicle control system according to claim 1, wherein:

the operation device includes at least one of a braking force generating device that generates braking forces at the respective wheels, and an adjusting device that adjusts the operating state of an internal combustion engine of the vehicle, and an electric motor that operates as a drive source for rotationally driving the wheels.

8. The vehicle control system according to claim 7, wherein:

the control unit calculates a basic control quantity based on an accelerator pedal operation by a driver, calculates the control quantities for suppressing the vibrations that occur in the vehicle vibration model as correction control quantities, and controls the operation device based on the basic control quantities and the correction control quantities, so that the operation device adjusts the operating state of the internal combustion engine of the vehicle.

9. The vehicle control system according to claim 7, wherein:

the control unit calculates a basic control quantity based on accelerator pedal operation by a driver, calculates the control quantities for suppressing the vibrations that occur in the vehicle vibration model as correction control quantities, and controls the braking force generating device based on the basic control quantities and the correction control quantities, so that the operation device generates the braking forces in the respective wheels.