Vehicle chassis system control method and apparatus

• US 5,895,433 A
• Filed: 05/23/1996
• Issued: 04/20/1999
• Est. Priority Date: 05/23/1996
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Chin, Yuen-Kwok, Chen, Hsien Heng, Bedner, Edward John, Leaphart, Eldon Gerrald
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US08/660,150
• Time in Patent Office: 1,062 Days
• Field of Search: 701/1, 701/41, 701/70, 701/72, 701/73, 701/79, 701/78, 701/90, 701/91, 701/93, 701/71, 701/69, 180/197, 180/414, 303/121, 303/146, 303/163, 303/169, 303/173
• US Class Current: 701/41
• CPC Class Codes: B60G 17/0185 for failure detection
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/208 of wheel rotation
• CPC Class Codes: B60G 2400/412 of steering wheel or column
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/04 Means for informing, instructing or displaying
• CPC Class Codes: B60G 2600/08 Failure or malfunction detecting means
• CPC Class Codes: B60G 2600/16 Integrating means, i.e. integral control
• CPC Class Codes: B60G 2600/70 Computer memory; Data storage, e.g. maps for adaptive control
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/21 Traction, slip, skid or slide control
• CPC Class Codes: B60G 2800/22 Braking, stopping
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: B60G 2800/244 Oversteer
• CPC Class Codes: B60G 2800/246 Understeer
• CPC Class Codes: B60G 2800/92 ABS - Brake Control
• CPC Class Codes: B60T 2260/06 Active Suspension System
• CPC Class Codes: B60T 2260/09 Complex systems; Conjoint control of two or more vehicle active control systems
• 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

Abstract

A vehicle chassis system control method, comprising the steps of: measuring vehicle yaw rate, vehicle speed, and vehicle lateral acceleration; determining, responsive to the yaw rate, vehicle speed and lateral acceleration, an index ratio; comparing the index ratio to a predetermined threshold indicating a limit above which active chassis control is not desired; and responsive to the comparison, setting a signal indicating termination of active chassis control if the index ratio is above the predetermined threshold.

Claims

1. A vehicle chassis system control method, comprising the steps of:

measuring vehicle yaw rate, vehicle speed, and vehicle lateral acceleration;

determining, responsive to the yaw rate, vehicle speed and lateral acceleration, an index ratio indicative of vehicle slip angle;

first comparing the index ratio to a first predetermined threshold indicating a limit above which an active chassis control is not desired;

responsive to the first comparison, setting a signal indicating termination of the active chassis control if the index ratio is above the first predetermined threshold; and

terminating the active chassis control responsive to the signal when the index ratio indicates that the vehicle slip angle is so high as to render the active chassis control ineffective.

2. A vehicle chassis system control method according to claim 1, wherein the index ratio represents a ratio of a product of yaw rate and vehicle speed to vehicle lateral acceleration.

3. A vehicle chassis system control method according to claim 1, also comprising the steps of:

measuring steering wheel angle;

determining a second index ratio responsive to the measured steering wheel angle, vehicle speed and yaw rate; and

second comparing the second index to a second predetermined threshold,

wherein the step of setting the signal is also responsive to the second comparing step.

4. A vehicle chassis system control method according to claim 3, also comprising the step of:

determining the second predetermined threshold as a function of speed.

5. A vehicle chassis system control method according to claim 4, wherein the second predetermined threshold is determined from a look-up table stored in computer memory.

6. A vehicle chassis system control method according to claim 3, also comprising the steps of:

integrating the second index ratio to determine an integration result; and

third comparing the integration result to a third predetermined threshold, wherein the step of setting the control signal is also responsive to the third comparison.

7. A vehicle chassis system control method according to claim 6, also comprising the step of fourth comparing an absolute value of the yaw rate to a fourth predetermined threshold, wherein the step of setting the control signal is also responsive to the fourth comparison.

8. A vehicle chassis system control method according to claim 1, also comprising the steps of:

initiating a timer when the signal indicating termination of active chassis control is set; and

resetting the signal indicating termination of active chassis control when the timer reaches a time-out value.

9. A vehicle chassis system control apparatus comprising:

a set of sensors for measuring and providing signals indicative of vehicle speed, yaw rate and lateral acceleration;

a controller, including a microprocessor, receiving the signals and determining a first index responsive thereto;

a memory for storing the first index;

a brake control on/off indicator maintained by the controller, wherein the brake control on/off indicator is switched to an off state when the first index is below a predetermined threshold; and

a timer, responsive to the brake control on/off indicator, wherein the timer is initiated when the on/off indicator is switched to an off state and wherein the brake control on/off indicator is switched to an on state after the timer reaches a time-out value.

10. A vehicle chassis system control apparatus according to claim 9, wherein the first index represents a ratio of a product of yaw rate and vehicle speed to vehicle lateral acceleration.

11. A vehicle chassis system control apparatus comprising:

at least one actuator for imparting an active chassis control force on a vehicle;

a set of sensors for providing signals indicative of vehicle yaw rate, vehicle speed, and vehicle lateral acceleration;

a controller, including a microprocessor and coupled to the actuator, receiving the signals and determining responsive thereto an index ratio indicative of vehicle slip angle;

a memory for storing the index ratio; and

a brake control on/off indicator maintained by the controller and having an on state and an off state, wherein the brake control on/off indicator is switched to the off state when the index ratio is greater than a predetermined threshold indicating a limit above which the active chassis control force is ineffective, wherein the imparting of the active chassis control force on the vehicle by the actuator is terminated when the brake control on/off indicator is switched to the off state.