Roll control system in vehicle admissive of counter steering

• US 5,177,681 A
• Filed: 02/26/1991
• Issued: 01/05/1993
• Est. Priority Date: 04/27/1990
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha 1 Toyota-Cho Toyota-Shi Aichi-Ken Japan
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sato, Shinsuke
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US07/660,854
• Time in Patent Office: 679 Days
• Field of Search: 364/424.01, 364/424.05, 364/426.02, 280/707, 280/689, 280/840
• US Class Current: 701/38
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 2202/154 with an accumulator
• CPC Class Codes: B60G 2204/81 front and rear unit
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/106 longitudinal with regard to vehicle, e.g. braking
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/30 Propulsion unit conditions
• CPC Class Codes: B60G 2400/38 Speed of engine rotation
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2400/50 Pressure
• CPC Class Codes: B60G 2500/40 Steering
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/08 Failure or malfunction detecting means
• CPC Class Codes: B60G 2600/26 Electromagnets; Solenoids
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B60G 2800/704 predicting unorthodox driving conditions for safe or optimal driving
• CPC Class Codes: B62D 6/04 responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel
• CPC Class Codes: G05D 1/0891 : specially adapted for land vehicles

Abstract

In a roll control system in a vehicle adapted to suppress the rolling of the vehicle body along with an increase of the rate of change of the lateral acceleration of the vehicle body estimated from vehicle speed and steering angle velocity, a side sliding of the vehicle relative to the road surface is detected, and if the steering angle is opposite to the turning direction of the vehicle when a side sliding is detected, the roll suppressing operation of the roll control system is attenuated to avoid an augmentation of the rolling by the roll control.

Claims

1. A roll control system in a vehicle, comprising:

a means for detecting a side sliding of the vehicle relative to a road surface during steering of the vehicle, a means for detecting or estimating lateral acceleration of a vehicle body, a means for detecting vehicle speed, a means for determining steering angle velocity, a means for estimating rate of change of the lateral acceleration of the vehicle body from vehicle speed and steering angle velocity, a means for detecting direction of the steering angle velocity, a roll stiffness control means for controlling stiffness against rolling of the vehicle body at each of front and rear wheels, and a means for controlling said roll stiffness control means based upon the estimated rate of change of the lateral acceleration so as to increase the stiffness against rolling of the vehicle body along with an increase of the estimated rate of change of the lateral acceleration, wherein said means for controlling said roll stiffness control means is adapted to attenuate said increase of the stiffness against rolling of the vehicle body when the side sliding is detected and the directions of the lateral acceleration and the steering angle velocity are determined to be opposite to one another.

2. A roll control system according to claim 1, wherein said roll stiffness control means is an active suspension of the vehicle having fluid actuators each controlling a load to be supported at each one of vehicle wheels of the vehicle, said load at each vehicle wheel being determined in reference to relative vehicle heights between respective ones of the vehicle wheels and the lateral acceleration of the vehicle body, said attenuation of the increase of the stiffness against rolling of the vehicle body being effected by a modification of a factor in said reference to the lateral acceleration in the determination of the load supported by each said actuator.

3. A roll control system according to claim 2, wherein said factor is modified by reducing the importance of the lateral acceleration in said determination of the load supported by each said actuator.

4. A roll control system in a vehicle, comprising:

a means for detecting steering angle;

a means for detecting vehicle speed;

a means for calculating an estimated yaw rate based upon the steering angle and the vehicle speed;

a means for detecting an actual yaw rate;

a means for detecting a side sliding of the vehicle relative to a road surface during steering of the vehicle based upon the estimated yaw rate and the actual yaw rate;

a means for detecting or estimating lateral acceleration of a vehicle body;

a means for calculating a steering angle velocity;

a means for estimating rate of change of the lateral acceleration of the vehicle body from the vehicle speed and the steering angle velocity;

a roll stiffness control means for controlling stiffness against rolling of the vehicle body at each of front and rear wheels; and

a means for controlling said roll stiffness control means based upon the estimated rate of change of the lateral acceleration so as to increase the stiffness against rolling of the vehicle body along with increase of the estimated rate of change of the lateral acceleration,

wherein said means for controlling said roll stiffness control means is adapted to attenuate said increase of the stiffness against rolling of the vehicle body when the side sliding is detected and the directions of the lateral acceleration and the steering angle velocity are determined to be opposite to one another.