Hydraulic active suspension system for a vehicle for controlling the attitude of vehicle body responding to lateral acceleration

• US 5,103,397 A
• Filed: 04/06/1990
• Issued: 04/07/1992
• Est. Priority Date: 04/14/1989
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ikemoto, Hiroyuki, Hamada, Toshiaki, Buma, Shuuichi, Yonekawa, Takashi, Onuma, Toshio, Watanabe, Tsukasa, Aburaya, Toshio
• Primary Examiner(s): Black, Thomas G.
• Application Number:
  US07/505,472
• Time in Patent Office: 732 Days
• Field of Search: 364/424.01, 364/424.05, 364/157, 364/161, 364/162, 280/707
• US Class Current: 701/38
• CPC Class Codes: B60G 17/016 characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input B60G17/017 takes precedence
• CPC Class Codes: B60G 17/0185 for failure detection
• 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 2400/30 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 2400/73 of other part than suspension unit
• 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 2600/20 Manual control or setting means
• CPC Class Codes: B60G 2800/012 Rolling condition
• 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: B60G 2800/80 Detection or control after a system or component failure

Abstract

In a hydraulic active suspension system, a plurality of actuators having working fluid chambers are provided corresponding to vehicle wheels. Each actuator is adapted to increase and decrease vehicle height in response to the pressure within its working chamber, which is controlled by a pressure control device. Vehicle speed and lateral acceleration are detected by corresponding sensors. A control device is further provided for controlling the pressure control device by compensating values determined base upon the lateral acceleration detected. The control device is adapted to reduce the compensating values in magnitude when the vehicle speed is lower than a predetermined value under which the lateral acceleration sensor sometimes detects a false lateral acceleration, thereby reducing the possibility that the vehicle body may generate an unpleasant roll due to the erroneous control on the pressures within the working fluid chambers based upon a false lateral acceleration.

Claims

1. A hydraulic active suspension system for a vehicle having a vehicle body and vehicle wheels comprising:

a plurality of actuators each being provided between said vehicle body and said associated vehicle wheel for increasing and decreasing vehicle height in response to the pressure within its working fluid chamber;

a means for controlling the pressures within said working fluid chambers;

a means for detecting vehicle speed;

a means for detecting a lateral acceleration of said vehicle body; and

a control means for controlling said pressure control means by a compensating value determined based upon the lateral acceleration detected by said lateral acceleration detecting means;

wherein said control means calculates said compensating value as the sum of a first component proportional to a parameter which increases in magnitude along with an increase of the lateral acceleration and a second component proportional to the differentiation by time of said parameter and reduces a proportioning coefficient in said second component when said vehicle speed is lower than a predetermined value.

2. A hydraulic active suspension system for a vehicle according to claim 1, wherein said coefficient is reduced in magnitude so that the lower the vehicle speed is, the smaller said coefficient may be.