Active-suspension controlling system of vehicles

• US 4,967,361 A
• Filed: 09/06/1989
• Issued: 10/30/1990
• Est. Priority Date: 04/17/1987
• Status: Expired due to Fees

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Mine, Atsushi, Hiwatashi, Yutaka, Konno, Toshihiro, Oshita, Saiichiro, Kamimura, Katsuyoshi
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/404,049
• Time in Patent Office: 419 Days
• Field of Search: 364/424.05, 280/707, 280/708, 280/840, 280/DIG. 1, 318/615
• US Class Current: 701/37
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 2500/2014 Closed systems

Abstract

An active suspension of a motor vehicle is controlled by a system and a method which comprise combining a controller and an actual flow quantity estimation circuit for estimating by logic operation the flow quantity of the fluid actually flowing through each control valve of the suspension with respect to a total desired flow quantity, and calculating the difference between the actual flow quantity value thus estimated and the desired flow quantity, thereby correcting the desired flow quantity. A command signals is generated and transmitted in accordance with the desired flow quantity thus corrected for operating the control valve to undergo opening/closing operation.

Claims

1. A control system for controlling an active suspension system of a vehicle, said active suspension system having a fluid suspension system made up of a plurality of suspension units and containing a sealed-in fluid, sensors for detecting motions of the suspension units, a controller operating in response to sensor signals from said sensors to determine a desired flow quantity of the fluid to be charged into or discharged from the suspension units and to output command signals on the basis of said desired flow quantity, control valves operating in response to said command signals to undergo on-off operation thereby to cause the fluid to be charged into or discharged out from the suspension units, the improvement of said control system comprising:

a flow quantity estimation circuit for estimating the flow quantity of the fluid flowing through each control valve;

means for calculating a corrected desired flow quantity by adding the difference between said flow quantity thus estimated by the quantity estimation circuit and a preceding desired flow quantity to said desired flow quantity determined by said controller based on the sensor signals; and

means in response to the corrected desired flow quantity to generate and transmit said command signals for operating each control valve to undergo said on-off operation.

2. The system according to claim 1, wherein

said control valves are pressure control valves.

3. A method of controlling an active suspension system of a vehicle, said active suspension system having a fluid suspension system made up of a plurality of suspension units and containing a sealed-in fluid, sensors for detecting motions of the suspension units, and a controller operating in response to sensor signals from said sensors to determine a desired flow quantity of the fluid to be charged into or discharged from the suspension units and to output command signals on the basis of said desired flow quantity, and control valves operating in response to said command signals to undergo on-off operation thereby to cause the fluid to be charged into or discharged out from the suspension units, the improvement of the method comprising:

estimating the flow quantity of the fluid flowing through each control valve by a flow quantity estimation circuit,

calculating a corrected desired flow quantity by adding the difference between said flow quantity thus estimated by the flow quantity estimation circuit and preceding desired flow quantity to said desired flow quantity determined by said controller based on the sensor signals and

generating and transmitting in accordance with the corrected desired flow quantity said command signals for operating said control valves to undergo said on-off operation thereof.

4. In a control system for controlling an active suspension system of a vehicle having a plurality of suspension units each including a fluid chamber and an on-off type flow control valve mounted on each suspension unit, respectively, to control a fluid quantity in said fluid chamber, respectively, sensing means for detecting actuating conditions of a suspension unit of the suspension units and for producing a suspension signal, and means responsive to the suspension signal for calculating a desired fluid quantity to supply to said suspension unit and for producing a desired fluid quantity signal depending on the actuating conditions of the suspension unit, the improvement in the system which comprises

adding means for correcting said desired fluid quantity signal to produce a corrected desired fluid quantity signal,

filter means for filtering said corrected desired fluid quantity signal by multiplying the latter with a predetermined coefficient representing a maximum flow quantity passing through said on-off type flow control valve, and for producing a filtered desired fluid quantity signal,

valve control means responsive to said filtered desired fluid quantity signal for calculating a duty ratio representing on and off conditions of the on-off type flow control valve and for producing on and off signals to control the supplying of the fluid quantity to the suspension unit,

flow estimating means for estimating the fluid quantity passing through said control valve and producing a corresponding estimated fluid quantity signal, and

said adding means calculating said corrected desired fluid quantity signal by adding to said desired fluid quantity signal a preceding corrected desired fluid quantity signal minus said estimated fluid quantity signal, so as to correct said fluid quantity supplied to said suspension unit.

5. The system according to claim 4, wherein said on-off type flow control valve comprises

a charging-side valve responsive to said on and off signals for charging the corrected fluid quantity, and a discharging-side valve responsive to said on and off signals for discharging said corrected fluid quantity.

6. The system according to claim 4, wherein

said flow estimating means estimates the fluid quantity actually passing through said control valve based on said filtered desired fluid quantity signal and data of the flow control valve.