Patent ID: 6202011
Filing Date: 2001-03-13
Classification: B60G

Abstract:
An electronic controlled suspension system (ECS) using wheel speed capable of determining the condition of the road surface comprising:a) a wheel speed sensor for measuring front and rear wheel speed;b) a throttle position sensor (TPS) for sensing an open status of the throttle valve;c) a stop lamp switch for sensing braking status;d) an inhibitor switch for sensing positions of an automatic transmission; ande) a rough road detecting algorithm wherein data obtained from each above recited element a) to d) are inputted to a control unit, and a rough road detecting device of the said control unit decides the condition of the road surface by performing Fourier Frequency Transforms (FFT) of the inputted data, multiplying the frequency gain, integrating and adding,wherein the said rough road detecting algorithm includes the following stages:1) a stage wherein the predetermined wheel speed sensor value is inputted and the front left wheel speed (V.sub.H) is determined whether larger than an established value or not;2) a stage wherein FFT is performed;3) a stage wherein the frequency gain is multiplied and the frequency component integration value is determined whether larger than a threshold value or not;4) a stage wherein if the said frequency component integration value is larger than the threshold value the damper becomes hard, and the front actuator feedback value is determined whether hard or not;5) a stage wherein if the said front actuator feedback value is hard no regulation is performed, and otherwise the damper actuator is actuated to make it equal to or larger than hard and maintained as hard for 3 seconds;6) a stage wherein if the said frequency component integration value is smaller than the threshold value the damper is determined whether hard or not, and if it is hard the frequency component integration value is determined whether larger than the threshold-low value;7) a stage wherein if the said frequency component integration value is larger than the threshold-low value the damper becomes hard, and otherwise the damper becomes soft;8) a stage wherein if the said damper is soft the front actuator feedback value is determined whether soft or not; and9) a stage wherein if the said front actuator feedback value is soft the damper actuator is actuated to make it equal to or larger than soft and maintained as soft for 3 seconds.