Fluid-pressure and analogous brake systems – Speed-controlled – Specific mu determination
Reexamination Certificate
1999-09-29
2002-09-10
Schwartz, Christopher P. (Department: 3683)
Fluid-pressure and analogous brake systems
Speed-controlled
Specific mu determination
C303S194000, C303S177000
Reexamination Certificate
active
06447076
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a physical quantity estimation device for estimating a physical quantity relating to the ease of slippage between a wheel and the surface of a road, and particularly to a physical quantity estimation device capable of accurately estimating a physical quantity relating to the ease of slippage between a road surface and a wheel even when an unsprung resonance phenomenon is generated, and to an ABS control device for controlling braking pressure using this physical quantity estimation device.
2. Description of the Related Art
Japanese Patent Application Laid-Open (JP-A) No. 10-114263 (corresponding to U.S. Pat. No. 6,122,585) discloses an anti-lock braking system (ABS) control device for performing, on the basis of a wheel deceleration dynamic model, a calculation to estimate the torque gradient, i.e. the road surface &mgr; gradient (the change of the road surface &mgr; to the change of the slip) from the time series data of a wheel velocity signal, and for then controlling the manipulation variable of the braking force so that the road surface &mgr; gradient is 0.
When a vehicle travels from an icy road surface onto a dry road surface while the braking force is being controlled so as to be at the maximum amount by the above described ABS control device, then, as is shown in
FIG. 1A
, an oscillation phenomenon is generated in the wheel velocity. This wheel velocity oscillation phenomenon causes the accuracy of the &mgr; gradient estimation to be reduced. As is shown in
FIG. 1B
, in some cases, a delay in the adaptation of the ABS control is also generated.
The present inventors discovered that this phenomenon of oscillation in the wheel velocity is due to resonance movement between the tires and the suspension in the longitudinal direction of the vehicle.
SUMMARY OF THE INVENTION
The present invention is based on the above discovery and aims to provide a physical quantity estimating device capable of accurately estimating a physical quantity relating to the ease of slippage between a wheel and the surface of a road even when longitudinal resonance movement is generated between the tires and the suspension.
In order to achieve the above aim, the present invention comprises: wheel velocity detection means for detecting a wheel velocity and outputting a wheel velocity signal; and physical quantity estimation means for identifying a parameter of a physical model representing unsprung resonance characteristics from the wheel velocity signal, and estimating a physical quantity relating to ease of slippage between a road surface and a wheel from the identified parameter.
According to the present invention, the wheel velocity is detected by the wheel velocity detection means and a wheel velocity signal is output. The physical quantity estimation means identifies the parameter of a physical model representing the unsprung resonance from the wheel velocity signal and estimates a physical quantity relating to the ease of slippage between the road surface and the wheel from the identified parameter.
The physical model of the present invention can be a resonance model which has the unsprung resonance frequency as the undamped natural frequency. In this case, the physical quantity estimation means estimates a physical quantity relating to the ease of slippage between the road surface and the wheel on the basis of the damping ratio of the resonance model.
In the present invention, because a parameter of a physical model representing unsprung resonance characteristics is identified and a physical quantity relating to the ease of slippage between the road surface and a wheel is estimated from the identified parameter, the physical quantity can be accurately estimated even when an unsprung resonance phenomenon is generated.
The present invention is capable of being used in an ABS control device for controlling braking pressure on the basis of the estimated physical quantity.
REFERENCES:
patent: 4875171 (1989-10-01), Fujioka et al.
patent: 4912967 (1990-04-01), Shiraishi et al.
patent: 5085288 (1992-02-01), Shiraishi et al.
patent: 5435635 (1995-07-01), Watanabe
patent: 5583772 (1996-12-01), Kitano et al.
patent: 5588721 (1996-12-01), Asano et al.
patent: 5634699 (1997-06-01), Ichikawa et al.
patent: 5662393 (1997-09-01), Kamiya et al.
patent: 5809445 (1998-09-01), Yamamoto et al.
patent: 5878365 (1999-03-01), Onogi et al.
patent: 5948961 (1999-09-01), Asano et al.
patent: 6182001 (2001-01-01), Sugai et al.
patent: C2 38 12 600 (1988-11-01), None
patent: A2-0 645 288 (1995-03-01), None
patent: 0 699 568 (1996-03-01), None
patent: 0 747 691 (1996-12-01), None
patent: 747691 (1996-12-01), None
patent: 0 825 080 (1998-02-01), None
patent: 825080 (1998-02-01), None
patent: 699568 (1998-03-01), None
patent: 0 891 904 (1999-01-01), None
patent: 08119086 (1996-05-01), None
patent: A-8-183439 (1996-07-01), None
patent: 9-188238 (1997-07-01), None
patent: 10002813 (1998-01-01), None
patent: A-10-114263 (1998-05-01), None
patent: WO 89/01888 (1989-03-01), None
Asano Katsuhiro
Ito Shoji
Ono Eiichi
Onozawa Satoru
Sugai Masaru
Oliff & Berridg,e PLC
Schwartz Christopher P.
Siconolfi Robert A.
Toyota Jidosha & Kabushiki Kaisha
LandOfFree
Device and method for estimating physical quantity and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device and method for estimating physical quantity and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and method for estimating physical quantity and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2847457