Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2000-03-31
2001-10-02
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C188S266100, C701S036000, C701S070000, C280S843000, C280S791000, C280S791000
Reexamination Certificate
active
06298293
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 11-98915 filed on Apr. 6, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a kinetic state quantity estimating device and to a kinetic state quantity estimating method which are applied to a vehicle having a damper that generates a damping force corresponding to an orifice opening degree and designed to estimate a vertical kinetic state quantity of a sprung member relative to an unsprung member by means of an observer.
2. Description of Related Art
Relevant devices of this kind are disclosed, for example, in Japanese Patent Applications Laid-Open Nos. HEI 10-913 and HEI 9-309316. In these devices, a vertical acceleration of a sprung member is detected as a vertical kinetic state quantity thereof relative to absolute space. An observer estimates the relative speed of a sprung member by using the detected vertical acceleration as an input variable and a non-linear component of a damping force of a damper determined by an orifice opening degree as a control input. The estimated relative speed is indicative of a vertical kinetic state quantity of the sprung member relative to an unsprung member.
The aforementioned kinetic state quantity estimating devices according to the related art make it possible to precisely estimate a kinetic state quantity of the sprung member relative to the unsprung member at the time of heaving movements of the vehicle. However, a spring force of a stabilizer that influences movements of the sprung member and changes in road holding load resulting from roll and pitch movements of the sprung member are not taken into account in the devices of the related art. Therefore if the sprung member makes roll movements due to disturbance from a road surface, or if the sprung member makes roll movements when the vehicle turns, or if the sprung member makes pitch movements when the vehicle is accelerated or decelerated, the aforementioned relative kinetic state quantity cannot be estimated with high precision.
SUMMARY OF THE INVENTION
The present invention has been made with a view to solving the aforementioned problems. It is an object of the present invention to provide a vehicular kinetic state quantity estimating device and a vehicular kinetic state quantity estimating method which make it possible to precisely estimate a kinetic state quantity of a sprung member relative to an unsprung member even when the sprung member makes roll movements due to disturbance from a road surface, or the sprung member makes roll movements when the vehicle turns, or the sprung member makes pitch movements when the vehicle is accelerated or decelerated.
In order to address the above-stated problem, a kinetic state quantity estimating device according to a first aspect of the present invention comprises an absolute kinetic state quantity detector, an observer and a first compensator. The absolute kinetic state quantity detector detects a vertical kinetic state quantity of the sprung member relative to absolute space. The observer estimates the vertical kinetic state quantity of the sprung member relative to the unsprung member based upon the vertical kinetic state quantity detected by the absolute kinetic state quantity detector and a non-linear component of the damping force of the damper determined by the orifice opening degree as a control input The first compensator compensates for the control input of the observer based upon a spring force of a stabilizer. The spring force of the stabilizer is determined based upon an amount of displacement of the sprung member relative to the unsprung member. The determined spring force is used to compensate for the control input of the observer. Thus, the observer estimates the vertical kinetic state quantity of the sprung member relative to the unsprung member based on the compensated control input.
According to the first aspect of the present invention, even when the sprung member makes roll movements due to disturbance from a road surface or the like and the spring force of the stabilizer affects the movements of the sprung member, the first compensator compensates for the control input of the observer based upon the spring force of the stabilizer. Therefore a kinetic state quantity of the sprung member relative to the unsprung member can be estimated with high precision.
The first compensator may confine the spring force of the stabilizer to within a predetermined range. In this construction, since the spring force of the stabilizer is inhibited from becoming unsuitably great owing to an error, the value estimated by the observer does not oscillate. Therefore a kinetic state quantity of the sprung member relative to the unsprung member is estimated with high stability.
Furthermore, the first aspect of the present invention may include a lateral acceleration detector that detects a lateral acceleration of the vehicle, and a second compensator. The second compensator determines a change in road holding load generated by roll movements of the sprung member based on the lateral acceleration detected by the lateral acceleration detector and compensates for the control input of the observer based upon the determined change in road holding load. In this construction, even when the sprung member makes roll movements at the time of the turning of the vehicle and the road holding load of the sprung member changes, the second compensator compensates for the control input of the observer based upon the change in road holding load resulting from the roll movements. Therefore a kinetic state quantity of the sprung member relative to the unsprung member can be estimated with high precision.
Furthermore, the first aspect of the present invention may also include a longitudinal acceleration detector that detects a longitudinal acceleration of the vehicle, and a third compensator. The third compensator determines a change in road holding load generated by pitch movements of the sprung member based on the longitudinal acceleration detected by the longitudinal acceleration detector and compensates for the control input of the observer based upon the determined change in road holding load. In this construction, even when the sprung member makes pitch movements at the time of acceleration or deceleration of the vehicle and the road holding load of the sprung member changes, the third compensator compensates for the control input of the observer based upon the change in road holding load resulting from the pitch movements. Therefore a kinetic state quantity of the sprung member relative to the unsprung member can be estimated with high precision.
A kinetic state quantity estimating method of the present invention detects a vertical kinetic state quantity of the sprung member relative to absolute space, inputs the vertical kinetic state quantity detected by the absolute kinetic state quantity detector into an observer that estimates the vertical kinetic state quantity of the sprung member relative to the unsprung member using the input detected vertical kinetic state quantity and a non-linear component of the damping force of the damper determined by the orifice opening degree as a control input. The method also uses an amount of displacement of the sprung member relative to the unsprung member to determine a spring force of a stabilizer, and compensates for the control input of the observer based upon the determined spring force. In this mode of implementation, even when the sprung member makes roll movements due to disturbance from a road surface or the like and the spring force of the stabilizer affects the movements of the sprung member, the control input of the observer is compensated for based upon the spring force of the stabilizer. Therefore a kinetic state quantity of the sprung member relative to the unsprung member can be estimated with high precision.
Furthermore, a change in road holding load generated by roll or pitch movement
Nguyen Tan
Oliff & Berridg,e PLC
To Tuan C
Toyoto Jidosha Kabushiki Kaisha
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