Abstract: An apparatus and method for estimating a turning characteristic of a vehicle provided with a controller that performs the following steps are provided. That is, the controller estimates a value corresponding to a standard turning state based on vehicle running data of when the vehicle is turning, estimates a transfer function between the value corresponding to the turning state and a value corresponding to an actual turning state, estimates a turning characteristic of the vehicle based on the transfer function, determines whether the vehicle is in a critical turning state, and the prohibits the estimated turning characteristic from being used when it is determined that the vehicle is in the critical turning state.

Abstract: An apparatus and method for estimating a turning characteristic of a vehicle provided with a controller that performs the following steps are provided. That is, the controller estimates a value corresponding to a standard turning state based on vehicle running data of when the vehicle is turning, estimates a transfer function between the value corresponding to the turning state and a value corresponding to an actual turning state, estimates a turning characteristic of the vehicle based on the transfer function, determines whether the vehicle is in a critical turning state, and the prohibits the estimated turning characteristic from being used when it is determined that the vehicle is in the critical turning state.

Abstract: A damping force control device and method controls damping forces of dampers at locations of respective wheels. A first target damping force that inhibits vibrations of a vehicle body in the heave direction is calculated for each of the wheels, based on a single wheel model of the vehicle which employs the skyhook theory. A second target damping force that inhibits vibrations of the vehicle body in the pitch direction is calculated for each of the wheels, based on a model of front and rear wheels of the vehicle. A third target damping force that inhibits vibrations of the vehicle body in the roll direction is calculated for each of the wheels, based on a model of left and right wheels of the vehicle. One of the first through third target damping forces that has the greatest absolute value is selected for each of the wheels. The damping force exerted by the damper at the location of each wheel is set to the selected target damping force.

Abstract: A control system for a resilient support mechanism such as a suspension mechanism of a wheeled vehicle including a damper disposed between an unsprung mass member and a sprung mass member of the vehicle, wherein a damping coefficient of the damper is divided into a linear portion and a nonlinear portion, and wherein the nonlinear portion of the damping coefficient is defined as a control input u and applied with a frequency weight Wu(s), while a vertical velocity of the sprung mass member, a relative velocity of the sprung mass member to the unsprung mass member and a vertical acceleration of the sprung mass member are defined as an evaluation output zp and applied with a frequency weight Ws(s).

Abstract: A speed (Zw′−Zb′) and an amount (Zw−Zb) of displacement of a wheel relative to a vehicle body are estimated with the aid of an observer, based on a vertical acceleration Zb″ of the vehicle body detected by a sensor. In this observer, a non-linear component fnl(Zw′−Zb′, P) of a damping force of a damper is derived from an estimated relative speed y1ob and an opening position P of the damper, and the component fnl(Zw′−Zb′, P) is used as a control input.

Abstract: A damping force control device and method controls damping forces of dampers at locations of respective wheels. A first target damping force that inhibits vibrations of a vehicle body in the heave direction is calculated for each of the wheels, based on a single wheel model of the vehicle which employs the skyhook theory. A second target damping force that inhibits vibrations of the vehicle body in the pitch direction is calculated for each of the wheels, based on a model of front and rear wheels of the vehicle. A third target damping force that inhibits vibrations of the vehicle body in the roll direction is calculated for each of the wheels, based on a model of left and right wheels of the vehicle. One of the first through third target damping forces that has the greatest absolute value is selected for each of the wheels. The damping force exerted by the damper at the location of each wheel is set to the selected target damping force.

Abstract: A sprung mass estimating apparatus applied to a vehicle having a suspension device detects a sprung mass acceleration "a" and an amount of relative displacement "s" of a sprung member relative to an unsprung member by using an acceleration sensor and a stroke sensor, respectively. The apparatus calculates a relative velocity ds/dt based on the amount of relative displacement "s". The apparatus then derives a damping force F corresponding to the relative velocity ds/dt and a set switch level of the damping coefficient, with reference to a damping force characteristic table. Based on a data row a(k), a data row s(k) and a data row F(k) (where k=1, 2, . . . , N) indicating sprung mass accelerations "a", amounts of relative displacement "s", and damping forces F obtained over such a sufficiently long time that the ratio .beta. of the spring constant to the sprung mass M can be considered constant, the apparatus calculates a sprung mass M.

Abstract: Acceleration detecting sensor (60) is provided in a sprung structure (50), while a vibration model comprising the sprung mass of a vehicle, the spring, and the shock absorber is previously stored in control unit (58). The deviation of the detected acceleration from the estimated vertical acceleration of the sprung structure is computed by a control unit (58) and then amplified. The vertical acceleration of the sprung structure and the relative velocity between sprung and unsprung structures are estimated by a control unit (58) according to the amplified deviation and the vibration model. The stored vibration model has one degree of freedom and a simple structure.

Abstract: A suspension system of an automotive vehicle including a spring disposed between an unsprung mass and a sprung mass for resiliently supporting thereon the sprung mass and a damping force generating mechanism arranged in parallel with the spring for absorbing vibration of the sprung mass relative to the unsprung mass, wherein the suspension system is provided with a spring element disposed in series with the damping force generating mechanism between the unsprung and sprung masses and an electrically operated control mechanism for controlling a spring coefficient of the spring element.