Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Naohiro Kishimoto

Hiroaki Yoshida

Tadao Tanaka

Takao Morita

Akihiko Togashi

Kiichi Yamada

Kazuya Hayafune

A determining method of this invention includes a step of continuously measuring the relative movement between the wheel and the vehicle body by use of a linear stroke sensor while a motor vehicle is running; a step of creating spectral distribution by subjecting the output of the linear stroke sensor to the frequency analysis; a step of calculating characteristic values inherent to various types of road surfaces; and a step of specifying the type of the road surface based on the calculated characteristic values. When the type of the road surface is specified, the control device of this invention changes the damping force of the suspension to a level corresponding to the type of the road surface.

Road surface condition determining method and suspension controlling

A suspension system includes air suspensions provided for individual wheels of a motor vehicle, each including a damping force switching actuator and an air supply/discharge actuator for the air spring. It further includes sensor for detecting the steering angle of a steering wheel, a sensor for detecting the vehicle velocity, and a control device for controlling the damping force and spring constant of each air suspension in accordance with the values detected by means of the sensors. This thereby reduces the roll of the vehicle body and modifies the steering characteristic of the motor vehicle. The control device includes a controller for detecting the gradient and flexure degree of a road. It further includes a controller for discriminating the road conditions by fuzzy inference in accordance with the gradient and flexure degree, and for determining the delay time or time interval between the start of the roll control for the rear portion of the vehicle body and the start of the roll control for the front portion of the vehicle body in accordance with the result of the discrimination.

System for controlling suspension in accordance with road conditions

A system is for controlling a suspension performance detecting the road surface condition in front of an automotive vehicle. A road surface sensor generates an output corresponding to the size of roughness on a road surface located at a predetermined distance in front of the vehicle. A suspension damping coefficient is changed to a smaller value upon lapse of a delay time. The delay time is calculated on the basis of the output of a speed sensor, the delay time being the time required for the wheel to reach the detected rough roads surface. The changing of the suspension damping coefficient occurs on condition that the output of the road surface sensor falls within a control region defined by a lower threshold value and an upper threshold value. Accordingly, the change of the suspension damping coefficient to a smaller value is inhibited when an extremely rough road surface is detected in front of the vehicle, whereby a bottoming out of the suspension which may occur is prevented when the vehicle runs over the extremely rough road surface. Further, the ride feeling is improved when the vehicle runs over a moderately rough road surface.

Suspension control system for automotive vehicle

A vehicular suspension control apparatus includes a selector valve for changing at least one of spring rigidity or damper rigidity of a suspension which is installed between a wheel and a body of a vehicle and extensibly and retractably supports the vehicle body on the wheel, a forward road surface sensor attached to the vehicle body and adapted to detect an irregularity of a road surface located in front of the vehicle body at a predetermined distance from the mounting position of the sensor when the vehicle body is in a predetermined attitude, a vehicle speed sensor for detecting a vehicle speed, and a controller for calculating a point of time when the wheel reaches the irregularity of the road surface, in accordance with the vehicle speed detected by the vehicle speed sensor, when the irregularity of the road surface is detected by the forward road surface sensor, and delivering a command signal for lowering at least one of the spring rigidity and the damper rigidity of the suspension to the selector valve by not later than the calculated time point.

Method and apparatus for controlling vehicle suspension such that

An active suspension apparatus is provided for a vehicle which includes an actuator being extensible and retractable and provided between a vehicle body and a wheel so that the force of the vehicle body to support the wheel is adjustable, a sprung G sensor or a vehicle height sensor for detecting a vibration input to the vehicle body, and a control valve and a controller for controlling the supporting force of the actuator in accordance with the vibration input detected by the sprung G sensor or the vehicle height sensor, and thereby restraining the stroke of the actuator. The suspension apparatus further comprises a forward road surface sensor for detecting the size of irregularities of a road surface in front of the vehicle, and the control valve and the controller are adapted to execute normal control such that the equivalent spring constant of the actuator is adjusted to a first spring constant when a surface irregularity of a size larger than a predetermined size is detected by the forward road surface sensor, and to execute inverse spring control such that the equivalent spring constant of the actuator is adjusted to a second spring constant lower than the first spring constant, and thereby lengthening the stroke of the wheel, when no surface irregularity of a size larger than the predetermined size is detected by the forward road surface sensor. As a result, the ride is greatly improved when the vehicle runs on a smooth road.

Growing community of inventors

Okazaki, Japan

Naohiro Kishimoto