Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyota Jidosha Kabushiki Kaisha

Toyota Central Research and Development Laboratories, Inc.

Kabushiki Kaisha Toyoda Jidoshokki Seisakusho

Yasutaka Hayashi

Shunichi Doi

Hiroyuki Ikemoto

Yuzo Yamamoto

Kazuo Miki

Katsuhiko Fukui

Junzo Hasegawa

Eiichi Yasuda

Kazumasa Sumi

Nobutaka Oowa

Noboru Sugiura

Katsuhiko Hattori

Michio Ishiguro

Tsugiharu Matsunaga

Hiroyuki Yamaguchi

Yasuhiko Suzuki

Yasushi Amano

Takashi Katoh

Hideo Arakawa

Takahiko Tsunekawa

Akira Tanaka

Kazukata Takei

Satoru Matsushima

Masahiko Mizuno

Nobutaka Owa

Mutsuo Sawa

Apparatus for controlling the steerable wheels of a power-assisted steering unit of a vehicle in which an angle detector is connected to the power assist unit and to a power controller. An abnormality detector is arranged between the steering shaft of the steering wheel and an output shaft of the angle detector to detect an abnormal state based on relative displacement of the steering shaft and the output shaft of the angle detector to produce a signal which is sent to the power controller. The steering shaft is controlled by the power controller to avoid the abnormal state based on the signal from the abnormality detector, a control signal from an electronic control unit based on steering angle of the wheels and a signal from a sensor detecting steering angle of the steering wheel.

Vehicle rudder angle control apparatus

In a steering gear having a steering correction function for causing a vehicle to correct steering when disturbance acts on a power steering gear or the vehicle, there are provided a connecting portion for connecting the input shaft to output shaft and for detecting the abnormal state; and a releasable portion for a drive unit operation of the steering drive unit interlocked with a connecting operation of the connecting mechanism. In a normally 'OFF' (disengagement) state of the clutch, a steering drive control device controls a steering drive unit in accordance with a steering command from a steering control device, and a steering driving force is transmitted from the steering drive unit to the steering device through a transmissional mechanism for the steering driving force, thereby performing steering. However, in an abnormal state, the clutch mechanically detects the abnormal state and is engaged from the 'OFF' state to an 'ON' (engagement) state to connect the input device and the steering device. During this connection, a force acting from the steering drive unit to the steering device is released by a releasable mechanism for a drive unit operation, thereby performing manual steering.

Steering gear for a vehicle

A vibration control apparatus detects a physical value influencing characteristics of a suspension supporting a vibrating body and a state value representing movement of the suspension, calculates an optimal target control force in consideration of an external force or disturbance acting on the suspension on the basis of the physical and state values as outputs from a state detecting system, calculates the detection control force corresponding to the detected physical value, and continuously variably controls the suspension characteristics so as to generate a control force corresponding to the difference between the target and detection control forces in consideration of the external force or disturbance acting on the suspension, whereby vibrations are prevented by equivalently applying the target control force on the suspension.

Vibration control apparatus

In a vibration control apparatus, a physical value influencing characteristics of a suspension for supporting a vibrating body and a state value representing movement of the suspension are detected. A frequency distribution of these values with respect to levels is calculated every predetermined period of time. A target control force is calculated on the basis of the frequency distribution in consideration of a continuous change in external state. An actual control force (detection control force) is calculated by the detected physical value. The suspension characteristics are continuously, variably controlled so as to equivalently generate a control force corresponding to a difference between the target and detection control forces. As a result, the target control force is equivalently applied to the suspension, thereby damping the vibrations. The vibration control apparatus can generate an optimal target control force free from the influence of an external state change on the basis of the frequency distribution of the state and physical values of the suspension.

An apparatus for controlling steering of wheels of a vehicle comprises a control means, a driving means, and an actuator means. The control means comprises a feed forward signal operating means, a feed back signal operating means for generating signals for variables representing vehicle behaviors and output from a vehicle behavior sensor, and a control signal operating means for calculating a difference or sum of the signals output from the feed forwad and feedback signal operating means. The feed forward signal operating means comprises a steering angle signal circuit, a steering angular velocity signal operating circuit, a steering angle signal operating circuit having a first coefficient circuit for multiplying a steering angle signal with a coefficient, and an adder for adding the outputs from the steering angle signal circuit, the steering angle signal operating circuit, and the steering angular velocity operating circuit. A behavior correction capacity against a side wind or disturbance is very high, and a steering system can be controlled to shorten the response time for changes in vehicle behaviors with respect to a steering input, thereby providing optimal steering. The control means further comprises a gain changing means to supply optimal coefficients to the feed forward and feedback signal operating means.

Apparatus for controlling steering of wheels of a vehicle

In this system for vehicle roll control, one actuator assembly is provided corresponding to each vehicle wheel and resiliently suspends it from the vehicle body. Each of these actuator assemblies is adapted to increase or decrease the vehicle height at its vehicle wheel as a result of a control signal being supplied. Control means are provided corresponding to the actuator assemblies and serve to supply control signals to them. A vehicle speed detecting means senses road speed, a steering angle detecting means senses steering angle, a means senses the rate of change of steering angle, and a means detects the actual roll angle .phi..sub.t of the vehicle body. A computing and control means computes a steady state roll angle .phi..sub..infin. of the vehicle body from the vehicle speed and the steering angle, advances the phase of a signal representative of the steady state roll angle .phi..sub..infin. to thereby compute a compensating value .PHI..sub..infin. of roll angle, computes an amendment value .phi..sub.x of roll angle in accordance with the rate of change of steering angle, computes the difference .phi. based upon the desired roll angle .phi..sub.a of the vehicle body, the compensating value .PHI..sub..infin., the amendment value .phi..sub.x, and the actual roll angle .phi..sub.t following the equation: .phi.=.phi.a- (k.sub.1 .PHI..sub..infin. +k.sub.2 .PHI.t+k.sub.3 .PHI.x), where k1, k2 and k3 are positive constants; and controls the actuator assemblies, via the control means, in accordance with the difference .phi., when the absolute value of the difference .phi. is larger than a predetermined value.

System for vehicle body roll control detecting and compensating for

In this roll control system, suspension means are provided for resiliently suspending the vehicle wheels with variable hardness/softness characteristics, each suspension means including an actuator with a pressure chamber which increases or decreases wheel suspension height according to the supply or discharge of working fluid. Working fluid supply/discharge means are provided for the actuators, to supply and discharge working fluid to and from actuator pressure chambers. The road speed, the steering angle, and the actual body roll angle are detected. Means for computing and control computes a steady state vehicle body roll angle .phi..sub..infin. from the vehicle speed and steering angle, advances the phase of a signal indicative of .phi..sub..infin. to compute a compensating roll angle value .PHI..sub..infin., and then computes a difference value .phi. based upon a desired roll angle .phi..sub.a, .PHI..sub..infin., and the actual roll angle .phi..sub.t, according to the equation:

System for vehicle body roll control performing suspension hardness

An active suspension apparatus using hydropneumatic springs is disclosed to control damping characteristics in accordance with the vibration state of the passenger compartment of a vehicle during travel. An absolute acceleration of the floor of the passenger's compartment is detected and is compared with a reference value to discriminate the actual vibration state of the passenger compartment. The openings of restrictors arranged between hydropneumatic spring chambers and actuators are controlled in accordance with the discrimination result. In order to accurately detect the vibration state, specific vibration components are extracted by band-pass filters from the absolute acceleration signal.

Active suspension apparatus

In this system for vehicle roll control, a suspension device or an actuator is provided corresponding to each wheel of a vehicle, and resiliently suspends it from the vehicle body. Each such suspension device can alter its hardness or softness characteristics according to a control signal, while similarly the actuators are adapted to alter the suspended height of their wheels. A vehicle speed detecting device senses road speed, a steering angle detecting device senses steering angle, and a device detects the total vehicle body weight. A computing control device computes a predictive roll angle of the vehicle body from road speed and steering angle, and: if suspension devices are provided, controls them to be relatively hard when the absolute value of the predictive roll angle is larger than a threshold value, while controlling them to be relatively soft when the absolute value of the predictive roll angle is less than this threshold value; while, if actuators are provided, when the absolute value of the predictive roll angle is larger than a threshold value, it controls them in accordance with this predictive roll angle. Particularly, this computing device varies the threshold roll angle value according to the total vehicle body weight as detected by the weight detector, so as to decrease the threshold roll angle value along with increase of the total vehicle body weight.

A rear wheel steer angle controlling apparatus for vehicles having steerable front and rear wheels, adapted for controlling the steer angle of rear wheels in response to the operation of the steering wheel for steering the front wheels. When the steering wheel is operated quickly, a rear wheel steer angle is formed in the counter direction to the direction of the front wheel steer angle, so that the response to the steering input for turning the vehicle is improved. Conversely, when the steering wheel is operated slowly, a rear wheel steer angle is formed in the same direction as the front wheel steer angle, thus enhancing the stability of the vehicle running straight. When the vehicle is running at a high speed, the rear wheel steer angle is formed always in the same direction as the front wheel steer angle regardless of the speed of operation of the steering wheel, so that the steering stability during high speed running is improved. When a yawing moment is generated due to a disturbance such as lateral wind, the rear wheel steer angle is automatically controlled in such a manner as to negate the yawing moment, thus compensating for the lateral displacement of the vehicle without requiring correcting steering operation by the driver.

Apparatus for controlling steer angle of rear wheels of vehicle

An active suspension apparatus detects an absolute acceleration Z in a passenger's compartment of a vehicle and a relative displacement X between an axle and a body, calculates an absolute value .vertline.Z.vertline. of the absolute acceleration, an absolute value .vertline.X.vertline. of the relative displacement and an absolute value .vertline.X.vertline. of a rate X of change in relative displacement, multiplies the absolute values .vertline.X.vertline., .vertline.X.vertline., and .vertline.Z.vertline. with coefficients A11, A12 and A13, and adding the resultant product to obtain a sum Y=A11.vertline.X.vertline.+A12.vertline.X.vertline.+A13.vertline.Z.vertlin e., compares the sum Y with a reference value C for evaluating the predetermined movement of the vehicle, and controls the damping forces of the hydropneumatic springs, thereby improving steering stability and riding comfort.

Adjustable hydropneumatic active suspension apparatus

A rear wheel steer angle controlling apparatus for vehicles having steerable front and rear wheels, adapted for controlling the steer angle or rear wheels in response to the operation of the steering wheel for steering the front wheels. The speed with which the steering wheel is turned is detected and compared with a reference value which varies in accordance with changes in a physical amount related to the vehicle velocity. When the speed of operation of the steering wheel is larger than the reference value, a rear wheel steer angle is formed in the counter direction to the direction of the front wheel steer angle, so that the response to the steering input for turning the vehicle is improved. Conversely, when the speed of operation of the steering wheel is smaller than the reference value, a rear wheel steer angle is formed in the same direction as the front wheel steer angle, thus enhancing the stability of the vehicle running straight.

In this system for vehicle roll control, a plurality of actuator assemblies are provided, one corresponding to each one of the vehicle wheels and resiliently suspending it from the vehicle body. These actuator assemblies have pressure chambers, and each is adapted to increase or decrease the vehicle height at a location corresponding to its corresponding vehicle wheel as respective results of supplying or discharging of working fluid to or from its pressure chamber. A plurality of working fluid supplying and discharging valves are provided corresponding to the actuator assemblies and serve to supply working fluid to the working fluid chambers and to discharge working fluid from the working fluid chambers. A vehicle speed detector senses the road speed of the vehicle, and a steering angle detector senses the steering angle of the vehicle. A control computer computes a steady state roll angle .phi..sub..infin. of the vehicle body from the vehicle speed sensed by the vehicle speed detector and the steering angle sensed by the steering angle detector, and computes a difference value .phi. based thereon, the control computer being adapted to control the working fluid supplying and discharging valves according to the difference value .phi. when the absolute value of the difference value .phi. is larger than a determinate value.

System for vehicle body roll control utilizing steering angle detection

An apparatus for controlling steer angle of rear wheels of a 4-wheel steering vehicle in accordance with the operation of a steering wheel for generating steer angle of front wheels. The apparatus comprises a first member which moves in response to the operation of the steering wheel; a second member which moves in response to the operation of the steering wheel in a direction counter to that of the first member; an output shaft for controlling the steer of the rear wheels; a resilient member disposed between the first member and the output shaft and a controller disposed between the second member and the output shaft for controlling the direction of movement of the output shaft in accordance with the speed of operation of the steering wheel. When the steering wheel is operated at high speed, the resilient member absorbs the force from the first member so that the output shaft moves in the same direction as the second member, whereby the rear wheels are turned in a direction counter to that of the front wheels. When the steering wheel is operated at low speed, the force from the second member is damped so that the output shaft moves in the same direction as the first member, whereby the rear wheels are turned in the same direction as the front wheels.

Apparatus for controlling steering angle of rear wheels of a vehicle

An active suspension apparatus detects a relative displacement (x) between an axle and a vehicle body, discriminates a road surface state in accordance with the relative displacement and a change rate (x) in unit time which is derived from the relative displacement (x), and optimally controls characteristics of damping forces of hydropneumatic suspensions in accordance with a discrimination result (i.e., a road surface state). This discrimination is performed in accordance with a sum (Ax+Bx) of a signal obtained by multiplying the relative displacement (x) with a predetermined coefficient and a signal obtained by multiplying the change rate (x) with another predetermined coefficient. These coefficients are obtained in accordance with riding comfort against vibrations. The characteristics of the damping force of the hydropneumatic suspension are controlled by controlling the opening of throttle valves disposed between hydropneumatic chambers and actuators.

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Seto, Japan

Yasutaka Hayashi