Jtekt Corporation

University Public Corporation Osaka

Tatsuma Kouchi

Shingo Maeda

Kosuke Yamanaka

Naoki Maeda

Atsushi Ishihara

Masanori Arima

Daisuke Maeda

Yuji Kariatsumari

Takeshi Ueda

Ken Matsubara

Yasuyuki Yoshii

Yuichi Miura

Tomoyuki Takei

Osamu Ishikawa

Hiroki Tanaka

Kunio Ohara

Yasuyuki Yoshi

A thermoacoustic device includes a loop tube in which a working gas is sealed; a stack in which a temperature gradient is generated in a tube axis direction of the loop tube, the stack being provided in the loop tube; and a diaphragm structure including a diaphragm provided in the loop tube and an operation unit, the diaphragm having a surface extending in a direction intersecting the tube axis direction and being configured to vibrate with a component of vibration in the tube axis direction, and the operation unit being configured to apply a physical quantity that is required, to the diaphragm to change a rigidity of the diaphragm in the tube axis direction.

Thermoacoustic device with diaphragm structure

In an electric power steering system, a low-pass filter executes a low-pass filtering process on a detected steering torque value detected by a torque sensor. A steering torque deviation computing unit computes a deviation &#x394;T between a detected steering torque value T* obtained through the low-pass filtering process and the detected steering torque value detected by the torque sensor. A PI control unit generates a vibration compensation value used to lead the detected steering torque value to the steering torque value obtained through the low-pass filtering process, by executing PI computation on the steering torque deviation computed by the steering torque deviation computing unit.

Electric power steering system

A vehicle steering system includes an axial force sensor that detects a vibration of a vehicle wheel; and a control device including an FFT analysis unit that resolves the vibration of the vehicle wheel into a power spectrum. The control device executes compensation assist control that suppresses one of a deflection of the vehicle and a vibration of a steering component that are caused by a puncture or a burst of the vehicle wheel, based on the vibration calculated based on a radius of the vehicle wheel when the vehicle wheel is normal and a vehicle speed and an abnormal-wheel frequency calculated based on a radius of the vehicle wheel when the vehicle wheel is punctured or burst and the vehicle speed.

Vehicle steering system

In a warning device for a vehicle, a basic target current value setting unit sets a basic target current value based on a steering torque and a vehicle speed. When a lane deviation determining unit determines that there is a high possibility that a vehicle will deviate from a lane, a warning vibration wave generator generates a warning vibration wave containing a plurality of frequency components. A target current value is computed by adding the warning vibration wave to the basic target current value. A motor current to be applied to an electric motor is controlled so as to approach the target current value.

Warning device for vehicle

A road friction coefficient estimating unit calculates a tire sideslip angle and a cornering force, and estimates a road friction coefficient on the basis of the ratio of the calculated cornering force to the calculated tire sideslip angle. A vehicle travels on multiple road surfaces that differ in road friction coefficient, and tire sideslip angles and cornering forces on the road surfaces are detected in advance. The road friction coefficient estimating unit stores, in a memory, a correlation among the detected tire sideslip angles, the detected cornering forces, and the road friction coefficients in the form of numerical values or a mathematical expression, and estimates a road friction coefficient using the correlation stored in the memory.

Road friction coefficient estimating unit and road friction coefficient estimating method

An acceleration sensor is attached to a rack housing. A FFT processing unit converts a signal output from the acceleration sensor, which is a time-domain signal, into a frequency-domain signal. An inverse input vibration component extraction unit extracts a signal, of which the frequency (f) falls within a predetermined range (fL&#x2266;f&#x2266;fH (fH&#x3e;fL)) and of which the power density (&#x3c1;) falls within a predetermined range (&#x3c1;L&#x2266;&#x3c1;&#x2266;&#x3c1;H (&#x3c1;H&#x3e;&#x3c1;L)), from the frequency-domain signal obtained by the FFT processing unit. An IFFT processing unit converts the frequency-domain signal extracted by the inverse input vibration component extraction unit into a time-domain signal (estimated inverse input vibration).

A vehicle steering device performs a tilt operation of a steering shaft to a predetermined position by using a driving force of a motor, a steering wheel being mounted to an upper end of the steering shaft. The vehicle steering device includes: a tilt drive motor allows the steering shaft to move during the tilt operation; and a control unit which controls driving of the tilt drive motor. The control unit drives the tilt drive motor so as to determine a tilt displacement amount from an open loop transfer function of a mechanical system which takes inertia and viscosity of a steering column into consideration, based on a resultant force of torque of the tilt drive motor and steering torque, which is generated in the steering column in which the steering shaft is rotatably supported.

Vehicle steering device

There is provided a vehicle steering system which includes an electric motor for imparting a steering force to a steering mechanism of a vehicle and an automatic parking controller for executing an automatic parking control by controlling the electric motor, wherein the automatic parking controller controls an energizing voltage of the electric motor by imparting a square wave to the electric motor and increasing/decreasing a neutral point voltage of a winding of the electric motor.

In a steering-without-driving state, a larger current limit value, drive limit time and steering angle deviation threshold value are set than when a low-speed driving state occurs. An automatic parking mode is held until a time period over which a state where a motor current value of an electric motor which drives a steering mechanism is equal to the current limit value reaches the drive limit time. Even though the state where the motor current value is equal to the current limit value has continued over the drive limit time, the automatic parking mode is held during the steering angle deviation not exceeding the steering angle deviation threshold value. When the state where the motor current value is equal to the current limit value has continued over the drive limit time Ta and that the steering angle deviation exceeds the threshold value, the automatic parking control is cancelled.

A brake application speed is compared with a speed threshold value so as to judge whether or not a braking operation being performed is an emergency braking operation. If not the emergency braking operation, an automatic parking mode is held. When the emergency braking operation is in effect, control information related to a state of an automatic parking control then is stored in a control information storage section, and the automatic parking control is cancelled. Thereafter, when a steering operation or a gearshift operation is performed before a cancellation of application of the brake is detected, the process is ended, and the control mode is held in an assist mode. When the application of the brake is cancelled with neither the steering operation nor the gearshift operation performed, the control information is read in so as to resume the automatic parking control.

A vehicle steering system includes: a steering actuator that imparts a steering force to a steering mechanism of a vehicle; an automatic steering controller that performs an automatic steering control by controlling the steering actuator; a driving state detector that detects a driving state of the vehicle during the automatic steering control; a threshold value setting unit that variably sets a threshold value for permitting an intervention in the automatic steering control; and an automatic steering intervention unit that intervenes in the automatic steering control based on a threshold value set by the threshold value setting unit.

An automatic parking control is cancelled when a motor current has not yet reached a maximum current value Iwith a steering angle deviation exceeding a deviation threshold value. In addition, the automatic parking control is cancelled when a steering speed has not yet reached a maximum steering speed with a state where the motor current has reached and remains at the maximum steering speed continuing over a first time period. On the other hand, when a state where the steering speed has reached and remains at the maximum steering speed continues over a second time period, it is determined that there occurs an output shortage of a steering actuator, an automatic parking condition is recalculated, so as to allow the automatic parking continue to continue.

Growing community of inventors

Kashiwara, Japan

Tatsuma Kouchi