Toyoda Koki Kabushiki Kaisha

Other

Toyota Jidosha Kabushiki Kaisha

Jtekt Corporation

Koyo Seiko Company, Ltd.

Favess Co., Ltd.

Kazumasa Kodama

Yutaka Mori

Kunihiko Eto

Takahiro Kojo

Masatoshi Nakatsu

Junji Kawamuro

Masahiro Miyata

Hirozumi Eki

Shigeo Tanooka

Shiro Takeuchi

Akihiro Ohno

Satoru Mikamo

Yukio Okamura

Tsutomu Matsumoto

Michiyuki Sugiyama

Yoshiharu Amano

Akihiro Oono

Hisashi Koba

Yuzo Kubota

Kimio Yamaguchi

A variable gear ratio hydraulic power steering deviceis provided with a variable ratio transmission mechanismhaving a drive motor; a flow volume control valvefor controlling the discharge flow volume of an oil pumpwhich circulates operating fluid; and a steering angle sensorfor measuring a handle steering angle input to a steering handle. A valve controlling controlleris constructed to take thereinto a measured ACT angle which is the rotational angle of the drive motorand to calculate a target ACT angle for the drive motorbased on the handle steering angle. Further, the valve controlling controllercontrols the flow volume control valveto make the discharge flow volume equal to or greater than a predetermined flow volume when the magnitude of a difference ACT angle which is the difference between the target ACT angle and the measured ACT angle is equal to or greater than a threshold value.

Variable gear ratio hydraulic power steering device

The invention provides an electric power steering apparatus in which a dead zone is not generated even at a low duty ratio while slow starting a switching element. When a duty ratio of a PWM control becomes more than a preset value (NO in S), a switching cycle is set to a predetermined value (a fixed value) (S). When the duty ratio becomes equal to or less than the preset value (Yes in S), the switching cycle is made longer than the predetermined value (S). It is possible to securely apply a current to a motor and it is possible to prevent a dead zone from being generated, by elongating the switching cycle even in a low duty ratio while slow starting an FET and preventing a noise from being generated.

Electric power steering apparatus

An electric steering control device is provided which is capable of enabling the driver to perform steering manipulation stably without being substantially affected by the ambient temperature and the heat generation of the control device. The control device comprises a temperature sensor for detecting the temperature of a circuit board mounting a motor drive circuit thereon and a compensation section for compensating an electric current command value based on the board temperature detected by the temperature sensor, so that en electric motor for exerting an assist force on a vehicle steering mechanism is driven by the compensated electric current command value output from a motor drive circuit. Therefore, the steering operation can be done stably without being substantially affected by the ambient temperature and the heat generation of the control device. In particular, since the temperature sensor is arranged not on the motor drive circuit per se but on a circuit board mounting the motor drive circuit thereon, the freedom can be heightened in arranging the temperature sensor. Further, since the temperature sensor for heat control of a spiral cable provided on the electric motor is utilized also for compensation of the electric current command value, the components for the control device can be reduced in number.

Electric steering control device

A drive controlling unit includes a final angle position memorizing device for memorizing a final angle position at a time of termination of the vehicle driving operation, an input complete data memorizing device capable of switching the memory content between a first memory condition and a second memory condition. The first memory condition indicates completeness of writing of the final angle position in the final angle position memorizing device. The second memory condition indicates failure in writing the final angle position therein. The input complete data memorizing device is capable of maintaining the memory content even when the vehicle is stationary.

Vehicle steering control system

The terminal voltages of respective phase coils of a steering shaft driving motor constituted by a three-phase brushless motor are separately detected. When the terminal voltages detected at at least three different conducting terminals u, v, and w are made Vu, Vv, and Vw, respectively, and the values when those detected values Vu, Vv, and Vw are arranged in order from largest to smallest voltage are made V, V, and V, respectively, provided that V&#x2267;V&#x2267;V, a calculation is performed to determine if V+Vcoincides with 2*Vwithin a predetermined allowable range, and a failure is determined based on results obtained from such a calculation.

A vehicle steering control system is provided which is capable of reliably protecting a motor for driving a wheel steering shaft. In the system, a current sensor and a motor rotational speed detection section respectively detect a current applied to the steering shaft drive motor and the motor rotational speed of the steering shaft drive motor, and current inference means infers the motor current applied to the steering shaft drive motor based on the detected motor rotational speed. Abnormal judgment means compares the current inference value obtained by the current inference means with a current detection value indicated by the current sensor to judge whether the current sensor is normal or not. Abnormal judgment output means outputs the result of the abnormal judgment when the current sensor is judged to be abnormal. When a trouble occurs that the current sensor fails to operate normally due to the malfunction or the like, such a trouble can be recognized at the early stage of the malfunction. Therefore, it can be successfully obviated that the current sensor has fallen in the malfunction, nevertheless the operation of the motor is continued as usual.

A PWM control includes a first PWM control and a second PWM control. In the first PWM control, a first power supply terminal of a first coil is kept non-switched under being connected to a first pole of a direct current power source, and a second power supply terminal of a second coil is capable of being switched under being connected to a second pole of the direct current power source. The second PWM control is performed by switching a first connected condition and a second connected condition by turns. The first connected condition is established with the first power supply terminal connected to the first pole and the second power supply terminal connected to the second pole. The second connected condition is established with the first power supply terminal being connected to the second pole and the second power supply terminal being connected to the first pole.

A angle sensor identifies a angle phase of a rotatable member based on a kind of an identified pattern of the angle phase to detect an angular position of a steering shaft driven by a motor A steering controller identifies a rotational direction based on an identified pattern output of the angle and performs a sampling of the pattern output at a predetermined interval, identifies an order of combination order of the identified pattern of an angle phase in a first sampling and a second sampling following to the first sampling, and determines a pattern exchange number with the rotational direction from the order in the first sampling to the order in the second sampling. The steering controller adds a number corresponding to the pattern exchange number to a counting number when the rotational direction is plus and decrease a number corresponding to the pattern exchange number from the counting number when the rotational direction is minus in order to identify the angular position of the steering shaft by the counted number.

Steering control system for vehicle

A vehicle steering control system is provided which is capable of reliably protecting a motor for driving a wheel steering shaft. The offset output characteristic of a current sensor for detecting the electric current applied to the steering shaft drive motor is actually measured prior to the actual use of the steering control system, and offset compensation information is prepared based on the measured value of the offset output characteristic for storage in an EEPROM. Further, an output value of the current sensor and an output value of a reference current measuring system are measured independently of each other with the supply voltage for use in measurement being set to a constant value. Then, current gain compensation information is prepared based on the output values so measured and is stored in the EEPROM. In the later actual use (i.e., after shipment) of the control system, the output of the current sensor is compensated based on the offset compensation information and the current gain compensation information.

A vehicular steering device of the present invention aims at suppressing heat generation. If a voltage is applied to a solenoid, a drive force is generated in a lock arm. If the drive force exceeds an urging force of a torsion coil spring, an electric motor is released and assumes an unlocked state. Accordingly, the drive force that is required for the maintenance of the electric motor in the unlocked state can be smaller than the drive force that is required for switching the electric motor from a locked state to the unlocked state. Thus, after the electric motor has been released in the unlocked state, a voltage is intermittently applied to the solenoid so that the electric motor is held in the unlocked state. In this manner, heat generation from the solenoid is suppressed.

Vehicular steering device, program, and record medium

A control apparatus for a power-assisted steering system which includes a servo valve associated with a hydraulic power cylinder to selectively direct the flow of fluid under pressure from a source of hydraulic pressure to opposite fluid chambers of the power cylinder in response to operation of a steering wheel and an electrically operated control valve arranged to control hydraulic pressure for power assist applied to the servo valve in accordance with a control current applied thereto. The control apparatus is arranged to control the value of the control current in such a manner that the hydraulic pressure for power assist is decreased when the steering wheel is returned to its neutral position from its steered position during low speed travel of the vehicle and that the hydraulic pressure for power assist is increased when the steering wheel is returned to its neutral position from its steered position during high speed travel of the vehicle.

Control apparatus for power-assisted steering system

An apparatus for controlling the ratio of a assisting force produced by a power steering system installed in an vehicle to a steering torque supplied by the driver wherein the ratio is changed by a solenoid valve arranged in the power steering system. The CPU of the apparatus changes control current to be applied to the solenoid valve using a characteristic map defining change of a base current with respect to changes of the vehicle speed and the steering angle. Further, the CPU increases the control current, when the steering wheel is returned to its neutral angle position, so as to decrease the ratio, increasing the self returning ability of the steering mechanism. The control current applied to the solenoid valve during the returning operation is changed depending upon both the steering angle and the steering speed of the steering wheel using additional characteristic maps.

Apparatus for controlling steering force produced by power steering

A power steering apparatus wherein a heated state of the electric motor is detected without employing any temperature sensor. There are previously stored plural temperature characteristics each representing the relationship between the temperature variation caused per unit time in the electric motor and the load current, which are prepared, for plural motor temperatures or plural differences between the motor temperature and the ambient temperature. A temperature characteristic is selected on the basis of the present predicted motor temperature or the difference between the motor temperature and the ambient temperature. The present load current is detected, and the temperature variation caused per unit time correspondingly to such load current is calculated from the selected temperature characteristic. The unit-time temperature variations thus obtained are integrated with the lapse of time to predict the present motor temperature. Upon rise of the predicted motor temperature beyond a predetermined point, the electric motor is considered to be in a heated state.

Power steering apparatus with electric motor

A device for detecting driving condition faced by an operator of an automobile. The device includes an automobile speed sensor, first arithmetic means, second arithmetic means and compensating means. The first arithmetic means computes a driving condition index by using automobile speed information. The second arithmetic means computes limit value changing according to the increment in the automobile speed. The compensating means compare the change amount of the driving condition index for a predetermined time period with the limit value and compensate the driving condition index in such a way that the change amount of the driving condition is limited to the limit value when the change amount exceeds the limit value in order to give the operator a natural feel of the road.

Device for detecting driving condition for automobile

There is disclosed a device for controlling steering force in a power steering apparatus having an electromagnetic control valve according to road and driving conditions. The device includes a car speed sensor, a steering angle sensor, first arithmetic means, second arithmetic means, correcting means, control current arithmetic means and controlling means. The first arithmetic means computes a driving condition index by using car speed information. The second arithmetic means computes a road condition index by using steering angle signals. The correcting means converts the driving condition index into a correction driving condition index which takes any one of several stepwise-varied values. The control current arithmetic means computes an output control current value applied to electromagnetic control valve by the controlling means. The device further includes means for detecting lateral acceleration utilized for controlling the steering force.

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Toyota, Japan

Kazumasa Kodama