Koyo Seiko Company, Ltd.

Toyota Jidosha Kabushiki Kaisha

Matsushita Electric Industrial Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Jtekt Corporation

Koyo Seikoco., Ltd.

Mitsuhiko Nishimoto

Hirofumi Matsuoka

Kazuyuki Yoshida

Takayuki Kato

Toshihiko Daido

Hidetoshi Tabuse

Makoto Inoue

Hiroshi Kawaguchi

Osamu Sano

Masataka Izawa

Hideki Higashira

Mitsunori Kawashima

Yuki Matsuoka

Akio Hayama

Atsushi Igo

Masanori Sugimoto

Takahiro Aoki

Eiki Sugimoto

Hiroki Amako

An abnormality judging apparatus of a rotation angle detecting apparatus generating a sine wave signal and a cosine wave signal according to the rotation angle of a rotor is provided with an interface which receives the sine wave signal, an interface which receives the cosine wave signal, a signal arithmetic circuit which successively calculates the sum of each square of the received sine wave signal and cosine wave signal, a memory which stores as a threshold value the value of the sum of each square of the sine wave signal and cosine wave signal received from the rotation angle detecting apparatus at a predetermined point in time, and a judging circuit which judges that abnormality has occurred at the rotation angle detecting apparatus when the difference between the value calculated by the signal arithmetic circuit and the value stored in the memory is out of a predetermined range.

Abnormality judging apparatus

The present invention provides an electric power steering device. The ECU of the device includes a microcomputer; a PWM signal generating circuit for generating a PWM signal according to the command value; a motor drive circuit for impressing a voltage corresponding to the PWM signal upon the motor; an electric current detector for detecting an electric current flowing in the motor; an off-set limit value storage circuit for storing the restricting value showing the allowable range of the middle point voltage; a middle point off-set voltage generation circuit for generating a voltage signal of the predetermined restricting voltage in the range of the restricting value when the actually measured middle point voltage stored in the microcomputer as the middle point voltage is compared with the restricting value; and an amplifier for outputting a signal amplified a difference voltage between the signal sent from the torque sensor and the middle point off-set voltage generation circuit.

Electric power steering device

An electric power steering apparatus for assisting steering based on an output of a torque sensor which detects a steering torque, the apparatus cumulates the outputs at each detection for a predetermined period of time, then compares the cumulated value with a predetermined value, and detects a displacement of the torque sensor's neutral point based on the comparison result. Therefore it is possible to detect even a small displacement of the torque-sensor neutral point.

Electric power steering apparatus

An electric power steering apparatus is disclosed in which steering return control is maintained when vehicle speed reaches a predetermined vehicle speed range after the vehicle speed has been lower than the speed range, and steering return control is disabled when the vehicle speed reaches the predetermined vehicle speed range after the vehicle speed has been higher than the speed range and steering angular velocity has been higher than a predetermined value. Therefore, the control state between the steering return control and convergence control can preferably be switched so that the steering wheel settles quickly to a steering angle predetermined point based on the vehicle speed and the steering angular velocity even while the steering state is not changing.

A vehicle steering apparatus comprising a driver's hands free state detector detecting a driver's hands free state when returning of a steering wheel to its neutral position, for controlling a reaction force to be applied to the steering wheel a steering operating angle of the steering wheel or a returning angular speed of the steering wheel, on the basis of the detection signal issued from the driver's hands free state detector. The driver's hands free state detector detects a driver's hands free state on the basis of at least vehicle speed and steering torque.

Vehicle steering apparatus

A steering apparatus for a vehicle comprising a reaction force control means for controlling an increase and decrease in a reaction force to be applied to a steering operating means on the basis of a reaction force instruction signal, a motor for applying the reaction force to a steering operating means with control of the reaction force control means, means for detecting an overload state of the motor, means for notifying a reaction force instruction means of the overload state when the overload state is detected, and a reaction force instruction means for decreasing to correct the reaction force instruction signal in a predetermined ratio when receiving the notification of the overload state from the reaction force control means.

Steering apparatus for a vehicle

An electric power steering apparatus wherein a motor driving prohibiting means prohibits driving of a motor when a driving logic determining unit determines that a detected torque is outside a specified range, a direction in which the motor is to be driven on the basis of a motor current target value and the direction of the steering torque are opposite with respect to each other, and the direction in which the motor is to be driven on the basis of the motor current target value and the change direction detected by the torque change direction detecting unit are opposite with respect to each other, and when an abnormal current determining unit detects that a driving current is greater than a specified value.

An electric power steering apparatus comprising dead zone detecting device for detecting whether a detected value of a steering torque is no more than a predetermined value, that is, in a dead zone or not, steering angular velocity detecting device for detecting the rotation speed of a steering wheel, and motor braking device for braking a motor by short-circuiting the terminals of the motor by the PWM control corresponding to the rotation speed of the steering wheel detected by the steering angular velocity detecting device when the detected value of the steering torque is detected to lie in the dead zone.

In an electric power steering apparatus, it is judged whether or not a value of primary delay of temperature increase in a driving circuit for an electric motor tends to decrease, and when the value of primary delay is judged to tend to decrease, a new value of primary delay is obtained with a time constant set smaller, so that an upper limit value of a motor current can be decided on the basis of the new value of primary delay. Thus, a steering power can be rapidly recovered.

An electric power steering apparatus which quickly returns the steering wheel to the neutral position with a satisfactory steering feeling by switching a steering wheel return control for assisting the steering wheel return and a steering wheel convergence control for converging the steering wheel to the neutral position by braking a motor, according to the steering condition such as the rotational speed of the steering wheel is fast or slow when returning the steering wheel to the neutral position even when the vehicle speed is equal.

The invention provides an electric power steering apparatus in which a duty ratio upper limit value is obtained on the basis of a vehicle speed of a vehicle and a supply voltage for a motor and a target duty ratio is determined as a value not exceeding the duty ratio upper limit value, so as to prevent an excessive steering assisting force from being caused by the malfunction of a driving current detecting circuit for the motor.

In an electric power steering apparatus, a motor current target value of a steering force assisting motor is determined on the basis of a torque detected by a torque sensor. The drive of the motor is controlled using the motor current target value as a target value of an automatic control, and using the driving current of the motor as a feedback value of the automatic control. When the detected torque is within a predetermined range, the motor is inhibited from being driven in the direction opposite to the detected torque. The electric power steering apparatus has a motor non-drive detecting circuit for detecting that the motor current target value is zero, and a drive inhibition holding circuit for holding the motor drive inhibition state, wherein the motor is inhibited from being driven in the direction opposite to the detected torque, until the motor non-drive detecting circuit detects that the motor current target value is zero. Even when a CPU runs away and the motor current target value becomes excessive, self-rotation of a steering wheel and reverse assist caused by the flow of excess motor current are prevented. Even when a CPU runs away exists and assist and assist inhibition are repeated, steering is prevented from becoming unstable.

Torque sensing power steering device with abnormality detection, dead

The present invention provides an electric power steering apparatus in which it is decided whether or not steering torque is in a predetermined drive inhibition area, and when the term in which the decision result is logically inconsistent with driving instruction for the motor in accordance with the steering torque is shorter than a predetermined period of time, a timer is reset to drive the motor. As a result, the compensation of the inertia of said motor can be controlled even when the steering torque is small. Further, in the electric power steering apparatus, the timer is also reset to drive the motor when the steering torque is in a dead zone and a driving current for the motor is smaller than a predetermined value. As a result, the drive of the motor can be controlled also when a steering wheel is returned to its initial position.

The invention provides an electric power steering apparatus, in which one of a pair of switching elements that has been PWM controlled is turned off and the other switching element is PWM controlled instead when a steering wheel is returning to its neutral position, thereby allowing the steering wheel to return smoothly and preventing a control hunting.

An electric power steering apparatus which is provided with a CPU for outputting a drive control signal of an electric motor for assisting the steering force on the basis of the detected steering torque, and a drive inhibition circuit for outputting a signal to stop the operation of the electric motor when the direction of the electric motor operation and the direction of the detected steering torque are opposite to each other, the output of the drive inhibition circuit is inputted to the CPU, which monitors the normal or abnormal condition of the drive inhibition circuit. While the abnormal condition of the CPU continues for a predetermined time period, the drive stop condition of the electric motor is kept. When the detected torque is not smaller than the predetermined value, the drive of the electric motor in the direction opposite to that of the detected torque is inhibited.

Growing community of inventors

Kashihara, Japan

Mitsuhiko Nishimoto