Toyota Jidosha Kabushiki Kaisha

Jtekt Corporation

Eiji Kasai

Shuji Fujita

Ippei Yamazaki

Masaharu Yamashita

Kenichiro Aoki

Kohei Morotomi

Tomonori Akiyama

Masaki Fujimoto

Hiroshi Kawamura

Jun Hasegawa

Yoshihisa Yamada

Toshihiro Takahashi

Satoru Mikamo

Yutaka Aoki

Yuichiro Ido

Akira Nambu

Akihiro Tomita

Keitaro Niki

Akihiro Ohtomo

Hideo Kometani

Junro Yamamoto

Tsutomu Onagi

Yasunori Shintani

Takatoshi Saito

Megumu Nishikohri

Yoichi Fujinori

A collision avoidance assistance device configured to perform driver steering assistance to avoid a collision between a vehicle and an obstacle, the device includes a steering control unit configured to perform the steering assistance in a case where it is determined that there is a possibility of the collision between the vehicle and the obstacle. During a period from commencement of the steering assistance to elapsing of a first time determined by response characteristics of a lateral acceleration of the vehicle, the steering control unit is configured to rotate a steering wheel of the vehicle in a collision avoidance direction by a control amount determined based on a steering holding force of the driver.

Collision avoidance assistance device and collision avoidance assistance method

In a state in which the energization in the first direction is possible between the motor and the drive circuit and the motor is not rotating at high speed, when the phase induced voltage value of the specific phase that is the target of determination is continuously equal to or smaller than the abnormality determination threshold, the abnormality detecting unit determines that an open malfunction has occurred in the relay FET of the specific phase.

Motor control device and steering device for vehicle

A collision avoidance assistance device includes a target control amount calculation unit configured to calculate a target control amount used for travelling on a target trajectory through which the vehicle passes, a first control amount calculation unit configured to calculate a first control amount to be applied by the first steering assistance system out of the target control amount, and output the first control amount to the first steering assistance system, and a second control amount calculation unit configured to calculate a second control amount to be applied by the second steering assistance system out of the target control amount, and output the second control amount to the second steering assistance system. The first control amount is set to be larger than the second control amount during a predetermined time period from a time of starting the collision avoidance assistance.

A steering angle estimation section calculates a front-wheel-side estimative steering angle and a rear-wheel-side estimative steering angle through use of wheel speeds of respective wheels, and averages these steering angles to thereby obtain an accurate estimative steering angle. It also calculates an estimative steering angle difference between the steering angles. An axial force estimation section calculates a base axial force through use of the estimative steering angle and a vehicle speed, and calculates a correction axial force which applies an axial force difference (hysteresis) to the base axial force in accordance with a turning or returning operation by a driver. The axial force estimation section adds the base axial force and the correction axial force together to thereby calculate an accurate estimative axial force. An assist computation section compares a target steering torque, which changes with the vehicle speed, and the accurate estimative axial force, and subtracts the target steering torque from the estimative axial force, to thereby calculate an assist torque.

Electric power steering apparatus for vehicle

An electric power steering device for a vehicle includes an estimation mechanism estimating if there is a possibility that a backward electric current flows in a booster circuit toward a vehicle battery device, and a boosting controller stopping the boosting operation of the booster circuit to prevent a backward electric current from flowing in the booster circuit when it is estimated that there is a possibility that a backward electric current flows by the estimation mechanism. The estimation mechanism estimates that there is a possibility that a backward electric current flows in the booster circuit when the steering condition of a steering wheel is a returning condition or a steering-held condition. Otherwise, the estimation mechanism estimates if a backward electric current flows on the basis of input and output voltages of the booster circuit and information on the switching of a first boosting switching element. Thereby, overheat of the booster circuit can be prevented.

Electric power steering device

A battery condition diagnosis apparatus for a vehicle gradually supplies electricity to an electric motor of an electric power steering apparatus when a predetermined time elapses after an ignition switch is turned off. The apparatus diagnoses the deteriorated condition of the battery on the basis of the amount of supplied electricity and the detected battery voltage which changes in accordance therewith. The electric motor may be a brushless DC motor. In this case, current is supplied to the electric motor such that only d-axis armature current Id in the d-q coordinate system flows, to thereby prevent the electric motor from rotating, whereby safety is secured. Accordingly, the condition of the battery can be accurately diagnosed by supplying electricity to the electric motor without changing the condition of the vehicle.

Battery condition diagnosis apparatus

An electric power steering device, including an electric motor supplied with power from a power supply device to generate a predetermined steering assistance force for a steered wheel, and an assistance control device the controls the amount of electrical power supplied to the electric motor, according to the steering state of a steering wheel. The assistance control device detects the power supply voltage of the power supply device. The assistance control device controls the electrical current supplied to the electric motor, so as to maintain the power supply voltage greater than or equal to a set voltage which is set in advance.

In a power supply apparatus, a power supply circuit includes a primary power supply circuit including a high-voltage battery and a step-down circuit for stepping down the voltage of the high-voltage battery, and a secondary power supply circuit including a low-voltage battery and a step-up circuit for stepping up the voltage of the low-voltage battery. The primary power supply circuit and the secondary power supply circuit are connected in parallel. An output voltage of the secondary power supply circuit is set to be lower than an output voltage of the primary power supply circuit. When the output voltage of the primary power supply circuit becomes lower than a target voltage of the secondary power supply circuit, the voltage stepped-up by the step-up circuit is supplied to a motor drive circuit. Accordingly, power supply backup of an electric power steering apparatus can be performed at low cost.

Electric power steering system apparatus

An electric power steering apparatus includes an electric power supply device that includes a main electric power unit that supplies high-tension electric power and a sub-electric power supply unit that supplies low-tension electric power, the main electric power unit and the sub-electric power supply unit being connected to each other in parallel, and that supplies electric power to the electric motor from one of the main electric power supply unit and the sub-electric power supply unit. An assist ECU calculates a correction coefficient based on which a d-axis target current increases with a decrease in voltage output from the electric power supply device, and calculates a final corrected d-axis target current by multiplying the d-axis target current by the correction coefficient.

Electric power steering apparatus and method for controlling the electric power steering apparatus

When it is determined that a malfunction has occurred in a rotational angle sensor, an electronic control unit changes the control manner from the normal assist control to the sensorless assist control. In the sensorless assist control, an assist stop command unit receives the information concerning the motor rotational angular speed &#x3c9;m from an angular speed conversion unit. Then, the motor rotational angular speed &#x3c9;m is compared with the threshold value &#x3c9;m. If the motor rotational angular speed &#x3c9;m is equal to or higher than the threshold value &#x3c9;m, an assist enabling signal is transmitted to a PWM voltage production unit to continue the power assist. On the other hand, if the motor rotational angular speed &#x3c9;m is lower than the threshold value &#x3c9;m, a stop command signal is transmitted to the PWM voltage production unit to stop the power assist.

Electric power steering apparatus

The CPU calculates axial force matching external force that acts on a rack bar by combining steering torque MT that acts on a steering shaft with assist torque AT generated by an electric motor. The CPU then determines whether a vehicle is running straight based on a steering angle &#x3b8;, a vehicle speed V, and the axial force F. Thus, even in a state where a control steering angle midpoint is deviated and a driver applies torque so as to return a turning position of a steering wheel to a neutral position, whether the vehicle is running straight can be accurately determined by making a determination by using the axial force F that acts on the rack bar. The CPU can set a considerably accurate control steering angle midpoint by calculating a smoothed steering angle midpoint by using an instantaneous steering angle midpoint in an accurately determined straight-running state.

Electric power steering system

When it is determined that the torque output from the electric motor abnormally fluctuates or the torque output from the electric motor varies between clockwise and counterclockwise turning operations of the driver's steering wheel, the steering assist control is continued if the vehicle speed v is equal to or lower than the reference speed v. In this case, the width of the dead band of the steering torque in the assist map used to calculate the target assist torque is increased. Thus, only in a case where the vehicle is moving at a low speed and the driver's steering wheel is operated with a great force, the steering assist torque is produced to alleviate the burden on the driver. In the other cases, the electric motor is stopped to minimize a sense of discomfort in the steering operation.

An electric power steering device controls an electric motor through a program processing based on a steering torque detected by a torque sensor and a vehicle speed detected by a vehicle speed sensor, and applies a suitable assisting force to rotational motion of a steering handle. Occurrence of an abnormality in the torque sensor and a power circuit is detected through the program processing. The torque sensor is activated upon receipt of a power-supply voltage from the power circuit and detects a steering torque. If a power-supply voltage outputted from the power circuit has dropped, detection of an abnormality in the torque sensor is forbidden. If a power-supply voltage supplied from a battery to the power circuit has dropped, detection of an abnormality in the power circuit is forbidden.

Vehicular electric power steering device and methods for controlling same

A DC motor is connected to diagonal positions of a bridge circuit having of four sides including switching elements and reflux diodes. At least one of two terminals is connected to a power line, and at least the other terminal is grounded. By performing pulse width modulation control of the switching elements, operation of the DC motor is controlled. When the DC motor is in operation, the sum of the terminal voltages of the DC motor is equal to the power voltage. When the DC motor is out of operation, the sum of the voltages is set to a predetermined voltage. If the sum of the voltages has deviated from the power voltage or the predetermined voltage by at least a predetermined value, the occurrence of a malfunction is judged.

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Toyota, Japan

Eiji Kasai