Koyo Seiko Company, Ltd.

Koji Kanda

A current sensordetects a motor current of a steering motorwhich supplies a steering mechanismwith steering force corresponding to the steering amount applied to a steering wheel. A main controllerextracts component within a predetermined frequency range out of a motor current detected by the current sensor, amplifies the extracted component and drives a reaction force motorin a controlled manner so as to supply the steering wheelwith steering reaction force corresponding to the steering amount applied to the steering wheeland steering reaction force corresponding to a current of the component, which has been extracted and amplified. The vehicle steering apparatus constructed as above can supply steering means with steering reaction force corresponding to component within a predetermined frequency range of a motor current of the steering motor.

Vehicle steering apparatus

An electric power steering apparatus comprising a torque sensor for detecting the steering torque applied on the steering member of a vehicle; the first control unit for outputting the first control signal to drive a motor for steering assist, based on the steering torque detected by the torque sensor; the steering angle sensor for detecting the steering angle of the steering member; the norm steering unit for outputting a norm steering angle, based on a norm steering model which defines the relation between the steering torque and the norm steering angle; the second control unit for outputting the second control signal to drive the motor in order to reduce the difference between the norm steering angle outputted from the norm steering unit based on the steering torque and the detected steering angle; and the changing unit for switching between the first control signal and the second control signal, thereby being capable of switching between the driving at the steering torque determined regardless of the conditions of the road surface and the driving at the steering torque of the conventional steering assist.

Electric power steering apparatus

A power steering apparatus for assisting steering by conferring a steering assisting force according to a steering manipulation to a steering mechanism. The apparatus includes an electric motor being driven under control according to the steering manipulation, and a deteriorated condition judging factor storage portion for storing a factor used for judging a deteriorated condition of the electric motor. The factor used for judging the deteriorated condition of the electric motor includes, for example, an accumulated value of load exerted on the electric motor.

Power steering apparatus

A reduction gear ratio n of a reduction gear is multiplied by a steering angular speed by a multiplier, and the deviation e achieved by subtracting a motor rotational speed from the multiplication value is integrated and then multiplied by an integration gain to achieve a current target value. The current target value is added with the multiplication value of the deviation e and a proportional gain in a phase compensator to perform phase compensation. The phase-compensation result is added with the value achieved by differentiating the motor rotational speed and multiplying the differential value thus achieved by a control gain in an inertia compensator to perform inertia compensation. Further, the value achieved by multiplying the motor rotational speed by a control gain is subtracted from the inertia-compensation result in a damping controller to perform damping control, and a final current target value. It is achieved from an adder.

Electric power steering device

An electric power steering system is provided which employs an electric motor as a driving source to apply a steering assist force to a steering mechanism. The system includes: an operation degree detecting section for detecting an operation degree of an operation member; a motor current detecting section for detecting an electric current flowing through the electric motor; and a steering angle detecting section for detecting a steering angle of the steering mechanism. A reaction force from a road surface is computed on the basis of outputs of the operation degree detecting section, the motor current detecting section and the steering angle detecting section, and a driving target value of the electric motor is determined on the basis of the reaction force and the operation degree of the operation member.

Electric power steering system

The invention provides a linkless steering apparatus for vehicle in which a steering mechanism and steering wheel are not mechanically connected. The steering apparatus drives a steering motor of the steering mechanism in accordance with a steering torque so as to increase or decrease a steering angle. The steering torque for this purpose is calculated based on results obtained by detecting a rotational angle of an electric motor (a reaction-force motor) connected to a rotational shaft of the steering wheel and an electric current flowing to the electric motor, a moment of inertia of the steering wheel, and a moment of inertia of the electric motor. Therefore, it is possible to avoid use of a torque sensor which requires a large space for installation thereof and high cost.

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Kyoto, Japan

Koji Kanda