Abstract: An electric power steering apparatus which transmits a driving force of an electric motor to a steering mechanism for steering assist. The apparatus is provided with: a torque sensor which detects a steering torque applied to an operation member for steering a vehicle; a basic assist characteristic determining section which determines a basic assist characteristic defining a basic characteristic of a motor driving target value for the steering torque; a motor driving target value determining section which determines the motor driving target value for the steering torque in accordance with a modified assist characteristic prepared by shifting the basic assist characteristic along a steering torque coordinate axis; a shift amount determining section which determines the amount of the shift from the basic assist characteristic to the modified assist characteristic on the basis of the steering torque; and a motor driving section which drives the electric motor on the basis of the motor driving target value.

Abstract: An electric power steering apparatus for performing steering assist. The apparatus is provided with an operation amount sensor for sensing an operation amount of an operation member for steering a motor vehicle; a reference assist characteristics setting section for setting reference assist characteristics; and a motor driving target value setting section for setting a motor driving target value in accordance with a corrected assist characteristics obtained by shifting the reference assist characteristics along the axis of coordinates of the operation amount. The apparatus is further provided with a shifting amount setting section for setting, when forward stroke steering is done, the shifting amount to zero, while setting, when return stroke steering is done, the shifting amount to a value at which corrected assist characteristics is obtained in which the absolute value of the motor driving target value corresponding to the operation amount is increased.

Abstract: An electric power steering apparatus for performing steering assist. The apparatus is provided with an operation amount sensor for sensing an operation amount of an operation member for steering a motor vehicle; a reference assist characteristics setting section for setting reference assist characteristics; and a motor driving target value setting section for setting a motor driving target value in accordance with a corrected assist characteristics obtained by shifting the reference assist characteristics along the axis of coordinates of the operation amount. The apparatus is further provided with a shifting amount setting section for setting, when forward stroke steering is done, the shifting amount to zero, while setting, when return stroke steering is done, the shifting amount to a value at which corrected assist characteristics is obtained in which the absolute value of the motor driving target value corresponding to the operation amount is increased.

Abstract: The present invention provides an electric power steering device enabled to compensate for the influence of the inertia of a steering-assisting-force generating motor on steering with accurate timing even when a steering direction is reversed at high speed. Based on steering torque and a rotation angular speed of a steering-assisting-force generating motor, a steering angular acceleration correspondence value is obtained. The device has means for regulating a gain, which is multiplied to a change acceleration of the steering torque. The motor is controlled so that the steering assisting force is corrected according to a motor output correction value obtained on the basis of the relation between the motor output correction value and the steering angular acceleration correspondence value, which is preliminarily determined and stored in such a way as to compensate for the influence of the inertia on steering, and the obtained steering angular acceleration correspondence value.

Abstract: A power steering apparatus is provided, which is adapted to generate a steering assist force by a hydraulic pressure of a pump driven by an electric motor. The apparatus includes: a pulse width modulation control circuit for controlling the electric motor through a pulse width modulation control; a load detection circuit for detecting a load applied on the electric motor; and a control circuit for progressively increasing the PWM duty of the pulse width modulation control circuit up to 100% if the load on the electric motor is not lower than a predetermined level.

Abstract: A power steering apparatus is provided which is adapted to generate a steering assist force by a hydraulic pressure generated by a pump driven by an electric motor. The apparatus includes: a steering angle detection section (11, S1, S4) for detecting an absolute steering angle on the basis of a steering angle midpoint and a relative steering angle; a first control section (31, S6, S8 to S10) for actuating the electric motor in response to the steering angle detection section detecting an absolute steering angle of not smaller than a first threshold value; and a second control section (31, S6, S11, S9, S10) for actuating the electric motor in response to a steering angle change becoming not smaller than a second thresold value which is smaller than the first threshold value when the absolute steering angle detection is not carried out by the steering angle detection section.

Abstract: A power steering apparatus for generating a steering assist force by a hydraulic pressure generated by a pump driven by an electric motor. The apparatus includes: a steering torque detecting mechanism (13) for detecting a steering torque; a steering urgency level calculating section (S5) for calculating a steering urgency level by using a time-based second-order differential value of the steering torque detected by the steering torque detecting mechanism; a target speed determining section (31, S6, S7) for determining, on the basis of the steering urgency level calculated by the steering urgency level calculating section, an assist starting speed as an initial target speed at which the electric motor (M) is actuated; and a control section (31) for controlling driving of the electric motor to equate the speed of the electric motor to the target speed determined by the target speed determining section.

Abstract: A vehicle steering device has a steering inhibition portion that enables the steering device to be switched between a steering inhibition application mode and a steering inhibition release mode--regardless of whether or not the vehicle is being steered by a driver. This arrangement avoids the need to determine whether or not the vehicle is being steered before determining whether or not to inhibit steering.

Abstract: A power steering device uses a control value set in accordance with a vehicle's detected steering torque to control an actuator, which generates steering assistance power. When the vehicle appears to be on a collision course with an obstacle detected in its steering direction, the control value is modified so as to inhibit the steering. The control value after the modification for the steering inhibition is a function of the control value prior to the modification. When the detected value of the steering torque is greater than the preset value, the function is modified such that the degree of steering inhibition is increased by comparison with a situation in which the detected torque is less than the preset value.

Abstract: An electric power steering system of this invention can inform the driver of potential danger by providing control by way of safety precaution before a vehicle enters a dangerous situation. The occurrence of dangerous situations is determined based on a signal from an obstacle sensor. If a steering wheel is turned in a dangerous situation, a warning control is performed on a motor. The motor outputs a torque for t1 seconds, for example, which counters against turning of the steering wheel. Then, the motor enters a "non-assist" state wherein no current is applied thereto for t2 seconds. If an intermittent counter torque is applied by the motor, it is hard to turn the steering wheel and the steering wheel is caused to vibrate, thereby preventing the vehicle from being steered to collide with an obstacle and, warning the driver of the danger with vibration caused in the steering wheel.