A control computing unit blends a feedforward axial force and a feedback axial force at an allocation ratio, based on an axial force difference, a lateral acceleration, a vehicle velocity, a steering angle, and a steering angular velocity so as to set a final axial force. Then, the control computing unit applies a steering reaction force based on the final axial force that has been set.

Steering control device

A target pinion angle computation unit (62) computes a target pinion angle (θp*) on the basis of a basic assist component (Ta1*) and a steering torque (Th), and computes the target pinion angle (θp*) so as to rapidly increase a steering reaction force when it is determined based on the target pinion angle (θp*) that a rack shaft of a rack-and-pinion mechanism reaches a position near a limit of a movable range of the rack shaft. In an EPS, a correction component for the basic assist component (Ta1*), which is necessary to increase the steering reaction force rapidly, is computed through execution of PID control for causing an actual pinion angle to coincide with the target pinion angle (θp*). Because the correction component is added to the basic assist component (Ta1*), the steering reaction force is increased rapidly when the rack shaft reaches the position near the limit of the movable range.

Electric Power Steering System

A method of controlling an electric power steering system of a vehicle is provided. The method estimates steering rack force to be caused by a tire of the vehicle and a surface of a ground with which the tire is in contact in response to determining that one or more hand wheel torque sensors of the vehicle are not enabled. The method generates a steering assist torque command based on the estimated steering rack force. The method controls the electric power steering system using the steering assist torque command.

Providing assist torque without hand wheel torque sensor for zero to low vehicle speeds

A motor drive device has an inverter circuit, in which at least three sets of a pair of upper and lower arms including a semiconductor switching element on an upper arm and a lower arm is arranged, for supplying voltage to a motor based on ON/OFF operation of each semiconductor switching element by a PWM (Pulse Width Modulation) signal, an inverter drive unit for outputting the PWM signal to each semiconductor switching element of the inverter circuit, a fail safe circuit, arranged between the inverter circuit and the motor, including a semiconductor switching element for shielding the voltage supply from the inverter circuit to the motor for each phase, and a fail safe drive unit for outputting a signal for turning ON/OFF the semiconductor switching element of the fail safe circuit.

Motor drive device

A base assist section generates a base assist command so that a steering reaction according to a road surface reaction returns to a steering wheel side. A modifying section generates a torque modifying command for modifying the base assist command so that an unstable movement of a vehicle converges appropriately. A sum of the each command becomes a final assist torque command. The base assist section estimates a road surface force based on the self-generated base assist command and a steering torque actually detected. A target steering torque is generated based on the estimated force, and the base assist command is generated based on a deviation of the target steering torque and the steering torque.

Electric power steering control device

PROBLEM TO BE SOLVED: To provide an electric power steering device which prevents a bus bar of an electric motor from contacting a housing of an electronic control unit (ECU) and electronic parts.SOLUTION: The electric motor 18 for assisting the steering includes the bus bar 32 extended from the electric motor 18. The ECU, which controls the drive of the electric motor 18, includes a housing 30 and a power source module 31 consisting of an insulator provided in the ECU, while the power source module 31 includes a power supply bus bar 33 extended from the power source module 31. On the power source module 31, an extension part 35 is also formed that contacts the electric motor 18. This extension part 35 is inserted into a through-hole formed in the housing 30 of the ECU. In the extension part, a bus bar insertion hole 34, through which the bus bar 32 extended from the electric motor 18 is passed, is formed.

Tani Naoki

Papers

Electric power steering device