[Problem] An object of the present invention is to provide an electric power steering apparatus that constitutes a control system based on a physical model, constitutes a model following control that an output (a distance to a rack end) of a controlled object follows-up to a reference model, suppresses the occurrences of a noisy sound and a shock force at an end hitting without giving any uncomfortable steering feeling to a driver, and is capable of smoothly steering.

[Means for solving the problem] In the electric power steering apparatus that calculates a first current command value based on at least a steering torque and performs an assist-control of a steering system by driving a motor based on the first current command value, the apparatus comprises a configuration of a model following control comprising a feed-back control section including a viscoelastic model as a reference model within a predetermined angle at front of a rack end, wherein the configuration of the model following control comprises a feed-back control section, and the model following control has a noise-reducing function to reduce a noise so as to suppress a rack end hitting.

An electric power steering apparatus that calculates a first current command value based on at least a steering torque and performs an assist-control of a steering system by driving a motor based on the first current command value, including: a configuration of a model following control including a viscoelastic model as a reference model within a predetermined angle at front of a rack end, wherein an offset is given to input or output of the viscoelastic model for preventing an overheat, resulting in suppressing a rack end hitting.

[Problem]

An object of the present invention is to provide a high-performance electric power steering apparatus that constitutes a control system based on a physical model, constitutes a model following control that an output (a distance to a rack end) of a controlled object follows-up to a reference model, eliminates or reduces the occurrences of a noisy sound and a shock force at an end hitting without giving any uncomfortable steering feeling to a driver, and reduces the end hitting.

[Means for solving the problem]

The present invention is the electric power steering apparatus that calculates a current command value based on at least a steering torque and performs an assist-control of a steering system by driving a motor based on the current command value, comprising: a configuration of a model following control including a viscoelastic model as a reference model within a predetermined angle at front of a rack end so as to suppress a rack end hitting.

[Problem]

An object of the present invention is to provide a motor control unit that the heat generation of FETs is not concentrated in one FET and the heat generation is distributed to the plural FETs by operating the duties of all three-phases in a case that the driving of the motor is stopped.

[Means for Solving the Problem]

The present invention is the motor control unit comprising a current detector; an upper-stage maximum heat generation-phase specifying means to calculate respective heat generation amounts of upper-stage FETs and specify an upper-stage maximum heat generation phase; a lower-stage maximum heat generation-phase specifying means to calculate respective heat generation amounts of lower-stage FETs and specify a lower-stage maximum heat generation phase; an upper-stage selecting means to select an upper-stage selecting duty and an upper-stage selecting phase current based on the upper-stage maximum heat generation phase; a lower-stage selecting means to select a lower-stage selecting duty and a lower-stage selecting phase current based on the lower-stage maximum heat generation phase; a duty operating amount calculating section to calculate a duty operating amount; and a duty operating section to operate the respective phase duties based on the duty operating amount.

A turning control device includes: a steering angular displacement calculation unit configured to, when a third steering angle that is either a first steering angle of a turning mechanism or a second steering angle of a steering mechanism, is in an angular range from a maximum angle to a threshold steering angle, calculate a steering angular displacement of the third steering angle with the threshold steering angle used as a reference; a steering angle correction value calculation unit configured to calculate a steering angle correction value according to at least the steering angular displacement; a steering angle correction value limiting unit configured to limit the steering angle correction value according to at least a steering state, the third steering angle, and angular velocity thereof; a corrected target steering angle calculation unit configured to correct the target steering angle of the turning mechanism with a limited steering angle correction value.

In order to suppress an electric power steering device from generating a contact noise due to operation of a mechanical stopper and a rack stopper, there is provided a control unit in which a command signal Io applied to an electric motor used for assisting the steering power is calculated taking into consideration both a rack stopper side damping correction represented by a rack side damping correction signal Dr calculated in a rack side damping correction amount calculation part 21 and a mechanical stopper side damping correction represented by a mechanical side damping correction signal Dm calculated in a mechanical side damping correction amount calculation part 23.

An electric power steering apparatus includes a control section that includes a feed-back control section which sets a viscoelastic model as a reference model within a predetermined angle at front of a rack end. The feed-back control section includes a feed-back element to calculate a target rack displacement based on an input-side rack axial force and a control element to output an output-side rack axial force based on a position deviation between the target rack displacement and a rack displacement.

Disclosed is a method of control a motor driven power steering system. The method includes determining an end holding driving, by a control unit, turning on/off a damping boost gain application mode according to a result of determination for the end holding driving, by the control unit, multiplying an output value according to turning on/off of the damping boost gain application mode by an output value from the damping output value detection unit, and outputting the multiplied value as a damping correction value, by the control unit, and reflecting the damping correction value to control an output torque of a motor in a rack-end-stop control period, by the control unit.

The present disclosure relates to a steering control system, a steering control device, and a steering control method. More specifically, a steering control system according to the present disclosure comprises: an actuator driven at a target driving speed and with a target output current on the basis of an input control signal; a rack bar axially moving by the drive of the actuator; a location sensor for detecting the location of a rack included in the rack bar; and a steering control device for calculating a target rack stroke of the rack on the basis of at least one of a driving speed of a vehicle, a steering angle of a steering wheel and a rotation speed of the steering wheel, and generating a control signal such that the rack moves by the target rack stroke to control the drive of the actuator.

A steering control device for a vehicle controls a steering device having a steering mechanism and a drive unit configured to provide the steering mechanism with steering force for the wheels. The steering control device includes a detection unit to detect the steering angle; and a control unit to calculate a target value of a current to be supplied to the drive unit as a current command value, and execute automatic steering control to automatically control steering of the vehicle by causing the drive unit to be supplied with the current of the current command value. When an absolute value of the steering angle comes to a predetermined first threshold or more during the automatic steering control, the control unit decreases an upper limit value of an absolute value of the current command value as the absolute value of the steering angle increases.