Disclosed herein is a method and arrangement for safe limiting of torque overlay intervention in a power assisted steering system of a road vehicle having an autonomous steering function arranged to selectively apply a steering wheel overlay torque to a normal steering assistance torque. A wheel self-aligning torque (ƒ.sub.R) of the road vehicle is modelled for a current vehicle velocity (ν) and pinion angle (δ.sub.w). A steering wheel overlay torque request (τ.sub.R) is received. Based on the received steering wheel overlay torque request (τ.sub.R) is provided a steering wheel overlay torque (τ.sub.A) in hands-off applications limited to a safe set interval that is symmetrical around the modeled wheel self-aligning torque (ƒ.sub.R).

In a control device for an AC rotary machine, having an angle detector for detecting an electrical angle of the AC rotary machine, a detection error produced by the angle detector due to a noise magnetic field generated by a multi-phase alternating current flowing through an inverter connection unit is corrected using a correction signal having a phase and an amplitude that are determined in accordance with a relative positional relationship between the inverter connection unit and the angle detector and a current vector of the multi-phase alternating current, whereupon an inverter is controlled on the basis of the corrected electrical angle. As a result, a simple, low-cost control device for an AC rotary machine with which an angular position of a rotor can be detected with a high degree of precision is obtained.

A vehicle is provided including an electronic power steering system, an electronic throttle control system, and a stability control system.

A method of operating an electric power assisted steering system of the kind in which an electric motor applies an assistance torque to a part of the steering system as a function of an assistance torque signal, the assistance torque reducing the force required by the driver to turn a steering wheel, comprises during normal operation generating an assistance torque signal that is dependent on the torque applied by the driver, and during a fault operation in which the torque applied by the driver is not reliably known to the system generating an assistance torque signal that is derived from a first term that has a value that varies as a function of the angular position of the steering relative to a changeable datum, the angular position of the changeable datum being updated in the event that the direction of rotation of the steering changes.

A steering holding judging apparatus for the vehicle including: at least two steering angle sensors to detect a steering angle; and a steering state judging section to calculate a hysteresis central value by using a hysteresis signal that sets a hysteresis width to the two steering angle sensor, judge a steering state using the hysteresis central value, and output provisional steering information, wherein a steering holding state is detected based on the provisional steering information, and the electric power steering apparatus equipped with the steering holding judging apparatus for the vehicle.

A power steering apparatus includes: a first detection element arranged to sense a rotation angle of the first gear based on a variation of a magnetic field generated by the first magnetic member; a second detection element arranged to sense a rotation angle of the second gear based on a variation of a magnetic field generated by the second magnetic member; an absolute steering angle calculating circuit configured to calculate an absolute steering angle of the steering wheel from an neutral position of the steering wheel at which the steered wheel directs in a straight direction, by a combination between the rotation angle of the first gear and the rotation angle of the second gear; and a control section configured to drive and control the electric motor based on the absolute steering angle.

An electric power steering device includes: a steering torque sensor that detects a steering torque; a current command value calculation unit that calculates a current command value based on the steering torque; an electric motor that generates a steering assist torque; a motor control unit that controls and drives the electric motor based on the current command value; a navigation controller and a GPS receiver that detects position information of a vehicle; and an operation assist unit that stores, in a map database, the steering torque detected by the steering torque sensor and the position information of the vehicle upon detection of the steering torque in association with each other and executes operation assist processing for assisting the driver in operating the steering wheel based on a past steering torque corresponding to current position information.

A method for synchronizing an MDPS motor and a motor position sensor may include: sequentially aligning, by a controller, a rotor of the MDPS motor by sequentially applying preset three-phase current pulses to the MDPS motor, the three-phase current pulses corresponding to one electrical-angle cycle of the rotor of the MDPS motor, and detecting an actual rotational position of the aligned rotor through the motor position sensor; determining a zero point rotational position of the rotor based on the actual rotational position; determining a reference rotational position of the rotor based on the actual rotational position and the number of pole pairs in the MDPS motor, and determining an offset rotational position of the rotor based on the actual rotational position and the reference rotational position; and correcting the zero point rotational position by adding the offset rotational position to the zero point rotational position.

A steering control device controls an assist torque to be outputted by a motor connected to a steering system mechanism generating a steering torque. A response compensation filter performs a filter process compensating for a response in a specific frequency band with respect to a target steering torque generated by a target generation unit, and outputs a response-compensated target steering torque (Ts**). A servo controller calculates an assist torque command value (Ta*) in order for a torque deviation (ΔTs), which is a difference between the steering torque (Ts) and the response-compensated target steering torque (Ts**), to become zero. A transfer characteristic of the response compensation filter is set to suppress a mechanical resonance frequency band where a gain due to resonance of the steering system mechanism becomes large.

In a drive assist system, a map data acquiring section acquires at least one of a driver's operation ability and a load of a vehicle. An adjustment section determines an assist control amount as a control parameter of drive assist for the vehicle so that a degree of the driver's operation is increased according to reduction of the driver's operation ability or increasing of the load of the vehicle. An assist control amount calculation section transmits the assist control amount to a steering motor and a notification section so as to execute the drive assist for the vehicle.