A control system calculates inputs to a control target that has m inputs and n outputs (m=n, each of m and n is a natural number that is more than one), while designating a plurality of combinations of the inputs and the outputs. A feedback controller calculates, with respect to each designated combination, a control input to a non-interference controller based on a difference between a target value and a current value of the control quantity to make the current value follow the target value. The non-interference controller executes, with respect to each designated combination, a non-interference control to reduce influence due to mutual interference between n control quantities. This reduces the number of combinations of the inputs and the outputs, the combinations whose mutual interference needs considering; thereby, the non-interference control may be easily achieved.

A steered-angle command value calculation circuit calculates a steered-angle command value by adding a steering torque to a first assist component that is a sum of a basic assist control amount, a hysteresis control amount and a damping control amount. A steered-angle feedback control circuit calculates a second assist component by angle feedback control based on the steered-angle command value. A compensation control circuit generates the hysteresis control amount and the damping control amount based on a determination flag generated by a hand release determination circuit and indicating whether or not the steering state corresponds to a hand release state. The hand release determination circuit determines whether or not the steering state corresponds to the hand release state based on signs of a steering angle calculated by a steering-angle calculation circuit, a steering angular velocity that is a differential value of the steering angle, and a steering angle acceleration.

A steered-angle command value calculation circuit calculates a steered-angle command value by adding a steering torque to a first assist component that is a sum of a basic assist control amount, a hysteresis control amount and a damping control amount. A steered-angle feedback control circuit calculates a second assist component by angle feedback control based on the steered-angle command value. A compensation control circuit generates the hysteresis control amount and the damping control amount based on a determination flag generated by a hand release determination circuit and indicating whether or not the steering state corresponds to a hand release state. The hand release determination circuit determines whether or not the steering state corresponds to the hand release state based on signs of a steering angle calculated by a steering-angle calculation circuit, a steering angular velocity that is a differential value of the steering angle, and a steering angle acceleration.

A synchronization signal generating portion of a transmitter microcomputer generates a synchronization signal that is synchronized with a drive timing of the own microcomputer and also causes to synchronize the drive timing of microcomputers, and transmits to a receiver microcomputer. A timing corrector of the receiver microcomputer is capable of correcting the drive timing of the own microcomputer so as to synchronize with the received synchronization signal, and includes a timing determiner which determines whether the received synchronization signal is normal or abnormal. The receiver microcomputer permits the timing correction if the synchronization signal is determined to be normal in the timing determination, and prohibits timing correction and drives the motor asynchronously with the transmitter microcomputer if the synchronization signal is determined to be abnormal.

A synchronization signal generating portion of a transmitter microcomputer generates a synchronization signal that is synchronized with a drive timing of the own microcomputer and also causes to synchronize the drive timing of microcomputers, and transmits to a receiver microcomputer. A timing corrector of the receiver microcomputer is capable of correcting the drive timing of the own microcomputer so as to synchronize with the received synchronization signal, and includes a timing determiner which determines whether the received synchronization signal is normal or abnormal. The receiver microcomputer permits the timing correction if the synchronization signal is determined to be normal in the timing determination, and prohibits timing correction and drives the motor asynchronously with the transmitter microcomputer if the synchronization signal is determined to be abnormal.

Provided are a steering control device and the like, including the steps of: calculating a steering assist torque to be applied to an actuator for applying the steering assist torque to a steering system of a vehicle in order to improve return characteristics of the steering system; determining a steering state of a driver; correcting the steering assist torque depending on a result of the steering state determination; and controlling the actuator depending on the corrected steering assist torque, in which the step of determining a steering state of a driver includes determining the steering state of the driver based on a combination of at least two of the following: a manually-operating steering state determination; an abrupt steering wheel return determination; a high-acceleration steering wheel return determination; a manual return steering determination; and an additional-steering determination.

Provided are a steering control device and the like, including the steps of: calculating a steering assist torque to be applied to an actuator for applying the steering assist torque to a steering system of a vehicle in order to improve return characteristics of the steering system; determining a steering state of a driver; correcting the steering assist torque depending on a result of the steering state determination; and controlling the actuator depending on the corrected steering assist torque, in which the step of determining a steering state of a driver includes determining the steering state of the driver based on a combination of at least two of the following: a manually-operating steering state determination; an abrupt steering wheel return determination; a high-acceleration steering wheel return determination; a manual return steering determination; and an additional-steering determination.

A vehicle comprising a closed-loop electric power assisted steering (EPAS) system comprising a control unit configured to compute an artificial friction component and to compute a desired reference torque (τref) incorporating the artificial friction component, wherein the artificial friction component is dependent upon steering wheel angle (α).

A vehicle comprising a closed-loop electric power assisted steering (EPAS) system comprising a control unit configured to compute an artificial friction component and to compute a desired reference torque (τref) incorporating the artificial friction component, wherein the artificial friction component is dependent upon steering wheel angle (α).

A method of controlling disturbances associated with electric power steering (EPS) systems maintains an original assist torque to feedback signal in the EPS, such as a column torque, and further minimizes the impact from the disturbance source to the feedback signal so that the disturbance is rejected while the original steering feel is maintained. The method further considers interaction of the rejection feature with other functions of the EPS. In one embodiment, relationships for isolating the disturbance are achieved by utilizing a combined feedback and feed-forward compensator.