A system for determining driver torque includes a rack torque estimator module that determines an estimated rack torque value based on a motor angle, and a motor velocity. The system further includes a driver intent detection module that computes a disturbance torque scaling factor based on the estimated rack torque value. The system further includes a blend module that generates a motor torque assist command based on a scaled value of the estimated rack torque value using the disturbance torque scaling factor.

The power control unit sets a drive interval for driving the sensor by providing power intermittently to the sensor to a first time interval when no change is detected in the sine-wave signal and the cosine-wave signal, sets to the second time interval that is shorter than the first time interval when a change in only one of the sine-wave signal and the cosine-wave signal is detected, and sets to the third time interval that is shorter than the second time interval when a change in one of the sine-wave signal and the cosine-wave signal is detected and then a change in the other is detected.

An electric power steering device includes a steering angle reference yaw rate calculation section that calculates a steering angle reference yaw rate by using a speed of a vehicle and a steering angle of a steering wheel, a torque estimation device that estimates a self-aligning torque (SAT) generated in a turning wheel of the vehicle on the basis of a measured yaw rate or the steering angle reference yaw rate, the absolute value of which is smaller, and the speed of the vehicle, and estimates a required assist torque on the basis of the estimated SAT, and an abnormality determination section that determines whether or not a steering torque sensor is abnormal. If the steering torque sensor is abnormal, an EPS control device controls drive of an assist motor using the required assist torque estimated by the torque estimation device, in place of a steering torque.

A rotation detection apparatus, a rotation angle detection apparatus are provided which allow appropriate detection of an abnormality in a portion that detects rotation of a rotating shaft. A first arithmetic circuit calculates a rotating direction and a number of rotations of the rotating shaft based on a change in a combination of positivity and negativity of a first electric signal (first sine signal) and a third electric signal (first cosine signal). A second arithmetic circuit calculates a rotating direction and a number of rotations of the rotating shaft based on a change in a combination of positivity and negativity of a second electric signal (second sine signal) and a fourth electric signal (second cosine signal). An abnormality determination circuit determines whether each of the first and second arithmetic circuits and is abnormal based on the two rotating directions and calculated by the first and second arithmetic circuits respectively.

A control device for a motor including a first coil and a second coil which are insulated from each other is provided. The control device includes a first circuit and a second circuit that switches a first process to a second process when the first circuit fails. The external circuit generates an instruction for performing a process of increasing an amount of operation which is calculated by one of the first circuit and the second circuit according to the number of control systems when the other of the first circuit and the second circuit fails.

A power steering system includes a torque modifier module that generates a modified torque command in response to a current sensor fault, a magnitude of the modified torque command changes over a time period. The power steering system also includes a feedforward selection module that applies a dynamic feedforward compensation to a motor current command, thereby generating a motor voltage that is applied to a motor of the power steering system, the dynamic feedforward compensation modifies a frequency response of the power steering system.

A fail safe apparatus for an MDPS system may include: a vehicle speed sensor configured to measure a vehicle speed; a gear stage input unit configured to receive a gear stage from a transmission of the vehicle; a GPS vehicle speed calculation unit configured to calculate a GPS vehicle speed based on location information of the vehicle; and a control unit configured to determine whether the vehicle speed is an error, based on one or more of the vehicle speed, the gear stage, and the GPS vehicle speed, and determine vehicle speed data of the MDPS system based on one or more of the gear stage and the GPS vehicle speed.

An electric power steering apparatus that performs an assist control of a steering system, including: at least two respectively independent torque sensors and angle sensors, wherein having a function that respectively calculates steering angles from the torque sensors and the angle sensors to utilize, wherein comparison diagnoses of independent signals are performed and also concurrently individual diagnoses of each individual signal are performed, in a case that it is judged that there is an abnormality in the comparison diagnoses, the angle sensor signals are not used, in a case that it is judged that at least one of the individual diagnoses is abnormal, the angle sensor signal is treated as downgrading, and in a case that it is judged that two or more of the individual diagnoses are abnormal, the angle sensor signals are not used.

In a power steering device and a vehicle-mounted instrument, an abnormality detection accuracy of a state quantity detection means is increased. In an electric power steering device and a vehicle-mounted instrument that are each provided with a plurality of state quantity detection means, an abnormality detection for the state quantity detection means is carried out by comparing detection signals issued from the state quantity detection means provided on a redundant system, and by comparing the detection signals issued from the state quantity detection means with signals that are issued from other state quantity detecting means and calculated to be matched with the same unit as the compared detection signals, a value or close value that is possessed by the largest number of signals is set as a normal value.

An apparatus for monitoring a signal path is provided. The signal path includes a first processing unit, which generates a first signal based on an input signal of the signal path, and a second processing unit, which generates an output signal of the signal path, wherein the output signal depends on the first signal. The apparatus includes an output estimation module configured to determine an estimated output signal of the second processing unit based on the input signal. Further, the apparatus includes a comparison module configured to determine a state of the signal path based on a deviation of the output signal from the estimated output signal.