Abstract: A malfunction detection method detects a malfunction in an electronic control device. The electronic control device includes a normal power supply terminal connected to a normal power supply mounted on a vehicle, a starting power supply terminal connected to a starting power supply, a controller activated by supply of a normal voltage, and a wake-up circuit having a wake-up switch to open and close a power supply path from the normal power supply terminal to the controller. The wake-up circuit turns on the wake-up switch when a starting voltage input to the starting power supply terminal is equal to or greater than an ON threshold. The malfunction detection method includes determining by the controller that the wake-up switch has an ON sticking malfunction when the normal voltage is equal to or greater than a threshold and the starting voltage is less than the ON threshold.

Abstract: A sensor device includes multiple sensors, a controller, and multiple communication paths. Each of the sensors includes a sensor element and a sensor-side communication circuit. The sensor element detects a change in a physical quantity. The sensor-side communication circuit transmits a signal having a response signal according to a detected value of the sensor element, in response to a request signal transmitted by a controller. The controller includes a controller-side communication circuit and an arithmetic processing unit. The controller-side communication circuit transmits the request signal and receives the response signal. The arithmetic processing units calculates detection data according to the response signal. The communication paths respectively connect the sensors to the controller. The arithmetic processing unit calculates detection data by adopting respective response signals in parallel acquired from the sensors.

Abstract: A steer-by-wire rudder system includes a first system having a first motor unit that drives a rudder mechanism and a first control unit that controls the first motor unit, and a second system having a second motor unit that drives the rudder mechanism and a second control unit that controls the second motor unit. The first control unit and the second control unit perform cooperative control for controlling the first motor unit and the second control unit to cooperate with each other. When the cooperative control is not performed, one of the control of the first motor unit by the first control unit and the control of the second motor unit by the second control unit continues, and the other thereof stops.

Abstract: Control calculation units of a back system in each actuator operate by a collaborative drive mode in which a torque is output to a motor drive unit by using an information transmitted and received mutually by a communication between the systems in common. Cooperative control calculation units in a reaction force actuator and a turning actuator can operate in cooperation with each other based on the information transmitted and received mutually by a communication between actuators. A communication between adjacent systems and a communication between adjacent actuators are restored, when a focus control calculation unit is restored, after the focus control calculation unit is stopped during operation and at least one of the communication between adjacent systems or the communication between adjacent actuators is interrupted.

Abstract: A motor drive system is provided in a steer-by-wire system in which a steering mechanism and a turning mechanism of a vehicle are mechanically separated. The motor drive system includes a reaction force actuator and a turning actuator. The reaction force actuator functions as a motor configured to output a reaction force torque corresponding to a steering torque of a driver and a road surface reaction force. The turning actuator functions as a motor configured to output a turning torque for turning wheels. Each of the reaction force actuator and the turning actuator includes a plurality of control calculation units provided redundantly and each configured to perform a calculation related to a motor drive control, and a plurality of motor drive units provided redundantly and each configured to drive and output the torque based on a drive signal generated by a corresponding control calculation unit.

Abstract: A position detecting device for a motor includes a resolver, amplifiers and a microcomputer. The microcomputer corrects an amplified sine wave signal to have the same amplitude in both positive and negative polarities, and corrects an amplified cosine wave signal to have the same amplitude in both positive and negative polarities. The microcomputer further corrects the corrected sine wave signal or the corrected cosine wave signal to have the same amplitude therebetween. The rotation position is determined accurately based on the sine wave signal and the cosine wave signal of the same amplitude, even if the amplifiers have different operation characteristics.

Abstract: A fault detection unit detects a fault occurred in a detecting device which detects a rotational angle of a rotor with respect to a stator from sine and cosine wave signals having amplitudes modulated in a sinusoidal wave shape in a cycle of rotation of the rotor. The unit produces a judging value from the signals, judges occurrence of a fault from the value placed out of a normal range, and judges the device to be in a tentative fault state when the judgment is continued. After this judgment, when the rotational angle is changed over its entire range while the value is placed within the normal range, the unit judges the device to have returned to a normal state. In contrast, when the judgment is still continued, the unit judges the device to be in a determinate fault state and decides the occurrence of the fault.

Abstract: A storage part stores an initial sum, which is obtained by summing a steering angle of a steering wheel and a rotational angle of an electric actuator before checking of unlocking of a transmission ratio variable mechanism by a computer part. The computer part determines that the storage part is abnormal when a sum, which is obtained by summing the steering angle of the steering wheel and the rotational angle of the electric actuator after the checking of the unlocking of the transmission ratio variable mechanism by the computer part, differs from the initial sum, which is retrieved from the storage part.

Abstract: A position detecting device for a motor includes a resolver, amplifiers and a microcomputer. The microcomputer corrects an amplified sine wave signal to have the same amplitude in both positive and negative polarities, and corrects an amplified cosine wave signal to have the same amplitude in both positive and negative polarities. The microcomputer further corrects the corrected sine wave signal or the corrected cosine wave signal to have the same amplitude therebetween. The rotation position is determined accurately based on the sine wave signal and the cosine wave signal of the same amplitude, even if the amplifiers have different operation characteristics.

Abstract: An inverter circuit includes a bridge circuit constituted of a plurality of pairs of a high-side switching element and a low-side switching element, a command signal processing section, a pulse generating section for generating pulse signals to control the inverter bridge circuit according to the command signal to have a dead time to prevent short circuiting of the dc power source and a command signal compensation section. The compensation section modifies the command signal according to a current voltage level of the dc power source to control the dead zone, thereby preventing deformation of ac output power of the bridge circuit.

Abstract: A fault detection unit detects a fault occurred in a detecting device which detects a rotational angle of a rotor with respect to a stator from sine and cosine wave signals having amplitudes modulated in a sinusoidal wave shape in a cycle of rotation of the rotor. The unit produces a judging value from the signals, judges occurrence of a fault from the value placed out of a normal range, and judges the device to be in a tentative fault state when the judgment is continued. After this judgment, when the rotational angle is changed over its entire range while the value is placed within the normal range, the unit judges the device to have returned to a normal state. In contrast, when the judgment is still continued, the unit judges the device to be in a determinate fault state and decides the occurrence of the fault.

Abstract: A storage part stores an initial sum, which is obtained by summing a steering angle of a steering wheel and a rotational angle of an electric actuator before checking of unlocking of a transmission ratio variable mechanism by a computer part. The computer part determines that the storage part is abnormal when a sum, which is obtained by summing the steering angle of the steering wheel and the rotational angle of the electric actuator after the checking of the unlocking of the transmission ratio variable mechanism by the computer part, differs from the initial sum, which is retrieved from the storage part.

Abstract: A motor driving system for an electric motor includes a pulse width modulating circuit which provides driving pulse signals whose pulse width is modulated to have a prescribed duty ratio, an inverter having PWM-controlled switch elements, a voltage calculating circuit which calculates levels of voltage to be respectively applied between the power source and the phase windings, a current calculating circuit which calculates reference values of current of the inverter from levels of the voltage applied between the power source and the phase windings of the electric motor and resistances disposed between the power source and the phase windings, a current detecting circuit which detects actual values of current of the inverter, and a processor which judges abnormality if one of the actual value of current of the inverter is a preset value different from corresponding one of the reference values.

Abstract: An inverter circuit includes a bridge circuit constituted of a plurality of pairs of a high-side switching element and a low-side switching element, a command signal processing section, a pulse generating section for generating pulse signals to control the inverter bridge circuit according to the command signal to have a dead time to prevent short circuiting of the dc power source and a command signal compensation section. The compensation section modifies the command signal according to a current voltage level of the dc power source to control the dead zone, thereby preventing deformation of ac output power of the bridge circuit.

Abstract: A resolver output correction device receives sine output signal and cosine output signal from a resolver. Each of the sine output signal and the cosine output signal has an offset error and a gain differential error due to a secular variation. The correction device detects maximal and minimal values with respect to both the sine output signal and the cosine output signal. It calculates average values between the maximal values and the minimal values. Then, it corrects the offsets of the signals based on the average values. It also calculates gain differentials between the maximal value and the minimal value with respect to both the sine and cosine signals. Then, it corrects the gain differentials of the signals based on the calculated gain differentials. As a result, both the offset and gain errors of the signals are corrected with accuracy.

Abstract: A motor driving system for an electric motor includes a pulse width modulating circuit which provides driving pulse signals whose pulse width is modulated to have a prescribed duty ratio, an inverter having PWM-controlled switch elements, a voltage calculating circuit which calculates levels of voltage to be respectively applied between the power source and the phase windings, a current calculating circuit which calculates reference values of current of the inverter from levels of the voltage applied between the power source and the phase windings of the electric motor and resistances disposed between the power source and the phase windings, a current detecting circuit which detects actual values of current of the inverter, and a processor which judges abnormality if one of the actual value of current of the inverter is a preset value different from corresponding one of the reference values.

Abstract: A variable transmission-ratio steering apparatus comprises an input shaft coupled to a steering wheel, an output shaft operatively coupled to steerable road wheels. The apparatus comprises an electric motor varying a rotation angle of the output shaft by providing a drive force to the output shaft, the drive force being decided based on a rotation angle of the input shaft, a lock member locking the input shaft to the output shaft in an unlockable manner, and an excitation coil enabling the lock member to be actuated to unlock a lock between the input and output shafts. The apparatus further comprises a unit controlling current to be supplied to the excitation coil and a unit detecting abnormality of the excitation coil based on both of a command value of current to flow through the excitation coil and a value of the current actually flowing through the excitation coil.

Abstract: A variable transmission-ratio steering apparatus comprises an input shaft coupled to a steering wheel, an output shaft operatively coupled to steerable road wheels. The apparatus comprises an electric motor varying a rotation angle of the output shaft by providing a drive force to the output shaft, the drive force being decided based on a rotation angle of the input shaft, a lock member locking the input shaft to the output shaft in an unlockable manner, and an excitation coil enabling the lock member to be actuated to unlock a lock between the input and output shafts. The apparatus further comprises a unit controlling current to be supplied to the excitation coil and a unit detecting abnormality of the excitation coil based on both of a command value of current to flow through the excitation coil and a value of the current actually flowing through the excitation coil.

Abstract: A monitoring system monitors a microcomputer in which an angle calculator calculates the electrical angle of a motor using output signals from a rotation angle sensor. In the microcomputer, a control signal generator generates a coded control signal that indicates the range to which the calculated electrical angle belongs. In the monitoring system, the electrical angle detected by the rotation angle sensor is multiplied by an excitation signal provided for the rotation angle sensor, and an angle detector detects the resultant signals. Based on the detected signals, a supervisory signal generator outputs a coded supervisory signal that indicates the range to which the electrical angle detected by the rotation angle sensor belongs. Then a fault detector determines that a failure occurs in the microcomputer, if a comparator determines that the coded control signal disagrees with the coded supervisory signal.

Abstract: A resolver output correction device receives sine output signal and cosine output signal from a resolver. Each of the sine output signal and the cosine output signal has an offset error and a gain differential error due to a secular variation. The correction device detects maximal and minimal values with respect to both the sine output signal and the cosine output signal. It calculates average values between the maximal values and the minimal values. Then, it corrects the offsets of the signals based on the average values. It also calculates gain differentials between the maximal value and the minimal value with respect to both the sine and cosine signals. Then, it corrects the gain differentials of the signals based on the calculated gain differentials. As a result, both the offset and gain errors of the signals are corrected with accuracy.