A turning device includes: a motor configured to generate a drive force for independently steering a steered wheel; a speed reducer connected to a rotary shaft body of the motor; and a brake configured to suppress transfer of torque between the motor and the speed reducer.

A motor controller includes: a main motor drive circuit configured to control driving of a multi-phase electric motor; a backup motor drive circuit configured to control driving of the multi-phase electric motor, when an abnormality occurs at the main motor drive circuit; and an abnormality diagnosis unit configured to diagnose the abnormality of the main and backup motor drive circuits. In a normal drive state, only the main motor drive circuit is configured to drive the multi-phase electric motor, and in a backup drive state, when the abnormality diagnosis unit diagnoses that the abnormality occurs at the main motor drive circuit as a diagnoses result, a motor current of a phase output unit where the abnormality occurs is cut off, and the phase output unit that has been cut off is replaced with another phase output unit of a same phase in the backup motor drive circuit.

A steer-by-wire system for a motor vehicle includes at least two wheels which are steerable independently of one another in a normal operating mode of the steer-by-wire system, at least two steering actuators, each one being assigned to one of the steerable wheels and being configured for adjusting a steering angle of the particular steerable wheel, and at least one steering electronics system which is signally connected to the steering actuators and which is configured for controlling the steering actuators individually on the basis of steering commands.

An electric power steering apparatus that calculates a current command value based on at least a steering torque, performs a PWM-control of a brushless motor by an inverter based on the current command value, performs a current control by detecting a rotational angle of the brushless motor, and performs an assist-control of a steering system. The apparatus includes three rotational angle detecting systems to detect three rotational angles of the brushless motor; and an angle diagnosing section that compares absolute values of differences on respective angles outputted from the three rotational angle detecting systems with a threshold, and performs a process by diagnosing whether the rotational angle detecting systems are normal or abnormal; wherein the assist control is continuously performed by using output angles outputted from systems diagnosed as being normal.

A steering control device capable of suppressing a reduction in reliability even in the case where the redundancy of the power source is increased is provided. A steering ECU includes two control systems in which different external power sources are connected to two drive circuits. The low potential sides of the drive circuits and the low potential sides of the corresponding external power sources are independently connected to each other via power source ground lines for the two control systems. The low potential sides of the drive circuits are connected to each other via an internal ground. Two current detection circuits are provided between the power source ground lines and the internal ground to detect power source ground current values, respectively. The steering ECU includes microcomputers that detect a ground abnormality on the basis of the results of detection performed by the current detection circuits.

A current sensor state determination device determines that an abnormality is caused in a current sensor when a sum of phase currents based on current detection values from each of the current sensors in three phases is greater than a first determination value, and determines that no abnormality is caused in the current sensor when the sum of phase currents is equal to or less than the first determination value. The state determination device determines that the current sensor is normal when it is determined that (i) no abnormality is caused in a preset electric angle range equal to or less than one electric-angle cycle of the rotating electric machine and (ii) a value of an electric current flowing in the rotating electric machine in a rotating coordinates system calculated based on the current detection value is equal to or greater than a second determination value.

A steering system for a steerable vehicle includes at least two steerable wheels, to each of which an electrically operable steering actuator to enable the steering actuator to adjust the steering angle of the particular steerable wheel by application of a steering torque. The at least two steering actuators can be mechanically coupled to each other so that, in the event of a failure or a malfunction of the one steering actuator, the steering torque provided by the other steering actuator can be transferred to the one steering actuator, to enable the steering angle of the steerable wheel assigned to the failed steering actuator to still be changed via the other steering actuator. The at least two steering actuators can be mechanically coupled to each other via a bendable shaft or via a universal joint shaft which includes at least two rigid shafts hingedly connected via a universal joint.

Determining a sealing integrity of a steering assembly determining when the steering assembly is performing a steering event, determining an expected pressure change associated with the steering event, and receiving data from the pressure sensing member. During performance of the steering event, the controller analyzes the data from the pressure sensing member and determines when the pressure sensing member detects the expected pressure change and reduces an incident counter. When the pressure sensing member does not detect the expected pressure change, the incident counter is increased.

A motor drive circuit for use in driving a motor having two or more phases comprising a motor bridge having, for each phase of the motor, a bridge arm comprising an upper switch and a lower switch that in normal operation may be opened and closed to modulate the voltage applied to the respective phases in response to drive signals from a motor control circuit, at least one solid state phase isolation relay that is provided in series in an electrical path connecting a respective phase of the motor to a respective bridge arm, the relay being closed in normal operation so that current can flow in the phase and is held open in a fault mode of operation to prevent the flow of current in the phase. The circuit also includes monitoring means for monitoring the current waveform in the phase to provide, at least in a fault mode of operation, an output indicative of when it is safe to open the SSPIR without causing damage due to the SSPIR due to an avalanche mode, and a control circuit that during normal operation applies a voltage to each device that is sufficient to hold the SSPIR closed and which, in the fault mode of operation, responds to the output of the monitoring means to reduce the voltage applied to each SSPIR to a level that causes the SSPIR to open at the safe time.

The microcomputer calculates a first assist component based on a vehicle speed value and a steering torque, calculates a rotation angle command value based on at least the vehicle speed value and a first assist component, and calculates a second assist component by adjusting a rotation angle to the rotation angle command value through feedback control. The microcomputer sets a limited state 1 where the second assist component is disabled when a vehicle is stationary. During an abnormality determination period during which the vehicle speed value is determined to be abnormal, the microcomputer sets the vehicle speed value to a provisional vehicle speed value. Further, in a limited state 2 that is set when the vehicle is stationary during the abnormality determination period, the microcomputer calculates the first assist component based on a provisional vehicle speed value, and disables the second assist component.