A servo controller calculates a base assist command, which is a basic command value of the assist torque, so that the steering torque follows a target steering torque. An estimated load torque calculation section calculates an estimated load torque. A target steering torque calculation section calculates a target steering torque using a map that defines a relationship between the estimated load torque and the target steering torque. The estimated load torque calculation section calculates the estimated load torque based on the steering torque or the target steering torque and an estimated load calculation assist command corresponding to a calculation result of only a proportional integral control calculation among the control calculations in the servo controller.

A steering apparatus is for turning steerable wheels of a vehicle. The steering apparatus includes a steering wheel rotatable about a steering axis to effect turning of the steerable vehicle wheels. A first shaft is connected to the steering wheel and rotatable about a first shaft axis. A first nut is threadably connected to and longitudinally movable along the first shaft. A second nut is connected to the first nut such that the first and second nuts are prevented from moving longitudinally relative to one another. A second shaft is rotatable about a second shaft axis. The second nut is threadably connected to and longitudinally movable along the second shaft. A motor is connected to the second shaft and controllable to apply a force to the steering wheel through the first and second shafts and the first and second nuts.

A rotary electric machine control apparatus is provided which controls energization of a rotary electric machine having a plurality of winding sets. The apparatus includes an energization control circuit that is provided for each of the winding sets and has a switching element related to switching of energization to the winding set, a driver circuit that outputs a drive signal to the switching element through a signal line connected to the switching element, and a protection element that is connected to the signal line and in parallel with the switching element. When combinations of the winding sets and electronic components including the energization control circuit provided for each of the winding sets are regarded as systems, in at least one of the systems, performance of the protection element is differentiated from that in the other system to make noise resistance different from noise resistance in the other system.

A work vehicle includes an automatic steering mechanism to automatically steer a vehicle body so that the vehicle body travels on a target travel path. The automatic steering mechanism includes a motor to drive a steering shaft to rotate, and is in a steering tower. The motor is under a steering wheel and laterally adjacent to the steering shaft.

A rack bar assembly for a rack electric power steering system is provided. The rack bar assembly includes a first rack bar extending axially. The rack bar assembly also includes a second rack bar extending axially, wherein the first rack bar and the second rack bar are spaced a radial distance from each other and oriented parallel to each other.

An input torque fundamental component computation circuit includes: a torque command value computation circuit that computes a torque command value corresponding to a target value for steering torque that is to be input by a driver for drive torque obtained by adding the steering torque to an input torque fundamental component; and a torque F/B control circuit that computes the input torque fundamental component through execution of torque feedback control for causing the steering torque to follow the torque command value. A target steering angle computation circuit computes a target steering angle on the basis of the input torque fundamental component. A steering-side control circuit computes target reaction force torque on the basis of execution of angle feedback control for causing a steering angle to follow a target steering angle. The torque command value computation circuit computes the torque command value in consideration of the grip state amount.

An electric power steering apparatus has a rotation detection device that includes a sensor section that detects a rotation of a motor and outputs a mechanical angle and a count value, and a signal obtainer that obtains the mechanical angle and the count value from the sensor section. The rotation detection device also includes an absolute angle calculator that calculates an absolute angle based on the mechanical angle and the count value and a storage area for storing a reference value that is used for correcting calculation errors in the absolute angle.

A rotary electric machine control device for controlling a rotary electric machine having multiple winding sets includes multiple inverter circuits, multiple power supply relays, and multiple controllers provided for respective systems. Each of the controllers is configured to monitor an abnormality of a subject system and an abnormality of a different system and is configured to turn off a power supply relay in the subject system when an abnormality requiring a power supply stop occurs in the subject system. Each of the controllers is further configured to acquire power supply relay information related to a state of the power supply relay of the different system through a signal line, and is configured to monitor the abnormality of the different system based on the power supply relay information.

Provided is a steering control unit for supplying an appropriate steering reaction force in accordance with situations. A reaction force component calculation circuit includes a base reaction force calculation circuit that calculates a base reaction force, an end reaction force calculation circuit that calculates an end reaction force, an obstruction-hit reaction force calculation circuit that calculates an obstruction-hit reaction force, and a steered-side limit reaction force calculation circuit that calculates a steered-side limit reaction force. A reaction force selector circuit selects, as a selected reaction force, one of the end reaction force, the obstruction-hit reaction force, and the steered-side limit reaction force. The reaction force component calculation circuit calculates and outputs a reaction force component by adding the selected reaction force to the base reaction force.

A rotary electric machine control apparatus is provided which controls energization of a rotary electric machine having a plurality of winding sets. The apparatus includes an energization control circuit that is provided for each of the winding sets and has a switching element related to switching of energization to the winding set, a driver circuit that outputs a drive signal to the switching element through a signal line connected to the switching element, and a protection element that is connected to the signal line and in parallel with the switching element. When combinations of the winding sets and electronic components including the energization control circuit provided for each of the winding sets are regarded as systems, in at least one of the systems, performance of the protection element is differentiated from that in the other system to make noise resistance different from noise resistance in the other system.