Provided is a steering controller configured to suppress deterioration of the operability of a steering wheel for steering steered wheels even when a driving voltage for a steering system has been decreased. When a clutch is in a disengaged state and steered wheels are steered by a steered-operation actuator while a reaction force is applied to steering wheel by a reaction-force actuator, if a driving voltage for the steered-operation actuator is decreased, a CPU opens relays and stops generation of torque by the steered-operation actuator. Meanwhile, a CPU engages the clutch and steers the steered wheels through cooperation between a steering torque input into the steering wheel and an assist torque generated by a reaction-force motor.

Provided is a steering controller configured to switch from an interruption state to a transmission state. In a state where power transmission from the steering wheel to steered wheels is interrupted, a maximum value selection processing circuit outputs a maximum value, out of a steered angle and a steering angle, to a limiting reaction force setting processing circuit. When the absolute value of the maximum value has become equal to or larger than a limitation start threshold value, the limiting reaction force setting processing circuit rapidly increases a limiting reaction force. An operation signal generation processing circuit controls a reaction-force motor to achieve a reaction force command value corresponding to the limiting reaction force. When the absolute value of the maximum value has become equal to or larger than an engagement threshold value, a clutch is engaged to transmit reaction force from the steered wheel-side to the steering wheel.

An active suspension system comprises at least one biasing device configured to support a body from a structure, and at least one motor. A magnetorheological (MR) fluid clutch apparatus(es) is coupled to the at least one motor to receive torque from the motor, the MR fluid clutch apparatus controllable to transmit a variable amount of torque. A mechanism is between the at least one MR fluid clutch apparatus and the body to convert the torque received from the at least one MR fluid clutch apparatus into a force on the body. Sensor(s) provide information indicative of a state of the body or structure. A controller receives the information indicative of the state of the body or structure and for outputting a signal to control the at least one MR fluid clutch apparatus in exerting a desired force on the body to control movement of the body according to a desired movement behavior.

An independent steering mechanism of controllable hydraulic locking type for left and right wheels is provided. The independent steering mechanism includes a power steering mechanism, a steering drive mechanism, a hydraulic locking mechanism and an electronic control unit. Power of the left and right steering motors flows through the worm, the worm gear, the gear to drive left and right racks to translate. Outer ends of the left and right racks are connected to left and right tie rods via spherical hinges respectively. Inner ends of the left and right racks are connected to a piston rod and a cylinder barrel via spherical hinges respectively. A left chamber and a right chamber in the hydraulic cylinder are connected to an oil reservoir via an electro-hydraulic valve. The left and right steering motor controllers for the left and right steering motor and the electro-hydraulic valve controller are communicated via CAN bus.

A vehicle steering system includes a clutch provided on a power transmission path extending from a steering wheel to steered wheels, a reactive-force motor connected to a first portion of the power transmission path, which is closer to the steering wheel than the clutch is, a steering motor including a first motor coil and a second motor coil, and connected to a second portion of the power transmission path, which is closer to the steered wheels than the clutch is, a driving circuit configured to supply electric power to the reactive-force motor, a first driving circuit configured to supply electric power to the first motor coil, and a second driving circuit configured to supply electric power to the second motor coil.

An operation mode of a first actuator engaged with a steering rack is determined. An operation mode of a second actuator engaged with a steering column is determined. The operation mode of one of the first and second actuators is adjusted upon detecting a failure in the other of the first and second actuators. At least one of the steering rack and the steering column is actuated based on the operation mode. In an angle control mode, a predetermined steering angle is provided to the first and second actuators to adjust the steering rack according to the steering angle. In a torque control mode, a steering column torque from a torsion sensor disposed on the steering column is provided to the first and second actuators to adjust the steering rack according to the steering column torque.

A correction circuit receives a steering torque and an electric signal indicative of an operating state of a clutch. The correction circuit selectively uses a first correction value and a second correction value in accordance with the operating state of the clutch. The first correction value is set to correct deviation of the steering torque relative to its zero point when an exciting coil of the clutch is not energized. The second correction value is set to correct deviation of the steering torque relative to its zero point, caused by magnetic flux generated by energization of the exciting coil of the clutch. Adding the first correction value or the second correction value to the steering torque in accordance with the operating state of the clutch suitably corrects deviation of the steering torque relative to its zero point in accordance with the operating state of the clutch.

To improve silence in a vehicle interior space in an idle reduction state, a vehicle includes an idle reduction function of stopping the idling of the engine and restarting the engine when the vehicle starts moving. When the engine is in a working state, the clutch is disengaged and control of driving of a turning actuator is performed, and when the engine is in a stop state, the clutch is engaged and the control of driving of the turning actuator is stopped. Furthermore, a disconnected state of the clutch is maintained when idling of the engine is stopped by the idle reduction function.

To achieve a fail-safe fully utilizing the advantage of plural motors, a second controller performs a one-motor SBW mode when at least one of a first turning controller, a first turning motor and a torque sensor malfunctions in a state where the first turning controller and the second turning controller perform a two-motor SBW mode. Furthermore, the first controller performs a one-motor EPS mode when at least one of the second turning controller and the second turning motor malfunctions in the state where the first turning controller and the second turning controller perform a two-motor SBW mode.

A steering system for controlling a direction of travel of a work machine includes a steering device controllable by an operator of the work machine. The steering device is coupled to an axle of the work machine for controlling an angular orientation of the wheels. A brake is coupled to the steering device and is controllably applied to apply a first amount of resistance to the steering device. A motor is coupled to the steering device and is controllably activated to apply a second amount of resistance to the steering device. A controller controls the steering system of the work machine in at least a first operating mode and a second operating mode. In the first operating mode, the controller controls the brake between an applied position and an unapplied position, whereas in the second operating mode, the controller controls the motor between an active position and a de-activated position.