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.

An electro-hydraulic steering system (1) comprises a hydraulic steering actuator (11) and a hydro-mechanical steering unit (6) for actuating the hydraulic steering actuator in response to a steering demand from a steering wheel (2) connected to the hydro-mechanical steering unit by a steering shaft (3). An electric motor (5) is operative to apply a torque to the steering shaft and is controlled to provide a haptic steering torque feedback to a user through the steering wheel. The motor (5) is controlled to provide haptic steering torque feedback during a dead band range of movement of the steering member (2) before the hydro-mechanical steering unit begins supplying fluid to the steering actuator. The motor (5) may be controlled to provide a haptic steering torque feedback that follows a predetermined profile compensating for the effects of a spring in the hydro-mechanical steering unit which opposes movement of the steering member.

A method includes receiving a handwheel angle signal, generating a handwheel speed signal and a handwheel acceleration signal, and synchronizing the handwheel speed signal and the handwheel acceleration signal. The method also includes delaying the handwheel angle signal, calculating a sum of the delayed handwheel angle signal and a phase value, converting the sum of the delayed handwheel angle signal and the phase value to radians, determining an offset correction value by calculating a sine function value of the converted sum of the operator torque estimation signal and the phase value, calculating a product of the offset correction value and a calibratable value of an offset mass magnitude, adjusting the operator torque estimation signal by adding the product and the calibratable value of an offset mass magnitude, and determining whether hands of an operator of the vehicle are on the handwheel based on the adjusted operator torque estimation signal.

An electric-control multimode steering valve comprises: a flow distributing and collecting valve, a first electromagnetic valve, and a second electromagnetic valve. A valve body comprises four groups of paired valve oil ports. First oil ports of the first and second electromagnetic valves are in communication with a first group. Second oil ports of the first and second electromagnetic valves are in communication with a second group. A third oil port of the first electromagnetic valve is in communication with a flow collecting port of the flow distributing and collecting valve. A first flow distributing port of the flow distributing and collecting valve and a third oil port of the second electromagnetic valve are in communication with a third group. A second flow distributing port of the flow distributing and collecting valve and the third oil port of the second electromagnetic valve are in communication with a fourth group.

An auxiliary steering device for a hydrostatic vehicle steering system, includes an input shaft, which can be actuated or set in rotation by a steering wheel, an output shaft for actuating a steering metering valve, and a planetary gearing. The planetary gearing includes a planetary wheel carrier with multiple planetary wheels, which mesh with a sun gear and a surrounding ring gear. The input shaft is connected to the planetary wheel carrier and the output shaft is connected to the sun gear in each case for conjoint rotation. The auxiliary steering device has an electric drive for exerting a torque on the ring gear, a braking device for fixing the input shaft, and a coupling device for producing a rotationally fixed connection between the output shaft and the planetary wheel carrier.

A valve system includes a valve configured to adjust a flow rate of hydraulic fluid in order to steer a work machine, and a control section configured to determine a command signal sent to the valve. The command signal determines a command flow rate of the hydraulic fluid based on a target flow rate corresponding to an input operation command and a change amount in the target flow rate. The control section is configured to control the change amount according to a magnitude of a reversal operation command when receiving the reversal operation command in order to operate the work machine in a direction opposite to a direction in which steering is operating. A work machine includes the valve system, a front frame, a rear frame, an articulate mechanism rotatably connecting the front frame to the rear frame, and a hydraulic actuator.

An auxiliary steering device for a hydrostatic vehicle steering system, includes an input shaft, which can be actuated or set in rotation by a steering wheel, an output shaft for actuating a steering metering valve, and a planetary gearing. The planetary gearing includes a planetary wheel carrier with multiple planetary wheels, which mesh with a sun gear and a surrounding ring gear. The input shaft is connected to the planetary wheel carrier and the output shaft is connected to the sun gear in each case for conjoint rotation. The auxiliary steering device has an electric drive for exerting a torque on the ring gear, a braking device for fixing the input shaft, and a coupling device for producing a rotationally fixed connection between the output shaft and the planetary wheel carrier.

A method for steering control includes receiving at least one steering input value, receiving at least one vehicle speed value, and determining, based on the at least one steering input value and the at least one vehicle speed value, a vehicle sideslip angle and a yaw rate. The method also includes generating an initial steering control value based on the vehicle sideslip angle, the yaw rate, and a reference yaw rate value. The method also includes determining a final steering control value based on the initial steering control value and the at least one steering input value, and selectively controlling at least one aspect of a vehicle steering system based on the final steering control value.