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 electronic control unit (ECU) may receive, from an autonomous vehicle controller, an instruction to set a hydraulic steering actuator, of a vehicle, to a particular machine steering angle setting. The ECU may provide, to a steering controller torque device, a current to set a steering controller, of the vehicle, to a particular steering controller angle that corresponds to the particular machine steering angle setting. The ECU may provide, to a hydraulic control system, a current to set the hydraulic steering actuator to the particular machine steering angle setting.

A redundant steering system comprises a primary power source; a secondary power source; first and second pumps operatively coupled to the primary and secondary power sources, respectively, to output first and second supplies of hydraulic fluid to a steering cylinder based on operation of the primary and secondary power source, respectively; first and second pairs of selector valves respectively coupled to the first and second pumps; and a charge circuit coupled to respective control inputs of the first and second pairs of selector valves to selectively supply hydraulic fluid to the control inputs of the first and second pairs of selector valves to stop hydraulic fluid from only one of the first pump and the second pump from being provided to the steering cylinder and to provide hydraulic fluid to the steering cylinder from only one of the other of the first pump and the second pump.

A steering system for controlling an agricultural machine having a pair of front wheels and a pair of rear wheels includes a controller, an operator steer input for communicating a steer command, a steer input sensor for detecting and outputting the steer command to the controller, a primary differential steering system for operably controlling the pair of front wheels, and a secondary steering system for operably controlling the pair of rear wheels. The secondary steering system includes a first actuator for controlling a first rear wheel and a second actuator for controlling a second rear wheel. The primary differential steering system is controlled based on the steer command. The controller outputs a control signal to operably actuate the first and second actuators at a non-linear steering gain rate as a function of the steer command.

An active steering system using planetary gear set with less tooth difference and a control method thereof. The system includes a first input shaft with one end connected to a steering wheel of an automobile and the other end fixedly sleeved with a first gear; a ring gear sleeve, where a ring gear is fixedly mounted in the ring gear sleeve circumferentially, and a hollow shaft protrudes from a center of an end of the ring gear sleeve and is fixedly sleeved with a second gear engaged with the first gear; a second input shaft with one end fixedly connected to an output end of a coupled motor and the other end fixedly sleeved with a third gear; an eccentric shaft with one end fixedly sleeved with a fourth gear engaged with the third gear and the other end sleeved in the hollow shaft and eccentrically provided with a boss.

An articulated work vehicle in which front and rear frames are linked includes a joystick lever configured to be operated by an operator, a hydraulic actuator driven by hydraulic pressure, a control valve, a force imparting component, and a controller. The joystick lever is usable to set a target steering angle. The hydraulic actuator performs an articulation to change an actual steering angle of the front frame with respect to the rear frame in response to operation of the joystick lever. The control valve controls flow of fluid supplied to the hydraulic actuator so as to make the actual steering angle coincide with the target steering angle. The force imparting component applies an assisting force or a counterforce to operation of the joystick lever. The controller controls the force imparting component so as to generate resistance to operation of the joystick lever based on a start timing of an articulation.

A hydraulic arrangement for distributing a fluid in pressure coming from a source among multiple hydraulic units of a work vehicle. At least one of the hydraulic units provides an electronic load sensing signal and of the hydraulic units provides a hydraulic load sensing signal. The hydraulic arrangement includes a priority valve configured to divide the flow of fluid between the hydraulic units. The priority valve and source are hydraulically controlled by a first hydraulic load sensing signal resulting as the greatest of a plurality of hydraulic load pressure signals taken from the hydraulic unit. The hydraulic arrangement also includes a conversion unit configured to transform an electronic load sensing signal of at least one of the hydraulic units in an equivalent hydraulic load sensing signal so as to define the first hydraulic load sensing signal.

1. Hydraulic power steering system.

2. A hydraulic power steering system, at least consisting of a steering actuator (10), for the actuation of which in opposite steering directions two subsystems (12; 14) are used, each in the form of flow-regulating valve arrangements (16; 18) having release valves (V3; V6), a fault detection device (30), by means of which at least one faulty component (V1, V2; V4, V5) of a respective subsystem (12; 14) can be determined and deactivated and by means of which the fault-free components (V1, V2, V3; V4, V5, V6) of at least one subsystem (12; 14) can be caused to keep up the actuation of the steering actuator (10), is characterized in that each flow-regulating valve arrangement (16; 18) has supply valves (V1; V4) and discharge valves (V2; V5), which are assigned to each other in pairs, and designed as proportional servo valves (28), which can be actuated electrically by means of actuation signals, which, compared to each other by means of the fault detection device (30), lead to deactivation of at least one valve (V1, V2, V3; V4, V5, V6) detected as faulty in the event of deviations detected as relevant.

A method of controlling a work machine having at least one wheel includes providing a controller, an operator control, and a steering system including a steering wheel position sensor, a road wheel angle sensor, a speed sensor, and a feedback device. The method includes detecting a change in steering wheel position via the steering wheel position device and a wheel speed of the at least one wheel via the speed sensor. A predicted lateral acceleration is calculated by the controller as a function of wheel speed and a feedback torque is determined by the controller as a function of the predicted lateral acceleration. The feedback torque is determined from a plurality of feedback torque curves stored by the controller, where each of the plurality of feedback torque curves corresponds to a sensitivity level selectable from the operator control. The feedback torque is commanded to the feedback device.

A work vehicle includes a hydraulic actuator that changes an actual steering angle, an actual steering angle detecting part, an operating unit that performs a steering operation, a position adjusting control part that controls the position adjusting part based on the actual steering angle, and a steering control part that controls the hydraulic actuator. The operating unit includes a support part, a rotating part supported rotatably by the support part, an operating part supported rotatably by the support part or the rotating part, a biasing part that biases the operating part to a predetermined position with respect to the rotating part, a position adjusting part that adjusts a rotation angle of the rotating part with respect to the support part, and a rotation angle detecting part configured to detect the rotation angle of the operating part with respect to the support part or the rotating part.