A method of estimating hydraulic flow in a steering system of an articulated vehicle, a controller configured for the method and an articulated vehicle are provided. The method comprises: a) sensing a yaw rate of the articulated vehicle; b) sensing a velocity of the articulated vehicle; c) determining an estimate of a steering angle rate of the front part of the articulated vehicle using the sensed yaw rate and the sensed velocity; d) determining an estimate of the hydraulic flow in the steering system of the articulated vehicle using the estimate of the steering angle rate and one or more geometrical parameters of the steering system.

A hydraulic system for a mobile work vehicle is configurable in a hybrid mode and a hydrostatic mode. The hydraulic system includes a pump/motor, a propel circuit, a pump, a hydraulic accumulator, and an accessory circuit. The pump/motor is adapted to exchange power with a drive train of the mobile work vehicle. The propel circuit is adapted to exchange hydraulic fluid power with the pump/motor. The pump is adapted to transfer power from a prime mover of the mobile work vehicle to the propel circuit. The hydraulic accumulator is adapted to exchange hydraulic fluid power via an accumulator isolation valve with the propel circuit when the hydraulic system is configured in the hybrid mode. The accessory circuit is adapted to receive hydraulic fluid power from the hydraulic accumulator, at least when the hydraulic system is configured in the hydrostatic mode and the accumulator isolation valve is closed.

A hydraulic system for a mobile work vehicle is configurable in a hybrid mode and a hydrostatic mode. The hydraulic system includes a pump/motor, a propel circuit, a pump, a hydraulic accumulator, and an accessory circuit. The pump/motor is adapted to exchange power with a drive train of the mobile work vehicle. The propel circuit is adapted to exchange hydraulic fluid power with the pump/motor. The pump is adapted to transfer power from a prime mover of the mobile work vehicle to the propel circuit. The hydraulic accumulator is adapted to exchange hydraulic fluid power via an accumulator isolation valve with the propel circuit when the hydraulic system is configured in the hybrid mode. The accessory circuit is adapted to receive hydraulic fluid power from the hydraulic accumulator, at least when the hydraulic system is configured in the hydrostatic mode and the accumulator isolation valve is closed.

An unmanned vehicle control system includes: a determination unit that determines whether or not to output a heating request for a hydraulic oil based on hydraulic oil data supplied to a hydraulic actuator disposed in an unmanned vehicle and operated by the hydraulic oil; a vehicle receiver that receives a heating command for the hydraulic oil generated based on the heating request; and a heating processor that executes a heating process of the hydraulic oil based on the heating command.

A hydraulic control device includes: a hydraulic pump connected in parallel to steering and boom cylinders; a steering control valve that controls the direction of operating oil flowing through the steering cylinders; a boom control valve that connects the hydraulic pump to a tank when the valve is at a neutral position and controls the direction of the oil flowing through the boom cylinders when the valve is at an offset position; a meter-in pressure compensator that increases flow rate of the oil flowing through a variable restrictor of the steering control valve in accordance with pressure in front of and behind the restrictor; and a bleed-off pressure compensator that decreases flow rate of the oil flowing through the boom control valve in accordance with the increase in pressure of the oil flowing through the steering cylinders to maintain the predetermined pressure of the oil in the steering control circuit.

A hydraulic control device includes: a hydraulic pump connected in parallel to steering and boom cylinders; a steering control valve that controls the direction of operating oil flowing through the steering cylinders; a boom control valve that connects the hydraulic pump to a tank when the valve is at a neutral position and controls the direction of the oil flowing through the boom cylinders when the valve is at an offset position; a meter-in pressure compensator that increases flow rate of the oil flowing through a variable restrictor of the steering control valve in accordance with pressure in front of and behind the restrictor; and a bleed-off pressure compensator that decreases flow rate of the oil flowing through the boom control valve in accordance with the increase in pressure of the oil flowing through the steering cylinders to maintain the predetermined pressure of the oil in the steering control circuit.

A hydraulic system (40) for a work machine comprising a priority circuit (41) including at least a first priority actuator (47, 48) and a priority control valve (58) for controlling the supply of hydraulic fluid to the first priority actuator (47, 48) and for providing a load sense signal indicative of the load acting on the first priority actuator (47, 48); an auxiliary circuit (42) including at least a first auxiliary actuator (51) and at least a first auxiliary control valve (80) for controlling the supply of hydraulic fluid to the first auxiliary actuator (51); at least a first pump (46) for producing a flow of hydraulic fluid; and a priority valve (74) for distributing the flow from the pump (46) to the priority circuit (41) and auxiliary circuit (42) for operating the respective actuators thereof, with priority being given to the priority circuit (41) as a function of the load sense signal.

A hydraulic steering system 1 is described comprising a steering unit and a priority valve, said steering unit comprising a working port arrangement having two working ports, a supply port arrangement having a high pressure port and a low pressure port, a load sensing port, a main flow path having a main bleed and a metering device and being arranged between said high pressure port and said working port arrangement, an amplification flow path having an amplification bleed and being arranged between said high pressure port and said working port arrangement, said main bleed and said amplification bleed being controlled together by means of a steering handle and being closed in neutral position of said steering handle, wherein said priority valve comprises a priority outlet connected to said high pressure port of said steering unit, a valve element moveable in a priority direction to connect an inlet of said priority valve to said priority outlet, and a load sensing connection connected to said load sensing port of said steering unit, said priority outlet being connected to said load sensing connection via a priority valve bleed, a pressure at a point downstream said priority bleed acting on said valve element in said priority direction, wherein said load sensing port is connected to said low pressure port via a drain bleed being open in neutral position of said steering handle and closing upon actuation of said steering handle out of said neutral position.

A system and method for interrupting a Global Navigation Satellite System (GNSS)-based automatic steering mode of a hydraulic steering system on a vehicle. When a steering wheel is manually turned by an operator, pressurized hydraulic fluid from a steering directional control valve activates an interrupter having an interrupter valve. The interrupter valve blocks pressurized fluid flow to the automatic steering system, thus overriding automatic steering and giving the operator full manual steering control via the steering wheel. The hydraulic interrupt system is mechanical with no electronic elements.

Systems and methods for steering a vehicle that adjust how quickly a selected steering input is achieved based on a speed at which the vehicle is traveling are disclosed. The systems and methods include receiving a steering input, detecting a vehicle speed, and selecting a steering ramp rate that defines how quickly a steering amount corresponding to the steering input is achieved by one or more steerable components of the vehicle. In some implementations, the steering ramp rate may be affected as a result of whether the steering input is greater than or less than a previous steering input.