To make it possible to prevent a decrease in work speed due to a decrease in the speed of a given actuator when an operator unintentionally performs a fine operation of the control lever of the other actuator in a state in which the given actuator is driven by the hydraulic fluid delivered from a plurality of pumps, a controller (41) sets, as a composite dead zone line serving as a boundary of a composite dead zone, a composite dead zone line such that as an operation amount in one direction of a control lever (12L) or (13L) of a control lever device (12) or (13) is increased, the width of the composite dead zone corresponding to an operation amount in the other direction of the control lever is widened, and corrects the operation amount in the other direction such that the demanded flow rate of an actuator increases from zero, when the control lever is operated in the other direction in a state in which the operation amount in the one direction of the control lever remains within a range of the composite dead zone, and the operation amount in the other direction exceeds the composite dead zone line.

An engine (12) drives a variable capacity-type hydraulic pump (16), discharged hydraulic oil is selectively supplied to a cooling fan (19) and a hoist cylinder (11) in accordance with switching of a selection valve (17), thereby controlling the same on the basis of each target value. A pump discharge pressure (Pp) of the hydraulic oil discharged from the hydraulic pump (16) and a motor supply pressure (Pm) of the hydraulic oil supplied to a hydraulic motor (18) via the selection valve (17) are detected by sensors (27, 28) and are compared with pressure determination values stored in advance as a pump discharge pressure (Pp) and an actuator supply pressure (Pm) generated when the target value is achieved. Presence/absence of abnormality in the hydraulic actuator control device (15) is determined on the basis of a result of the comparison, and when abnormality is determined to have occurred, control is performed to minimize the capacity of the hydraulic pump (16).

A hydraulic system includes a first electric machine connected to a first hydraulic machine and a second electric machine connected to a second hydraulic machine. An output side of the second hydraulic machine is connected to an input side of the first hydraulic machine. A hydraulic consumer is hydraulically coupled to an output side of the first hydraulic machine via a supply line and is powered by the first hydraulic machine. A return line hydraulically couples the hydraulic consumer to an input side of the first hydraulic machine. The second hydraulic machine provides a flow of hydraulic fluid to the input side of the first hydraulic machine if a requested flow from the first hydraulic machine exceeds a flow of the return line and recuperates energy if the requested flow from the first hydraulic machine is lower than the flow of the return line.

Method for controlling a hydraulic system for a working machine, the system including a first electric machine connected to a first hydraulic machine the first hydraulic machine including an input side and an output side a second electric machine connected to a second hydraulic machine the second hydraulic machine including a high-pressure side and a low-pressure side the high-pressure side connected to the input side; a hydraulic consumer coupled to the output side via a supply line and configured to be powered by the first hydraulic machine; a first return line hydraulically coupling the hydraulic consumer to the input side and to the high-pressure side; wherein the method includes detecting a return flow from the hydraulic consumer through the first return line; and controlling the second hydraulic machine to maintain a pressure in the first return line at a pressure level higher than a predetermined minimum pressure level.

A control device for a power machine includes a target circuit pressure specifying unit configured to specify a target circuit pressure of the hydrostatic continuously variable transmission, a measurement value acquisition unit configured to acquire an actual circuit pressure of the hydrostatic continuously variable transmission, a brake torque determination unit configured to determine a brake torque based on the target circuit pressure and the actual circuit pressure, and a pump control unit configured to control the hydraulic pump based on the brake torque. The brake torque is a torque consumed by the hydraulic pump.

An infrared light-transmitting system for determining the position (e.g., angle and extension) of a boom is provided. The system includes a vehicle with wheels or a track that move the cab. A chassis or frame supports the cab and boom. In various embodiments, the boom extends and rotates; for example, the boom can rotate in 1 or 2 dimensions. The boom interconnects the chassis at the first end to the attachment at the second end. At least one pivot couples the boom to the chassis to rotate the boom about the pivot relative to the chassis. A transmitter emits infrared light signals that are reflected off a reflector to a detector to determine the real-time position of the attachment and/or boom.

In a work machine including a solenoid valve that generates a pilot pressure to drive a directional control valve with use of the delivery pressure of a pilot pump as a source pressure, a shut-off valve that shuts off a hydraulic operating fluid from the pilot pump to the solenoid valve, a first sensor that senses the amount of operation of an operation lever, and a second sensor that senses a state amount relating to operation of the solenoid valve, whether or not an abnormality of the second sensor exists is determined on the basis of a sensing signal of the second sensor. When it is determined that the second sensor is abnormal, on the basis of a sensing signal of the first sensor, an opening command is made to the shut-off valve if operation of the operation lever is sensed, and a closing command is made to the shut-off valve if the neutral state of the operation lever is sensed.

One example is directed to an end effector position estimation system for an off-road vehicle, which includes at least one inertial measurement unit (IMU) configured to be positioned on at least one of actuators and links of the vehicle that together move the end effector of the vehicle, and configured to generate measurement signals. The position estimation system includes at least one other IMU configured to be positioned on a base of the vehicle, and configured to generate other measurement signals. The position estimation system includes an estimation unit to estimate a position of the end effector of the vehicle based at least in part on the measurement signals and the other measurement signals, wherein the estimation unit is configured to perform an estimation method that removes an influence of terrain-induced vibrations and terrain slope in the measurement signals based on the other measurement signals.

A hose assembly for a hydraulic system is shown. The hose assembly includes a first hose that fluidly couples a pump with a hydraulic actuator using a first port. The first hose includes a first electronic device that provides identification information for the first hose. The hose assembly further includes a second hose that fluidly couples the hydraulic actuator with a reservoir tank using a second port. The second hose includes a second electronic device that provides identification information for the second hose. The hose assembly further includes a controller that receives a first connection signal and a second connection signal. The controller is further configured to determine that the first hose has fluidly coupled using the first port based on the first connection signal and determine that the second hose has fluidly coupled using the second port based on the second connection signal.

A hydraulic system for a work machine includes a tank to store an operation fluid, a hydraulic device to be operated by the operation fluid, a control valve to control the hydraulic device, a first fluid tube connecting the hydraulic device and the control valve, the first fluid tube being to supply the operation fluid from the control valve to the hydraulic device, a second fluid tube branching from the first fluid tube and connected to the tank, a switch valve provided to the second fluid tube, the switch valve being to control a flow rate of the operation fluid, and an oil cooler provided to the second fluid tube between the switch valve and the tank.