Abnormality detection device for a hydraulic circuit with oil pump capable of increasing pressure of oil sucked through a suction port and discharging the oil through discharge ports; a switching unit switching between fully and partially discharged states; a pressure regulation unit regulating oil pressure; and a hydraulic pressure detection unit that detects the oil pressure includes: a storage unit that stores a maximum discharge pressure in the partially discharged state; a switching control unit that switches to either one of the discharged states; a pressure regulation control unit that sets a target pressure higher than the maximum discharge pressure in the partially discharged state, and performs pressure regulation control to achieve the target pressure; and a determination unit that determines whether the switching unit has a fixation abnormality in one of the discharged states by comparing hydraulic pressure with maximum discharge pressure in the partially discharged state.

Method for the load-dependent regulation of a hydrostatic drive (1), with a closed hydraulic fluid circuit comprising a first hydraulic motor (5) and, parallel to this, a second hydraulic motor (6), whereby both hydraulic motors (5 and 6) are capable of being powered by a hydraulic pump (3) via a high-pressure line (7) and a low-pressure line (8) and are mechanically coupled to each other via a transmission (70). The displacement of the first hydraulic motor (5) can be adjusted proportionally to an electrical signal of an electronic control system (50) by means of an electro-proportional control valve (10) and the displacement of the second hydraulic motor (6) can be adjusted by means of a pressure-proportional control valve (20) which is hydraulically connected to the high-pressure line (7) via a control pressure line (21). The pressure-proportional control valve can be activated by means of a control pressure which is dependent on the high pressure. By means of automatic opening of the pressure-proportional control valve (20) dependent on the high pressure, proportional to the exceedance of a predefinable pressure limit in the high-pressure line (7), the displacement of the second hydraulic motor (6) is adjusted by means of a second servo control unit which can be controlled via the pressure-proportional control valve (20). By means of the electronic control system (50), the actual volume flow passing through the first hydraulic motor (5) is determined and compared with a target value for the volume flow. Based on a deviation between the actual and target value for the volume flow, the electronic control system (50) calculates an adapted control signal and transmits this to the electro-proportional control valve (10), as a result of which the displacement of the first hydraulic motor (5) is adaptable by means of a first servo control unit (14), which is controlled via the electro-proportional control valve (10).

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

Subject inventions use a bunch of hydraulic cylinders with cross section area in a series of powers of 2 multiples of the least common denominator. By selection from N pieces of such cylinders with corresponding digital-controllable valves array, the enumerateable quantity of different areal sums shall read: Nth power of 2. With proper switching on the bunch of cylinders, adjustable fluid power supply can be realized to adapt very wide pressure fluctuation of input. Also a novel system of hydrostatic transmission & powertrain is presented, and it features automatic quasi CVT (Continuously Variable Transmission) & regenerative brake with reclaimed energy round trip via same tranny, by virtue of not expensively using planetary gears or variable displacement hydraulic pump/motor. All vehicles, even powered only by fossil fuel, deserve economic regenerative brake, now this invention can make it come true!

An connecting structure of an electromagnetic valve includes: a first connecting structure body that prohibits a relative movement between a hydraulic pressure circuit body and an electromagnetic valve in an axis line direction; a second connecting structure body that prohibits a relative movement therebetween in a plane orthogonal to the axis line direction; a third connecting structure body that prohibits a relative rotation about the axis therebetween; and a connection body that is prohibited from moving relatively to the hydraulic pressure circuit body, wherein the first connecting structure body includes a first target connection tool that is provided in an accommodation body and a first connection tool that locks the first target connection tool in the axis line direction at a wall portion constituting an accommodation space.

Disclosed is a hydraulic control valve assembly of automatic steering system for agricultural machine including a proportional directional valve (3). A balancing valve (1) is arranged between the proportional directional valve (3) and the steering cylinder. A first shuttle valve (2) is arranged between the proportional directional valve (3) and the balancing valve (1). The first shuttle valve (2) is positioned on one side of the proportional directional valve (3). An overflow valve (4) is positioned on another side of the proportional directional valve (3). The overflow valve (4) is connected to a second shuttle valve (6) and a logic valve (5) respectively. The hydraulic control valve assembly has a large control power, a rapid response, and is more suitable for the autonomous navigation operation of agricultural machine. Moreover, the system saves more energy, such that the autonomous navigation operation of agricultural machine is more stable.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

The present invention provides a controller for a pendulum type wave-power generating apparatus. Electric power produced by wave-power generation has been pointed out as being of low efficiency and more expensive than wind-power generation. To overcome the above problems, the present invention uses resonance and impedance matching of the sea waves, thus making it possible to markedly enhance the efficiency of wave-power generation. The present invention does not use a wave-height meter which is generally expensive and controls the generating apparatus in response to variation of the conditions of the sea, thus automatically maintaining the resonance and impedance matching operation, thereby making high-efficiency operation possible. As a result, the cost of the wave-power generation can be reduced, so that the wave-power generation can be widely commercialized.

A fluidic control system (1) for controlling a vehicle, which includes a controller (2) and a closed fluidic circuit. The circuit includes a pump (3) for pressurizing fluid in the circuit, valve means (40, 50, 60), an actuator (4, 5, 6) and a precharge accumulator (7). The valve means (40, 50, 60) is fluidly connected to the inlet and outlet of the pump (3) and the actuator (4, 6) is fluidly connected to the valve means (40, 50, 60) for selectively receiving pressurized fluid therefrom. The precharge accumulator (7) includes a movable member (73, FIG. 2) that describes a variable volume (71) fluidly connected to the circuit between the valve means (40, 50, 60) and the inlet of the pump (3). The system (1) also includes a sensor (70) for determining the position of the movable member (73) for estimating the quantity of fluid and/or detecting an abnormal pressure variation within the circuit.

In one embodiment, a system, comprising: one or more pairs of oppositely rotatable, laterally extending rolls, wherein for each pair, at least one of the rolls is moveable relative to the other of the rolls; a hydraulic circuit, comprising: a tensioner circuit comprising: for each pair of rolls, one or more pairs of hydraulic cylinders arranged in parallel, each configured to resist movement of the at least one of the rolls at a respective end of the at least one of the rolls; an accumulator arranged in parallel to the hydraulic cylinders; and plural control valves; and a computing system configured to cause the one or more pairs of hydraulic cylinders to adjust the resistance to movement of the at least one of the rolls of the respective pair of rolls by sending signals to one or more of the plural control valves.