Abstract:
Systems and methods for auto-commissioning first and second valve assemblies associated with an actuator in an electro-hydraulic system are disclosed. In one method, a controller performs an automatic test protocol to determine a bulk modulus over fluid volume parameter used by the controller to control the valve assemblies. In one aspect, the test protocol can include pressurizing each side of the actuator to two different pressures with one of the first and second valve assemblies and blocking the other side of the actuator with the other of the first and second valve assemblies. The bulk modulus over fluid volume parameter for each valve assembly can be calculated based on recorded fluid pressures at the actuator and consumed flow at the first and second valve assemblies.
Abstract:
The present disclosure relates to a hydraulic control circuit for crane slewing gear having directional valves arranged in work lines and controllable separately for the inflow and outflow to the hydraulic motor for the carrying out of a rotational movement of the slewing gear, wherein an inflow valve serves the control of the oil inflow from a hydraulic pump via the work line to the hydraulic motor and an outflow valve is provided via which the hydraulic motor can be relieved to the tank, wherein the work lines are each connected via at least one check valve to a common inlet of the outflow valve to relieve the hydraulic motor independently of the direction of rotation of the slewing gear via an outflow valve into the tank.
Abstract:
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.
Abstract:
A hydraulic system for an aircraft includes a brake operation device, a pressure supply, a reservoir, a shut-off valve, and a wheel brake. The shut-off valve is in fluid communication with and is disposed between the pressure supply and the brake valve. The shut-off valve can include a poppet, a first valve seat and a second valve seat. Movement of the poppet is controlled by operation of the brake operation device. The poppet is movable between a first position where the poppet acts against the first valve seat and a second position where the poppet acts against the second valve seat. In the first position, fluid flow is blocked between the pressure supply and the brake valve through the shut-off valve. In the second position, fluid flow is allowed between the pressure supply and the brake valve through the shut-off valve. The wheel brake is in fluid communication with and downstream from the shut-off valve.
Abstract:
A valve operating device includes a mounting for attachment to a vehicle and an elongate arm, the free end of which is only moveable across the underlying ground. The joints of the arm pivot around vertical axes and the arm is locked into a desired orientation by a brake at each joint. A valve turning machine is at the free end of the arm. The brakes are engaged and released by a control on the valve turning machine.
Abstract:
An online method for reconfiguring pressure and position sensors in a hydraulic system is disclosed. In one step, a sensor drift condition, a recalibration request, or an unisolated fault condition is detected. In another step, a system pressure sensor or another sensor, such as a load-sense pressure sensor, is verified as a trusted master reference sensor. Another step includes measuring and recording a first pressure reading at the master reference sensor and first voltage readings associated with first, second, third, and fourth pressure slave sensors at a first pump pressure set point. Another step includes, repeating the previous step at a second pump pressure set point. A new gain and offset for each of the first, second, third, and fourth pressure sensors can be calculated based on a comparison of the recoded first and second pressure readings and the recorded first and second voltage readings.
Abstract:
A hydraulic system for an aircraft includes a master cylinder, a wheel brake, a pressure supply, a reservoir, and a shut-off valve in communication with the master cylinder, the wheel brake, the pressure supply and the reservoir. The shut-off valve can include a seal that is configured to preclude fluid flow between the pressure supply and the reservoir through the valve. The shut-off valve can be operable in a first position which blocks fluid flow between the pressure supply and the wheel brake through the valve and a second position which allows fluid flow between the pressure supply and the wheel brake through the valve. Fluid pressure from the master cylinder can control operation of the valve between the first position and the second position. Failure of the seal can result in fluid flow from the brake pressure supply toward the master cylinder.
Abstract:
Disclosed is a hydraulic control system for matching the drive speed of a boom up and a swing device according to the operation environment when compound-driving for manipulating boom and swing for excavation compensating error operation. The hydraulic control system of the present invention comprises: an operation mode selection switch for enabling the selection of an operation mode according to the operation environment; an electronic proportional pressure control valve for outputting a control signal pressure that is proportional to the manipulation of the operation mode selection switch when manipulating a boom operation lever for driving the boom up; a variable flow control valve that is placed on a flow channel between a first hydraulic pump and a spool for the swing device, and has an open area thereof that is variably matched proportional to the control signal pressure from the electronic proportional pressure control valve; and a controller having various types of operation modes previously set and stored thereon so as to control the flow being supplied to the spool for the swing device and a spool for the boom merge, according to the operation mode selected when manipulating the operation mode selection switch.
Abstract:
A control valve has a pressure chamber 24 causing a pressure to act on a valve element 21 of a check valve 20, an oil chamber 39 around the valve 21, a slot 40 formed in the valve element 21 and interconnecting the oil chamber 39 and the pressure chamber 24with each other and, a control valve 25 connected directly to a divergence portion 17 and the oil chamber 39 and capable of permitting or cutting off communication between the divergence portion 17 and the oil chamber 39 and changing an opening degree of the communication, an intra-valve-element passage 42, a slot 41 formed in an outer peripheral wall of the valve element 21 and communicating the passage 42 and the chamber 39 with each other, and a spring-return auxiliary check valve 43 for allowing pressure oil to flow from a supply passage 15 into the intra-valve-element passage 42.
Abstract:
A valve operating device includes a mounting for attachment to a vehicle and an elongate arm, the free end of which is only moveable across the underlying ground. The joints of the arm pivot around vertical axes and the arm is locked into a desired orientation by a brake at each joint. A valve turning machine is at the free end of the arm. The brakes are engaged and released by a control on the valve turning machine.