An example valve assembly includes a housing having an accumulator fluid passage configured to be fluidly coupled to an accumulator, a supply fluid cavity configured to be fluidly coupled to a source of fluid, a reservoir fluid cavity configured to be fluidly coupled to a reservoir of fluid, a head fluid cavity configured to be fluidly coupled to a head-side chamber of a hydraulic actuator, and a rod fluid cavity configured to be fluidly coupled to a rod-side chamber of the hydraulic actuator; a main spool that is axially-movable within the housing; and a balancing spool that is axially-movable within the housing based on an axial position of the main spool.

A shovel includes a lower traveling body, and an upper swiveling body mounted on the lower traveling body. The upper swiveling body is rotatable. An attachment is attached to the upper swiveling body. A traveling actuator is configured to drive the lower traveling body. An attachment actuator is configured to move the attachment. A control device is provided in the upper swiveling body. The control device is configured to autonomously operate at least one of the traveling actuator and the attachment actuator depending on an inclination of a ground on which the lower traveling body is traveling.

A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic actuator, and a second chamber (118, 116) of the hydraulic actuator may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The first blocking valve prevents the fluctuating hydraulic fluid flow from opening the first counter-balance valve. The first blocking valve may drain leakage from the first counter-balance valve.

An example valve assembly includes a housing having an accumulator fluid passage configured to be fluidly coupled to an accumulator, a supply fluid cavity configured to be fluidly coupled to a source of fluid, a reservoir fluid cavity configured to be fluidly coupled to a reservoir of fluid, a head fluid cavity configured to be fluidly coupled to a head-side chamber of a hydraulic actuator, and a rod fluid cavity configured to be fluidly coupled to a rod-side chamber of the hydraulic actuator; a main spool that is axially-movable within the housing; and a balancing spool that is axially-movable within the housing based on an axial position of the main spool.

A hydraulic system can include a hydraulic actuator including a piston rod slidably disposed within a housing having a base-side port and a rod-side port, a hydraulic pump, a hydraulic reservoir, an accumulator, a first control valve operable to selectively control flow from the pump to the base-side port and from the base-side port to the reservoir, a second control valve operable to selectively control flow from the pump to the rod-side port and from the rod-side port to the reservoir, a third control valve operable to selectively allow flow between the base-side port and the accumulator, and a controller for operating the hydraulic system and including a ride control mode in which damping is provided to the hydraulic actuator by operation of the first, second, and third control valves.

A system for damping mass-induced vibrations in a machine having a long boom or elongate member, the movement of which causes mass-induced vibration in such boom or elongate member. The system comprises at least one motion sensor operable to measure movement of such boom or elongate member resulting from mass-induced vibration, and a processing unit operable to control a first control valve spool in a pressure control mode and a second control valve spool in a flow control mode in order to adjust the hydraulic fluid flow to the load holding chamber of an actuator attached to the boom or elongate member to dampen the mass-induced vibration. The system further comprises a control manifold fluidically interposed between the actuator and control valve spools that causes the first and second control valve spools to operate, respectively, in pressure and flow control modes.

A mobile hydraulic system includes a hydraulic actuator coupled to a load, and a control unit coupled to the load and/or to the hydraulic actuator. The control unit is adapted to anticipate an over-center transition of the load relative to a gravity vector prior to the over-center transition through the use of sensors configured with accelerometers, gyroscopes and magnetometers. In some examples, the over-center transition is from an overrunning driving of the load to a passive driving of the load. In some examples, the over-center transition is from a passive driving of the load to an overrunning driving of the load. In some examples, the control unit is adapted to control change in a metered flow through one or more ports of the associated actuator to minimize and/or prevent one or more hydraulic effects of the anticipated over-center transition. In some examples, the control unit controls the metered flow by causing one or more actuators (e.g., a solenoid) to shift one or more valve positions to change the flow through one or more ports of the associated actuator.

The present disclosure relates to a travel stability system, a backhoe loader and a control method. The travel stability system includes: a hydraulic actuator; a first hydraulic oil source, operatively connected with the hydraulic actuator, and configured to provide pressure oil to the hydraulic actuator; an energy storage element operatively connected with a first oil supply path between the first hydraulic oil source and the hydraulic actuator; and a controller configured to compare an oil pressure of the hydraulic actuator with an oil pressure of the energy storage element after the travel stability system is turned on, and achieve a balance between the oil pressure of the energy storage element and the oil pressure of the hydraulic actuator before the energy storage element is accessed to the first oil supply path.

A working machine comprises an operation member for operating a hydraulic device via a control valve. An oscillation calculator acquires a specific value corresponding to a feature representing oscillation of the operation member when the feature appears in variation of an control signal output according to an operation amount of the operation member within one of a sequence of predetermined periods, and calculates an evaluation value representing a degree of oscillation of the operation member by adding up the specific value or values obtained within one or more of the predetermined periods. A control signal generator generates a control signal for controlling the control valve based on the operation signal. The control signal generator decreases a value of the control signal per a unit value of the operation signal as the evaluation value gradually increases with the elapse of one or more of the sequence of the predetermined periods.

A system for damping mass-induced vibrations in a machine having a long boom or elongate member, the movement of which causes mass-induced vibration in such boom or elongate member. The system comprises at least one motion sensor operable to measure movement of such boom or elongate member resulting from mass-induced vibration, and a processing unit operable to control a first control valve spool in a pressure control mode and a second control valve spool in a flow control mode in order to adjust the hydraulic fluid flow to the load holding chamber of an actuator attached to the boom or elongate member to dampen the mass-induced vibration. The system further comprises a control manifold fluidically interposed between the actuator and control valve spools that causes the first and second control valve spools to operate, respectively, in pressure and flow control modes.