The disclosure discloses an electro-hydraulic servo actuator capable of implementing long-stroke and high-frequency loading and a control method. The actuator includes: a long hydraulic cylinder with a piston, a short hydraulic cylinder with a piston, a fixed-end rod, low frequency and high frequency electro-hydraulic servo valves, a left rod chamber, a right rod chamber, a force applying end head, and a force applying end rod. With this structure, the displacement of the piston of the short hydraulic cylinder is a combination of small-displacement and high-frequency movement and large-displacement and low-frequency movement, so as to realize the generation of large-displacement and high-frequency movement. Therefore, a target large-displacement and high-frequency excitation is applied to the specimen under load test. The actuator can output high-frequency and large-displacement target excitation of 0.1 Hz to 200 Hz and 0 mm to 1500 mm, and has a simple mechanical structure, advanced control process, and good practicability.

A main winch system of a rotary drilling rig includes a main action loop, a pilot control loop, and a feedback control loop. The main action loop includes an engine, a hydraulic pump, a main control valve, a balance valve, a main winch motor, and an oil tank. The pilot control loop includes a pilot handle, a solenoid valve I, a pressure relay, and the main control valve in the main action loop. The feedback control loop includes a solenoid valve II and the hydraulic pump and the main control valve in the main action loop. In response to a lifting action of the pilot handle for the main winch, under the control of a button, the solenoid valve II is energized continuously, and the solenoid valve I is energized and de-energized according to a given rule.

A linear actuator system has a rotary spool valve configuration having a spool, a piston, and a cylinder. The spool and piston have return apertures so positioned, configured and angled to direct return flow towards the center of a spool central return port and spool pressure ports to direct pressurized flow into upper or lower chambers. Rotation of the spool synchronizes and aligns ports and apertures to reverse flows and effect upward and downward translation of the cylinder to vibrationally drive an implement to perform work. The positioned and angled apertures direct the fluid to a region demarcated by a total length of 1.5 times the interior diameter of the spool central return port centered about a piston shoulder. A base plug member having a bull-nose tip, baffles and cavities is disposed within the spool central return port to reduce or eliminate cavitation.

Control method for actuating a loader (WL) comprising an arm (B) to which a bucket (BK) is connected, the method comprising in cyclic execution checks (FB) that a first mono-stable button is depressed, if it is depressed, then execution (Sequence) of the following sequence of operations: unloading, shaking, returning to dig position or if the vehicle is equipped with a 4 in 1 shovel: unloading, 4 in 1 shovel opening, shaking, 4 in 1 shovel closing, returning to dig position, otherwise if the first button (FB) is released then stop (STOP) of the execution of the sequence.

Provided is a work machine that can selectively establish a closed circuit connection between a single rod-type hydraulic cylinder and a plurality of bidirectional-type hydraulic pumps, the work machine being capable of enhancing responsiveness of the single rod-type hydraulic cylinder when a high-speed lever switching operation is conducted in a state in which a rod pressure of the single rod-type hydraulic cylinder is higher than a bottom pressure. When a bucket lever (70a) is operated to a side of extending the bucket cylinder in a state in which a pressure in a rod chamber (5b) of the bucket cylinder (5) is higher than a pressure in a bottom chamber (5a), a controller (50) opens a rod-side proportional valve (45) and discharges a working fluid in the rod chamber to a working fluid tank (25) such that a differential pressure between the pressure in the rod chamber and the pressure in the bottom chamber is reduced below a switching pressure (Psw) of a flushing valve (33).

A linear actuator system has a rotary spool valve configuration having a spool, a piston, and a cylinder. The spool and piston have return apertures so positioned, configured and angled to direct return flow towards the center of a spool central return port and spool pressure ports to direct pressurized flow into upper or lower chambers. Rotation of the spool synchronizes and aligns ports and apertures to reverse flows and effect upward and downward translation of the cylinder to vibrationally drive an implement to perform work. The positioned and angled apertures direct the fluid to a region demarcated by a total length of 1.5 times the interior diameter of the spool central return port centered about a piston shoulder. A base plug member having a bull-nose tip, baffles and cavities is disposed within the spool central return port to reduce or eliminate cavitation.

Provided is a work machine that can selectively establish a closed circuit connection between a single rod-type hydraulic cylinder and a plurality of bidirectional-type hydraulic pumps, the work machine being capable of enhancing responsiveness of the single rod-type hydraulic cylinder when a high-speed lever switching operation is conducted in a state in which a rod pressure of the single rod-type hydraulic cylinder is higher than a bottom pressure. When a bucket lever (70a) is operated to a side of extending the bucket cylinder in a state in which a pressure in a rod chamber (5b) of the bucket cylinder (5) is higher than a pressure in a bottom chamber (5a), a controller (50) opens a rod-side proportional valve (45) and discharges a working fluid in the rod chamber to a working fluid tank (25) such that a differential pressure between the pressure in the rod chamber and the pressure in the bottom chamber is reduced below a switching pressure (Psw) of a flushing valve (33).

An implement vibration system and method is disclosed that includes a vibration activation device; an electrohydraulic mechanism and a controller. The controller monitors the vibration activation device and sends movement signals to the electrohydraulic mechanism to control implement movement. When the vibration activation device is activated, the controller sends vibration signals to the electrohydraulic mechanism to cause the implement to vibrate. An operator control can send implement commands where the movement signals are based on the implement commands, and when vibration is activated the controller can superimpose the vibration signals on the movement signals. The vibration signals can cause a hydraulic cylinder to repeatedly extend and retract. An electrohydraulic control valve can receive the movement signals and control hydraulic flow to the hydraulic cylinder based on the movement signals. The vibration signals can be complementary signals. The amplitude and/or frequency of the vibration signals can be adjustable.

An implement vibration system and method is disclosed that includes a vibration activation device; an electrohydraulic mechanism and a controller. The controller monitors the vibration activation device and sends movement signals to the electrohydraulic mechanism to control implement movement. When the vibration activation device is activated, the controller sends vibration signals to the electrohydraulic mechanism to cause the implement to vibrate. An operator control can send implement commands where the movement signals are based on the implement commands, and when vibration is activated the controller can superimpose the vibration signals on the movement signals. The vibration signals can cause a hydraulic cylinder to repeatedly extend and retract. An electrohydraulic control valve can receive the movement signals and control hydraulic flow to the hydraulic cylinder based on the movement signals. The vibration signals can be complementary signals. The amplitude and/or frequency of the vibration signals can be adjustable.

A hydraulic system includes a pressure-driven actuator operable to provide a mechanical output in response to a pressure input, a single hydraulic circuit communicating with the pressure-driven actuator, a vibratory actuator in the single hydraulic circuit and operable to generate a first component of the mechanical output at a first frequency, and a hydraulic supply apparatus separate from the vibratory actuator, in the single hydraulic circuit, and operable to generate a second component of the mechanical output at a second frequency less than the first frequency.