A load-sensitive asymmetric electro-hydrostatic actuator and working method

Abstract

The present invention belongs to the field of electro-hydrostatic actuators, and discloses a load-sensitive asymmetric electro-hydrostatic actuator and a working method. The actuator includes a speed-regulating motor, a load-sensitive hydraulic pump, a load-sensitive mechanism, a pressure-selecting shuttle valve, a pilot-operated directional valve, an accumulator, and an asymmetric actuator cylinder. The asymmetric actuator cylinder is an asymmetric hydraulically actuated cylinder, one oil chamber of which is connected to port A of the load-sensitive hydraulic pump, and the other oil chamber is connected to port B of the load-sensitive hydraulic pump. The load-sensitive hydraulic pump is a bidirectional hydraulic pump, which is controlled and switched tangentially by the speed-regulating motor connected thereto. The load-sensitive mechanism is connected to the pressure of port A or port B of the load-sensitive hydraulic pump through the pressure-selecting shuttle valve and adjusts the displacement of the load-sensitive hydraulic pump. The pilot-operated directional valve selects one end to be connected to the accumulator according to the pressure magnitudes of port A and port B of the load-sensitive hydraulic pump. The structure size of the present invention is smaller, the use of unconventional hydraulic components is avoided, and the processing design and control difficulties are reduced.

Description

Technical Field

[0001] This application belongs to the field of electro-hydrostatic actuators, and relates to an asymmetric electro-hydrostatic actuator, specifically to a load-sensitive asymmetric electro-hydrostatic actuator and its working method. Background Art

[0002] Based on the trade-off of comprehensive factors such as reliability, safety, maintainability, and economy, the more-electric aircraft using power-by-wire technology simplifies the hydraulic pipelines throughout the fuselage, obtaining benefits in multiple aspects such as testing, control management, and fault tolerance, and gradually occupies the modern civil aircraft market. The highly integrated electro-hydrostatic actuator is a key link in realizing the power-by-wire actuation system of the more-electric aircraft. The research and development of high-performance electro-hydrostatic actuators has become the focus of attention of global aircraft hydraulic suppliers.

[0003] The electro-hydrostatic actuator integrates components such as motors, pumps, valves, sensors, and actuating cylinders, resulting in a relatively large self-volume and size, which limits its use in scenarios with strict local space constraints. Due to the control problems brought about by the inconsistent cavity volume of the symmetric pump-controlled asymmetric actuating cylinder, and the technical maturity of the asymmetric pump cannot meet the industrialization requirements, the currently applied and relatively mature electro-hydrostatic actuators mainly adopt a symmetric actuating cylinder structure, which leads to the axial dimension of the electro-hydrostatic actuator covering twice the working stroke of the actuating cylinder, making its structural size disadvantage more obvious compared with traditional hydraulic servo actuators. In addition, the highly integrated design of the electro-hydrostatic actuator also brings heat dissipation problems, and it is necessary to solve the system heating problems under different working loads of long-term no-load and full-load to ensure its safe and reliable operation.

[0004] In order to reduce the volume and size of the electro-hydrostatic actuator, Patent [Application No.: 201810178711.6] proposed an electro-hydrostatic actuator with an asymmetric pump-controlled asymmetric hydraulic cylinder, but the design and processing of the asymmetric pump are difficult and the technical maturity is not high; Patent [Application No.: 201711348907.7] proposed an asymmetric electro-hydrostatic actuator based on a pressure selection valve, which is suitable for occasions where the electro-hydrostatic actuator has a large working stroke and has high requirements for its size and weight. In order to reduce the heat generation of the electro-hydrostatic actuator, Patent [Application No.: 201811227191.X] proposed an active load-sensitive control method for an electro-hydrostatic actuator using a symmetric actuating cylinder. Patent [Application No.: 201510120019.4] applied the load-sensitive technology to an electro-hydrostatic actuator using an asymmetric actuating cylinder, but this method only achieved unilateral load-sensitive control. Summary of the Invention

[0005] To solve the above problems, the present invention provides a load-sensitive asymmetric electro-hydrostatic actuator and a working method, which can shorten the axial dimension of the electro-hydrostatic actuator while suppressing its heat generation. Without increasing the difficulty of component design and manufacturing, an asymmetric actuator cylinder is used to reduce the volume of the electro-hydrostatic actuator, and a load-sensitive mechanism is used to reduce the heat generation of the electro-hydrostatic actuator, thereby reducing the difficulty of processing, manufacturing, driving and controlling.

[0006] The present invention is realized through the following technical solutions:

[0007] A load-sensitive asymmetric electro-hydrostatic actuator includes a speed-regulating motor, a load-sensitive hydraulic pump, a load-sensitive mechanism, a pressure-selecting shuttle valve, a pilot-operated directional valve, an accumulator and an asymmetric actuator cylinder; the asymmetric actuator cylinder is an asymmetric hydraulic-driven actuator cylinder, one oil chamber of which is connected to port A of the load-sensitive hydraulic pump, and the other oil chamber is connected to port B of the load-sensitive hydraulic pump; the load-sensitive hydraulic pump is a bidirectional hydraulic pump, which is controlled and switched tangentially by the speed-regulating motor connected thereto; the load-sensitive mechanism is connected to the pressure of port A or port B of the load-sensitive hydraulic pump through the pressure-selecting shuttle valve and adjusts the displacement of the load-sensitive hydraulic pump; the pilot-operated directional valve selects one end to be connected to the accumulator according to the pressure magnitudes of port A and port B of the load-sensitive hydraulic pump.

[0008] Further, the speed-regulating motor is a motor-generator integrated unit.

[0009] Further, the two oil inlets of the pressure-selecting shuttle valve are respectively connected to port A and port B of the load-sensitive hydraulic pump, and the pressure at the higher-pressure end is transmitted to the load-sensitive mechanism through the working port.

[0010] Further, the load-sensitive mechanism adjusts the displacement of the load-sensitive hydraulic pump according to the sensed pressure, and the smaller the displacement of the load-sensitive hydraulic pump is when the pressure is higher.

[0011] Further, the pilot-operated directional valve senses the pressures of port A and port B of the load-sensitive hydraulic pump and selects the port with the lower pressure among port A and port B of the load-sensitive hydraulic pump to communicate with the accumulator.

[0012] Further, the spool of the pilot-operated directional valve is a two-position four-way spool with symmetric arrangement. The two control oil ports of the pilot-operated directional valve are respectively connected to port A and port B of the load-sensitive hydraulic pump. The first working oil port and the second working oil port of the pilot-operated directional valve are respectively connected to port A and port B of the load-sensitive hydraulic pump. The third working oil port and the fourth working oil port of the pilot-operated directional valve are connected to the accumulator; the pilot-operated directional valve selects the working oil port at the end of the control oil port with the lower pressure to be connected to the accumulator.

[0013] Further, port A and port B of the load-sensitive hydraulic pump are also connected through a safety valve.

[0014] A working method for a load-sensitive asymmetric electro-hydrostatic actuator, including a method for providing motive power by a load-sensitive hydraulic pump:

[0015] The load-sensitive hydraulic pump pumps oil from the low-pressure end to the high-pressure end; under the action of the high-pressure oil, the high-pressure working port of the pressure selection shuttle valve is connected to the load-sensitive mechanism, and the high-pressure oil pushes the spool through the high-pressure control oil port of the pilot-operated directional valve, so that the accumulator is connected to the low-pressure working oil port of the pilot-operated directional valve;

[0016] The load-sensitive hydraulic pump injects hydraulic oil into the high-pressure oil chamber of the asymmetric actuator cylinder, and the piston rod of the asymmetric actuator cylinder provides motive load force. The low-pressure end of the load-sensitive hydraulic pump serves as an oil suction port to suck hydraulic oil from the low-pressure oil chamber of the asymmetric actuator cylinder. The accumulator is used to compensate for the difference in oil suction volume caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator cylinder.

[0017] Furthermore, it also includes a method for using the load as motive power:

[0018] The oil in the high-pressure chamber of the asymmetric actuator cylinder drives the load-sensitive hydraulic pump to work as a motor, and the speed control motor serves as a generator to provide resistance; under the action of the high-pressure oil, the high-pressure working port of the pressure selection shuttle valve is connected to the load-sensitive mechanism, and the high-pressure oil pushes the spool through the high-pressure control oil port of the pilot-operated directional valve, so that the accumulator is connected to the low-pressure working oil port of the pilot-operated directional valve;

[0019] The high-pressure end of the load-sensitive hydraulic pump serves as an oil suction port to suck hydraulic oil from the high-pressure oil chamber of the asymmetric actuator cylinder. When the piston rod of the asymmetric actuator cylinder moves, the low-pressure end of the load-sensitive hydraulic pump serves as an oil discharge port to inject hydraulic oil into the low-pressure oil chamber of the asymmetric actuator cylinder. The accumulator absorbs the difference in oil volume caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator cylinder.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The load-sensitive asymmetric electro-hydrostatic actuator of the present invention uses an asymmetric actuator cylinder, and its structural size is smaller than that of the electro-hydrostatic actuator in the form of a symmetric actuator cylinder;

[0022] (2) The present invention uses a pilot-operated directional valve and an accumulator to achieve the control of an asymmetric actuator cylinder by a symmetric pump, avoiding the use of unconventional hydraulic components, and reducing the processing design and control difficulty;

[0023] (3) The present invention uses the structure of a load-sensitive mechanism and a pressure selection shuttle valve to achieve load-sensitive control, which is beneficial to reducing the heat generation of the electro-hydrostatic actuator and improving energy efficiency;

[0024] (4) The principle of the present invention is simple, and all components of the load-sensitive asymmetric electro-hydrostatic actuator adopt mature industrial components, so it has higher reliability and feasibility. Description of the Drawings

[0025] Figure 1 is the schematic diagram of a load - sensitive asymmetric electro - hydrostatic actuator;

[0026] Figure 2 is the schematic diagram of the implementation scheme when the rodless cavity of the asymmetric actuator cylinder of the load - sensitive asymmetric electro - hydrostatic actuator is the high - pressure cavity;

[0027] Figure 3 is the schematic diagram of the implementation scheme when the rod - end cavity of the asymmetric actuator cylinder of the load - sensitive asymmetric electro - hydrostatic actuator is the high - pressure cavity;

[0028] Wherein, 1 - speed - regulating motor, 2 - load - sensitive hydraulic pump, 3 - load - sensitive mechanism, 4 - pressure - selecting shuttle valve, 5 - hydraulically controlled directional valve, 6 - accumulator, 7 - first safety valve, 8 - second safety valve, 9 - asymmetric actuator cylinder. Detailed Implementation Modes

[0029] This part is the embodiment of the present invention, used to explain and illustrate the technical solution of the present invention.

[0030] A load - sensitive asymmetric electro - hydrostatic actuator includes a speed - regulating motor 1, a load - sensitive hydraulic pump 2, a load - sensitive mechanism 3, a pressure - selecting shuttle valve 4, a hydraulically controlled directional valve 5, an accumulator 6 and an asymmetric actuator cylinder 9; the asymmetric actuator cylinder 9 is an asymmetric hydraulic - driven actuator cylinder, one oil cavity of which is connected to port A of the load - sensitive hydraulic pump 2, and the other oil cavity is connected to port B of the load - sensitive hydraulic pump 2; the load - sensitive hydraulic pump 2 is a bidirectional hydraulic pump, which is controlled and rotated tangentially by the connected speed - regulating motor 1; the load - sensitive mechanism 3 is connected to the pressure of port A or port B of the load - sensitive hydraulic pump 2 through the pressure - selecting shuttle valve 4 and adjusts the displacement of the load - sensitive hydraulic pump 2; the hydraulically controlled directional valve 5 selects one end with lower pressure between port A and port B of the load - sensitive hydraulic pump 2 to be connected to the accumulator 6 according to the pressure magnitudes of port A and port B of the load - sensitive hydraulic pump 2.

[0031] The speed - regulating motor 1 is a motor - generator integrated unit.

[0032] The two inlet ports of the pressure - selecting shuttle valve 4 are respectively connected to port A and port B of the load - sensitive hydraulic pump 2, and transmit the pressure of the end with larger pressure to the load - sensitive mechanism 3 through the working port.

[0033] The load - sensitive mechanism 3 adjusts the displacement of the load - sensitive hydraulic pump 2 according to the sensed pressure. The larger the pressure, the smaller the displacement of the load - sensitive hydraulic pump 2.

[0034] The hydraulically controlled directional valve 5 selects the port with lower pressure between port A and port B of the load - sensitive hydraulic pump 2 to communicate with the accumulator 6 by sensing the pressures of port A and port B of the load - sensitive hydraulic pump 2.

[0035] The spool of the hydraulic control directional valve 5 is a two-position four-way spool with a symmetrical layout. The two control oil ports of the hydraulic control directional valve 5 are respectively connected to the A port and the B port of the load-sensing hydraulic pump 2. The first working oil port and the second working oil port of the hydraulic control directional valve 5 are respectively connected to the A port and the B port of the load-sensing hydraulic pump 2. The third working oil port and the fourth working oil port of the hydraulic control directional valve 5 are connected to the accumulator 6. The working oil port at one end of the hydraulic control directional valve 5 that selects the control oil port with a smaller pressure is connected to the accumulator 6.

[0036] The A port and the B port of the load-sensing hydraulic pump 2 are also connected through a safety valve.

[0037] A working method for a load-sensing asymmetric electro-hydrostatic actuator, including a method with a load-sensing hydraulic pump as the main power:

[0038] The load-sensing hydraulic pump pumps oil from the low-pressure end to the high-pressure end. Under the action of the high-pressure oil, the high-pressure working port of the pressure selection shuttle valve is connected to the load-sensing mechanism, and the high-pressure oil pushes the spool through the high-pressure control oil port of the hydraulic control directional valve, so that the accumulator is communicated with the low-pressure working oil port of the hydraulic control directional valve.

[0039] The load-sensing hydraulic pump injects hydraulic oil into the high-pressure oil chamber of the asymmetric actuator. The piston rod of the asymmetric actuator provides an active load force. The low-pressure end of the load-sensing hydraulic pump serves as an oil suction port to suck hydraulic oil from the low-pressure oil chamber of the asymmetric actuator. The accumulator is used to compensate for the difference in the oil suction volume caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator.

[0040] It also includes a method with the load as the main power:

[0041] The oil in the high-pressure chamber of the asymmetric actuator pushes the load-sensing hydraulic pump to work as a motor, and the speed control motor serves as a generator to provide resistance. Under the action of the high-pressure oil, the high-pressure working port of the pressure selection shuttle valve is connected to the load-sensing mechanism, and the high-pressure oil pushes the spool through the high-pressure control oil port of the hydraulic control directional valve, so that the accumulator is communicated with the low-pressure working oil port of the hydraulic control directional valve.

[0042] The high-pressure end of the load-sensing hydraulic pump serves as an oil suction port to suck hydraulic oil from the high-pressure oil chamber of the asymmetric actuator. When the piston rod of the asymmetric actuator moves, the low-pressure end of the load-sensing hydraulic pump serves as an oil discharge port to inject hydraulic oil into the low-pressure oil chamber of the asymmetric actuator. The accumulator absorbs the volume difference of the oil caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator.

[0043] The embodiments of the present invention will be described below with reference to the accompanying drawings.

[0044] The speed control motor 1 of the load-sensitive asymmetric electro-hydrostatic actuator of the present invention is connected to the mechanical shaft of the load-sensitive hydraulic pump 2. The port A of the load-sensitive hydraulic pump 2 is connected to the rodless cavity of the asymmetric actuator cylinder 9, and the port B of the load-sensitive hydraulic pump 2 is connected to the rod cavity of the asymmetric actuator cylinder 9.

[0045] A pressure selection shuttle valve 4 is arranged between the port A and the port B of the load-sensitive hydraulic pump 2 for feeding back the control pressure at the outlet of the load-sensitive hydraulic pump 2.

[0046] A load-sensitive mechanism 3 is arranged between the pressure regulating port of the load-sensitive hydraulic pump 2 and the pressure selection shuttle valve 4 for regulating the outlet pressure of the load-sensitive hydraulic pump 2.

[0047] A pilot-operated directional valve 5 is arranged between the port A and the port B of the load-sensitive hydraulic pump 2. The first oil port M of the pilot-operated directional valve 5 is connected to the port A of the load-sensitive hydraulic pump 2, the second oil port N of the pilot-operated directional valve 5 is connected to the port B of the load-sensitive hydraulic pump 2, the first control oil port X of the pilot-operated directional valve 5 is connected to the port A of the load-sensitive hydraulic pump 2, the second control oil port Y of the pilot-operated directional valve 5 is connected to the port B of the load-sensitive hydraulic pump 2. The spool of the pilot-operated directional valve 5 is a symmetrically arranged two-position four-way spool. The outer sides of the two-position four-way spool close to the first control oil port X and the second control oil port Y are symmetrically arranged as the cut-off positions, and the inner sides far from the first control oil port X and the second control oil port Y are symmetrically arranged as the communication positions.

[0048] The third oil port and the fourth oil port of the pilot-operated directional valve 5 are connected and are connected to the outlet W of the accumulator 6.

[0049] A first safety valve 7 and a second safety valve 8 are arranged between the rodless cavity and the rod cavity of the asymmetric actuator cylinder 9. When the pressure in the rodless cavity is higher than the set value of the first safety valve 7, the oil in the rodless cavity can flow into the rod cavity through the first safety valve 7. When the pressure in the rod cavity is higher than the set value of the second safety valve 8, the oil in the rod cavity can flow into the rodless cavity through the second safety valve 8 to ensure the safety of the mechanism.

[0050] When the rodless cavity of the asymmetric actuator cylinder 9 of the load-sensitive asymmetric electro-hydrostatic actuator of the present invention is the high-pressure cavity, as Figure 2 shown, under the action of high-pressure oil, the P port of the pressure selection shuttle valve 4 is connected to the load-sensitive mechanism 3. The high-pressure oil pushes the two-position four-way spool through the first control oil port X of the pilot-operated directional valve 5, so that the outlet W of the accumulator 6 is connected to the second oil port N of the pilot-operated directional valve 5. At this time, the working state of the electro-hydrostatic actuator is divided into two cases:

[0051] (1) The A port of the load-sensing hydraulic pump 2 serves as the oil discharge port to inject hydraulic oil into the rodless chamber of the asymmetric actuator 9. The piston rod of the asymmetric actuator 9 provides an active load force to extend. The B port of the load-sensing hydraulic pump 2 serves as the oil suction port to suck hydraulic oil from the rod chamber of the asymmetric actuator 9 and the accumulator 6. The hydraulic oil provided by the accumulator 6 is used to compensate for the difference in oil suction volume caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator 9.

[0052] When the active load force provided by the piston rod of the asymmetric actuator 9 is relatively small, the pressure at the A port of the load-sensing hydraulic pump 2 is not sufficient to control the load-sensing mechanism 3 to adjust the swash plate angle of the load-sensing hydraulic pump 2 to change its displacement. The operating speed of the electro-hydrostatic actuator is adjusted by controlling the speed of the speed-regulating motor 1. When the active load force provided by the piston rod of the asymmetric actuator 9 increases, the pressure at the A port of the load-sensing hydraulic pump 2 increases. The load-sensing mechanism 3 adjusts the swash plate angle of the load-sensing hydraulic pump 2 to reduce the output displacement of the load-sensing hydraulic pump 2 and increases the speed of the speed-regulating motor 1 to ensure the output speed of the electro-hydrostatic actuator, thereby avoiding the increase in current caused by the increase in motor torque and reducing the heat generation of the motor.

[0053] (2) The A port of the load-sensing hydraulic pump 2 serves as the oil suction port to suck hydraulic oil from the rodless chamber of the asymmetric actuator 9. When the piston rod of the asymmetric actuator 9 is retracted under the action of the load, the B port of the load-sensing hydraulic pump 2 serves as the oil discharge port to inject hydraulic oil into the rod chamber of the asymmetric actuator 9 and the accumulator 6. At this time, the load-sensing hydraulic pump 2 acts as a motor to drive the speed-regulating motor 1 in the power generation mode, and the accumulator 6 absorbs the difference in oil volume caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator 9.

[0054] When the rod chamber of the asymmetric actuator 9 of the load-sensing asymmetric electro-hydrostatic actuator of the present invention is the high-pressure chamber, as Figure 3 shown, under the action of the high-pressure hydraulic oil, the Q port of the pressure selection shuttle valve 4 is connected to the load-sensing mechanism 3. The high-pressure oil pushes the two-position four-way spool through the second control oil port Y of the hydraulic control reversing valve 5, so that the outlet W of the accumulator 6 is communicated with the first oil port M of the hydraulic control reversing valve 5. At this time, the working state of the electro-hydrostatic actuator is divided into two cases:

[0055] (1) The B port of the load-sensing hydraulic pump 2 serves as the oil discharge port to inject hydraulic oil into the rod chamber of the asymmetric actuator 9. The piston rod of the asymmetric actuator 9 provides an active load force to retract. The A port of the load-sensing hydraulic pump 2 serves as the oil suction port to suck hydraulic oil from the rodless chamber of the asymmetric actuator 9 and the accumulator 6. The accumulator 6 absorbs the difference in oil volume caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator 9.

[0056] When the active load force provided by the piston rod of the asymmetric actuator 9 is relatively small, the pressure at port B of the load-sensing hydraulic pump 2 is insufficient to control the load-sensing mechanism 3 to adjust the swashplate angle of the load-sensing hydraulic pump 2 and change its displacement. The operating speed of the electro-hydrostatic actuator is adjusted by controlling the speed of the speed-regulating motor 1. When the active load force provided by the piston rod of the asymmetric actuator 9 increases, the pressure at port B of the load-sensing hydraulic pump 2 increases. The load-sensing mechanism 3 adjusts the swashplate angle of the load-sensing hydraulic pump 2 to reduce the output displacement of the load-sensing hydraulic pump 2 and increases the speed of the speed-regulating motor 1 to ensure the output speed of the electro-hydrostatic actuator, thereby avoiding an increase in current caused by an increase in motor torque and reducing the heat generated by the motor.

[0057] (2) Port B of the load-sensing hydraulic pump 2 serves as the oil suction port to suck hydraulic oil from the rod chamber of the asymmetric actuator 9. When the piston rod of the asymmetric actuator 9 extends under the action of the forward load, port A of the load-sensing hydraulic pump 2 serves as the oil discharge port to inject hydraulic oil into the rodless chamber of the asymmetric actuator 9. At this time, the load-sensing hydraulic pump 2 acts as a motor to drive the speed-regulating motor 1 in the power generation mode, and the accumulator 6 provides the oil volume difference caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator 9 to the rodless chamber of the asymmetric actuator 9.

[0058] In summary, the load-sensing asymmetric electro-hydrostatic actuator system of the present invention has a simple composition, all of which use mature components, with low manufacturing difficulty and simple control. The use of the asymmetric actuator 9 reduces the structural size of the electro-hydrostatic actuator, and the heat generated by the electro-hydrostatic actuator is effectively suppressed through the load-sensing technology, meeting the actual application requirements of the electro-hydrostatic actuator.

Claims

1. A load-sensitive asymmetric electro-hydrostatic actuator, characterized in that, It includes a speed-regulating motor (1), a load-sensing hydraulic pump (2), a load-sensing mechanism (3), a pressure-selecting shuttle valve (4), a hydraulically controlled directional valve (5), an accumulator (6), and an asymmetric actuator (9); the asymmetric actuator (9) is an asymmetric hydraulically driven actuator, one oil chamber of the asymmetric actuator (9) is connected to port A of the load-sensing hydraulic pump (2), and the other oil chamber is connected to port B of the load-sensing hydraulic pump (2); the load-sensing hydraulic pump (2) is a bidirectional hydraulic pump, and its control and tangential direction are controlled by the connected speed-regulating motor (1); the load-sensing mechanism (3) is connected to the pressure of port A or port B of the load-sensing hydraulic pump (2) through the pressure-selecting shuttle valve (4) and adjusts the displacement of the load-sensing hydraulic pump (2); the hydraulically controlled directional valve (5) selects one end to be connected to the accumulator (6) according to the pressure magnitudes of port A and port B of the load-sensing hydraulic pump (2).

2. The load-sensitive asymmetric electro-hydrostatic actuator according to claim 1, wherein The speed-regulating motor (1) is a combined generator and motor.

3. The load-sensitive asymmetric electro-hydrostatic actuator according to claim 1, wherein The two inlet ports of the pressure-selecting shuttle valve (4) are respectively connected to port A and port B of the load-sensing hydraulic pump (2), and the pressure at the higher-pressure end is transmitted to the load-sensing mechanism (3) through the working port.

4. A load-sensitive asymmetric electro-hydrostatic actuator according to claim 3, characterized in that, The load-sensing mechanism (3) adjusts the displacement of the load-sensing hydraulic pump (2) according to the sensed pressure. The greater the pressure, the smaller the displacement of the load-sensing hydraulic pump (2).

5. A load-sensitive asymmetric electro-hydrostatic actuator according to claim 1, characterized in that, The hydraulically controlled directional valve (5) senses the pressures of port A and port B of the load-sensing hydraulic pump (2) and selects the port with the lower pressure among port A and port B of the load-sensing hydraulic pump (2) to communicate with the accumulator (6).

6. The load-sensitive asymmetric electro-hydrostatic actuator according to claim 5, characterized in that, The spool of the hydraulically controlled directional valve (5) is a symmetrically arranged two-position four-way spool. The two control oil ports of the hydraulically controlled directional valve (5) are respectively connected to port A and port B of the load-sensing hydraulic pump (2). The first working oil port and the second working oil port of the hydraulically controlled directional valve (5) are respectively connected to port A and port B of the load-sensing hydraulic pump (2). The third working oil port and the fourth working oil port of the hydraulically controlled directional valve (5) are connected to the accumulator (6); the hydraulically controlled directional valve (5) selects the working oil port at one end of the control oil port with the lower pressure to be connected to the accumulator (6).

7. The load-sensitive asymmetric electro-hydrostatic actuator according to claim 1, characterized in that Port A and port B of the load-sensing hydraulic pump (2) are also connected through a safety valve.

8. A working method for a load-sensitive asymmetric electro-hydrostatic actuator, using a load-sensitive asymmetric electro-hydrostatic actuator as described in any one of claims 1-7, characterized in that, It includes a method for the load-sensing hydraulic pump to provide the main power: The load-sensing hydraulic pump pumps the oil fluid from the low-pressure end to the high-pressure end; under the action of the high-pressure oil fluid, the high-pressure working port of the pressure-selecting shuttle valve is connected to the load-sensing mechanism, and the high-pressure oil pushes the spool through the high-pressure control oil port of the hydraulically controlled directional valve, so that the accumulator is communicated with the low-pressure working oil port of the hydraulically controlled directional valve; The load-sensing hydraulic pump injects hydraulic oil into the high-pressure oil chamber of the asymmetric actuator. The piston rod of the asymmetric actuator provides the main load force. The low-pressure end of the load-sensing hydraulic pump serves as the oil suction port to suck hydraulic oil from the low-pressure oil chamber of the asymmetric actuator. The accumulator is used to compensate for the difference in the oil suction amounts caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator.

9. A working method for a load-sensitive asymmetric electro-hydrostatic actuator, which uses a load-sensitive asymmetric electro-hydrostatic actuator as described in any one of claims 1-7, characterized in that, It includes a method for the load to be the main power: The oil in the high-pressure chamber of the asymmetric actuator pushes the load-sensitive hydraulic pump to work as a motor, and the speed-regulating motor acts as a generator to provide resistance. Under the action of the high-pressure oil, the high-pressure working port of the pressure-selecting shuttle valve is connected to the load-sensitive mechanism, and the high-pressure oil pushes the spool through the high-pressure control oil port of the pilot-operated check valve, so that the accumulator is connected to the low-pressure working oil port of the pilot-operated check valve. The high-pressure end of the load-sensitive hydraulic pump serves as the oil suction port to suck hydraulic oil from the high-pressure oil chamber of the asymmetric actuator. When the piston rod of the asymmetric actuator moves, the low-pressure end of the load-sensitive hydraulic pump serves as the oil discharge port to inject hydraulic oil into the low-pressure oil chamber of the asymmetric actuator, and the accumulator absorbs the oil volume difference caused by the area difference between the rodless chamber and the rod chamber of the asymmetric actuator.

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