Electro-hydraulic actuator underwater working condition simulation test system and loading method

Abstract

The invention discloses an electro-hydraulic actuator underwater working condition simulation test system and a loading method. Based on a test system with a gear pump, a pressure compensator, a loading valve group and a loading cylinder as main bodies, multi-working-condition hydraulic load simulation of the electro-hydraulic actuator in the underwater high-pressure environment is realized by adjusting the opening pressure of a proportional overflow valve in the loading valve group and supplying oil by the pressure compensator and the gear pump in a combined manner. According to the invention, the oil path pressure of the system can be adjusted through the pressure compensator, and the active extension and retraction of the piston rod of the loading cylinder and the pressure of the control cavity are adjusted and controlled through the proportional overflow valve, so that multi-working-condition hydraulic load simulation under the underwater high-pressure environment is realized; the safety condition of the system can be judged through the sensor, the oil immersion motor is closed through the controller under the unsafe condition, the electromagnetic reversing valve is in a power-off state, and the safety of the system is guaranteed; and the overflow valve and the proportional overflow valve are connected in series, so that high-precision control on the pressure of the control cavity and the loading acting force of the loading cylinder can be realized.

Description

Technical Field

[0001] The present invention relates to a test system for an electro-hydraulic actuator, belonging to the field of hydraulic technology, and particularly to an underwater condition simulation test system and a loading method for an electro-hydraulic actuator. Background Art

[0002] The underwater electro-hydraulic actuator EHA (Electro-Hydrostatic Actuator) is the core unit for ocean engineering equipment to achieve movement and complete operations. Its pressure resistance, sealing performance, working life, and movement performance under complex deep-sea conditions are related to whether the ocean engineering equipment can operate normally and stably. However, due to the high cost and long test cycle of sea trials, it is difficult to truly conduct performance test trials in the marine environment, especially in the deep-sea environment. Therefore, it is necessary to design a simulation test platform to conduct full-condition load simulation tests on the underwater electro-hydraulic actuator EHA.

[0003] In the field of hydraulic transmission, when testing and verifying the response characteristics of the actuator of the test device and electro-hydraulic control algorithms, etc., it is necessary to simulate the actual working conditions of the test equipment as much as possible, and simulate the load faced by the actuator through mechanical loading or hydraulic loading methods. In linear motion, hydraulic load simulation is mainly achieved by combining a loading cylinder with a proportional relief valve, a proportional throttle valve, or a balance valve, and forming a certain back pressure by setting the valve opening to simulate the load force, and the magnitude of the set back pressure is controlled by an external electrical signal.

[0004] Currently, the existing high-pressure sealed cabins can only test the pressure resistance and sealing performance of the object under test, and cannot complete the load simulation test of the electro-hydraulic actuator under various operating conditions in a pressure environment. Moreover, traditional actuator load simulation test platforms mostly adopt passive loading methods, that is, the loading cylinder cannot actively exert force to extend or retract, and cannot actively generate and apply a load force. Summary of the Invention

[0005] In order to solve the problems existing in the background art, the present invention proposes an underwater condition simulation test system and a loading method for an electro-hydraulic actuator. The system and method of the present invention can realize the simulation of positive and negative load conditions of the electro-hydraulic actuator under an underwater high-pressure environment.

[0006] The technical solution adopted by the present invention is as follows: I. An underwater condition simulation test system for an electro-hydraulic actuator: The test system includes an oil source assembly for supplying oil power during the test of the underwater condition simulation test system under an underwater high-pressure environment; The test system includes a safety valve group, which is connected to the oil source assembly and is used for safety control during the test of the underwater condition test system under an underwater high-pressure environment; The test system includes a loading valve group, which is connected to the oil source assembly and the safety valve group and is used to simulate different underwater load conditions under an underwater high pressure environment to perform active loading of the underwater working condition test system; The test system includes an actuator connected to a loading valve group, and is used to simulate active loading of different underwater load conditions under the regulation of an oil source component and a loading valve group in an underwater high-pressure environment to test the electro-hydraulic actuator.

[0007] An underwater high pressure environment is an environment where the water pressure is higher than the preset water pressure.

[0008] The loading valve group includes a second one-way valve, a third one-way valve, a fourth one-way valve, a fifth one-way valve, a second pressure measuring joint, a third pressure measuring joint, a second pressure sensor, a third pressure sensor, a second relief valve, a third relief valve, a first proportional relief valve, a second proportional relief valve and an electromagnetic reversing valve. The oil inlets of the second one-way valve and the third one-way valve are both connected to the safety valve group. The oil circuit connected between the oil outlet of the second one-way valve and the actuator is the second oil circuit b, and the oil circuit connected between the oil outlet of the third one-way valve and the actuator is the third oil circuit c; the oil inlet of the fifth one-way valve is connected to the second oil circuit b between the oil outlet of the second one-way valve and the oil inlet of the electromagnetic reversing valve, the oil outlet of the fifth one-way valve, the oil inlet of the second proportional relief valve and the third relief valve The oil outlet of the fourth check valve, the oil inlet of the first proportional relief valve and the second relief valve are connected in sequence, the oil outlet of the second relief valve and the oil outlet of the third relief valve are connected to the oil circuit of the safety valve group as the fourth oil circuit d, the oil inlet of the fourth check valve is connected to the third oil circuit c between the oil outlet of the third check valve and the oil inlet of the electromagnetic reversing valve, and the oil inlet and oil outlet of the electromagnetic reversing valve are connected to the second oil circuit b and the third oil circuit c respectively; the second pressure measuring joint and the second pressure sensor are connected to the second oil circuit b, and the third pressure measuring joint and the third pressure sensor are connected to the third oil circuit c; the loading valve group is also threadedly connected with a second pressure compensator for oil pressure compensation of the underwater working condition simulation test system under a simulated underwater high pressure environment. The second pressure compensator is threadedly connected to the loading valve group through a flange to achieve fixed connection.

[0009] The safety valve group includes a first one-way valve, a pressure oil filter, a first relief valve, a first pressure measuring joint and a first pressure sensor. The oil inlet of the first one-way valve is connected to the oil source component, the oil outlet of the first one-way valve is connected to the oil inlet of the first relief valve via the pressure oil filter, the oil inlet of the first relief valve is connected between the oil inlets of the second one-way valve and the third one-way valve of the loading valve group, the oil circuit connected between the oil outlet of the first relief valve and the oil source component is used as the first oil circuit a, the oil outlet of the first relief valve and the oil outlet of the second relief valve of the loading valve group are connected via the fourth oil circuit d; the first pressure measuring joint and the first pressure sensor are connected to the oil inlet of the first relief valve.

[0010] The oil source assembly includes an oil tank, a pressure-resistant temperature sensor, an oil suction filter, an oil-immersed motor and a gear pump. The oil-immersed motor is connected to the gear pump through a coupling, the oil suction port of the gear pump is connected to the oil tank through the oil suction filter, and the pressure-resistant temperature sensor is located inside the oil tank; the oil outlet of the gear pump is connected to the oil inlet of the first one-way valve of the safety valve group, and the oil tank is connected to the oil outlet of the first overflow valve of the safety valve group through the first oil circuit a; the oil tank and the safety valve group are also threadedly connected with a first pressure compensator for performing oil pressure compensation on the underwater working condition simulation test system under a simulated underwater high-pressure environment.

[0011] The actuator includes a pressure-resistant displacement sensor, a loading cylinder and an articulated mechanism. The loading cylinder is a symmetrical cylinder. The first cavity A of the loading cylinder is connected to the oil outlet of the second one-way valve of the loading valve group via the second oil circuit b, and the second cavity B of the loading cylinder is connected to the oil outlet of the third one-way valve of the loading valve group via the third oil circuit c. The pressure-resistant displacement sensor is installed at the end of the piston rod on the side of the first cavity A of the loading cylinder, and the piston rod on the side of the second cavity B of the loading cylinder is connected to the piston rod of the actuator hydraulic cylinder of the electro-hydraulic actuator EHA to be tested through a hinged mechanism.

[0012] 2. A loading method for an underwater working condition simulation test system of an electro-hydraulic actuator: The underwater working condition simulation test system first sets the opening pressure of the first relief valve of the safety valve group to be higher than the preset maximum pressure of the underwater working condition simulation test system to protect the normal operation of the hydraulic system; when the underwater working condition simulation test system is not working, the electromagnetic reversing valve is in a power-off state, and the second oil circuit b and the third oil circuit c are connected. When the underwater working condition simulation test system is performing testing, the oil-immersed motor and the gear pump are in a working state, the electromagnetic reversing valve is in a power-on state, and the first cavity A and the second cavity B of the loading cylinder are not connected; at this time, the underwater working condition simulation test system is placed in a simulated underwater high-pressure environment in a pressure vessel, wherein the first proportional relief valve, the second proportional relief valve, the electromagnetic reversing valve and the controller of the oil-immersed motor are all located outside the pressure vessel. During the test, the second oil circuit b and the third oil circuit c of the underwater working condition simulation test system are disconnected, the gear pump sucks oil from the oil tank through the oil suction filter, and the oil outlet of the gear pump flows the high-pressure hydraulic oil with a pressure higher than the preset threshold through the first one-way valve and the oil pressure filter to the second one-way valve and the third one-way valve. Valve, high-pressure hydraulic oil flows into the second oil circuit b and the third oil circuit c through the second one-way valve and the third one-way valve respectively, the fourth one-way valve and the fifth one-way valve are in the open state, by adjusting the oil source component, the loading valve group and the two pressure compensators, that is, adjusting the opening pressure of the first proportional relief valve and the second proportional relief valve, and the first pressure compensator, the second pressure compensator and the gear pump are combined to supply oil to simulate the active loading of four underwater load conditions, so as to test the actuator hydraulic cylinder of the electro-hydraulic actuator EHA to be tested. The four underwater load conditions include two positive load conditions and two negative load conditions, and the oil temperature, pressure and piston rod displacement of the underwater working condition simulation test system are monitored in real time by a pressure-resistant temperature sensor, three pressure sensors and a pressure-resistant displacement sensor. When it is monitored during the test that the oil temperature exceeds the preset temperature, the oil pressure exceeds the preset pressure or the piston rod displacement of the loading cylinder exceeds the preset displacement range, the oil-immersed motor is turned off by the controller and the electromagnetic reversing valve is in a power-off state to ensure the safety of the system.

[0013] When the underwater load condition is at the first positive load condition, the condition simulation is completed by a gear pump and a second proportional overflow valve that regulates the pressure of the first port A of the loading cylinder; the first port A of the loading cylinder is the control chamber, and the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional overflow valve and the second overflow valve. The magnitude of the input current signal in the first proportional overflow valve is controlled to remain unchanged to maintain the oil pressure in the third oil circuit c constant. The pressure-reduced hydraulic oil flows to the second port B of the loading cylinder; the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional overflow valve and the third overflow valve. The magnitude of the input current signal in the second proportional overflow valve is controlled to adjust its own opening pressure, thereby reducing the oil pressure in the second oil circuit b. The pressure-reduced hydraulic oil flows to the first port A of the loading cylinder; by changing the opening pressure of the second proportional overflow valve, the pressure of the first port A of the loading cylinder is controlled to be greater than that of the second port B, and a dynamic load loading force to the right is formed in the loading cylinder. The piston rod of the actuating hydraulic cylinder extends and the generated thrust acts on the piston rod of the loading cylinder through the hinge mechanism. At this time, the direction of the dynamic load loading force of the loading cylinder is opposite to the direction of the driving force of the actuating hydraulic cylinder of the electro-hydraulic actuator EHA to be tested, completing the simulation loading of the first positive load condition.

[0014] When the underwater load condition is at the second positive load condition, the condition simulation is completed by a gear pump and a first proportional overflow valve that regulates the pressure of the second port B of the loading cylinder; the second port B of the loading cylinder is the control chamber, and the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional overflow valve and the third overflow valve. The magnitude of the input current signal in the second proportional overflow valve is controlled to remain unchanged to maintain the oil pressure in the second oil circuit b constant. The pressure-reduced hydraulic oil flows to the first port A of the loading cylinder; the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional overflow valve and the second overflow valve. The magnitude of the input current signal in the first proportional overflow valve is controlled to adjust its own opening pressure, thereby reducing the oil pressure in the third oil circuit c. The pressure-reduced hydraulic oil flows to the second port B of the loading cylinder; by changing the opening pressure of the first proportional overflow valve, the pressure of the second port B of the loading cylinder is controlled to be greater than that of the first port A, and a dynamic load loading force to the left is formed in the loading cylinder. The piston rod of the actuating hydraulic cylinder retracts and the generated pulling force acts on the piston rod of the loading cylinder through the hinge mechanism. At this time, the direction of the dynamic load loading force of the loading cylinder is opposite to the direction of the driving force of the actuating hydraulic cylinder of the electro-hydraulic actuator EHA to be tested, completing the simulation loading of the second positive load condition.

[0015] In the first negative load condition of the underwater load condition, the working condition simulation is completed by the gear pump and the first proportional relief valve that adjusts the pressure of the second cavity B of the loading cylinder; the second cavity B of the loading cylinder is the control cavity, and the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve and the third relief valve. The magnitude of the input current signal in the second proportional relief valve is controlled to remain unchanged to maintain the oil pressure in the second oil circuit b constant, and the hydraulic oil after decompression flows to the first cavity A of the loading cylinder; the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve and the second relief valve, and the oil pressure in the first proportional relief valve is controlled to remain constant. The size of the input current signal is used to adjust its own opening pressure, thereby reducing the pressure of the oil in the third oil circuit c, and the decompressed hydraulic oil flows to the second cavity B of the loading cylinder; the opening pressure of the first proportional relief valve is changed, and the pressure of the second cavity B of the loading cylinder is controlled to be greater than the first cavity A. The loading cylinder forms a dynamic load loading force to the left, and the piston rod of the execution hydraulic cylinder extends and the thrust generated acts on the piston rod of the loading cylinder through the articulated mechanism. At this time, the dynamic load loading force direction of the loading cylinder is connected with the main power direction of the execution hydraulic cylinder of the electro-hydraulic actuator EHA to be tested, completing the simulated loading of the first negative load condition.

[0016] When the underwater load working condition is in the second negative load working condition, the working condition simulation is completed by the gear pump and the second proportional relief valve that adjusts the pressure of the first cavity A of the loading cylinder; the first cavity A of the loading cylinder is the control cavity, and the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve and the second relief valve. The magnitude of the input current signal in the first proportional relief valve is controlled to remain unchanged to maintain the oil pressure in the third oil circuit c constant, and the hydraulic oil after decompression flows to the second cavity B of the loading cylinder; the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve and the third relief valve, and the oil pressure in the second proportional relief valve is controlled to remain constant. The size of the input current signal is used to adjust its own opening pressure, thereby reducing the pressure of the oil in the second oil circuit b. The decompressed hydraulic oil flows to the first cavity A of the loading cylinder; the opening pressure of the second proportional relief valve is changed to control the pressure of the first cavity A of the loading cylinder to be greater than the second cavity B. The loading cylinder forms a dynamic load loading force to the right, and the piston rod of the execution hydraulic cylinder retracts and acts on the piston rod of the loading cylinder through the articulated mechanism. At this time, the direction of the dynamic load loading force of the loading cylinder is the same as the main power direction of the execution hydraulic cylinder of the electro-hydraulic actuator EHA to be tested, completing the simulated loading of the second negative load condition.

[0017] The present invention is based on an underwater working condition simulation test system of an electro-hydraulic actuator with a gear pump, a pressure compensator, a loading valve group and a loading cylinder as the main body. By adjusting the opening pressure of the proportional relief valve in the loading valve group and the oil supply of the pressure compensator and the gear pump combination, the multi-working condition hydraulic load simulation of the electro-hydraulic actuator under an underwater high-pressure environment can be realized. The present invention adjusts the oil circuit pressure of the underwater working condition simulation test system through the pressure compensator, and realizes the hydraulic circuit oil compensation under an underwater high-pressure environment; by controlling the active extension and active retraction of the loading cylinder piston rod, the hydraulic load simulation of four working conditions of two positive load conditions and two negative load conditions can be realized; a state detection sensor is set to monitor the system oil temperature, pressure and displacement of the loading cylinder piston rod in real time. When the measured value of the pressure-resistant displacement sensor exceeds the set displacement range or the system temperature and pressure exceed the set value, the oil-immersed motor is turned off by the controller and the electromagnetic reversing valve is in a power-off state to ensure the safety of the hydraulic system; through the series setting of the relief valve and the proportional relief valve, the high-precision control of the pressure of the loading cylinder control chamber is realized, and then the high-precision loading force control of the loading cylinder is realized.

[0018] The beneficial effects of the present invention are: 1. Compared with the traditional onshore hydraulic load simulation method and hydraulic system, the present invention adjusts the oil circuit pressure of the hydraulic load simulation test system through a pressure compensator, thereby realizing hydraulic load simulation under underwater high-pressure environment.

[0019] 2. The present invention controls the active extension and active retraction of the loading cylinder piston rod, and the control chamber pressure of the active extension and active retraction can be adjusted by a proportional relief valve, so as to realize the simulation of four working conditions: positive load condition, positive load condition, negative load condition and negative load condition.

[0020] 3. The present invention is provided with a status detection sensor, which can monitor the system oil temperature, pressure, and displacement of the loading cylinder piston rod in real time. When the measured value of the pressure-resistant displacement sensor exceeds the set displacement range or the system temperature and pressure exceed the set value, the controller shuts down the oil-immersed motor and puts the electromagnetic reversing valve in a power-off state to ensure the safety of the hydraulic system.

[0021] 4. The present invention can achieve high-precision control of the pressure in the control chamber of the loading cylinder and high-precision control of the loading force of the loading cylinder by connecting the relief valve and the proportional relief valve in series. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the underwater working condition simulation test system of the present invention; Figure 2 This is a diagram of experimental results of simulating negative load conditions of the present invention; Figure 3 This is a diagram of experimental results of simulating positive load conditions of the present invention; Figure 4 This is a diagram of the experimental results of simulating positive and negative load dynamic constant value loading in the present invention; Figure 5 This is a diagram of the experimental results of simulating positive and negative load dynamic alternating loading in the present invention; In the figure: 1, oil tank, 2, first pressure compensator, 3, pressure-resistant temperature sensor, 4, oil suction filter, 5, oil-immersed motor, 6, gear pump, 7.1, first one-way valve, 7.2, second one-way valve, 7.3, third one-way valve, 7.4, fourth one-way valve, 7.5, fifth one-way valve, 8, oil pressure filter, 9, first overflow valve, 10.1, first pressure measuring joint, 10.2, second pressure measuring joint, 10.3, third pressure measuring joint, 11.1, first pressure sensor, 11.2, second pressure sensor, 11.3, third pressure sensor, 12.1, second overflow valve, 12.2, third overflow valve, 13.1, first proportional overflow valve, 13.2, second proportional overflow valve, 14, electromagnetic reversing valve, 15, pressure-resistant displacement sensor, 16, loading cylinder, 17, actuator hydraulic cylinder, 18, second pressure compensator. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] like Figure 1As shown, the underwater working condition simulation test system of the electro-hydraulic actuator of the present invention mainly includes an oil source component, a safety valve group, a loading valve group and an actuator. The safety valve group is connected to the oil source component, and the loading valve group is connected to the oil source component, the safety valve group and the actuator. When the underwater working condition simulation test system is tested in a high-pressure environment underwater that is higher than the preset water pressure, oil power is supplied through the oil source component, safety control is performed through the safety valve group, different underwater load conditions are simulated through the loading valve group to perform active loading of the underwater working condition test system, and active loading of different underwater load conditions is simulated through the actuator under the regulation of the oil source component and the loading valve group to test the electro-hydraulic actuator. The oil source assembly includes an oil tank 1, a pressure-resistant temperature sensor 3, an oil suction filter 4, an oil-immersed motor 5 and a gear pump 6. The safety valve group includes a first one-way valve 7.1, an oil pressure filter 8, a first relief valve 9, a first pressure measuring joint 10.1 and a first pressure sensor 11.1. The loading valve group includes a second one-way valve 7.2, a third one-way valve 7.3, a fourth one-way valve 7.4, a fifth one-way valve 7.5, a second pressure measuring joint 10.2, a third pressure measuring joint 10.3, a second pressure sensor 11.2, a third pressure sensor 11.3, a second relief valve 12.1, a third relief valve 12.2, a first proportional relief valve 13.1, a second proportional relief valve 13.2 and an electromagnetic reversing valve 14. The actuator includes a pressure-resistant displacement sensor 15, a loading cylinder 16 and an articulated mechanism.

[0025] The oil-immersed motor 5 of the oil source assembly of the underwater working condition simulation test system is connected to the gear pump 6 through a coupling, the oil suction port of the gear pump 6 is connected to the oil tank 1 through the oil suction filter 4, and the pressure-resistant temperature sensor 3 is placed inside the oil tank 1; the oil outlet of the gear pump 6 is connected to the oil inlet of the first one-way valve 7.1 of the safety valve group, and the oil tank 1 is connected to the oil outlet of the first overflow valve 9 of the safety valve group through the first oil circuit a; the oil tank 1 and the safety valve group are also threadedly connected with a first pressure compensator 2 for compensating the oil pressure of the underwater working condition simulation test system under a simulated underwater high-pressure environment.

[0026] The oil inlet of the first check valve 7.1 of the safety valve group of the underwater working condition simulation test system is connected to the oil outlet of the gear pump 6, the oil inlet of the first relief valve 9 is connected to the oil outlet of the first check valve 7.1 through the oil pressure filter 8, the oil inlet of the first relief valve 9 is connected between the oil inlets of the second check valve 7.2 and the third check valve 7.3 of the loading valve group, the oil circuit connected between the oil outlet of the first relief valve 9 and the oil source assembly is used as the first oil circuit a, the oil outlet of the first relief valve 9 is connected to the oil tank 1 through the first oil circuit a, the oil outlet of the first relief valve 9 and the oil outlet of the second relief valve 12.1 of the loading valve group are connected through the fourth oil circuit d, the opening pressure of the first relief valve 9 must be higher than the maximum pressure limit of the system to protect the normal operation of the hydraulic system, and the first pressure measuring joint 10.1 and the first pressure sensor 11.1 are connected to the oil inlet of the first relief valve 9. The first pressure compensator 2 is fixedly connected to the oil tank 1 and the safety valve group through a flange and threaded connection, so as to realize oil pressure compensation for the oil source component and the safety valve group under a high-pressure environment.

[0027] The oil inlet of the first overflow valve 9 of the loading valve group of the underwater working condition simulation test system is connected to the oil inlet of the second check valve 7.2 and the oil inlet of the third check valve 7.3 through two oil circuits, the oil outlet of the second check valve 7.2 is connected to the first cavity A of the loading cylinder 16 through the second oil circuit b, the oil circuit connecting the oil outlet of the second check valve 7.2 and the actuator is the second oil circuit b, the oil circuit connecting the oil outlet of the third check valve 7.3 and the actuator is the third oil circuit c, and the oil outlet of the fifth check valve 7.2 is connected to the first cavity A of the loading cylinder 16 through the second oil circuit b. The oil inlet of the second check valve 7.5 is connected to the second oil circuit b between the oil outlet of the second check valve 7.2 and the oil inlet of the electromagnetic reversing valve 14, the oil inlet of the second proportional relief valve 13.2 is connected to the oil outlet of the fifth check valve 7.5, the oil inlet of the third relief valve 12.2 is connected to the oil outlet of the second proportional relief valve 13.2, the oil outlet of the third check valve 7.3 is connected to the second cavity B of the loading cylinder 16 via the third oil circuit c, the oil inlet of the fourth check valve 7.4 is connected to the oil outlet of the third check valve 7.3 The oil inlet of the first proportional relief valve 13.1 is connected to the oil outlet of the fourth check valve 7.4, the oil inlet of the second relief valve 12.1 is connected to the oil outlet of the first proportional relief valve 13.1, the oil outlet of the second relief valve 12.1 and the oil outlet of the third relief valve 12.2 are connected to the oil circuit of the safety valve group as the fourth oil circuit d, the oil outlet of the second relief valve 12.1 is connected to the oil outlet of the third relief valve 12.2, and It is directly connected to the oil outlet of the first overflow valve 9 via the fourth oil circuit d, the oil inlet and oil outlet of the electromagnetic reversing valve 14 are respectively connected to the second oil circuit b and the third oil circuit c, the second oil circuit b is connected with the second pressure measuring joint 10.2 and the second pressure sensor 11.2, the third oil circuit c is connected with the third pressure measuring joint 10.3 and the third pressure sensor 11.3, the second pressure compensator 18 is fixedly connected with the loading valve group through a flange and a threaded connection, so as to realize oil pressure compensation for the loading valve group under a high-pressure environment.

[0028] The first pressure compensator 2 and the second pressure compensator 18 are both compensating diaphragm pressure compensators, which have two functions: environmental pressure compensation and dynamic pressure compensation. Environmental pressure compensation refers to the pressure compensator compensating for the volume change of hydraulic oil caused by the change of environmental pressure, and dynamic pressure compensation refers to the dynamic compensation of the return oil pressure of the hydraulic system by the pressure compensator under a certain environmental pressure. When the hydraulic system is placed in a high-pressure sealed cabin to simulate the high-pressure deep-sea environment, the internal compensation diaphragm of the pressure compensator will produce a certain displacement under the action of the hydraulic system pressure and the environmental pressure until the compensation diaphragm is balanced and stops moving under the action of the hydraulic oil and seawater pressure. At this time, the volume compression of the hydraulic oil caused by the high-pressure environment and the suction caused by the operation of the system are compensated.

[0029] In another embodiment of the present invention, the first proportional relief valve 13.1 and the second relief valve 12.1 connected in series can be replaced by a single proportional relief valve, and the second proportional relief valve 13.2 and the third relief valve 12.2 connected in series can be replaced by a single proportional relief valve.

[0030] The loading cylinder 16 of the actuator of the underwater working condition simulation test system is a symmetrical cylinder. The first cavity A of the loading cylinder 16 is connected to the oil outlet of the second one-way valve 7.2 of the loading valve group through the second oil circuit b, and the second cavity B of the loading cylinder 16 is connected to the oil outlet of the third one-way valve 7.3 of the loading valve group through the third oil circuit c. The end of the piston rod on the first cavity A side of the loading cylinder 16 is provided with an external pressure-resistant displacement sensor 15, and the piston rod on the second cavity B side is connected to the piston rod of the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested through a hinge mechanism.

[0031] The underwater working condition simulation test system and loading method of the present invention can complete active loading simulation of four working conditions, namely, two positive load conditions and two negative load conditions. 1) In the first positive load condition, the piston rod of the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested is extended, that is, the main force generated by the actuator hydraulic cylinder 17 is thrust, and the loading cylinder 16 is required to apply a load force in the opposite direction of the movement of the piston rod of the actuator hydraulic cylinder 17. 2) In the second positive load condition, the piston rod of the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested is retracted, that is, the main force generated by the actuator hydraulic cylinder 17 is tension, and the loading cylinder 16 is required to apply a load force in the opposite direction of the movement of the piston rod of the actuator hydraulic cylinder 17. 3) In the first negative load condition, the piston rod of the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested is extended, that is, the main force generated by the actuator hydraulic cylinder 17 is thrust, and the loading cylinder 16 is required to apply a load force in the same direction as the movement of the piston rod of the actuator hydraulic cylinder 17. 4) In the second negative load condition, the piston rod of the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested is retracted, that is, the main force generated by the actuator hydraulic cylinder 17 is a pulling force, and the loading cylinder 16 is required to apply a load force in the same direction as the movement direction of the piston rod of the actuator hydraulic cylinder 17.

[0032] The loading method of the underwater working condition simulation test system in the specific implementation of the present invention is as follows: Except for the first proportional relief valve 13.1, the second proportional relief valve 13.2, the electromagnetic reversing valve 14 and the controller of the oil-immersed motor 5, all components of the underwater working condition simulation test system are placed in a pressure vessel, and system pressure compensation is achieved through the first pressure compensator 2 and the second pressure compensator 18 to simulate the underwater high-pressure environment. The pressure-resistant temperature sensor 3 monitors the oil temperature of the oil tank 1 in real time, the first pressure sensor 11.1 monitors the inlet pressure of the loading valve group in real time, the second pressure sensor 11.2 monitors the pressure of the second oil circuit b and the first cavity A of the loading cylinder 16 in real time, the third pressure sensor 11.3 monitors the pressure of the third oil circuit c and the second cavity B of the loading cylinder 16 in real time, and the pressure-resistant displacement sensor 15 monitors the displacement of the piston rod of the loading cylinder 16 in real time. When the measured value of the pressure-resistant temperature sensor 3 exceeds the set temperature upper limit, the measured values ​​of the three pressure sensors 11.1, 11.2, and 11.3 exceed the set pressure upper limit, and the measured value of the pressure-resistant displacement sensor 15 exceeds the set displacement range, the oil-immersed motor 5 is turned off by the controller and the electromagnetic reversing valve 14 is in a power-off state to stop the underwater working condition simulation test system from working.

[0033] By adjusting the input current signal of the electromagnetic reversing valve 14, the connection and disconnection between the second oil circuit b and the third oil circuit c can be controlled. By increasing the input current signal so that the electromagnetic reversing valve 14 is in the energized state, the second oil circuit b and the third oil circuit c are disconnected to start the underwater working condition simulation test. By reducing the input current signal so that the electromagnetic reversing valve 14 is in the de-energized state, the second oil circuit b and the third oil circuit c are connected to quickly balance the pressure of the two chambers of the loading cylinder 16 to stop the underwater working condition simulation test. When the underwater working condition simulation test system is working, the pressure-resistant temperature sensor 3, the three pressure sensors 11.1, 11.2, 11.3 and the pressure-resistant displacement sensor 15 always keep working, the preset opening pressure of the two relief valves 12.1 and 12.2 always remain unchanged, and the opening pressure of the two proportional relief valves 13.1 and 13.2 is adjusted by the controller, and the two pressure compensators 2, 18 and the gear pump 6 are combined to supply oil, so as to realize the active loading of the hydraulic load simulation under the underwater high-pressure environment.

[0034] When the underwater working condition simulation test system is tested, the opening pressure of the first overflow valve 9 of the safety valve group is first set to be higher than the preset maximum pressure of the underwater working condition simulation test system to protect the normal operation of the hydraulic system; when the underwater working condition simulation test system is not working, the electromagnetic reversing valve 14 is in a power-off state, and the second oil circuit b is connected to the third oil circuit c. When the underwater working condition simulation test system is testing, the oil-immersed motor 5 and the gear pump 6 are in a working state, the electromagnetic reversing valve 14 is in a power-on state, and the first cavity A and the second cavity B of the loading cylinder 16 are not connected; at this time, the underwater The working condition simulation test system is placed in a simulated underwater high pressure environment in a pressure vessel, wherein the first proportional relief valve 13.1, the second proportional relief valve 13.2, the electromagnetic reversing valve 14 and the controller of the oil-immersed motor 5 are all located outside the pressure vessel. During the test, the second oil circuit b and the third oil circuit c of the underwater working condition simulation test system are disconnected, and the gear pump 6 sucks oil from the oil tank 1 through the oil suction filter 4. The oil outlet of the gear pump 6 flows the high-pressure hydraulic oil with a pressure higher than the preset threshold through the first one-way valve 7.1 and the oil pressure filter 8 to the second one-way valve 7.2 and the third one-way valve 7.3. The high-pressure hydraulic oil is The oil flows into the second oil circuit b and the third oil circuit c through the second one-way valve 7.2 and the third one-way valve 7.3 respectively, and the fourth one-way valve 7.4 and the fifth one-way valve 7.5 are in the open state. By adjusting the oil source component, the loading valve group and the two pressure compensators 2 and 18, that is, adjusting the opening pressure of the first proportional relief valve 13.1 and the second proportional relief valve 13.2, and the first pressure compensator 2, the second pressure compensator 18 and the gear pump 6 combined oil supply, the active loading of four underwater load conditions is simulated, so as to test the actuator hydraulic cylinder 17 of the electro-hydraulic actuator EHA to be tested. The four The underwater load conditions include two positive load conditions and two negative load conditions, and the oil temperature, pressure and piston rod displacement of the loading cylinder 16 of the underwater working condition simulation test system are monitored in real time through the pressure-resistant temperature sensor 3, three pressure sensors 11.1, 11.2, 11.3 and the pressure-resistant displacement sensor 15. When it is monitored during the test that the oil temperature exceeds the preset temperature, the oil pressure exceeds the preset pressure, or the piston rod displacement of the loading cylinder 16 exceeds the preset displacement range, the controller shuts down the oil-immersed motor 5 and puts the electromagnetic reversing valve 14 in a power-off state to ensure system safety.

[0035] The specific load conditions of the underwater working condition simulation test system are as follows: 1) First positive load condition: When the piston rod of the actuator hydraulic cylinder 17 extends, acts on the piston rod of the loading cylinder 16 through the hinge mechanism and forms a thrust force thereon, the loading cylinder 16 provides a load loading force in a direction opposite to the extension direction of the actuator hydraulic cylinder 17. At this time, the first positive load condition can be simulated, and the working condition simulation is completed by the gear pump 6 and the second proportional relief valve 13.2 that adjusts the pressure of the first cavity A of the loading cylinder 16; the first cavity A of the loading cylinder 16 is the control cavity. Specifically, the oil-immersed motor 5 is working, the gear pump 6 is in the open state, the first relief valve 9 is used as a safety valve, and its opening pressure is set to be higher than the preset maximum pressure of the system, and the electromagnetic reversing valve 14 is in the energized state. The gear pump 6 absorbs oil from the oil tank 1 through the oil suction filter 4. The high-pressure oil at the pump outlet flows to the second one-way valve 7.2 and the third one-way valve 7.3 through the first one-way valve 7.1 and the oil pressure filter 8. The high-pressure oil flows into the second oil circuit b through the second one-way valve 7.2 and flows into the third oil circuit c through the third one-way valve 7.3. At this time, the first proportional relief valve 13.1, the second relief valve 12.1, the second proportional relief valve 13.2, and the third relief valve 12.2 are all in the overflow state. The oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve 13.1 and the second relief valve 12.1. By controlling the input current signal of the first proportional relief valve 13.1 to remain unchanged, the oil pressure in the third oil circuit c can be maintained constant, and the pressure oil after decompression flows to the second cavity B of the loading cylinder 16. The oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve 13.2 and the third relief valve 12.2. The opening pressure can be adjusted by adjusting the magnitude of the input current signal in the second proportional relief valve 13.2, thereby adjusting the oil pressure in the second oil circuit b, and the pressure oil after decompression flows to the first cavity A of the loading cylinder 16. By changing the opening pressure of the second proportional relief valve 13.2, the pressure of the first cavity A is controlled to be greater than the second cavity B, so that the loading cylinder 16 forms a rightward dynamic load loading force, and the dynamic loading of the loading cylinder 16 can be realized. It should be noted that if the difference between the pressures of the two cavities A and B is greater than the main power of the actuator hydraulic cylinder 17, the piston of the loading cylinder 16 moves to the right, and the actuator hydraulic cylinder 17 is forced to retract; if the difference between the pressures of the two cavities A and B is less than the main power of the actuator hydraulic cylinder 17, the piston of the loading cylinder 16 is forced to move to the left. At this time, in order to prevent the second cavity B from sucking air, the gear pump 6 replenishes oil to the second cavity B of the loading cylinder 16 through the third oil circuit c.

[0036] 2) Second positive load condition: When the piston rod of the actuator hydraulic cylinder 17 retracts and acts on the piston rod of the loading cylinder 16 through the hinge mechanism and forms a pulling force thereon, the loading cylinder 16 provides a load loading force in a direction opposite to the extension direction of the actuator hydraulic cylinder 17. At this time, the second positive load condition can be simulated, and the working condition simulation is completed by the gear pump 6 and the first proportional relief valve 13.1 that adjusts the pressure of the second cavity B of the loading cylinder 16; the second cavity B of the loading cylinder 16 is the control cavity. Specifically, the oil-immersed motor 5 is working, the gear pump 6 is in the open state, the first relief valve 9 is used as a safety valve, and its opening pressure is set to be higher than the preset maximum pressure of the system, and the electromagnetic reversing valve 14 is in the energized state. The gear pump 6 absorbs oil from the oil tank 1 through the oil suction filter 4. The high-pressure oil at the pump outlet flows to the second one-way valve 7.2 and the third one-way valve 7.3 through the first one-way valve 7.1 and the oil pressure filter 8. The high-pressure oil flows into the second oil circuit b through the second one-way valve 7.2 and flows into the third oil circuit c through the third one-way valve 7.3. At this time, the first proportional relief valve 13.1, the second relief valve 12.1, the second proportional relief valve 13.2, and the third relief valve 12.2 are all in the overflow state. The oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve 13.2 and the third relief valve 12.2. The input current signal in the second proportional relief valve 13.2 is controlled to remain unchanged, so that the oil pressure in the second oil circuit b can be maintained constant, and the pressure oil after decompression flows to the first cavity A of the loading cylinder 16. The oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve 13.1 and the second relief valve 12.1. The opening pressure can be adjusted by adjusting the input current signal of the first proportional relief valve 13.1, and then the oil pressure in the third oil circuit c is adjusted, and the pressure oil after decompression flows to the second cavity B of the loading cylinder 16. By changing the opening pressure of the first proportional relief valve 13.1, the pressure of the second cavity B is controlled to be greater than the first cavity A, so that the loading cylinder 16 forms a dynamic load loading force to the left, and the dynamic loading of the loading cylinder 16 can be realized. It should be noted that if the difference between the pressures of the two cavities A and B is greater than the main power of the actuator hydraulic cylinder 17, the piston of the loading cylinder 16 moves to the left, and the actuator hydraulic cylinder 17 is forced to extend; if the difference between the pressures of the two cavities A and B is less than the main power of the actuator hydraulic cylinder 17, the piston of the loading cylinder 16 is forced to move to the right. At this time, in order to prevent the first cavity A from sucking air, the gear pump 6 replenishes oil to the first cavity A of the loading cylinder 16 through the second oil circuit b.

[0037] 3) The first negative load condition: When the piston rod of the actuator hydraulic cylinder 17 extends, acts on the piston rod of the loading cylinder 16 through the hinge mechanism and forms a thrust force thereon, the loading cylinder 16 provides a load loading force in the same direction as the extension direction of the actuator hydraulic cylinder 17. At this time, the first negative load condition can be simulated, and the working condition simulation is completed by the gear pump 6 and the first proportional relief valve 13.1 that adjusts the pressure of the second cavity B of the loading cylinder 16; the second cavity B of the loading cylinder 16 is the control cavity. Specifically, the oil-immersed motor 5 is working, the gear pump 6 is in the open state, the first relief valve 9 is used as a safety valve, and its opening pressure is set to be higher than the preset maximum pressure of the system, and the electromagnetic reversing valve 14 is in the energized state. The gear pump 6 absorbs oil from the oil tank 1 through the oil suction filter 4. The high-pressure oil at the pump outlet flows to the second one-way valve 7.2 and the third one-way valve 7.3 through the first one-way valve 7.1 and the oil pressure filter 8. The high-pressure oil flows into the second oil circuit b through the second one-way valve 7.2 and flows into the third oil circuit c through the third one-way valve 7.3. At this time, the first proportional relief valve 13.1, the second relief valve 12.1, the second proportional relief valve 13.2, and the third relief valve 12.2 are all in the overflow state. The oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve 13.2 and the third relief valve 12.2. The input current signal in the second proportional relief valve 13.2 is controlled to remain unchanged, so that the oil pressure in the second oil circuit b can be maintained constant, and the pressure oil after decompression flows to the first cavity A of the loading cylinder 16. The oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve 13.1 and the second relief valve 12.1. The opening pressure can be adjusted by adjusting the magnitude of the input current signal in the first proportional relief valve 13.1, thereby adjusting the oil pressure in the third oil circuit c, and the pressure oil after decompression flows to the second cavity B of the loading cylinder 16. By changing the opening pressure of the first proportional relief valve 13.1, the pressure of the second cavity B is controlled to be greater than the first cavity A, so that the loading cylinder 16 forms a dynamic load loading force to the left, and the dynamic loading of the loading cylinder 16 can be achieved. It should be noted that since the direction of the main force generated by the actuator hydraulic cylinder 17 is consistent with the direction of the load loading force provided by the loading cylinder 16, the piston of the loading cylinder 16 will move rapidly to the left. In order to prevent the loading cylinder 16 from sucking air in the second cavity B due to the rapid piston movement, the gear pump 6 replenishes oil to the second cavity B of the loading cylinder 16 through the third oil circuit c.

[0038] 4) Second negative load condition: When the piston rod of the actuator hydraulic cylinder 17 retracts, acting on the piston rod of the loading hydraulic cylinder 16 through the hinge mechanism and forming a pulling force on it, the loading hydraulic cylinder 16 provides a load loading force in the same direction as the extending direction of the actuator hydraulic cylinder 17. At this time, the second negative load condition can be simulated, and the working condition simulation is completed by the gear pump 6 and the second proportional overflow valve 13.2 that adjusts the pressure of the first port A of the loading hydraulic cylinder 16; the first port A of the loading hydraulic cylinder 16 is the control chamber. Specifically, the oil-immersed motor 5 works, the gear pump 6 is in the open state, the first overflow valve 9 is used as a safety valve, and its opening pressure is set higher than the preset maximum pressure of the system. The electromagnetic directional valve 14 is in the energized state. The gear pump 6 sucks oil from the oil tank 1 through the oil suction filter 4, and the high-pressure oil at the pump outlet flows through the first one-way valve 7.1 and the pressure oil filter 8 to the second one-way valve 7.2 and the third one-way valve 7.3. The high-pressure oil flows into the second oil circuit b through the second one-way valve 7.2 and into the third oil circuit c through the third one-way valve 7.3 respectively. At this time, the first proportional overflow valve 13.1, the second overflow valve 12.1, the second proportional overflow valve 13.2, and the third overflow valve 12.2 are all in the overflow state. The oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional overflow valve 13.1 and the second overflow valve 12.1. By keeping the magnitude of the input current signal in the first proportional overflow valve 13.1 unchanged, the oil pressure in the third oil circuit c can be maintained constant, and the pressure-reduced oil flows to the second port B of the loading hydraulic cylinder 16. The oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional overflow valve 13.2 and the third overflow valve 12.2. By adjusting the magnitude of the input current signal in the second proportional overflow valve 13.2, its opening pressure can be adjusted, and then the oil pressure in the second oil circuit b can be adjusted. The pressure-reduced oil flows to the first port A of the loading hydraulic cylinder 16. By changing the opening pressure of the second proportional overflow valve 13.2, controlling the pressure of the first port A to be greater than that of the second port B, a dynamic load loading force to the right is formed on the loading hydraulic cylinder 16, and the dynamic loading of the loading hydraulic cylinder 16 can be realized. It should be noted that since the direction of the driving force generated by the actuator hydraulic cylinder 17 is the same as the direction of the load loading force provided by the loading hydraulic cylinder 16, it will cause the piston of the loading hydraulic cylinder 16 to move quickly to the right. To prevent the first port A of the loading hydraulic cylinder 16 from being sucked empty due to the rapid piston movement, the gear pump 6 replenishes oil to the first port A of the loading hydraulic cylinder 16 through the second oil circuit b.

[0039] In the specific implementation of the present invention, a pressure vessel is used to simulate the deep-sea environment, and a dynamic load is applied to the underwater electro-hydraulic actuator EHA to be measured under onshore conditions. The internal environment of the pressure vessel is set to simulate the deep-sea environment at a depth of 3000 meters, with a pressure of 30 MPa and a temperature of 4 °C. As Figure 2 and Figure 3As shown, the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested executes a preset trajectory, the preset displacement is 0~150mm, and the loading cylinder 16 can apply dynamically changing negative load and positive load to the actuator hydraulic cylinder 17, the negative load range is -3000N~0N, and the positive load range is 0N~3000N. Figure 4 As shown, the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested executes a preset trajectory, and the preset displacement is 0~150mm. The loading cylinder 16 can simulate the positive load and negative load conditions of the actuator hydraulic cylinder 17, the positive load is 600N, and the negative load is -600N, and can quickly switch between the positive load and negative load conditions, and the switching time is about 1.5 seconds. Figure 5 As shown, the actuator hydraulic cylinder 17 of the underwater electro-hydraulic actuator EHA to be tested executes a preset trajectory, the preset displacement is 0-150 mm, and the loading cylinder 16 can simulate alternating positive load and negative load conditions for the actuator hydraulic cylinder 17, the alternating frequency is 0.1 Hz, the positive load peak is 2000 N, and the negative load peak is -2000 N. It can be seen that the present invention can simulate the underwater operating conditions of the underwater electro-hydraulic actuator EHA on land, and apply a dynamic load to the underwater electro-hydraulic actuator EHA to be tested, so as to verify the underwater working performance of the underwater electro-hydraulic actuator EHA.

[0040] When high-precision loading force control is implemented in the present invention, the first proportional relief valve 13.1 and the second relief valve 12.1 are connected in series and then connected to the third oil circuit c through the fourth one-way valve to achieve pressure control of the second cavity B of the loading cylinder 16. The second proportional relief valve 13.2 and the third relief valve 12.2 are connected in series and then connected to the second oil circuit b through the fifth one-way valve to achieve pressure control of the first cavity A of the loading cylinder 16. The second relief valve 12.1 and the third relief valve 12.2 achieve a wide range of opening pressure regulation to complete low-precision regulation of system pressure. The first proportional relief valve 13.1 and the second proportional relief valve 13.2 achieve a small range of opening pressure regulation, and complete online high-precision regulation of system pressure by controlling the input current signal. Further, high-precision loading force control of the loading cylinder 16 is achieved through high-precision system pressure regulation.

[0041] The above is only an embodiment of the present invention and is not intended to limit the present invention. Therefore, equivalent changes made within the scope of the present invention are still within the protection scope of the present invention.

Claims

1. An underwater working condition simulation test system for an electro-hydraulic actuator, characterized in that: include: The oil source component is used to supply oil power when the underwater working condition simulation test system is tested in an underwater environment; The safety valve group is connected to the oil source component and is used for safety control of the underwater working condition test system when it is tested in an underwater environment; A loading valve group, connected to the oil source assembly and the safety valve group, and used to simulate different underwater load conditions in an underwater environment to perform active loading of the underwater working condition test system; The actuator is connected to the loading valve group and is used to simulate active loading of different underwater load conditions under the regulation of the oil source component and the loading valve group in an underwater environment to test the electro-hydraulic actuator.

2. The underwater working condition simulation test system for an electro-hydraulic actuator according to claim 1, characterized in that: The loading valve group comprises a second one-way valve (7.2), a third one-way valve (7.3), a fourth one-way valve (7.4), a fifth one-way valve (7.5), a second pressure measuring joint (10.2), a third pressure measuring joint (10.3), a second pressure sensor (11.2), a third pressure sensor (11.3), a second overflow valve (12.1), a third overflow valve (12.2), a first proportional overflow valve (13.1), a second proportional overflow valve (13.2) and an electromagnetic reversing valve (14), the second The oil inlets of the one-way valve (7.2) and the third one-way valve (7.3) are both connected to the safety valve group; the oil circuit connected between the oil outlet of the second one-way valve (7.2) and the actuator is the second oil circuit b; the oil circuit connected between the oil outlet of the third one-way valve (7.3) and the actuator is the third oil circuit c; the oil inlet of the fifth one-way valve (7.5) is connected to the second oil circuit b between the oil outlet of the second one-way valve (7.2) and the oil inlet of the electromagnetic reversing valve (14); the oil outlet of the fifth one-way valve (7.5) and the second proportional valve (14) are connected to each other. The oil inlets of the overflow valve (13.2) and the third overflow valve (12.2) are connected in sequence, the oil outlet of the fourth check valve (7.4), the first proportional overflow valve (13.1) and the oil inlet of the second overflow valve (12.1) are connected in sequence, the oil outlet of the second overflow valve (12.1) and the oil outlet of the third overflow valve (12.2) are connected to the oil circuit of the safety valve group as the fourth oil circuit d, the oil inlet of the fourth check valve (7.4) is connected to the oil outlet of the third check valve (7.3) and the oil outlet of the electromagnetic reversing valve (14) The third oil circuit c between the oil inlets, the oil inlet and the oil outlet of the electromagnetic reversing valve (14) are respectively connected to the second oil circuit b and the third oil circuit c; the second pressure measuring joint (10.2) and the second pressure sensor (11.2) are connected to the second oil circuit b, and the third pressure measuring joint (10.3) and the third pressure sensor (11.3) are connected to the third oil circuit c; and the loading valve group is also threadedly connected with a second pressure compensator (18) for performing oil pressure compensation on the underwater working condition simulation test system in a simulated underwater environment.

3. The underwater working condition simulation test system of the electro-hydraulic actuator according to claim 2 is characterized in that: The safety valve group comprises a first one-way valve (7.1), a pressure oil filter (8), a first relief valve (9), a first pressure measuring joint (10.1) and a first pressure sensor (11.1); the oil inlet of the first one-way valve (7.1) is connected to the oil source assembly; the oil outlet of the first one-way valve (7.1) is connected to the oil inlet of the first relief valve (9) via the pressure oil filter (8); the oil inlet of the first relief valve (9) is connected between the oil inlets of the second one-way valve (7.2) and the third one-way valve (7.3) of the loading valve group; the oil path connected between the oil outlet of the first relief valve (9) and the oil source assembly is used as the first oil path a; the oil outlet of the first relief valve (9) is connected to the oil outlet of the second relief valve (12.1) of the loading valve group via the fourth oil path d; the first pressure measuring joint (10.1) and the first pressure sensor (11.1) are connected to the oil inlet of the first relief valve (9).

4. The underwater working condition simulation test system of the electro-hydraulic actuator according to claim 3 is characterized in that: The oil source assembly comprises an oil tank (1), a pressure-resistant temperature sensor (3), an oil suction filter (4), an oil-immersed motor (5) and a gear pump (6); the oil-immersed motor (5) is connected to the gear pump (6) via a coupling; the oil suction port of the gear pump (6) is connected to the oil tank (1) via the oil suction filter (4); the pressure-resistant temperature sensor (3) is located inside the oil tank (1); the oil outlet of the gear pump (6) is connected to the first check valve ( The oil inlet of the oil tank (1) is connected to the oil outlet of the first overflow valve (9) of the safety valve group through the first oil passage a; the oil tank (1) and the safety valve group are also threadedly connected with a first pressure compensator (2) for performing oil pressure compensation on the underwater working condition simulation test system under a simulated underwater environment.

5. The underwater working condition simulation test system for an electro-hydraulic actuator according to claim 2, characterized in that: The actuator comprises a pressure-resistant displacement sensor (15), a loading cylinder (16) and an articulated mechanism; a first cavity A of the loading cylinder (16) is connected to an oil outlet of a second non-return valve (7.2) of a loading valve group via a second oil circuit b; a second cavity B of the loading cylinder (16) is connected to an oil outlet of a third non-return valve (7.3) of the loading valve group via a third oil circuit c; the pressure-resistant displacement sensor (15) is mounted on the end of a piston rod on the first cavity A side of the loading cylinder (16); and a piston rod on the second cavity B side of the loading cylinder (16) is connected to a piston rod of an actuating hydraulic cylinder (17) of an electro-hydraulic actuator EHA to be tested via an articulated mechanism.

6. A loading method for an underwater working condition simulation test system of an electro-hydraulic actuator according to any one of claims 1 to 5, characterized in that: The underwater working condition simulation test system comprises: the opening pressure of the first overflow valve (9) of the safety valve group is first set to be higher than the preset maximum pressure of the underwater working condition simulation test system; when the underwater working condition simulation test system is not working, the electromagnetic reversing valve (14) is in a power-off state, the second oil circuit b is connected to the third oil circuit c; when the underwater working condition simulation test system is performing a test, the oil-immersed motor (5) and the gear pump (6) are in a working state, the electromagnetic reversing valve (14) is in a power-on state, and the first cavity A and the first cavity A of the loading cylinder (16) are connected. The second cavity B is not connected; at this time, the underwater working condition simulation test system is placed in a simulated underwater environment in the pressure vessel, wherein the first proportional relief valve (13.1), the second proportional relief valve (13.2), the electromagnetic reversing valve (14) and the controller of the oil-immersed motor (5) are all located outside the pressure vessel. During the test, the second oil circuit b and the third oil circuit c of the underwater working condition simulation test system are disconnected, the gear pump (6) sucks oil from the oil tank (1) through the oil suction filter (4), and the oil outlet of the gear pump (6) discharges high-pressure hydraulic oil having a pressure higher than a preset threshold through the first The one-way valve (7.1) and the oil pressure filter (8) flow to the second one-way valve (7.2) and the third one-way valve (7.3), and the high-pressure hydraulic oil flows into the second oil circuit b and the third oil circuit c through the second one-way valve (7.2) and the third one-way valve (7.3) respectively. By adjusting the oil source component, the loading valve group and the two pressure compensators (2, 18), the active loading of four underwater load conditions is simulated, so as to test the actuator hydraulic cylinder (17) of the electro-hydraulic actuator EHA to be tested. The four underwater load conditions include two positive load conditions and two negative load conditions. The invention discloses a method for controlling the oil temperature, pressure and displacement of the piston rod of the underwater working condition simulation test system in real time by means of a pressure-resistant temperature sensor (3), three pressure sensors (11.1, 11.2, 11.3) and a pressure-resistant displacement sensor (15). When the oil temperature exceeds a preset temperature, the oil pressure exceeds a preset pressure or the displacement of the piston rod of the loading cylinder (16) exceeds a preset displacement range during the test, the oil-immersed motor (5) is turned off by the controller and the electromagnetic reversing valve (14) is placed in a power-off state.

7. The loading method of the underwater working condition simulation test system of the electro-hydraulic actuator according to claim 6 is characterized by: In the first positive load condition of the underwater load working condition, the first cavity A of the loading cylinder (16) is the control cavity, the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve (13.1) and the second relief valve (12.1), the magnitude of the input current signal in the first proportional relief valve (13.1) is controlled to remain unchanged, and the hydraulic oil after decompression flows to the second cavity B of the loading cylinder (16); the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve (13.2) and the third relief valve (12.2), the magnitude of the input current signal in the second proportional relief valve (13.2) is controlled to adjust its own opening pressure , thereby reducing the pressure of the oil in the second oil circuit b, and the reduced-pressure hydraulic oil flows to the first cavity A of the loading cylinder (16); changing the opening pressure of the second proportional relief valve (13.2), controlling the pressure of the first cavity A of the loading cylinder (16) to be greater than the second cavity B, the loading cylinder (16) forms a dynamic load loading force, the piston rod of the actuator hydraulic cylinder (17) extends and the generated thrust acts on the piston rod of the loading cylinder (16) through the articulated mechanism, at this time, the direction of the dynamic load loading force of the loading cylinder (16) is opposite to the main power direction of the actuator hydraulic cylinder (17) of the electro-hydraulic actuator EHA to be tested, completing the simulated loading of the first positive load condition.

8. The loading method of the underwater working condition simulation test system of the electro-hydraulic actuator according to claim 6 is characterized by: In the second positive load condition of the underwater load working condition, the second cavity B of the loading cylinder (16) is the control cavity, the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve (13.2) and the third relief valve (12.2), the magnitude of the input current signal in the second proportional relief valve (13.2) is controlled to remain unchanged, and the hydraulic oil after decompression flows to the first cavity A of the loading cylinder (16); the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve (13.1) and the second relief valve (12.2), the magnitude of the input current signal in the first proportional relief valve (13.1) is controlled to adjust its own opening pressure , thereby reducing the pressure of the oil in the third oil circuit c, and the reduced-pressure hydraulic oil flows to the second cavity B of the loading cylinder (16); changing the opening pressure of the first proportional relief valve (13.1), controlling the pressure of the second cavity B of the loading cylinder (16) to be greater than the first cavity A, the loading cylinder (16) forms a dynamic load loading force, the piston rod of the execution hydraulic cylinder (17) retracts and the generated tension acts on the piston rod of the loading cylinder (16) through the hinge mechanism, at this time, the direction of the dynamic load loading force of the loading cylinder (16) is opposite to the main power direction of the execution hydraulic cylinder (17) of the electro-hydraulic actuator EHA to be tested, completing the simulated loading of the second positive load condition.

9. The loading method of the underwater working condition simulation test system of the electro-hydraulic actuator according to claim 6, characterized in that: In the first negative load condition of the underwater load working condition, the second cavity B of the loading cylinder (16) is the control cavity, the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve (13.2) and the third relief valve (12.2), the magnitude of the input current signal in the second proportional relief valve (13.2) is controlled to remain unchanged, and the hydraulic oil after decompression flows to the first cavity A of the loading cylinder (16); the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve (13.1) and the second relief valve (12.2), the magnitude of the input current signal in the first proportional relief valve (13.1) is controlled to adjust its own opening pressure , thereby reducing the pressure of the oil in the third oil circuit c, and the reduced-pressure hydraulic oil flows to the second cavity B of the loading cylinder (16); changing the opening pressure of the first proportional relief valve (13.1), controlling the pressure of the second cavity B of the loading cylinder (16) to be greater than the first cavity A, the loading cylinder (16) forms a dynamic load loading force, the piston rod of the actuator hydraulic cylinder (17) extends and the generated thrust acts on the piston rod of the loading cylinder (16) through the articulated mechanism, at this time, the direction of the dynamic load loading force of the loading cylinder (16) is connected to the main power direction of the actuator hydraulic cylinder (17) of the electro-hydraulic actuator EHA to be tested, and the simulated loading of the first negative load condition is completed.

10. The loading method of the underwater working condition simulation test system of the electro-hydraulic actuator according to claim 6, characterized in that: In the second negative load condition of the underwater load working condition, the first cavity A of the loading cylinder (16) is the control cavity, the oil pressure in the third oil circuit c is the sum of the opening pressures of the first proportional relief valve (13.1) and the second relief valve (12.1), the magnitude of the input current signal in the first proportional relief valve (13.1) is controlled to remain unchanged, and the hydraulic oil after decompression flows to the second cavity B of the loading cylinder (16); the oil pressure in the second oil circuit b is the sum of the opening pressures of the second proportional relief valve (13.2) and the third relief valve (12.2), the magnitude of the input current signal in the second proportional relief valve (13.2) is controlled to adjust its own opening pressure , thereby reducing the pressure of the oil in the second oil circuit b, and the reduced-pressure hydraulic oil flows to the first cavity A of the loading cylinder (16); changing the opening pressure of the second proportional relief valve (13.2), controlling the pressure of the first cavity A of the loading cylinder (16) to be greater than the second cavity B, the loading cylinder (16) forms a dynamic load loading force, the piston rod of the actuator hydraulic cylinder (17) retracts and the generated tension acts on the piston rod of the loading cylinder (16) through the hinge mechanism, at this time, the direction of the dynamic load loading force of the loading cylinder (16) is the same as the main power direction of the actuator hydraulic cylinder (17) of the electro-hydraulic actuator EHA to be tested, completing the simulated loading of the second negative load condition.

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