Deep sea underwater electro-hydraulic actuator EHA and control system thereof

Abstract

The invention discloses a deep sea underwater electro-hydraulic actuator (EHA) and a control system thereof. The system provides power through the power source module, balance of system oil pressure and pressure of external seawater is controlled through the pressure compensation module, oil circulation and oil pressure control are conducted through the integrated valve set module, a control instruction of the control module is executed through the execution mechanism module, and the control module conducts cooperative control over the whole system. According to the control system, the unbalanced pressure between the system and the deep sea high-water-pressure environment is compensated through the pressure compensator so as to reduce the influence of the deep sea high-water-pressure environment, meanwhile, the pressure compensator serves as an oil tank to supply oil, miniaturization of the system is achieved, and the reliability of the system during underwater work is improved; according to the deep-sea underwater electro-hydraulic actuator, the mounting positions and internal flow channels of all elements of the integrated valve bank are optimized, the pressure loss of fluid in the flow channels is reduced, and the energy utilization efficiency of the deep-sea underwater electro-hydraulic actuator is improved; the asymmetric hydraulic cylinder can operate in four working conditions of deep sea, and underwater high-precision movement can be completed.

Description

Technical Field

[0001] The present invention relates to an actuator control system, belonging to the technical field of body transmission and control, and particularly relates to a deep-sea underwater electro-hydraulic actuator EHA and its control system. Background Art

[0002] An actuator is the core unit for an engineering equipment to achieve motion and complete operations. Actuators are generally divided into electric actuators and hydraulic actuators. Among them, hydraulic actuators have the advantages of high power density, high output force, and the ability to withstand high external water pressure, and play a dominant role in marine engineering equipment, especially in the deep-sea application field. However, with the increase of the underwater operation depth, hydraulic actuators face problems such as low efficiency, high energy consumption, difficult maintenance, and poor reliability. The deep-sea high-water-pressure environment poses challenges to the pressure resistance and signal stability of the control system, and it is easy to cause leakage of hydraulic pipelines, making it difficult to carry out effective maintenance. Summary of the Invention

[0003] In order to solve the problems in the background art, the present invention provides a deep-sea underwater electro-hydraulic actuator EHA and its control system. The present invention has the advantages of modularization, high integration, high energy utilization efficiency, and strong adaptability to the deep-sea environment. It compensates for the seawater pressure through a pressure compensation system, and controls a variable-speed oil-immersed motor based on the control system to drive a piston pump to provide pressure oil for an asymmetric hydraulic cylinder, and realizes the motion control of the deep-sea underwater electro-hydraulic actuator by adjusting the motor speed.

[0004] The technical solution adopted by the present invention is as follows: The deep-sea underwater electro-hydraulic actuator EHA and its control system of the present invention include: A power source module for providing power for the control system.

[0005] A pressure compensation module, connected to the power source module and used to balance the oil pressure in the control system and the external seawater pressure. The pressure compensation module serves as the oil tank of the control system.

[0006] An integrated valve group module, installed between the power source module and the pressure compensation module and connected to the power source module and the pressure compensation module. The integrated valve group module includes two balance valves and two overflow valves for oil pressure control.

[0007] An actuator module, installed on the integrated valve group module and connected to the integrated valve group module. The actuator module includes an asymmetric hydraulic cylinder.

[0008] A control module, installed on the power source module and the asymmetric hydraulic cylinder and used for the coordinated control of the power source module, the pressure compensation module, and the asymmetric hydraulic cylinder of the actuator module.

[0009] The described integrated valve group module further includes a flow matching valve and an integrated valve block. The integrated valve block is installed between the power source module and the pressure compensation module. Two balance valves are spaced and installed on one side of the integrated valve block and are located inside the power source module. The flow matching valve and two overflow valves are spaced and installed on the other side of the integrated valve block and are located inside the pressure compensation module. The power source module includes a variable-speed oil-immersed motor, a bi-directional piston pump, and a power source housing. The power source housing is installed on one side surface of the integrated valve block where the two balance valves are located. The two balance valves are located inside the power source housing. The variable-speed oil-immersed motor and the piston pump are installed inside the power source housing. The output shaft of the variable-speed oil-immersed motor is connected to the output shaft of the bi-directional piston pump through a coupling and a spline. The body of the piston pump is installed at the center of one side surface of the integrated valve block where the two balance valves are located and is arranged at an interval with the two balance valves. The oil outlet and the oil inlet of the piston pump are respectively communicated with the first flow channel a and the second flow channel b inside the integrated valve block. The first flow channel a is branched into a third flow channel a1 and a fourth flow channel a2. The second flow channel b is branched into a fifth flow channel b1 and a sixth flow channel b2. The third flow channel a1 is communicated with the oil outlet of the overflow valve of the first balance valve and the oil inlet of the check valve. The fourth flow channel a2 is communicated with the A port and the C1 port of the flow matching valve. The fifth flow channel b1 is communicated with the oil outlet of the overflow valve of the second balance valve and the oil inlet of the check valve. The sixth flow channel b2 is communicated with the B port and the C2 port of the flow matching valve. The oil inlet of the overflow valve of the first balance valve and the oil outlet of the check valve are communicated with the seventh flow channel c inside the integrated valve block. The oil outlet of the overflow valve of the second balance valve and the oil inlet of the check valve are communicated with the eighth flow channel d inside the integrated valve block. The seventh flow channel c is branched into a ninth flow channel c1 and a tenth flow channel c2. The eighth flow channel d is branched into an eleventh flow channel d1 and a twelfth flow channel d2. The ninth flow channel c1 and the eleventh flow channel d1 are respectively communicated with the rod chamber and the non-rod chamber of the asymmetric hydraulic cylinder of the actuator module. The tenth flow channel c2 is communicated with the oil inlet of the first overflow valve. The twelfth flow channel d2 is communicated with the oil inlet of the second overflow valve. The oil outlets of the two overflow valves are connected and are both communicated to the T port of the flow matching valve through the thirteenth flow channel e opened inside the integrated valve block. The pressure compensation module is respectively communicated to the T port of the flow matching valve and the oil replenishing port of the bi-directional piston pump through the fourteenth flow channel f1 and the fifteenth flow channel f2 opened inside the integrated valve block. The control module is installed on the power source housing. The control module is electrically connected to the variable-speed oil-immersed motor and the asymmetric hydraulic cylinder.

[0010] The described pressure compensation module adopts a bladder-type pressure compensator. The body of the pressure compensator is installed on the other side surface of the integrated valve block where the flow matching valve and the two overflow valves are located. The flow matching valve and the two overflow valves are located in the hydraulic oil filled inside the pressure compensator. The pressure compensator serves as the oil tank of the control system for oil supply.

[0011] The described actuator module further includes a connecting member, which includes a sub-valve block and two steel pipes. The cylinder body of the asymmetric hydraulic cylinder is installed on the side of the integrated valve block through the sub-valve block. The two steel pipes are installed on the cylinder body of the asymmetric hydraulic cylinder and respectively connect the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder to the ninth flow channel c1 and the eleventh flow channel d1 inside the integrated valve block.

[0012] The described control module includes a displacement sensor, a composite transmission cable set, an oil-immersed sealed cabin, a main controller, and a motor driver. The displacement sensor is installed on the piston rod of the asymmetric hydraulic cylinder. The oil-immersed sealed cabin is installed on the power source housing through threads. The main controller and the motor driver are installed inside the oil-immersed sealed cabin through bolts. The composite transmission cable includes a DC cable, a first bus communication cable of the Controller Area Network (CAN), and a second bus communication cable. The main controller is electrically connected to the CAN communication interfaces of the displacement sensor and the motor driver through its own second CAN communication interface and the second bus communication cable. The main controller is electrically connected to an external upper computer through its own first CAN communication interface and the first bus communication cable. The DC cable is a DC power supply that supplies power to the main controller and the motor driver respectively. The inside of the oil-immersed sealed cabin is connected to the pressure compensation module, and the motor driver is electrically connected to a variable-speed oil-immersed motor.

[0013] The main controller internally integrates a trajectory planning algorithm, a state observation algorithm, and a position control algorithm. The upper computer sends control instructions to the main controller through the first bus communication cable. The main controller receives the operating states of the asymmetric hydraulic cylinder obtained by the displacement sensor and the operating states of the variable-speed oil-immersed motor obtained by the motor driver through the second bus communication cable. The motion states of the asymmetric hydraulic cylinder include the displacement and speed information of the piston rod. The operating states of the variable-speed oil-immersed motor include the motor speed and torque information. When the upper computer sends a position control instruction, the main controller obtains an expected trajectory through processing by the trajectory planning algorithm according to the preset trajectory instruction. The expected trajectory includes the expected position, expected speed, and expected acceleration. The operating states of the variable-speed oil-immersed motor and the asymmetric hydraulic cylinder and the expected trajectory are processed by the state observation algorithm to obtain the pressure values of the two chambers of the asymmetric hydraulic cylinder and the external load force. When a speed instruction is received, the pressure values of the two chambers of the asymmetric hydraulic cylinder and the external load force are processed by the position control algorithm to obtain the expected speed of the variable-speed oil-immersed motor. Then, through pulse width modulation (PWM) technology modulation by the motor driver, it is transmitted to the variable-speed oil-immersed motor for speed control. After the control is completed, the main controller transmits the real-time operating states of the variable-speed oil-immersed motor and the asymmetric hydraulic cylinder to the upper computer for display and real-time status monitoring.

[0014] The described control system drives a piston pump through a variable-speed oil-immersed motor, controls the flow direction of hydraulic oil to an asymmetric hydraulic cylinder, and realizes four operating conditions of the asymmetric hydraulic cylinder, including a resistance retraction condition, a overrun retraction condition, a resistance extension condition, and a overrun extension condition.

[0015] Under the described resistance retraction condition, the pressure in the rod chamber of the asymmetric hydraulic cylinder is higher than the pressure in the non-rod chamber. The variable-speed oil-immersed motor drives the piston pump to suck oil from the pressure compensator through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump flows to the check valve of the first balance valve, and generates a control pressure at the overflow valve control port of the second balance valve, making the overflow valve of the second balance valve conduct bidirectionally. The hydraulic oil flowing out of the check valve of the first balance valve flows into the rod chamber of the asymmetric hydraulic cylinder, and realizes the control of the oil pressure through connecting the first overflow valve. The hydraulic oil in the non-rod chamber of the asymmetric hydraulic cylinder realizes the control of the oil pressure through connecting the second overflow valve. The hydraulic oil overflowing through the first overflow valve or the second overflow valve flows back to the pressure compensator. The hydraulic oil in the non-rod chamber of the asymmetric hydraulic cylinder returns to the oil inlet of the piston pump through the overflow valve of the second balance valve. At the same time, the hydraulic oil at the oil outlet of the piston pump flows to port A of the flow matching valve, and generates a high control pressure at port C1 of the flow matching valve. The hydraulic oil flowing out of the non-rod chamber of the asymmetric hydraulic cylinder flows to port B of the flow matching valve, and generates a low control pressure at port C2 of the flow matching valve, making port A of the flow matching valve closed and ports B and T conduct. The excess hydraulic oil in the non-rod chamber of the asymmetric hydraulic cylinder returns to the pressure compensator through ports B and T of the flow matching valve, realizing the compensation of unmatched flow.

[0016] Under the described overrun retraction condition, the pressure in the rod chamber of the asymmetric hydraulic cylinder is lower than the pressure in the non-rod chamber. The variable-speed oil-immersed motor drives the piston pump to suck oil from the pressure compensator through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump flows to the check valve of the first balance valve, and generates a control pressure at the overflow valve control port of the second balance valve, making the overflow valve of the second balance valve conduct bidirectionally. The hydraulic oil flowing out of the check valve of the first balance valve flows into the rod chamber of the asymmetric hydraulic cylinder, and realizes the control of the oil pressure through connecting the first overflow valve. The hydraulic oil in the non-rod chamber of the asymmetric hydraulic cylinder realizes the control of the oil pressure through connecting the second overflow valve. The hydraulic oil overflowing through the first overflow valve or the second overflow valve flows back to the pressure compensator. The hydraulic oil in the non-rod chamber of the asymmetric hydraulic cylinder returns to the oil inlet of the piston pump through the overflow valve of the second balance valve. At the same time, the hydraulic oil at the oil outlet of the piston pump flows to port A of the flow matching valve, and generates a low control pressure at port C1 of the flow matching valve. The hydraulic oil flowing out of the non-rod chamber flows to port B of the flow matching valve, and generates a high control pressure at port C2 of the flow matching valve, making port B of the flow matching valve closed and ports A and T conduct. The excess hydraulic oil at the oil outlet of the piston pump returns to the pressure compensator through ports A and T of the flow matching valve, realizing the compensation of unmatched flow.

[0017] Under the described resistance extension condition, the pressure in the rod chamber of the asymmetric hydraulic cylinder is lower than that in the rodless chamber. The variable-speed oil-immersed motor drives the piston pump to suck oil from the pressure compensator through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump flows to the check valve of the second balance valve and generates a control pressure at the control port of the overflow valve of the first balance valve, causing the overflow valve of the first balance valve to conduct bidirectionally. The hydraulic oil flowing out of the check valve of the second balance valve flows into the rodless chamber of the asymmetric hydraulic cylinder, and the oil pressure is controlled by connecting the second overflow valve. The hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder is controlled by connecting the first overflow valve. The hydraulic oil overflowing through the first overflow valve or the second overflow valve flows back to the pressure compensator. The hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder returns to the oil inlet of the piston pump through the overflow valve of the first balance valve. At the same time, the hydraulic oil at the oil outlet of the piston pump flows to port B of the flow matching valve and generates a high control pressure at port C2 of the flow matching valve. The hydraulic oil flowing out of the rod chamber of the asymmetric hydraulic cylinder flows to port A of the flow matching valve and generates a low control pressure at port C1 of the flow matching valve, causing port B of the flow matching valve to close and ports A and T to conduct. The hydraulic oil in the pressure compensator flows into the oil inlet of the piston pump through ports A and T of the flow matching valve to achieve compensation for unmatched flow.

[0018] Under the described overrunning extension condition, the pressure in the rod chamber of the asymmetric hydraulic cylinder is higher than that in the rodless chamber. The variable-speed oil-immersed motor drives the piston pump to suck oil from the pressure compensator through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump flows to the check valve of the second balance valve and generates a control pressure at the control port of the overflow valve of the first balance valve, causing the overflow valve of the first balance valve to conduct bidirectionally. The hydraulic oil flowing out of the check valve of the second balance valve flows into the rodless chamber of the asymmetric hydraulic cylinder, and the oil pressure is controlled by connecting the second overflow valve. The hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder is controlled by connecting the first overflow valve. The hydraulic oil overflowing through the first overflow valve or the second overflow valve flows back to the pressure compensator. The hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder returns to the oil inlet of the piston pump through the overflow valve of the first balance valve. At the same time, the hydraulic oil at the oil outlet of the piston pump flows to port B of the flow matching valve and generates a low control pressure at port C2 of the flow matching valve. The hydraulic oil flowing out of the rod chamber of the asymmetric hydraulic cylinder flows to port A of the flow matching valve and generates a high control pressure at port C1 of the flow matching valve, causing port A of the flow matching valve to close and ports B and T to conduct. The hydraulic oil in the pressure compensator flows into the rodless chamber of the asymmetric hydraulic cylinder through ports B and T of the flow matching valve to achieve compensation for unmatched flow.

[0019] The present invention achieves the balance between the system oil pressure and the external seawater pressure through a pressure compensator, and at the same time serves as an oil tank to supply oil to the hydraulic system to reduce the overall volume of the equipment; through the optimization of the relative installation relationship of components and the hydrodynamic simulation of Fluent software, the optimized design of the integrated valve block is realized, improving the energy utilization efficiency; by adopting the CAN2.0 bus communication that transmits data in the form of digital quantity difference and the modular pressure-resistant oil-immersed control system design, the electromagnetic interference resistance of the system is improved, and the control performance of the system is enhanced.

[0020] The present invention integrates the core components of the hydraulic system together and uses power cables instead of hydraulic pipelines to transmit energy. While retaining the advantages of the hydraulic system, it effectively avoids the problem of poor reliability caused by the complexity of hydraulic pipelines. Moreover, it has the characteristics of high integration, miniaturization and distributed installation, and the advantages of more convenient maintenance and repair, and has broad application prospects in the field of deep-sea equipment.

[0021] The beneficial effects of the present invention are as follows: 1. Compared with the traditional onshore electro-hydraulic actuator system, the present invention compensates for the unbalanced pressure between the electro-hydraulic actuator and the deep-sea high-water-pressure environment through a pressure compensator to reduce the impact of the deep-sea high-water-pressure environment on the hydraulic system. At the same time, the pressure compensator serves as an oil tank to supply oil to the electro-hydraulic actuator, realizing the miniaturization of the electro-hydraulic actuator and improving the reliability of the electro-hydraulic actuator system during underwater operation.

[0022] 2. The present invention optimizes the installation positions of the components of the integrated valve group and realizes the optimization of the internal flow channels of the integrated valve block through hydrodynamic simulation using Fluent software, reducing the pressure loss of the fluid inside the flow channels and improving the energy utilization efficiency of the deep-sea underwater electro-hydraulic actuator.

[0023] 3. The present invention can control the deep-sea underwater electro-hydraulic actuator to complete high-precision underwater movements through the control system, realizing operation under four working conditions: resistance retraction, overrun retraction, resistance extension, and overrun extension, and the underwater movement control accuracy reaches 1 mm. Description of the Drawings

[0024] Figure 1 is the overall structure diagram of the present invention; Figure 2 is the overall structure sectional view of the present invention; Figure 3 is the overall structure side view of the present invention; Figure 4 is the schematic diagram of the component installation of the integrated valve group module of the present invention; Figure 5 is the schematic diagram of the plunger pump and the integrated valve group of the present invention, wherein, Figure 5 the (a) of is the front view of the plunger pump and the integrated valve of the present invention, Figure 5Figure (b) is the left view of the plunger pump and the integrated valve block of the present invention, Figure 5 Figure (c) is the right view of the plunger pump and the integrated valve block of the present invention; Figure 6 Figure is the schematic diagram of the pressure compensator of the present invention, where Figure 6 Figure (a) is the structural diagram of the pressure compensator of the present invention, Figure 6 Figure (b) is the sectional view of the pressure compensator of the present invention; Figure 7 Figure is the schematic diagram of the control system of the present invention; Figure 8 Figure is the schematic diagram of the hydraulic system of the present invention; Figure 9 Figure is the schematic diagram of the flow channel of the integrated valve block of the present invention, where Figure 9 Figure (a) is the schematic diagram of the right-angle type flow channel of the integrated valve block of the present invention, Figure 9 Figure (b) is the schematic diagram of the Z-shaped flow channel of the integrated valve block of the present invention; Figure 10 Figure is the schematic diagram of the trajectory of the piston rod of the asymmetric hydraulic cylinder in the embodiment of the present invention, where Figure 10 Figure (a) is the schematic diagram of the expected trajectory of the piston rod of the asymmetric hydraulic cylinder in the embodiment of the present invention, Figure 10 Figure (b) is the schematic diagram of the actual trajectory of the piston rod of the asymmetric hydraulic cylinder in the embodiment of the present invention, Figure 10 Figure (c) is the schematic diagram of the trajectory tracking error of the piston rod of the asymmetric hydraulic cylinder in the embodiment of the present invention; In the figure: 1. Variable-speed oil-immersed motor, 2. Plunger pump, 3. Pressure compensator, 4. Flow rate matching valve, 5.1. First balance valve, 5.2. Second balance valve, 6.1. First overflow valve, 6.2. Second overflow valve, 7. Asymmetric hydraulic cylinder, 8. Power source housing, 9. Integrated valve block, 10. Connector, 11. Control module, 12. Displacement sensor, 13. Composite transmission cable group 14. Oil-immersed sealing cabin, 15. Main controller, 16. Motor driver. Detailed implementation manners

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to 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 used 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.

[0026] As Figure 1 、 Figure 2 And Figure 3As shown, the deep - sea underwater electro - hydraulic actuator EHA and its control system of the present invention include a power source module, a pressure compensation module, an integrated valve group module, an actuator module, and a control module 11. The power source module provides power for the control system; the pressure compensation module is connected to the power source module and is used to balance the oil pressure of the control system and the pressure of external seawater. The pressure compensation module serves as the oil tank of the control system; the integrated valve group module is installed between the power source module and the pressure compensation module and is connected to the power source module and the pressure compensation module. The integrated valve group module includes two balance valves 5.1, 5.2 for oil pressure control and two overflow valves 6.1, 6.2; the actuator module is installed on the integrated valve group module and is connected to the integrated valve group module. The actuator module includes an asymmetric hydraulic cylinder 7; the control module 11 is installed on the power source module and the asymmetric hydraulic cylinder 7 and is used for the coordinated control of the power source module, the pressure compensation module, and the asymmetric hydraulic cylinder 7 of the actuator module.

[0027] As Figure 4 , Figure 5 of (a) in Figure 5 of (b) in Figure 5 of (c) in and Figure 8As shown, the integrated valve block module further includes a flow matching valve 4 and an integrated valve block 9. The integrated valve block 9 is installed between the power source module and the pressure compensation module. Two balance valves 5.1 and 5.2 are spaced apart and installed on one side of the integrated valve block 9 and are located inside the power source module. The flow matching valve 4 and two relief valves 6.1 and 6.2 are spaced apart and installed on the other side of the integrated valve block 9 and are located inside the pressure compensation module. The power source module includes a variable speed oil-immersed motor 1, a bi-directional piston pump 2, and a power source housing 8. The power source housing 8 is installed on one side surface of the integrated valve block 9 where the two balance valves 5.1 and 5.2 are located. The two balance valves 5.1 and 5.2 are located inside the power source housing 8. The variable speed oil-immersed motor 1 and the piston pump 2 are installed inside the power source housing 8. The output shaft of the variable speed oil-immersed motor 1 is connected to the output shaft of the bi-directional piston pump 2 through a coupling and a spline to provide hydraulic oil for the integrated valve block module. The mounting surface of the variable speed oil-immersed motor 1 and the end face G of the bi-directional piston pump 2 are connected by threads. The pump body of the piston pump 2 is installed at the center of one side surface of the integrated valve block 9 where the two balance valves 5.1 and 5.2 are located and is arranged at intervals with the two balance valves 5.1 and 5.2. The oil outlet and the oil inlet of the piston pump 2 are respectively communicated with a first flow channel a and a second flow channel b inside the integrated valve block 9. The first flow channel a is branched into a third flow channel a1 and a fourth flow channel a2. The second flow channel b is branched into a fifth flow channel b1 and a sixth flow channel b2. The third flow channel a1 is communicated with the oil outlet of the relief valve of the first balance valve 5.1 and the oil inlet of the check valve. The fourth flow channel a2 is respectively communicated with the A port and the C1 port of the flow matching valve 4 through a common oil circuit and a control oil circuit. The fifth flow channel b1 is communicated with the oil outlet of the relief valve of the second balance valve 5.2 and the oil inlet of the check valve. The sixth flow channel b2 is respectively communicated with the B port and the C2 port of the flow matching valve 4 through a common oil circuit and a control oil circuit. The oil inlet of the relief valve of the first balance valve 5.1 and the oil outlet of the check valve are communicated with a seventh flow channel c inside the integrated valve block 9. The oil outlet of the relief valve of the second balance valve 5.2 and the oil inlet of the check valve are communicated with an eighth flow channel d inside the integrated valve block 9. The seventh flow channel c is branched into a ninth flow channel c1 and a tenth flow channel c2. The eighth flow channel d is branched into an eleventh flow channel d1 and a twelfth flow channel d2. The ninth flow channel c1 and the eleventh flow channel d1 are respectively communicated with the rodless cavity and the rod cavity of the asymmetric hydraulic cylinder 7 of the actuator module. The tenth flow channel c2 is communicated with the oil inlet of the first relief valve 6.1. The twelfth flow channel d2 is communicated with the oil inlet of the second relief valve 6.2. The oil outlets of the two relief valves 6.1 and 6.2 are connected and are both communicated to the T port of the flow matching valve 4 through a thirteenth flow channel e opened inside the integrated valve block 9. The pressure compensation module is respectively communicated to the T port of the flow matching valve 4 and the oil replenishing port of the bi-directional piston pump 2 through a fourteenth flow channel f1 and a fifteenth flow channel f2 opened inside the integrated valve block 9. The control module 11 is installed on the power source housing 8. The control module 11 is electrically connected to the variable speed oil-immersed motor 1 and the asymmetric hydraulic cylinder 7.

[0028] The power source housing 8 is a pressure-resistant housing, which adopts a cylindrical outer contour and is machined with a rectangular opening on the side for installing the control module 11; the integrated valve block 9 is machined with cartridge screw holes for installing each valve; the integrated valve block 9 is also provided with a hollow structure for reducing weight and facilitating taking; the second end face H of the bi-directional piston pump 11 is threadedly connected to the first end face I of the integrated valve block 9, so as to realize the connection between the oil inlet and outlet of the bi-directional piston pump 11 and the orifice of the integrated valve block 9.

[0029] The design of the integrated valve block 9 of the present invention is as follows: The components of the integrated valve block 9 are distributed on two faces. The flow rate matching valve 4 and the overflow valves 6.1 and 6.2 are placed on the same side, and the piston pump 2 and the balance valves 5.1 and 5.2 are placed on the opposite side. Such an arrangement scheme can improve the utilization rate of the integrated valve block 9 while enabling the circuit layout to be clear after the integrated valve block 9 is connected with the oil pipes and not generating mutual influence during the disassembly of the components. After the components of the integrated valve block 9 are arranged, flow channels are machined inside the integrated valve block 9. The design of the flow channels takes into account the pressure loss. The internal flow channels of the integrated valve block 9 are optimized based on the fluid mechanics simulation results of Fluent software, and the pressure loss conditions at the right-angle flow channels and Z-shaped flow channels are analyzed. Under the condition of subtractive manufacturing, the flow channels are optimized: when designing and machining the right-angle flow channels, the length of the tip cavity is shortened and the tip cavity is directed towards the oil inlet, and when designing and machining the Z-shaped flow channels, the distance between the two flow channels is shortened. At the same time, on the basis of not affecting the minimum wall thickness of the integrated valve block, the diameter of the process hole is increased, so that the pressure loss of the fluid inside the flow channels is significantly reduced and the energy utilization efficiency is improved.

[0030] When the present invention is specifically implemented, numerical simulation is carried out on the right-angle flow channels. The flow channel model is as Figure 9 shown in (a) of the figure, which is formed by the intersection of two flow channels, and a tip cavity will be formed at the end of one of the flow channels. When setting parameters in the Fluent software, the Standard k-ε turbulence model is selected, the inlet flow velocity is 2 m / s, the outlet pressure is 10 MPa, the fluid medium is selected as No. 46 hydraulic oil, and the density is 900 kg / m 2 , and the dynamic viscosity is 0.0261 N·s / m 2 . Through simulation analysis, the relationship between the pressure difference before and after the hydraulic oil flows into / out of the right-angle flow channels and the length of the tip cavity and the tip orientation is obtained, as shown in Table 1.

[0031] Table 1

[0032] As can be seen from Table 1, the magnitude of the pressure loss is positively correlated with the length of the tool tip cavity, and the pressure loss is less when the tool tip cavity faces the oil inlet. Therefore, when designing and machining a right-angle flow channel, shorten the length of the tool tip cavity and make the tool tip cavity face the oil inlet to reduce the pressure loss inside the flow channel and improve the energy utilization efficiency.

[0033] Perform a numerical simulation on the Z-shaped flow channel. The flow channel model is as shown in Figure 9 (b). It is formed when the process hole penetrates two parallel flow channels at the same time. The distance T between the two parallel flow channels and the diameter U of the process hole are parameters that can be optimized. When setting parameters in the Fluent software, select the Standard k-ε turbulence model, the inlet flow velocity is 2 m / s, the outlet pressure is 10 MPa, the fluid medium is No. 46 hydraulic oil, and the density is 900 kg / m 2 , and the dynamic viscosity is 0.0261 N·s / m 2 . Through simulation analysis, the relationship between the pressure difference before and after the hydraulic oil flows into / out of the Z-shaped flow channel and the distance T between the two parallel flow channels is obtained, as shown in Table 2.

[0034] Table 2

[0035] As can be seen from Table 2, the magnitude of the pressure loss is positively correlated with the distance T between the two parallel flow channels, and the pressure loss is less when the tool tip cavity faces the oil inlet. Therefore, when designing and machining the Z-shaped flow channel, shorten the distance between the two flow channels to effectively reduce the pressure loss inside the integrated valve block 9.

[0036] Furthermore, set the diameter U of the process hole to 4 mm, 5 mm, 6 mm, and 8 mm respectively, the diameter of the two parallel flow channels is 5 mm, and the other simulation parameters remain unchanged. The relationship between the pressure difference before and after the hydraulic oil flows into / out of the Z-shaped flow channel and the diameter U of the process hole is obtained, as shown in Table 3.

[0037] Table 3

[0038] As can be seen from Table 3, the magnitude of the pressure loss is negatively correlated with the diameter of the process hole. Therefore, when designing and machining the Z-shaped flow channel, on the basis of not affecting the minimum wall thickness of the integrated valve block 9, by increasing the diameter of the process hole, the pressure loss inside the integrated valve block 9 can be effectively reduced.

[0039] As shown in Figure 6 (a) and Figure 6As shown in (b), the pressure compensation module uses a bladder-type pressure compensator 3. The body of the pressure compensator 3 is installed on the other side of the integrated valve block 9 where the flow matching valve 4 and two overflow valves 6.1 and 6.2 are located. The flow matching valve 4 and the two overflow valves 6.1 and 6.2 are located in the hydraulic oil filled inside the pressure compensator 3. The pressure compensator 3 serves as the oil tank of the control system to supply oil. The bladder-type pressure compensator 3 is composed of an oil bladder housing, a compensating oil bladder, an oil bladder flange, and a ferrule. The compensating oil bladder is connected to the oil bladder flange through the ferrule, the oil bladder housing is connected to the oil bladder flange through a toothed structure, and the oil bladder flange is fixedly connected to the second end face J of the integrated valve block 9 through a threaded connection. The material used for the compensating oil bladder is nitrile rubber, and the material of the oil bladder housing is POM acetal copolymer. As the seawater pressure changes, the compensating oil bladder contracts and expands inside the oil bladder housing, thereby achieving the balance between the system oil pressure and the external seawater pressure, and at the same time serving as an oil tank to supply oil to the hydraulic system to reduce the overall volume of the equipment.

[0040] The present invention realizes the compensation of the unbalanced pressure between the inside of the system and the deep-sea high-water-pressure environment through the pressure compensator 3, and its working principle is as follows: The pressure compensator 3 serves as an oil tank to supply oil to the hydraulic system to reduce the overall volume of the equipment. At the same time, it realizes the balance between the system oil pressure and the external seawater pressure by compensating the oil. It has three states during the working process: the initial state, the pressure increasing state, and the pressure decreasing state. In the initial state, the compensating oil bladder is pre-filled with hydraulic oil at a certain pressure, and the external pressure is in balance with the internal pressure of the hydraulic system. The compensating oil bladder neither compresses inward nor expands outward; in the pressure increasing state, the external pressure is transmitted to the surface of the compensating oil bladder, causing it to compress inward under the pressure, pushing the hydraulic oil into the hydraulic system, and increasing the internal pressure of the hydraulic system until a new balance is reached with the external water pressure; in the pressure decreasing state, the pressure on the surface of the compensating oil bladder decreases, and the internal pressure of the hydraulic system pushes the compensating oil bladder to expand outward, and the hydraulic oil flows from the hydraulic system into the compensating oil bladder, causing the internal pressure of the hydraulic system to decrease until a new balance is reached with the external water pressure. Based on the above three states, the pressure compensator 3 can realize the dynamic compensation of the return oil pressure of the underwater hydraulic system under the condition of large-range change of the working depth. This dynamic balance ensures that the hydraulic system will not fail due to too high or too low pressure.

[0041] The actuator module further includes a connecting member 10, which includes a sub-valve block and two steel pipes. The cylinder body of the asymmetric hydraulic cylinder 7 is installed on the side of the integrated valve block 9 through the sub-valve block. The two steel pipes are installed on the cylinder body of the asymmetric hydraulic cylinder 7 and connect the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder 7 to the ninth flow channel c1 and the eleventh flow channel d1 inside the integrated valve block 9 respectively. The actuator module uses 0Cr17Ni4Cu4Nb steel. At the contact between the inner wall of the cylinder of the asymmetric hydraulic cylinder 7 and the piston and at the contact between the end cap of the asymmetric hydraulic cylinder 7 and the piston rod, a double-acting seal structure with Y-shaped seals installed back to back is adopted. Two oil holes are machined on the first end face K of the sub-valve block connected to the integrated valve block 9, and are respectively connected to the first side end face L and the second side end face M of the sub-valve block through internal flow channels. Steel pipes are welded to both the first side end face L and the second side end face M of the sub-valve block. Through holes are machined on the side of the cylinder barrel of both the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder 7, and are connected to the two steel pipes by welding, realizing the connection between the first side end face L and the rod chamber and the connection between the second side end face M and the rodless chamber. The first end face K of the sub-valve block is threadedly connected to the second end face N of the integrated valve block 9, realizing the connection between the actuator module and the integrated valve block 9.

[0042] As Figure 7 shown, the control module 11 includes a displacement sensor 12, a composite transmission cable group 13, an oil-immersed sealed cabin 14, a main controller 15, and a motor driver 16. The displacement sensor 12 is installed on the piston rod of the asymmetric hydraulic cylinder 7. The oil-immersed sealed cabin 14 is installed on the power source housing 8 by threading. The main controller 15 and the motor driver 16 are installed inside the oil-immersed sealed cabin 14 by bolts. The composite transmission cable 13 includes DC cables for 300V DC and 24V DC power supply, a first bus communication cable and a second bus communication cable of the Controller Area Network (CAN). The main controller 15 is electrically connected to the CAN communication interface of the displacement sensor 12 powered by 24V and the CAN communication interface of the motor driver 16 powered by 300V through its own second CAN communication interface and the second bus communication cable. The main controller 15 is electrically connected to an external host computer through its own first CAN communication interface and the first bus communication cable. The DC cables respectively provide 24V and 300V DC power supplies to power the main controller 15 and the motor driver 16 respectively. The slots of the composite transmission cable group 13 are connected to the plugs of the cable-sealed cabin connectors. The connectors are connected to the main controller 15 and the motor driver 16 through power lines and data lines, and are fixedly connected to the outside of the oil-immersed sealed cabin 14 by threading. The inside of the oil-immersed sealed cabin 14 is connected to the pressure compensation module, and high-pressure oil is provided by the pressure compensator 3 to balance the high deep-sea water pressure. The motor driver 16 is electrically connected to the variable-speed oil-immersed motor 1.

[0043] The main controller 15 integrates trajectory planning algorithms, state observation algorithms, and position control algorithms internally to complete the precise motion control of the underwater electro-hydraulic actuator. During actual control, initialization is first performed. Initialization is carried out after the system is powered on, including interrupt initialization, communication initialization, and data initialization. At the same time, the main controller 15 powers the displacement sensor 12. The host computer sends control commands to the main controller 15 through the first bus communication cable. The main controller 15 parses the control commands. The control commands include start commands and working mode selection commands. After sending the start command, the main controller 15 sends start commands to the displacement sensor 12 and the motor driver 16. The displacement sensor 12 and the motor driver 16 start to feedback status information. The working mode selection commands include the command to return to the original position, the position control command, and the rotational speed command. When the host computer sends the command to return to the original position, the main controller 15 controls the rotational speed of the variable-speed oil-immersed motor 1, thereby controlling the asymmetric hydraulic cylinder 7 to quickly return to the initial position. Other control commands, such as commands to control the extension and retraction of the piston rod of the asymmetric hydraulic cylinder 7. The main controller 15 receives the operating state of the asymmetric hydraulic cylinder 7 obtained by the displacement sensor 12 and the operating state of the variable-speed oil-immersed motor 1 obtained by the motor driver 16 through the second bus communication cable. The motion state of the asymmetric hydraulic cylinder 7 includes the displacement and speed information of the piston rod. The operating state of the variable-speed oil-immersed motor 1 includes the motor speed and torque information. When the host computer sends the position control command, the main controller 15 obtains the desired trajectory through processing by the trajectory planning algorithm according to the preset trajectory command. The desired trajectory includes the desired position, desired speed, and desired acceleration. The operating states of the variable-speed oil-immersed motor 1 and the asymmetric hydraulic cylinder 7 are processed by the state observation algorithm to obtain the two-chamber pressure values and external load forces of the asymmetric hydraulic cylinder 7. When the rotational speed command is received, the two-chamber pressure values and external load forces of the asymmetric hydraulic cylinder 7 are processed by the position control algorithm to obtain the desired rotational speed of the variable-speed oil-immersed motor 1. Then, pulse width modulation technology PWM modulation is performed through the motor driver 16 and transmitted to the variable-speed oil-immersed motor 1 for rotational speed control. After the control is completed, the main controller 15 transmits the real-time operating states of the variable-speed oil-immersed motor 1 and the asymmetric hydraulic cylinder 7 to the host computer for display and real-time status monitoring.

[0044] The displacement sensor 12 is an in-built magnetostrictive sensor, installed inside the asymmetric hydraulic cylinder 7. Its guide rod is integrated with the piston rod of the asymmetric hydraulic cylinder 7. The magnetic ring moves together with the piston to measure the operating state of the asymmetric hydraulic cylinder 7 in real time, and is connected to the main controller 15 via the CAN bus. It can convert the actual position and operating speed into digital quantities and send them to the main controller 15 in the form of CAN communication. The oil-immersed sealed cabin 14 is a steel open cabin. The main controller 15 is used for event processing and calculation of the control algorithm for the underwater electro-hydraulic actuator. Its hardware circuit includes a main control chip, a power supply module, a CAN communication module, and a serial SWD (Serial Wire Debug) debugging module. Among them, the main control chip uses an ARM Cortex-M4 core microcontroller, whose system clock can reach up to 168 MHz at most, and supports single-precision floating-point number operations of the floating-point unit FPU (Floating-Point Unit) and the enhanced digital signal processor DSP (Digital Signal Processing) instruction set for fast floating-point hardware calculations, and can perform real-time time processing and high-precision control algorithm calculation tasks. The trajectory planning algorithm of the main controller 15 initializes the trajectory according to the set maximum stroke, maximum speed, and maximum acceleration information, and pre-calculates a point-to-point operating trajectory including start, acceleration, constant speed, and deceleration. The state observation algorithm of the main controller 15 is based on the displacement signal and speed signal of the displacement sensor, and estimates the pressure values of the two chambers of the asymmetric hydraulic cylinder 7 by designing a reduced-order observer. Further, based on the pressure difference between the two chambers and the effective area of the piston, the external load force is calculated. The position control algorithm of the main controller 15 adopts adaptive robust control, designs an online parameter estimation algorithm and an adaptive model compensation control law to compensate for model nonlinearity and parameter uncertainty online. Then, according to the parameter limit change range and external interference, a robust control law is designed to suppress model deviation and parameter estimation deviation. The main controller 15 only performs data acquisition and information transmission via the CAN bus, improving the anti-interference ability during data transmission and reducing the number of external interfaces to lower costs. The motor driver 16 is connected to the shipboard power distribution cabin via the composite transmission cable group 13 and connected to the main controller 15 via the CAN bus. It can receive the rotational speed command sent by the main controller 15 from the CAN bus, control the motor speed of the variable-speed oil-immersed motor 1 through PWM modulation, and at the same time can feedback the actual rotational speed and actual torque data of the variable-speed oil-immersed motor 1 to the main controller 15 in the form of CAN signals. The communication method only adopts the CAN2.0 bus communication that transmits data in the form of digital differential, which has high anti-electromagnetic interference and real-time performance, and can be used for long-distance data transmission between the upper computer and the main controller 15 and the communication between the main controller 15 and the motor driver 16 and the displacement sensor 12.

[0045] The control system of the present invention can perform tasks such as automatic return to the origin, constant speed control, motion trajectory planning, and trajectory tracking. At the same time, it can calculate the pressure values of the two chambers of the asymmetric hydraulic cylinder 7 based on the displacement and speed information of the asymmetric hydraulic cylinder 7 and the speed and torque information of the variable-speed oil-immersed motor 1 for the motion control algorithm. When the underwater electro-hydraulic actuator is operating, the main controller 15 obtains the control instructions from the host computer on the CAN bus of the composite transmission cable group 13. The trajectory planning algorithm module automatically generates the position, speed, and acceleration trajectory planning from point to point according to the set target points. At the same time, the main controller 15 collects the position and speed signals of the displacement sensor 12 and the speed and torque signals of the motor driver 16 from the CAN bus, calculates the pressures of the two chambers of the asymmetric hydraulic cylinder 7 required for motion control through the state observation algorithm. After the control algorithm module calculates the motor speed of the variable-speed oil-immersed motor 1 required for trajectory tracking according to the operating state of the deep-sea electro-hydraulic actuator, it sends it to the motor driver 16 through the CAN bus. At the same time, the operating state information of the electro-hydraulic actuator can be sent back to the shipborne control module through the composite transmission cable group 13 to monitor the operating state of the system.

[0046] The functions and hydraulic principles of the present invention are specifically as follows: The control system drives the piston pump 2 through the variable-speed oil-immersed motor 1 to control the flow direction of the hydraulic oil to the asymmetric hydraulic cylinder 7, realizing the four working conditions of the asymmetric hydraulic cylinder 7. In the working state, the pressure compensator 3 balances the system oil pressure and the external seawater pressure, and at the same time supplies oil to the piston pump 2 as a fuel tank through the flow channel f2 to reduce the overall volume of the equipment. The four working conditions include the resistance retraction condition, the overrun retraction condition, the resistance extension condition, and the overrun extension condition, which are specifically as follows: In the resistance retraction condition, the piston rod of the asymmetric hydraulic cylinder 7 retracts. The direction of the external load force on the piston rod is opposite to the direction of the piston rod movement. The pressure in the rod chamber of the asymmetric hydraulic cylinder 7 is higher than that in the non-rod chamber. The variable-speed oil-immersed motor 1 drives the piston pump 2 to suck oil from the pressure compensator 3 through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump 2 flows through the oil path a to the oil paths a1 and a2 respectively. The hydraulic oil in the oil path a1 flows to the check valve of the first balance valve 5.1 and generates a control pressure at the overflow valve control port of the second balance valve 5.2 through the control oil path, making the overflow valve of the second balance valve 5.2 conduct bidirectionally. The hydraulic oil in the oil path a1 flows out from the check valve of the first balance valve 5.1 and flows through the oil path c to the oil paths c1 and c2 respectively. The oil path c2 is connected to the first overflow valve 6.1 to control the oil pressure. The oil path c1 is connected to the rod chamber of the asymmetric hydraulic cylinder 7. At this time, the rod chamber is the high-pressure chamber for realizing the motion control of the actuator. The hydraulic oil in the non-rod chamber flows through the oil path d1 to the oil paths d and d2 respectively. The oil path d2 is connected to the second overflow valve 6.2 to control the oil pressure. If the pressure of the hydraulic oil in the oil path c2 or the oil path d2 is too high, the corresponding first overflow valve 6.1 or second overflow valve 6.2 will be in the overflow state, and the overflowing hydraulic oil will flow back to the pressure compensator 3 through the oil path e and the oil path f1. The oil path d is connected to the second balance valve 5.2. The hydraulic oil flows through the overflow valve of the second balance valve 5.2 to the oil path b1 and then flows to the oil paths b and b2 respectively. The hydraulic oil in the oil path b returns to the oil inlet of the piston pump 2. The hydraulic oil in the oil path a2 flows to the port A of the flow matching valve 4 and generates a high control pressure at the port C1 of the flow matching valve 4 through the control oil path. The hydraulic oil in the oil path b2 flows to the port B of the flow matching valve 4 and generates a low control pressure at the port C2 of the flow matching valve 4 through the control oil path. The port A of the flow matching valve 4 is closed, and the port B and the port T of the flow matching valve 4 are conducted. Due to the different piston areas of the rod chamber and the non-rod chamber of the asymmetric hydraulic cylinder 7, when the piston rod retracts, the hydraulic oil flowing out of the non-rod chamber is more than the hydraulic oil flowing into the rod chamber. The excess hydraulic oil in the non-rod chamber flows through the oil path b2 and the ports B and T of the flow matching valve 4 to the oil path f1 and finally returns to the pressure compensator 3 to realize the compensation of the unmatched flow.

[0047] When the piston rod of the asymmetric hydraulic cylinder 7 retracts, the direction of the external load force on the piston rod is the same as the direction of the piston rod movement, and the pressure in the rod chamber of the asymmetric hydraulic cylinder 7 is lower than the pressure in the rodless chamber. The variable-speed oil-immersed motor 1 drives the piston pump 2 to suck oil from the pressure compensator 3 through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump 2 flows through the oil path a to the oil paths a1 and a2 respectively. The hydraulic oil in the oil path a1 flows to the check valve of the first balance valve 5.1, and a control pressure is generated at the overflow valve control port of the second balance valve 5.2 through the control oil path, making the overflow valve of the second balance valve 5.2 conduct bidirectionally. The hydraulic oil in the oil path a1 flows out from the check valve of the first balance valve 5.1 and flows through the oil path c to the oil paths c1 and c2 respectively. The oil path c2 is connected to the first overflow valve 6.1 to control the oil pressure, and the oil path c1 is connected to the rod chamber of the asymmetric hydraulic cylinder 7. At this time, the rodless chamber is the high-pressure chamber for realizing the motion control of the actuator, and the hydraulic oil therein flows through the oil path d1 to the oil paths d and d2 respectively. The oil path d2 is connected to the second overflow valve 6.2 to control the oil pressure. If the pressure of the hydraulic oil in the oil path c2 or the oil path d2 is too high, the corresponding first overflow valve 6.1 or second overflow valve 6.2 will be in the overflow state, and the overflowing hydraulic oil flows back to the pressure compensator 3 through the oil path e and the oil path f1. The oil path d is connected to the second balance valve 5.2, and the hydraulic oil flows through the overflow valve of the second balance valve 5.2 to the oil path b1, and then flows to the oil paths b and b2 respectively. The hydraulic oil in the oil path b returns to the oil inlet of the piston pump 2. The hydraulic oil in the oil path a2 flows to the A port of the flow matching valve 4, and a low control pressure is generated at the C1 port of the flow matching valve 4 through the control oil path. The hydraulic oil in the oil path b2 flows to the B port of the flow matching valve 4, and a high control pressure is generated at the C2 port of the flow matching valve 4 through the control oil path. The B port of the flow matching valve 4 is closed, and the A port and the T port of the flow matching valve 4 are conducted. Since the direction of the external load force on the piston rod of the asymmetric hydraulic cylinder 7 is the same as the direction of the piston rod movement, to prevent the piston rod from retracting too fast, part of the hydraulic oil in the oil path a flows through the oil path a2 and the A and T ports of the flow matching valve 4 to the oil path f1, and finally returns to the pressure compensator 3 to realize the compensation of the mismatched flow and avoid the cavitation phenomenon in the rod chamber.

[0048] In the resistance extension condition, the piston rod of the asymmetric hydraulic cylinder 7 extends. The direction of the external load force on the piston rod is opposite to the direction of the piston rod movement. The pressure in the rod chamber of the asymmetric hydraulic cylinder 7 is lower than the pressure in the rodless chamber. The variable-speed oil-immersed motor 1 drives the piston pump 2 to suck oil from the pressure compensator 3 through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump 2 flows through the oil path b to the oil paths b1 and b2 respectively. The hydraulic oil in the oil path b1 flows to the check valve of the second balance valve 5.2, and a control pressure is generated at the control port of the overflow valve of the first balance valve 5.1 through the control oil path, making the overflow valve of the first balance valve 5.1 conduct bidirectionally. The hydraulic oil in the oil path b1 flows out from the check valve of the second balance valve 5.2 and flows through the oil path d to the oil paths d1 and d2 respectively. The oil path d2 is connected to the second overflow valve 6.2 to control the oil pressure. The oil path d1 is connected to the rodless chamber of the asymmetric hydraulic cylinder 7. At this time, the rodless chamber is the high-pressure chamber for realizing the motion control of the actuator. The hydraulic oil in the rod chamber flows through the oil path c1 to the oil paths c and c2 respectively. The oil path c2 is connected to the first overflow valve 6.1 to control the oil pressure. If the pressure of the hydraulic oil in the oil path c2 or the oil path d2 is too high, the corresponding first overflow valve 6.1 or second overflow valve 6.2 will be in the overflow state, and the overflowing hydraulic oil will flow back to the pressure compensator through the oil path e and the oil path f1. The oil path c is connected to the first balance valve 5.1. The hydraulic oil flows through the overflow valve of the first balance valve 5.1 to the oil path a1 and then flows to the oil paths a and a2 respectively. The hydraulic oil in the oil path a returns to the oil inlet of the piston pump 2. The hydraulic oil in the oil path a2 flows to the A port of the flow matching valve 4, and a low control pressure is generated at the C1 port of the flow matching valve 4 through the control oil path. The hydraulic oil in the oil path b2 flows to the B port of the flow matching valve 4, and a high control pressure is generated at the C2 port of the flow matching valve 4 through the control oil path. The B port of the flow matching valve 4 is closed, and the A port and the T port of the flow matching valve 4 are conducted. Since the piston areas of the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder 7 are different, when the piston rod extends, the hydraulic oil that needs to flow into the rodless chamber is more than the hydraulic oil flowing out of the rod chamber. Part of the hydraulic oil in the pressure compensator 3 flows through the oil path f1 and the A and T ports of the flow matching valve 4 to the oil path a2 and finally flows into the oil inlet of the piston pump 2 to realize the compensation of the unmatched flow.

[0049] In the extended working condition, the piston rod of the asymmetric hydraulic cylinder 7 extends, and the direction of the external load force acting on the piston rod is the same as the direction of the piston rod movement. The pressure in the rod chamber of the asymmetric hydraulic cylinder 7 is higher than that in the non-rod chamber. The variable-speed oil-immersed motor 1 drives the piston pump 2 to suck oil from the pressure compensator 3 through the oil suction port. The hydraulic oil flowing out of the oil outlet of the piston pump 2 flows through the oil path b to the oil paths b1 and b2 respectively. The hydraulic oil in the oil path b1 flows to the check valve of the second balance valve 5.2, and a control pressure is generated at the control port of the overflow valve of the first balance valve 5.1 through the control oil path, making the overflow valve of the first balance valve 5.1 conduct bidirectionally. The hydraulic oil in the oil path b1 flows out from the check valve of the second balance valve 5.2 and flows through the oil path d to the oil paths d1 and d2 respectively. The oil path d2 is connected to the second overflow valve 6.2 to control the oil pressure. The oil path d1 is connected to the non-rod chamber of the asymmetric hydraulic cylinder 7. At this time, the non-rod chamber is the high-pressure chamber for realizing the motion control of the actuator. The hydraulic oil in the rod chamber flows through the oil path c1 to the oil paths c and c2 respectively. The oil path c2 is connected to the first overflow valve 6.1 to control the oil pressure. If the pressure of the hydraulic oil in the oil path c2 or the oil path d2 is too high, the corresponding first overflow valve 6.1 or the second overflow valve 6.2 will be in the overflow state, and the overflowing hydraulic oil will flow back to the pressure compensator 3 through the oil path e and the oil path f1. The oil path c is connected to the first balance valve 5.1. The hydraulic oil flows through the overflow valve of the first balance valve 5.1 to the oil path a1, and then flows to the oil paths a and a2 respectively. The hydraulic oil in the oil path a returns to the oil inlet of the piston pump 2. The hydraulic oil in the oil path a2 flows to port A of the flow matching valve 4, and a high control pressure is generated at port C1 of the flow matching valve 4 through the control oil path. The hydraulic oil in the oil path b2 flows to port B of the flow matching valve 4, and a low control pressure is generated at port C2 of the flow matching valve 4 through the control oil path. Port A of the flow matching valve 4 is closed, and port B and port T of the flow matching valve 4 are conducted. Since the direction of the external load force acting on the piston rod of the asymmetric hydraulic cylinder 7 is the same as the direction of the piston rod movement, to prevent the piston rod from extending too fast and causing too little oil in the non-rod chamber, part of the hydraulic oil in the pressure compensator 3 flows through the oil path f1 and ports B and T of the flow matching valve 4 to the oil path b2, and finally flows into the non-rod chamber of the asymmetric hydraulic cylinder 7 to realize the compensation of unmatched flow and avoid the formation of cavitation due to the instantaneous low pressure in the non-rod chamber.

[0050] The control system of the present invention controls the variable-speed oil-immersed motor 1, drives the plunger pump 2 to control the flow direction of the hydraulic oil to the asymmetric hydraulic cylinder 7, and realizes the operation of four working conditions of the asymmetric hydraulic cylinder 7. The specific hydraulic circuit mainly includes a flow matching circuit, a hydraulic lock circuit and an overflow circuit. Among them, in the flow matching circuit, the flow matching valve 4 is used to adjust the unmatched flow generated during the extension and retraction of the asymmetric hydraulic cylinder 7; the hydraulic lock circuit realizes the position locking function of the asymmetric hydraulic cylinder 7 through two balance valves 5.1 and 5.2; the overflow circuit limits the maximum pressure in the system through two overflow valves 6.1 and 6.2 for safety protection. In the working state, the pressure compensation module balances the system oil pressure and the external seawater pressure, and at the same time supplies oil to the plunger pump 2 as a fuel tank through the flow channel.

[0051] In the specific implementation of the present invention, the deep-sea underwater electro-hydraulic actuator and its control system are placed in the deep-sea environment of 3000 meters. The environmental pressure is 30 MPa and the environmental temperature is 1.5 °C. The upper computer is used to send motion control instructions to the control system and read the data of the displacement sensor 12 in real time. The deep-sea underwater electro-hydraulic actuator executes the desired trajectory, as Figure 10 shown in (a) of, the actual trajectory read by the displacement sensor 12, as Figure 10 shown in (b) of, then the trajectory tracking error of the deep-sea underwater electro-hydraulic actuator is the difference between the desired trajectory and the actual trajectory, as Figure 10 shown in (c) of, and the trajectory tracking error is within 1 mm. It can be seen that the present invention can achieve high-precision motion control in the deep-sea environment and has good underwater working performance.

[0052] The above is only one embodiment of the present invention and cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the present invention still fall within the protection scope of the present invention.

Claims

1. A deep-sea underwater electro-hydraulic actuator (EHA) and its control system, characterized in that: include: Power source module, used to provide power to the control system; A pressure compensation module, connected to the power source module and used to balance the pressure of the system oil pressure and the external seawater. The pressure compensation module serves as an oil tank for the control system; An integrated valve group module is installed between the power source module and the pressure compensation module and connects the power source module and the pressure compensation module. The integrated valve group module includes two balancing valves (5.1, 5.2) and two overflow valves (6.1, 6.2) for oil pressure control; An actuator module is mounted on the integrated valve module and is connected to the integrated valve module, wherein the actuator module includes an asymmetric hydraulic cylinder (7); The control module (11) is mounted on the power source module and the asymmetric hydraulic cylinder (7) and is used for coordinated control of the power source module, the pressure compensation module and the asymmetric hydraulic cylinder (7) of the actuator module.

2. The deep-sea underwater electro-hydraulic actuator EHA and its control system according to claim 1, characterized in that: The integrated valve group module further comprises a flow matching valve (4) and an integrated valve block (9), wherein the integrated valve block (9) is installed between the power source module and the pressure compensation module, wherein two balancing valves (5.1, 5.2) are installed at intervals on one side of the integrated valve block (9) and are located inside the power source module, and wherein the flow matching valve (4) and two relief valves (6.1, 6.2) are installed at intervals on the other side of the integrated valve block (9) and are located inside the pressure compensation module; the power source module comprises a variable speed oil-immersed motor (1), a plunger pump (2) and a power source housing (8), wherein the power source housing (8) is installed at one side of the integrated valve block (9) where the two balancing valves (5.1, 5.2) are located, wherein the two balancing valves (5.1, 5.2) are located inside the power source housing (8), wherein the variable speed oil-immersed motor (1) and the plunger pump (2) are installed inside the power source housing (8), wherein the output shaft of the variable speed oil-immersed motor (1) passes through the oil-immersed motor housing (8). The coupling is connected to the output shaft of the plunger pump (2); the pump body of the plunger pump (2) is installed at the center of one side of the integrated valve block (9) where the two balancing valves (5.1, 5.2) are located and is arranged at intervals with the two balancing valves (5.1, 5.2); the oil outlet and oil inlet of the plunger pump (2) are respectively connected to the first flow channel a and the second flow channel b inside the integrated valve block (9); the first flow channel a is divided into the third flow channel a1 and the fourth flow channel a2; the second flow channel b is divided into the fifth flow channel b1 and the sixth flow channel b2; the third flow channel a1 is connected to the oil outlet of the overflow valve of the first balancing valve (5.1) and the oil inlet of the check valve; the fourth flow channel a2 is connected to the A port and the C1 port of the flow matching valve (4); the fifth flow channel b1 is connected to the oil outlet of the overflow valve of the second balancing valve (5.2) and the oil inlet of the check valve; the sixth flow channel b2 is connected to the B port and the C2 port of the flow matching valve (4); the first balancing valve ( The oil inlet of the overflow valve of the second balancing valve (5.1) and the oil outlet of the check valve are connected to the seventh flow channel c inside the integrated valve block (9), the oil outlet of the overflow valve of the second balancing valve (5.2) and the oil inlet of the check valve are connected to the eighth flow channel d inside the integrated valve block (9), the seventh flow channel c is divided into the ninth flow channel c1 and the tenth flow channel c2, the eighth flow channel d is divided into the eleventh flow channel d1 and the twelfth flow channel d2, the ninth flow channel c1 and the eleventh flow channel d1 are respectively connected to the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder (7) of the actuator module, and the tenth flow channel c2 is connected to the first overflow valve ( The twelfth flow channel d2 is connected to the oil inlet of the second overflow valve (6.2), the oil outlets of the two overflow valves (6.1, 6.2) are connected, and are both connected to the T port of the flow matching valve (4) through the thirteenth flow channel e opened inside the integrated valve block (9); the pressure compensation module is connected to the T port of the flow matching valve (4) and the oil replenishment port of the plunger pump (2) through the fourteenth flow channel f1 and the fifteenth flow channel f2 opened inside the integrated valve block (9); the control module (11) is mounted on the power source housing (8), and the control module (11) is electrically connected to the variable speed oil-immersed motor (1) and the asymmetric hydraulic cylinder (7).

3. The deep sea underwater electro-hydraulic actuator EHA and its control system according to claim 2, characterized in that: The pressure compensation module adopts a bladder-type pressure compensator (3). The body of the pressure compensator (3) is installed on the other side of the integrated valve block (9) where the flow matching valve (4) and the two overflow valves (6.1, 6.2) are located. The flow matching valve (4) and the two overflow valves (6.1, 6.2) are located in the hydraulic oil filled inside the pressure compensator (3). The pressure compensator (3) serves as an oil tank of the control system for oil supply.

4. The deep sea underwater electro-hydraulic actuator EHA and its control system according to claim 2, characterized in that: The actuator module further comprises a connecting member (10), the connecting member (10) comprising a sub-valve block and two steel pipes, the cylinder body of the asymmetric hydraulic cylinder (7) is mounted on the side of the integrated valve block (9) via the sub-valve block, the two steel pipes are mounted on the cylinder body of the asymmetric hydraulic cylinder (7) and respectively connect the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder (7) with the ninth flow channel c1 and the eleventh flow channel d1 inside the integrated valve block (9).

5. The deep sea underwater electro-hydraulic actuator EHA and its control system according to claim 2, characterized in that: The control module (11) comprises a displacement sensor (12), a composite transmission cable group (13), an oil-immersed sealed cabin (14), a main controller (15) and a motor driver (16); the displacement sensor (12) is mounted on the piston rod of the asymmetric hydraulic cylinder (7); the oil-immersed sealed cabin (14) is mounted on the power source housing (8); and the main controller (15) and the motor driver (16) are mounted inside the oil-immersed sealed cabin (14); The composite transmission cable (13) comprises a DC cable, a second bus communication cable electrically connected to the displacement sensor (12) and the motor driver (16), and the main controller (15) is electrically connected to an external host computer via the first bus communication cable; the DC cable DC power supply supplies power to the main controller (15) and the motor driver (16) respectively; the oil-immersed sealed cabin (14) is internally connected to the pressure compensation module, and the motor driver (16) is electrically connected to the variable speed oil-immersed motor (1); The main controller (15) internally integrates a trajectory planning algorithm, a state observation algorithm, and a position control algorithm. The host computer sends a control instruction to the main controller (15) via a first bus communication cable. The main controller (15) receives the operating state of the asymmetric hydraulic cylinder (7) obtained by the displacement sensor (12) and the operating state of the variable speed oil-immersed motor (1) obtained by the motor driver (16) via a second bus communication cable. The main controller (15) obtains a desired trajectory based on a preset trajectory instruction and processes the trajectory planning algorithm. The operating states of the variable speed oil-immersed motor (1) and the asymmetric hydraulic cylinder (7) are The two-chamber pressure values ​​and the external load force of the asymmetric hydraulic cylinder (7) are obtained after the state observation algorithm is used to process the two-chamber pressure values ​​and the external load force of the asymmetric hydraulic cylinder (7). The desired speed of the variable speed oil-immersed motor (1) is obtained after the position control algorithm is used to process the two-chamber pressure values ​​and the external load force of the asymmetric hydraulic cylinder (7). The desired speed of the variable speed oil-immersed motor (1) is then obtained after pulse width modulation (PWM) modulation is performed by the motor driver (16) and then transmitted to the variable speed oil-immersed motor (1) for speed control. After the control is completed, the main controller (15) transmits the real-time operating status of the variable speed oil-immersed motor (1) and the asymmetric hydraulic cylinder (7) to the upper computer for display and real-time status monitoring.

6. The deep-sea underwater electro-hydraulic actuator EHA and its control system according to claim 2, characterized in that: The control system drives the plunger pump (2) through a variable speed oil-immersed motor (1) to control the flow of hydraulic oil to the asymmetric hydraulic cylinder (7), thereby realizing four operating conditions of the asymmetric hydraulic cylinder (7), including a resistance retraction condition, a beyond retraction condition, a resistance extension condition and an beyond extension condition.

7. The deep-sea underwater electro-hydraulic actuator EHA and its control system according to claim 6, characterized in that: Under the resistance retraction condition, the pressure of the rod chamber of the asymmetric hydraulic cylinder (7) is higher than the pressure of the rodless chamber, the variable speed oil-immersed motor (1) drives the plunger pump (2) to suck oil from the pressure compensator (3) through the oil suction port, the hydraulic oil flowing out of the oil outlet of the plunger pump (2) flows to the one-way valve of the first balancing valve (5.1), and generates a control pressure in the overflow valve of the second balancing valve (5.2), so that the overflow valve of the second balancing valve (5.2) is bidirectionally conductive, the hydraulic oil flowing out of the one-way valve of the first balancing valve (5.1) flows into the rod chamber of the asymmetric hydraulic cylinder (7), and the oil pressure is controlled by connecting to the first overflow valve (6.1), the hydraulic oil in the rodless chamber of the asymmetric hydraulic cylinder (7) is controlled by connecting to the second overflow valve (6.2), and the oil pressure is controlled by the first overflow valve (6.1). Or the hydraulic oil overflowed by the second overflow valve (6.2) flows back to the pressure compensator (3), the hydraulic oil in the rodless chamber of the asymmetric hydraulic cylinder (7) returns to the oil inlet of the plunger pump (2) through the overflow valve of the second balancing valve (5.2), and at the same time, the hydraulic oil at the oil outlet of the plunger pump (2) flows to the A port of the flow matching valve (4), and generates a high control pressure at the C1 port of the flow matching valve (4), the hydraulic oil flowing out of the rodless chamber of the asymmetric hydraulic cylinder (7) flows to the B port of the flow matching valve (4), and generates a low control pressure at the C2 port of the flow matching valve (4), so that the A port of the flow matching valve (4) is closed and the B port and the T port are connected, and the hydraulic oil in the rodless chamber of the asymmetric hydraulic cylinder (7) returns to the pressure compensator (3) through the B port and the T port of the flow matching valve (4), thereby realizing compensation of mismatched flow.

8. The deep sea underwater electro-hydraulic actuator EHA and its control system according to claim 6, characterized in that: Under the overrunning retraction condition, the pressure in the rod chamber of the asymmetric hydraulic cylinder (7) is lower than the pressure in the rodless chamber, the variable speed oil-immersed motor (1) drives the plunger pump (2) to suck oil from the pressure compensator (3) through the oil suction port, the hydraulic oil flowing out of the oil outlet of the plunger pump (2) flows to the one-way valve of the first balancing valve (5.1), and generates a control pressure in the overflow valve of the second balancing valve (5.2), so that the overflow valve of the second balancing valve (5.2) is bidirectionally conductive, the hydraulic oil flowing out of the one-way valve of the first balancing valve (5.1) flows into the rod chamber of the asymmetric hydraulic cylinder (7), and the oil pressure is controlled by connecting the first overflow valve (6.1), the hydraulic oil in the rodless chamber of the asymmetric hydraulic cylinder (7) is controlled by connecting the second overflow valve (6.2), and the oil pressure is controlled by connecting the first overflow valve (6.2). The hydraulic oil overflowing from the flow valve (6.1) or the second overflow valve (6.2) flows back to the pressure compensator (3), and the hydraulic oil in the rodless chamber of the asymmetric hydraulic cylinder (7) returns to the oil inlet of the plunger pump (2) through the overflow valve of the second balancing valve (5.2). At the same time, the hydraulic oil at the oil outlet of the plunger pump (2) flows to the A port of the flow matching valve (4), and generates a low control pressure at the C1 port of the flow matching valve (4). The hydraulic oil flowing out of the rodless chamber flows to the B port of the flow matching valve (4), and generates a high control pressure at the C2 port of the flow matching valve (4), so that the B port of the flow matching valve (4) is closed and the A port and the T port are connected. The hydraulic oil at the oil outlet of the plunger pump (2) returns to the pressure compensator (3) through the A port and the T port of the flow matching valve (4), thereby achieving compensation for mismatched flow.

9. The deep sea underwater electro-hydraulic actuator EHA and its control system according to claim 6, characterized in that: Under the resistance extension working condition, the pressure of the rod chamber of the asymmetric hydraulic cylinder (7) is lower than the pressure of the rodless chamber, the variable speed oil-immersed motor (1) drives the plunger pump (2) to suck oil from the pressure compensator (3) through the oil suction port, and the hydraulic oil flowing out of the oil outlet of the plunger pump (2) flows to the one-way valve of the second balancing valve (5.2), and generates a control pressure in the overflow valve of the first balancing valve (5.1), so that the overflow valve of the first balancing valve (5.1) is bidirectionally conductive, and the hydraulic oil flowing out of the one-way valve of the second balancing valve (5.2) flows into the rodless chamber of the asymmetric hydraulic cylinder (7), and the oil pressure is controlled by connecting the second overflow valve (6.2). The hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder (7) is controlled by connecting the first overflow valve (6.1), and the oil pressure is controlled by the first overflow valve (6.1). .1) or the second overflow valve (6.2) flows back to the pressure compensator (3), the hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder (7) returns to the oil inlet of the plunger pump (2) through the overflow valve of the first balancing valve (5.1), and at the same time, the hydraulic oil at the oil outlet of the plunger pump (2) flows to the B port of the flow matching valve (4), and generates a high control pressure at the C2 port of the flow matching valve (4), the hydraulic oil flowing out of the rod chamber of the asymmetric hydraulic cylinder (7) flows to the A port of the flow matching valve (4), and generates a low control pressure at the C1 port of the flow matching valve (4), so that the B port of the flow matching valve (4) is closed and the A port and the T port are connected, and the hydraulic oil in the pressure compensator (3) flows into the oil inlet of the plunger pump (2) through the A port and the T port of the flow matching valve (4), thereby achieving compensation for mismatched flow.

10. The deep sea underwater electro-hydraulic actuator EHA and its control system according to claim 6, characterized in that: Under the above-mentioned overrunning extension working condition, the pressure of the rod chamber of the asymmetric hydraulic cylinder (7) is higher than the pressure of the rodless chamber, the variable speed oil-immersed motor (1) drives the plunger pump (2) to suck oil from the pressure compensator (3) through the oil suction port, the hydraulic oil flowing out of the oil outlet of the plunger pump (2) flows to the one-way valve of the second balancing valve (5.2), and generates a control pressure at the overflow valve control port of the first balancing valve (5.1), so that the overflow valve of the first balancing valve (5.1) is bidirectionally conductive, the hydraulic oil flowing out of the one-way valve of the second balancing valve (5.2) flows into the rodless chamber of the asymmetric hydraulic cylinder (7), and the oil pressure is controlled by connecting the second overflow valve (6.2), the hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder (7) is controlled by connecting the first overflow valve (6.1), and the first overflow valve (6.1) is used to control the oil pressure. 1) or the second overflow valve (6.2) flows back to the pressure compensator (3), the hydraulic oil in the rod chamber of the asymmetric hydraulic cylinder (7) returns to the oil inlet of the plunger pump (2) through the overflow valve of the first balancing valve (5.1), and at the same time, the hydraulic oil at the oil outlet of the plunger pump (2) flows to the B port of the flow matching valve (4), and generates a low control pressure at the C2 port of the flow matching valve (4), the hydraulic oil flowing out of the rod chamber of the asymmetric hydraulic cylinder (7) flows to the A port of the flow matching valve (4), and generates a high control pressure at the C1 port of the flow matching valve (4), so that the A port of the flow matching valve (4) is closed and the B port and the T port are connected, and the hydraulic oil in the pressure compensator (3) flows into the rodless chamber of the asymmetric hydraulic cylinder (7) through the B port and the T port of the flow matching valve (4), thereby realizing compensation of mismatched flow.

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