Hydraulic drive control device of underwater spiral propeller

Abstract

The invention relates to an underwater screw propeller hydraulic drive control device, and relates to the technical field of underwater propeller drive, the underwater screw propeller hydraulic drive control device comprises a closed pump, an LS valve group, a hot flush valve, a switching valve group and a plurality of propeller hydraulic motors, the closed pump is connected with each valve group through a hydraulic pipeline, and the switching valve group is connected with an oil way drive motor in parallel; the LS valve group feeds back a load pressure signal to the closed pump variable displacement mechanism to realize self-adaptive adjustment of the displacement; a pressure compensation valve is arranged in the switching valve group, and closed-loop control is combined to ensure constant flow and synchronous rotating speed of multiple motors; and the hot flushing valve maintains the temperature stability of the system through dynamic oil displacement. According to the invention, the single closed pump is combined with LS control to drive multiple motors, so that the system cost is obviously reduced; the size and the leakage risk are reduced through the modular integrated design; the problems that a traditional multi-pump system is high in cost and an open system is insufficient in power density are solved, and the system is suitable for scenes needing compact and efficient driving.

Description

Technical Field

[0001] The present application relates to the technical field of underwater thruster drive, and specifically provides a hydraulic drive control device for an underwater screw thruster, which is applicable to underwater robots, deep-sea exploration equipment, and industrial multi-driver synchronous control scenarios. Background Art

[0002] The hydraulic drive system of an underwater thruster is the core power unit in the fields of underwater robots, deep-sea exploration equipment, etc. Its performance directly affects the mobility, reliability, and endurance of the equipment. In traditional technologies, the hydraulic drive of underwater thrusters mainly adopts the following two types of solutions: (1) Multi-closed-loop pump independent drive system: Each thruster is equipped with an independent closed-loop hydraulic pump, and the speed of each thruster is adjusted by separately controlling the displacement of the pump. Although this solution can ensure the independent operation of the thrusters, it has the following defects: High cost: Multiple closed-loop pumps and supporting valve groups result in a multiple increase in hardware costs, especially significant in high-power multi-thruster systems; Large space occupation: The layout of multiple pumps requires complex pipeline connections, restricting the miniaturization design of the equipment; Low energy efficiency: The redundant operation of the pump group leads to energy waste and a reduction in the overall efficiency of the system.

[0003] (2) Open-loop variable pump combined with multi-way valve system: A single open-loop variable pump is used to distribute the flow to each thruster through a multi-way valve. Although this solution reduces the hardware cost, it has the following bottlenecks: Insufficient power density: The open-loop system is limited by the cavitation prevention requirements of the oil suction pipeline and is difficult to achieve high pressure (usually ≤20 MPa), resulting in an increase in the specifications of the pump and motor; Poor flow distribution accuracy: The multi-way valve control system is significantly affected by the load pressure fluctuation. When multiple thrusters are connected in parallel, the flow distribution is uneven, and the rotational speed synchronization error often exceeds ±5%; Difficult heat management: The oil circulation path of the open-loop system is long, the heat dissipation efficiency is low, and it is easy to cause seal failure due to too high oil temperature.

[0004] Therefore, there is an urgent need for a hydraulic drive solution for underwater thrusters with low cost, high power density, and precise synchronous control to solve the problems such as redundancy waste in traditional multi-pump systems, insufficient performance of open-loop systems, and poor environmental adaptability. Summary of the Invention

[0005] The purpose of the present application is to provide a hydraulic drive control device for an underwater screw thruster to solve the problems raised in the above background art.

[0006] In a first aspect, a hydraulic drive control device for an underwater screw thruster provided by the present application adopts the following technical solution: Its structure includes a closed-loop pump, an LS valve group, a hot flush valve, a switching valve group, and a thruster hydraulic motor; The closed pump is respectively connected to the LS valve group, the switching valve group and the hot flushing valve through hydraulic pipelines, and the switching valve group is connected to multiple thruster hydraulic motors through a parallel oil circuit; The LS valve group is configured to feedback the load-sensing signal of the switching valve group to the variable mechanism of the closed pump, the hot flushing valve is configured to keep the oil temperature of the closed system constant, and the switching valve group includes a pressure compensation mechanism to keep the flow pressure difference flowing through each thruster hydraulic motor constant.

[0007] Preferably, the switching valve group includes a number of parallel valve units, each valve unit is composed of a switching valve and a throttle valve connected in series, the throttle valve is configured with a two-way pressure compensation valve, and the spring stiffness of the two-way pressure compensation valve matches the flow-pressure difference curve of the throttle valve to maintain the flow pressure difference constant. The two-way pressure compensation valve, the pressure sensor and the controller form a closed-loop control system to adjust the throttle valve opening in real time.

[0008] Preferably, the LS valve group includes a load pressure feedback channel and a signal replication module. The load pressure feedback channel detects the highest load pressure of the switching valve group, and the signal replication module transmits the highest load pressure equally through a proportional relief valve and a pilot oil circuit to the servo chamber of the variable cylinder of the closed pump; The ratio of the equal transmission is 1:1 to 1:3 and can be adjusted and set.

[0009] Preferably, the hot flushing valve includes a bypass valve and a check valve. The bypass valve opens to drain oil to the heat exchanger when the oil temperature exceeds 60 - 80 °C, and at the same time the check valve dynamically supplements an equal amount of low-temperature oil, and the flow sensor feeds back to the controller in real time for dynamic matching of the oil replenishment flow.

[0010] Preferably, the bypass valve of the hot flushing valve integrates a PID temperature control algorithm to dynamically adjust the coolant flow according to the oil temperature change rate.

[0011] Preferably, the displacement control logic of the closed pump is to adjust the output displacement in real time to be equal to the sum of the flow requirements of all working thruster hydraulic motors, and the displacement adjustment is independent of the load pressure; The variable mechanism of the closed pump receives the load signal of the LS valve group through an electro-hydraulic proportional valve, and integrates a displacement sensor to feedback the displacement position in real time to form a closed-loop control.

[0012] Preferably, the number of parallel thruster hydraulic motors is 2 - 6, the rated speed deviation of each thruster hydraulic motor does not exceed ±2%, and it has a synchronous speed locking function. The synchronous speed locking function communicates with the central controller through the CAN bus protocol. When the speed deviation of a certain thruster hydraulic motor exceeds ±2%, the displacement compensation of the closed pump is triggered.

[0013] Preferably, the LS valve group, the hot flush valve and the switching valve group adopt a modular integrated design to form a pluggable composite valve block, and the modules are connected through flange interfaces.

[0014] Preferably, accumulators are provided in both the suction pipeline and the high-pressure pipeline of the closed pump, and the pre-charged pressure of the accumulator is 90% of the lowest working pressure of the system, which is used to suppress pressure pulsation.

[0015] Preferably, the closed pump is an axial piston variable pump or a radial piston variable pump, and its displacement specification is matched according to the total power requirement of the parallel propulsion hydraulic motors.

[0016] Preferably, the LS valve group, the hot flush valve and the switching valve group can be integrated together in different integration forms.

[0017] Preferably, an overflow valve is provided in the outlet pipeline of the closed pump. When the system pressure exceeds 120% of the rated value, the overflow valve opens to relieve pressure.

[0018] Preferably, the control device is configured with a touch screen to display the rotational speeds, oil temperature, and pressure parameters of each motor in real time, and provides a manual override interface.

[0019] In a second aspect, a hydraulic drive control device for an underwater screw propeller provided by the present application can be extended and applied to multi-driver synchronous control scenarios of underwater robots, deep-sea exploration equipment, or industrial cooling systems.

[0020] In a third aspect, a hydraulic drive control device for an underwater screw propeller provided by the present application can replace the propeller hydraulic motor with a fan drive motor of the same specification to form a multi-fan constant speed drive system.

[0021] In summary, the present application includes at least one of the following beneficial technical effects: 1. The main circuit is composed of a closed pump connected to an LS valve group, a switching valve group with LS feedback, and a hot flush valve through pipelines respectively. Among them, the closed pump is controlled by the load-sensing principle. One closed pump can drive multiple propeller hydraulic motors or a single propeller hydraulic motor at the same time. As the number of working motors changes, the closed pump adaptively controls the displacement to provide the required flow rate, and the flow output is independent of the load and only related to the opening of the throttle valve, maintaining a constant flow pressure difference flowing through the throttle valve, thus realizing a constant motor speed regulation; 2. The load-sensing system composed of a closed system can achieve higher load pressure applications, reduce the specifications of the closed pump and the propeller hydraulic motor, and improve the power density of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the overall structural schematic diagram of Embodiment 1 of the present application; Figure 2 It is a schematic diagram of the overall structure of Embodiment 2 of the present application; Explanation of reference numerals in the drawings: 1, closed pump; 2, LS valve group; 3, hot flush valve; 4, switching valve group; 5, thruster hydraulic motor. Detailed implementation manners

[0023] The following will Figure 1 - be described Figure 2 in further detail in conjunction with the accompanying drawings to the present application.

[0024] Embodiment 1: Please refer to the accompanying Figure 1 drawings. A hydraulic drive control device for an underwater screw thruster provided by the present application includes a closed pump 1, an LS valve group 2, a hot flush valve 3, a switching valve group 4 and a thruster hydraulic motor 5; The closed pump 1 is respectively connected to the LS valve group 2, the switching valve group 4 and the hot flush valve 3 through hydraulic pipelines, and the switching valve group 4 is connected to a plurality of thruster hydraulic motors 5 through a parallel oil circuit; The LS valve group 2 is configured to feedback the load sensitive signal of the switching valve group 4 to the variable mechanism of the closed pump 1, the hot flush valve 3 is configured to maintain the constant oil temperature of the closed system, the switching valve group 4 includes a pressure compensation mechanism to keep the flow pressure difference flowing through each thruster hydraulic motor 5 constant. By adapting a single closed pump 1 to the driving requirements of a plurality of thruster hydraulic motors 5, the system hardware cost can be significantly reduced. At the same time, through the control of the LS valve group 2, the flow rate is adaptively distributed to ensure the stability of the system when the load changes.

[0025] Among them, the switching valve group 4 includes a number of parallel valve units, each valve unit is composed of a switching valve and a throttle valve in series, the throttle valve is configured with a two-way pressure compensation valve, and the spring stiffness of the two-way pressure compensation valve matches the flow-pressure difference curve of the throttle valve to maintain the constant flow pressure difference. The two-way pressure compensation valve, the pressure sensor and the controller form a closed-loop control system to adjust the opening of the throttle valve in real time. By combining pressure compensation and closed-loop control, the influence of load fluctuation on the flow rate is eliminated, so as to realize the precise synchronization of the rotational speeds of a plurality of thruster hydraulic motors 5.

[0026] Among them, the LS valve group 2 includes a load pressure feedback channel and a signal replication module. The load pressure feedback channel detects the highest load pressure of the switching valve group 4, and the signal replication module transmits the highest load pressure to the servo chamber of the variable cylinder of the closed pump 1 in equal proportion through a proportional pressure reducing valve and a pilot oil circuit; the equal proportion for transmission is from 1:1 to 1:3, and can be adjusted and set; the proportionally adjustable design adapts to closed pumps 1 of different power levels to improve the system compatibility and control flexibility.

[0027] Among them, the hot flush valve 3 includes a bypass valve and a check valve. The bypass valve opens to drain oil to the heat exchanger when the oil temperature exceeds 60 - 80°C. At the same time, the check valve dynamically supplements an equal amount of low-temperature oil. The flow sensor provides real-time feedback to the controller for dynamic matching of the oil replenishment flow. By precisely controlling the temperature, overheating and deterioration of the oil are avoided, and the service life of hydraulic components is extended. The bypass valve of the hot flush valve 3 integrates a PID temperature control algorithm to dynamically adjust the coolant flow according to the oil temperature change rate, avoiding the aging of seals caused by sudden temperature changes.

[0028] Among them, the displacement control logic of the closed-loop pump 1 is to adjust the output displacement in real time to be equal to the total flow demand of all the propulsion hydraulic motors 5 in the working state, and the displacement adjustment is independent of the load pressure. The displacement is precisely matched to the demand and decoupled from the load, reducing energy loss. The variable mechanism of the closed-loop pump 1 receives the load signal of the LS valve group 2 through an electro-hydraulic proportional valve and integrates a displacement sensor to provide real-time feedback on the displacement position, forming a closed-loop control to improve the response speed and accuracy.

[0029] Among them, the number of parallel-connected propulsion hydraulic motors 5 is 2 - 6. The rated speed deviation of each propulsion hydraulic motor 5 does not exceed ±2%, and it has a synchronous speed locking function. The synchronous speed locking function communicates with the central controller 7 through the CAN bus protocol. When the speed deviation of a certain propulsion hydraulic motor 5 exceeds ±2%, the displacement compensation of the closed-loop pump 1 is triggered. Through the high-precision synchronous control of multiple propulsion hydraulic motors 5, it can adapt to complex working conditions, and the CAN bus communication is used to ensure real-time performance and reliability.

[0030] Among them, the LS valve group 2, the hot flush valve 3, and the switching valve group 4 adopt a modular integrated design to form a pluggable composite valve block. The modules are connected through flange interfaces. The modular design can simplify the installation and maintenance process and support rapid expansion or replacement of faulty components.

[0031] Among them, accumulators are installed in both the suction pipeline and the high-pressure pipeline of the closed-loop pump 1. The pre-charge pressure of the accumulator is 90% of the lowest working pressure of the system. The accumulator can effectively absorb pressure fluctuations, reduce pipeline vibration and noise, and improve the stability of the system. The closed-loop pump 1 is selected as an axial piston variable pump or a radial piston variable pump, and its displacement specification is matched according to the total power demand of the parallel-connected propulsion hydraulic motors 5, enabling flexible selection to adapt to different power scenarios, avoiding resource waste and optimizing costs. An overflow valve is installed in the outlet pipeline of the closed-loop pump 1. When the system pressure exceeds 120% of the rated value, the overflow valve opens to relieve pressure to prevent hydraulic shock from damaging components and improve the reliability of the system.

[0032] Among them, an overflow valve is installed in the outlet pipeline of the closed-loop pump 1. When the system pressure exceeds 120% of the rated value, the overflow valve opens to relieve pressure, preventing hydraulic shock from damaging components and improving the reliability of the system.

[0033] Among them, the control device is configured with a touch screen 13 to display the rotational speeds, oil temperatures, and pressure parameters of each motor in real time, and provides a manual override interface to improve operation convenience, facilitating on-site debugging and emergency handling.

[0034] Among them, the control device can be extended and applied to multi-drive synchronous control scenarios of underwater robots, deep-sea exploration equipment, or industrial cooling systems. It has strong technical reusability and covers the synchronous drive requirements in multiple fields such as underwater propulsion and industrial heat dissipation.

[0035] Among them, the propeller hydraulic motor 5 can be replaced with a fan drive motor of the same specification to form a multi-fan constant-speed drive system to meet the constant-speed heat dissipation requirements of fan equipment.

[0036] The working principle is as follows: First, system startup and initial pressure establishment Closed-loop pump startup: After the closed-loop pump 1 is powered on, hydraulic oil enters the pump body from the fuel tank through the suction pipeline, and the pump outlet pressure gradually rises to the minimum working pressure of the system, which is guaranteed by 90% of the pre-charged pressure setting value of the accumulator 8; LS signal initialization: The load pressure feedback channel of the LS valve group 2 real-time detects the load pressure of each valve unit in the switching valve group 4. In the initial state, since the propeller hydraulic motor 5 is not started, the load pressure is zero, and the closed-loop pump 1 maintains the minimum displacement to reduce energy consumption; Effect: The low-power standby mode reduces energy waste, and the accumulator suppresses the pressure impact during startup.

[0037] Second, control of the propeller hydraulic motor 5 and flow distribution Start-stop control of the propeller hydraulic motor 5: The operator selects the target propeller through the touch screen 13, and the corresponding switching valve in the switching valve group 4 is opened. Hydraulic oil flows through the throttle valve and enters the propeller hydraulic motor 5 to drive the propeller to rotate; Constant flow differential pressure: The throttle valve opening sets the target flow rate, that is, the rotational speed of the propeller hydraulic motor 5. The two-way pressure compensation valve dynamically adjusts the valve port according to the load pressure fluctuation to ensure that the differential pressure flowing through the throttle valve is constant (matched with the spring stiffness and the flow-differential pressure curve); Closed-loop feedback regulation: The pressure sensor detects the differential pressure across the compensation valve, and the controller real-time micro-adjusts the throttle valve opening to eliminate the flow deviation caused by external disturbances; Effect: When multiple propeller hydraulic motors 5 are connected in parallel, the flow distribution is accurate, and the rotational speed deviation ≤ ±2%, adapting to dynamic loads such as waves and ocean currents.

[0038] Third, adaptive adjustment of the closed-loop pump displacement LS signal transmission: The signal replication module of the LS valve group 2 transmits the highest load pressure signal of the switching valve group 4 to the servo chamber of the variable cylinder of the closed-loop pump 1 through a proportional pressure reducing valve Displacement closed-loop control: The electro-hydraulic proportional valve of the variable mechanism of the closed-circuit pump 1 receives the LS signal, drives the swash plate angle to change to adjust the displacement; the displacement sensor real-time feedbacks the swash plate position to form a closed-loop control, ensuring that the pump output flow is exactly equal to the total flow demand of all working thruster hydraulic motors 5; Effect: The displacement is decoupled from the load pressure and is only determined by the number of working thruster hydraulic motors 5 and the throttle valve opening. The system energy efficiency is increased by ≥20%.

[0039] Fourth, temperature management and safety protection Hot flush control: When the oil temperature exceeds 60 °C, the bypass valve of the hot flush valve 3 opens, and the high-temperature oil flows to the heat exchanger; at the same time, the check valve supplements an equal amount of low-temperature oil, and the flow sensor and the PID algorithm dynamically match the oil replenishment flow to maintain the oil temperature in the safe range of 50 - 70 °C; Overload protection: If the system pressure exceeds 120% of the rated value, such as when the thruster hydraulic motor 5 is stuck, the relief valve instantaneously opens to relieve pressure to avoid pipeline bursting; Effect: The oil temperature control accuracy is ±3 °C, the system reliability is improved, and it is suitable for long-time deep-sea operations.

[0040] Fifth, synchronization and fault tolerance of multiple thruster hydraulic motors 5 CAN bus synchronization: The rotation speeds of each thruster hydraulic motor 5 are fed back to the central controller through the CAN bus. If the rotation speed deviation of a certain thruster hydraulic motor 5 exceeds ±2%, the controller triggers the displacement compensation of the closed-circuit pump 1, such as increasing the flow by 2%, and adjusts the corresponding throttle valve opening to restore synchronization; Fault isolation: When a certain thruster hydraulic motor 5 fails, the controller closes its switching valve, and the rotation speeds of the remaining thruster hydraulic motors 5 increase proportionally to maintain the total thrust unchanged.

[0041] Effect: When multiple thruster hydraulic motors 5 cooperate, the thrust loss ≤5%, supporting the stable hovering or turning of the underwater robot.

[0042] Embodiment 2: Please refer to Figure 2 , an underwater screw propeller hydraulic drive control device provided by the present application includes a closed-circuit pump 1, an LS valve group 2, a hot flush valve 3, a switching valve group 4, and a thruster hydraulic motor 5; The closed-circuit pump 1 is respectively connected to the LS valve group 2, the switching valve group 4, and the hot flush valve 3 through hydraulic pipelines, and the switching valve group 4 is connected to multiple thruster hydraulic motors 5 through a parallel oil circuit; The LS valve group 2 is configured to feedback the load-sensitive signal of the switching valve group 4 to the variable mechanism of the closed-circuit pump 1. The hot flushing valve 3 is configured to maintain the constant oil temperature of the closed-circuit system. The switching valve group 4 includes a pressure compensation mechanism to keep the flow pressure difference of the hydraulic motors 5 of each thruster constant. By adapting a single closed-circuit pump 1 to the driving requirements of multiple thruster hydraulic motors 5, the system hardware cost can be significantly reduced. At the same time, through the control of the LS valve group 2, the flow is adaptively distributed to ensure the stability of the system when the load changes; The LS valve group 2, the hot flushing valve 3 and the switching valve group 4 can be integrated together in different integration forms, combining the three functional valve groups into a single physical module, reducing the external pipeline connection points, and the overall volume is reduced by 30%-50%. It can simplify the internal layout of the underwater equipment, adapt to the space-limited scenario, and only need to dock the oil inlet and outlet and the control signal line during installation, and the assembly efficiency is increased by more than 60%.

[0043] By flexibly selecting the integration form of the LS valve group 2, the hot flushing valve 3 and the switching valve group 4, the device can balance compactness, reliability, maintainability and scenario adaptability, and at the same time significantly reduce the manufacturing and operation and maintenance costs. This design is especially suitable for underwater propulsion systems with strict requirements for space, weight and reliability, and industrial multi-driver synchronous control scenarios.

[0044] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. The same components are represented by the same reference numerals. Therefore: All equivalent changes made according to the structure, shape and principle of this application should be covered within the protection scope of this application.

Claims

1. An underwater screw propeller hydraulic drive control device, characterized in that, Its structure includes a closed pump (1), an LS valve group (2), a hot flush valve (3), a switching valve group (4), and a thruster hydraulic motor (5); The closed pump (1) is respectively connected to the LS valve group (2), the switching valve group (4), and the hot flush valve (3) through hydraulic pipelines. The switching valve group (4) is connected to multiple thruster hydraulic motors (5) through a parallel oil circuit; The LS valve group (2) is configured to feedback the load-sensitive signal of the switching valve group (4) to the variable mechanism of the closed pump (1). The hot flush valve (3) is configured to maintain the constant oil temperature of the closed system. The switching valve group (4) includes a pressure compensation mechanism to keep the flow pressure difference flowing through each thruster hydraulic motor (5) constant.

2. The hydraulic drive control device for an underwater screw propeller according to claim 1, characterized in that The switching valve group (4) includes several parallel valve units. Each valve unit is composed of a switching valve and a throttle valve connected in series. The throttle valve is configured with a two-way pressure compensation valve. The spring stiffness of the two-way pressure compensation valve matches the flow-pressure difference curve of the throttle valve to maintain the constant flow pressure difference. The two-way pressure compensation valve, a pressure sensor, and a controller form a closed-loop control system to adjust the opening of the throttle valve in real time.

3. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, The LS valve group (2) includes a load pressure feedback channel and a signal replication module. The load pressure feedback channel detects the highest load pressure of the switching valve group (4). The signal replication module transmits the highest load pressure in proportion to the servo chamber of the variable cylinder of the closed pump (1) through a proportional relief valve and a pilot oil circuit; The ratio of the proportional transmission is 1:1 to 1:

3.

4. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, The hot flush valve (3) includes a bypass valve and a check valve. The bypass valve opens to drain oil to the heat exchanger when the oil temperature exceeds 60 - 80 °C. At the same time, the check valve dynamically supplements an equal amount of low-temperature oil, and the flow sensor feeds back to the controller in real time for dynamic matching of the oil replenishment flow.

5. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, The displacement control logic of the closed pump (1) is to adjust the output displacement in real time to be equal to the total flow demand of all thruster hydraulic motors (5) in the working state, and the displacement adjustment is independent of the load pressure; The variable mechanism of the closed pump (1) receives the load signal of the LS valve group (2) through an electro-hydraulic proportional valve and integrates a displacement sensor to feedback the displacement position in real time to form a closed-loop control.

6. The hydraulic drive control device for an underwater screw propeller according to claim 1, characterized in that, The number of parallel thruster hydraulic motors (5) is 2 - 6. The rated speed deviation of each thruster hydraulic motor (5) does not exceed ±2%, and it has a synchronous speed locking function. The synchronous speed locking function communicates with the central controller (7) through the CAN bus protocol. When the speed deviation of a certain thruster hydraulic motor (5) exceeds ±2%, the displacement compensation of the closed pump (1) is triggered.

7. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, The LS valve group (2), the hot flush valve (3), and the switching valve group (4) adopt a modular integrated design to form a pluggable composite valve block, and the modules are connected through flange interfaces.

8. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, Accumulators are provided in both the suction pipeline and the high-pressure pipeline of the closed pump (1). The pre-charge pressure of the accumulator is 90% of the lowest working pressure of the system, which is used to suppress pressure pulsation.

9. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, The closed pump (1) is selected as an axial piston variable pump or a radial piston variable pump, and its displacement specification is matched according to the total power demand of the parallel thruster hydraulic motors (5).

10. An underwater screw propeller hydraulic drive control device according to claim 1, characterized in that, The control device is extended and applied to the multi-driver synchronous control scenarios of underwater robots, deep-sea exploration equipment or industrial cooling systems.

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