An energy-saving planning system and method for water tunnel inspection AUV

Abstract

The present invention proposes an energy-saving planning system and method for an AUV for water tunnel inspection. The energy consumption of the tunnel inspection AUV is analyzed, and the energy consumption is divided into controllable energy consumption and variable load energy consumption. Energy consumption models of the tunnel inspection AUV in a water tunnel are established from the perspectives of variable load energy consumption and controllable energy consumption. An energy-saving scheme with the shortest comprehensive time and reduced control calculation amount is proposed. A thruster thrust curve experiment is carried out to obtain the relationship between the thrust and power of the thruster on the AUV, and a thruster power curve model is obtained by fitting a quartic function.

Description

Technical Field

[0001] The present invention belongs to the field of energy-saving technology for tunnel inspection AUVs, and in particular, relates to an energy-saving planning system and method for water conveyance tunnel inspection AUVs. Background Art

[0002] Currently, manual inspections require draining the tunnel and stopping water flow, consuming significant manpower, material, and financial resources. Remotely Operated Vehicle (ROV) inspections are also limited in their ability to cover long distances. With the advancement of science and technology, the use of unmanned, cable-free AUVs for water tunnel inspections has become a research hotspot.

[0003] Compared to traditional manual inspection methods, the use of AUVs for water tunnel inspection offers advantages such as low cost, ease of use, high detection accuracy, no impact on tunnel operation, and the ability to conduct long-term, large-scale inspections. Because water tunnels are enclosed waters with flow field interference, remote-controlled cabled robotic inspections can obtain real-time images and data. However, the umbilical cord is a hindrance, prone to friction and scraping against the tunnel walls, causing entanglement and breakage. Due to voltage drops and other factors, the umbilical cord cannot be very long, limiting the inspection distance. Furthermore, AUVs can only enter and exit through a limited number of branch tunnels. If an emergency occurs and the AUV misses the pre-set branch tunnel exit, and does not retain sufficient energy to reach the next branch tunnel exit, traditional emergency jettisoning and surfacing methods will be unable to recover the AUV in the tunnel, resulting in its loss and even disrupting tunnel operation. Therefore, ensuring energy security is crucial when AUVs conduct tunnel inspections. Because adjacent branch tunnels in water transfer tunnels are typically several kilometers apart, sometimes even tens of kilometers, the actual range of an AUV in a single operation is uncertain. Limited by existing battery technology, implementing a large number of batteries during the design phase to address this issue is not optimal. Therefore, to ensure the safety of AUV energy sources, research into energy-saving operation methods is needed in planning and control. Summary of the Invention

[0004] In response to the above problems, the present invention proposes an energy-saving planning system and method for water tunnel inspection AUV to extend the working time of tunnel inspection AUV.

[0005] The present invention is achieved through the following technical solutions:

[0006] An energy-saving planning system for AUVs used in water tunnel inspection: the planning system includes a surface monitoring system and an underwater control system;

[0007] The water surface monitoring system is a graphical control module running on the host computer, which is used to display the status information of the tunnel inspection AUV, set parameters or send instructions;

[0008] The underwater control system is an embedded computer PC104 module and a drive control module based on STM32 running on the tunnel inspection AUV, which are used to execute specific functional modules and hardware drivers. Data is transmitted between the surface monitoring system and the underwater control system through the communication module;

[0009] The embedded computer PC104 module is used for the embedded computer system inside the AUV: two PC104 modules are used, each responsible for a different function; one PC104 module serves as a mission controller, performing dead reckoning, thrust distribution, positioning control, and path planning, and receiving and processing information from various sensors; the other PC104 module serves as a data processor, processing the large amount of data information fed back to the tunnel inspection AUV by the side-scan sonar and transmitting it to the mission controller via network signals;

[0010] The STM32-based drive control module is used for the control and actuators inside the AUV. It is responsible for generating switch control signals for the tunnel inspection AUV's thrusters, steering gear actuators, and sensors, and communicating with the mission controller.

[0011] Furthermore, the execution of specific functional modules includes: navigation module, data acquisition module, hardware control module and function algorithm module

[0012] The navigation module is composed of a variety of sensors, including multi-beam imaging sonar, depth meter, altimeter, DVL, and electronic compass, which are used to provide the tunnel inspection AUV with underwater position, speed, and attitude information and communicate with the mission controller. In addition, the navigation module is also connected to the GPS module and radio module for real-time positioning when on the water surface and for real-time communication and information exchange with the shore-based monitoring system.

[0013] The data acquisition module obtains real-time data information from various sensors, navigation equipment and cameras, and performs pre-processing and storage to provide a basis for subsequent control decisions;

[0014] The hardware control module sends control instructions to various actuators, thrusters, and lights, and monitors their working status and feedback information to ensure the normal operation of the tunnel inspection AUV;

[0015] The functional algorithm module is used to realize the core functions of the tunnel detection AUV.

[0016] A method for energy-saving planning of an AUV for water tunnel inspection: the method specifically comprises the following steps:

[0017] Step 1: Analyze the energy consumption of the tunnel inspection AUV and divide the energy consumption into controllable energy consumption and variable load energy consumption; establish an energy consumption model for the tunnel inspection AUV;

[0018] Step 2: Analyze the motion phases of the tunnel inspection AUV and its corresponding mechanical model;

[0019] Step 3: Add restrictions on tunnel inspection AUV;

[0020] Step 4: By analyzing the motion state, force state, and energy consumption of the tunnel detection AUV during its mission, the energy consumption of the tunnel detection AUV is modeled to obtain an energy-saving solution with the shortest comprehensive time and reduced control calculation amount.

[0021] Furthermore, the energy consumption of tunnel inspection AUV is divided into variable load energy consumption and controllable energy consumption;

[0022] The variable load energy consumption is divided into variable energy consumption and load energy consumption; the controllable energy consumption is control energy consumption;

[0023] The load energy consumption is composed of the equipment and line losses that are fully turned on.

[0024] The variable energy consumption is composed of power consumption that varies with the operating conditions, which is the propeller power consumption;

[0025] The control energy consumption is composed of the control law power consumption, which is related to the navigation control law algorithm;

[0026] Since the task has been determined, the power of all load devices has been determined and classified as load energy consumption;

[0027] Therefore, the load energy consumption can be expressed as:

[0028] W1=P1t (1)

[0029] Where W1 is the load power consumption, P1 is the load power, and t is the operation time.

[0030] Furthermore, when performing underwater missions, the tunnel inspection AUV needs to adjust its speed and direction according to mission requirements and environmental conditions. During the speed change process, the movement of the tunnel inspection AUV can be divided into three stages: the tunnel inspection AUV accelerates, the tunnel inspection AUV maintains a constant speed, and the tunnel inspection AUV decelerates. The mechanical models and energy conversion mechanisms of these three stages are different, so they need to be analyzed separately.

[0031] During the acceleration phase, the tunnel inspection AUV converts the battery-generated energy into thrust through its thrusters, and can also utilize the water flow to generate its own kinetic energy. While ensuring mission completion, the energy consumption during acceleration can be reduced by utilizing the water flow as thrust to shorten the propulsion time of the tunnel inspection AUV.

[0032] F T +F w =ma (2)

[0033] Among them F T is the force exerted by the thruster on the tunnel inspection AUV, F W is the force exerted by the water flow on the tunnel detection AUV, m is the mass of the tunnel detection AUV, and a is the acceleration of the tunnel detection AUV.

[0034] Furthermore, during the uniform motion phase, the tunnel inspection AUV uses thrusters to maintain its required speed and balance the resistance exerted by the water flow. When the tunnel inspection AUV needs to maintain the same or similar speed as the water flow, it can stop or reduce the operation of the thrusters and use the water flow to drive it forward, thereby saving energy consumption.

[0035] F T =F w (3)

[0036] During the deceleration phase, the tunnel inspection AUV reduces its speed by adjusting the thruster direction or shutting down some thrusters, thereby consuming its own kinetic energy. This shortens the time and distance required for deceleration and avoids excessive energy consumption.

[0037] F T -F w =ma (4)

[0038] According to the relationship between power and energy, the work done by the propeller, that is, the energy it consumes, is the power integrated over time. The thrust generated by the propeller is the force F acting on the tunnel inspection AUV minus the force F acting on the tunnel inspection AUV by the water flow. w Then the variable energy consumption model is obtained:

[0039]

[0040] P2=P zt ·n (9)

[0041] Where W2 is the variable power consumption, P2 is the propeller power consumption, n is the number of propellers arranged in this direction; P zt 、P ct is the power of the main thruster and side thruster, and F is the combined force of the water flow and the thruster on the AUV.

[0042] Furthermore, the constraints on the tunnel inspection AUV during its operation are added;

[0043] Since the thrust of the propeller is related to the force exerted by the water flow, the relative speed at this time should first be subtracted from the speed of the water flow. The acceleration and deceleration process is related to the mass and the acceleration to be achieved, which can be obtained:

[0044] Constant speed: F T =140(vc -v auv ) 2 (14)

[0045] Acceleration and deceleration: F T =ma (15)

[0046] In a detection process of two adjacent detection points, the total displacement L of the movement is certain, then:

[0047]

[0048] For the speed of the AUV, the acceleration can be integrated to obtain:

[0049]

[0050] At the two detection points, the starting point and the end point are in the detection state, and the tunnel detection AUV is hovering controlled with the initial velocity v0 and the final velocity v f is 0m / s, then:

[0051] v0=v f =0 (18)

[0052] And the thrust generated by the propeller cannot exceed the sum of the maximum thrust that all propellers can generate. According to the arrangement of the propellers:

[0053] F≤F max (19)

[0054] Furthermore, by analyzing the motion state, force state, and energy consumption of the tunnel inspection AUV during its mission, a model of the tunnel inspection AUV’s energy consumption is established:

[0055] The energy consumption W associated with job planning consists of two parts: variable energy consumption W2 and load energy consumption W1:

[0056] W=W1+W2 (10)

[0057] The load energy consumption W1 is the energy consumed by the task sensor and the surrounding circuits, which is related to time t and has a linear relationship. A large number of tests are performed to obtain the average value as follows:

[0058] W1=P1t (11)

[0059] The variable energy consumption W2 is the energy consumption generated by the propeller when the tunnel inspection AUV is moving. It is related to the time t and the thrust curve of the propeller, as shown in the following formula:

[0060]

[0061] The load energy consumption W1 and variable energy consumption W2 of the variable load energy consumption W during the tunnel inspection AUV operation are substituted with the thruster power P2 to obtain:

[0062]

[0063] An electronic device includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0064] A computer-readable storage medium is used to store computer instructions, which implement the steps of the above method when executed by a processor.

[0065] Beneficial effects of the present invention

[0066] The energy consumption of underwater robots is an important factor affecting their endurance and task completion efficiency. In existing energy-saving planning methods, AUVs all reduce the impact of ocean currents on their energy consumption and use thrusters as the main driving force to achieve energy-saving planning movements. However, in a typical environment such as a water tunnel with confined waters and a stable flow field, tunnel inspection AUVs mainly use the force of water flow to achieve energy-saving navigation of the AUV, and thrusters only serve as auxiliary adjustments to achieve state stability and emergency obstacle avoidance. The present invention establishes an energy consumption model for the tunnel inspection AUV operation process. By analyzing the water tunnel inspection operation process and considering the equipment carried by AUVs, the AUV energy consumption is divided into variable load energy consumption and controllable energy consumption, and an energy consumption model suitable for tunnel inspection is constructed. It is proposed that the combined time of load and thruster use is the shortest and the variable load energy consumption is minimized under the premise of ensuring safe navigation; the control law is optimized to reduce the amount of control calculations for tunnel inspection AUVs and achieve an energy-saving solution with minimal control energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 The energy consumption composition of the tunnel detection AUV of the present invention;

[0068] Figure 2 Schematic diagram of the tunnel inspection AUV of the present invention;

[0069] Figure 3 Schematic diagram of the control system structure of the present invention;

[0070] Figure 4 (a) is the side-pushing fitting curve diagram; Figure 4 (b) The main fitting curve diagram;

[0071] Figure 5 (a) is the load energy consumption diagram; Figure 5 (b) is the variable energy consumption diagram. DETAILED DESCRIPTION

[0072] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0073] Combine Figure 1 To the figure;

[0074] like Figure 1 ,The energy consumption components of commonly used AUVs in the existing ,technology include basic computing energy consumption, mission payload energy consumption, propeller energy consumption, and rudder mechanism energy consumption;

[0075] Basic calculation energy consumption: It is composed of the equipment and line losses that are fully turned on, including flight control computers, relays, etc.

[0076] Mission payload energy consumption: This is composed of equipment that is not fully operational and its peripheral circuits, including side-scan sonar, forward-looking sonar, etc.

[0077] Navigation energy consumption: It is composed of propeller power consumption and is related to navigation speed and navigation attitude;

[0078] Actuator energy consumption: It is composed of the servo power consumption and is related to the frequency and amplitude of actuator use.

[0079] Basic computing energy and mission payload energy are fixed or variable, determined during the design phase; propulsion and actuator energy are controllable and can be reduced during operation through optimized control strategies and algorithms. Propulsion accounts for the largest share of controllable energy, increasing with increasing thrust. Since speed is fixed during path tracking, reducing actuator power can save energy.

[0080] The tunnel inspection AUV of the present invention is an autonomous underwater vehicle specially used for tunnel inspection and maintenance. Based on the original energy consumption structure, the energy consumption of the tunnel inspection AUV is optimized and divided, and an energy consumption structure model suitable for the tunnel inspection AUV is designed, such as Figure 2 As shown;

[0081] In the embodiment of the present invention, the tunnel inspection AUV has a total length of 2.91 meters, a maximum diameter of the main body of 0.60 meters, a side width including the wing panels of 1.10 meters, and a wing panel opening angle of 15 degrees. Figure 3As shown, the entire boat adopts a spindle-shaped design and is equipped with twelve thrusters. Four main thrusters are arranged at the bow and stern for forward and reverse movement. The bow and stern are equipped with one vertical thruster and one lateral thruster. The two vertical thrusters are responsible for completing submersible and buoyant movements, and the two lateral thrusters are responsible for lateral movement. A pair of wing panels are equipped in the middle. The wing panels adopt a conformal design. When the wing panels are closed, the entire boat has a streamlined shape. Generally, there is water flow in water transfer tunnels, and the normal navigation mode of tunnel inspection AUVs is a downstream drifting mode, which can greatly save energy. During the navigation phase, the wing panels are used to improve stability in the drifting state and quickly reach a stable drifting state, while the thrusters are mainly used to complete the attitude control of the tunnel inspection AUV.

[0082] An energy-saving planning system for AUV inspection of water tunnels, characterized by:

[0083] The planning system includes a surface monitoring system and an underwater control system;

[0084] The water surface monitoring system is a graphical control module running on the host computer, which is used to display the status information of the tunnel inspection AUV, set parameters or send instructions, etc.

[0085] The underwater control system is an embedded computer PC104 module and a drive control module based on STM32 running on the tunnel inspection AUV, which are used to execute specific functional modules and hardware drivers, etc. The surface monitoring system and the underwater control system are used to transmit data through the communication module;

[0086] The embedded computer PC104 module is used for the embedded computer system inside the AUV: two PC104 modules are used, each responsible for a different function; one PC104 module serves as a mission controller, executing complex mission control algorithms such as dead reckoning, thrust distribution, positioning control, and path planning, and receiving and processing information from various sensors; the other PC104 module serves as a data processor, processing the large amount of data information fed back to the tunnel inspection AUV by the side-scan sonar and transmitting it to the mission controller via network signals;

[0087] The STM32-based drive control module is used for the control and actuators inside the AUV. It is responsible for generating switch control signals for the tunnel inspection AUV's actuators such as thrusters and servos, as well as for various sensors, and communicating with the mission controller.

[0088] The communication module exchanges data with the water surface monitoring system, including sending status information of the tunnel detection AUV and receiving instructions or parameter adjustments from the water surface monitoring system.

[0089] The control system software of a tunnel inspection AUV is a key component in achieving its underwater mission. It is responsible for driving and coordinating various hardware modules and executing various functional algorithms, enabling the tunnel inspection AUV to complete underwater operations according to predetermined goals and strategies.

[0090] The specific functional modules include: navigation module, data acquisition module, hardware control module and function algorithm module

[0091] The navigation module utilizes a variety of sensors, including a multibeam imaging sonar, depth gauge, altimeter, DVL, and electronic compass, to provide the tunnel inspection AUV with underwater position, velocity, and attitude information, and to communicate with the mission controller. Furthermore, the module incorporates a GPS module and a radio module for real-time positioning while on the surface, as well as real-time communication and information exchange with shore-based monitoring systems.

[0092] The data acquisition module obtains real-time data information from various sensors, navigation equipment and cameras, and performs pre-processing and storage to provide a basis for subsequent control decisions.

[0093] The hardware control module sends control instructions to various actuators, thrusters, lights, etc., and monitors their working status and feedback information to ensure the normal operation of the tunnel inspection AUV.

[0094] The functional algorithm module realizes the core functions of the tunnel inspection AUV, such as autonomous navigation, target recognition, path planning, obstacle avoidance, etc.

[0095] Different types and quantities of payloads affect the AUV's total power requirements, battery capacity, weight, volume, and layout balance, ultimately impacting the AUV's endurance and mission duration. Therefore, when designing the tunnel inspection AUV, we selected appropriate payloads based on mission requirements and optimized their configuration to achieve optimal energy efficiency and inspection results.

[0096] To analyze the energy consumption of the tunnel inspection AUV's payloads, we first measured and compiled the power parameters of each payload. By consulting the equipment manuals and conducting multiple charge-discharge experiments, we determined the type, quantity, weight, and power of each payload, as shown in the table below.

[0097]

[0098]

[0099] Table 1 Load power table

[0100] The payload of the hole detection AUV refers to various equipment used to complete underwater detection tasks. The names and functions are as follows:

[0101] Lighting equipment: used to provide underwater lighting; Camera equipment: used to obtain underwater images or videos;

[0102] Detection sonar: used to detect pipes, structures, cracks, etc. in tunnels, such as side-scan sonar and circular sonar;

[0103] Forward-looking sonar: used to detect obstacles or targets in front of the tunnel, such as single-beam sonar, imaging sonar, etc.

[0104] Depth meter: used to measure the depth of the AUV; Ranging sonar / altimeter: used to measure the distance between the AUV and the tunnel wall or bottom, such as ultra-short baseline (USBL);

[0105] Inertial navigation: used to provide attitude and motion information of AUV, such as gyroscope, accelerometer, etc.

[0106] DVL: Doppler velocity meter, used to provide AUV speed information, such as multi-beam DVL;

[0107] Main propeller: used to provide forward thrust for the AUV, propeller thruster;

[0108] Lateral thrust and vertical thrust: used to provide lateral and longitudinal thrust to the AUV to adjust the heading and depth of the AUV;

[0109] Battery compartment: used to store batteries and protect them from water pressure and temperature differences;

[0110] Battery: used to provide power for AUV payload equipment;

[0111] Control cabin and system: used to store control computers and communication modules and protect them from water pressure and temperature differences; the control system is responsible for receiving instructions, processing data, executing tasks, adjusting parameters, etc.

[0112] Cable hub and system: used to connect various load devices and control systems, and protect the connecting cables from water pressure and temperature differences; the cable hub system is responsible for transmitting signals, distributing power, monitoring status, and other functions.

[0113] A method for energy-saving planning of an AUV for water tunnel inspection, the method specifically comprising the following steps:

[0114] Step 1: Analyze the energy consumption of the tunnel inspection AUV and divide the energy consumption into controllable energy consumption and variable load energy consumption; establish an energy consumption model for the tunnel inspection AUV;

[0115] Step 2: Analyze the motion phases of the tunnel inspection AUV and its corresponding mechanical model;

[0116] Step 3: Add restrictions on tunnel inspection AUV;

[0117] Step 4: By analyzing the motion state, force state, and energy consumption of the tunnel detection AUV during its mission, the energy consumption of the tunnel detection AUV is modeled to obtain an energy-saving solution with the shortest comprehensive time and reduced control calculation amount.

[0118] The energy consumption of tunnel inspection AUV is divided into variable load energy consumption and controllable energy consumption;

[0119] The variable load energy consumption is divided into variable energy consumption and load energy consumption; the controllable energy consumption is control energy consumption;

[0120] The load energy consumption is composed of the loss of equipment and lines that are fully turned on, including DVL, magnetic compass, positioning module, etc.; specifically, it is the consumption of peripheral circuits, mission sensors, various computers (aviation computers, mission computers, planning computers, etc.), navigation and positioning sensors, basic circuit modules and line losses;

[0121] The variable energy consumption is composed of power consumption that varies with the operating conditions, which is the propeller power consumption;

[0122] The control energy consumption is composed of the control law power consumption, which is related to the navigation control law algorithm;

[0123] Since the task has been determined, the power of all load devices has been determined and classified as load energy consumption;

[0124] Control law energy consumption and variable energy consumption are the most important parts of tunnel inspection AUV energy consumption and are also the focus of optimization design. In order to reduce energy consumption, the following aspects are mainly considered:

[0125] (1) Optimize the operation plan to minimize the combined time of navigation and propulsion and minimize the variable load energy consumption while ensuring safe navigation;

[0126] (2) Optimize the control law to reduce the amount of control calculations for tunnel inspection AUV and minimize the control energy consumption.

[0127] As can be seen from the table, the total power of the various load devices (excluding the thrusters) is 340W. In addition, we need to consider the energy consumption caused by other factors such as device switching and circuit loss, which is estimated to be approximately 100W, for a total of 440W. Therefore, the load energy consumption can be expressed as:

[0128] W1=P1t (1)

[0129] Where W1 is the load power consumption, P1 is the load power, and t is the operation time.

[0130] When performing underwater missions, tunnel inspection AUVs must adjust their speed and direction based on mission requirements and environmental conditions. During this speed change, the AUV's motion can be divided into three phases: acceleration, constant velocity, and deceleration. These three phases require different mechanical models and energy conversion mechanisms, necessitating separate analysis.

[0131] During the acceleration phase, the tunnel inspection AUV converts battery-generated energy into thrust through its thrusters. Alternatively, it can utilize the water flow to generate its own kinetic energy. According to Newton's second law, the acceleration of a tunnel inspection AUV is related to its mass, the thrust generated by its thrusters, and the force exerted by the water flow. Therefore, while ensuring mission completion, it is important to minimize energy consumption during acceleration by utilizing the water flow as a thrust force whenever possible to minimize the time the tunnel inspection AUV's thrusters are in use.

[0132] F T +F w =ma (2)

[0133] Among them F T is the force exerted by the thruster on the tunnel inspection AUV, F W is the force exerted by the water flow on the tunnel detection AUV, m is the mass of the tunnel detection AUV, and a is the acceleration of the tunnel detection AUV.

[0134] During the uniform motion phase, the tunnel inspection AUV uses thrusters to maintain its desired speed and balance the resistance exerted by the water flow. When the tunnel inspection AUV needs to maintain the same or similar speed as the water flow, it can stop or reduce the operation of the thrusters, allowing it to use the water flow to drive it forward, thus saving energy.

[0135] F T =F w (3)

[0136] During the deceleration phase, tunnel inspection AUVs reduce their speed by adjusting thruster direction or disabling some thrusters, thereby consuming their own kinetic energy. According to Newton's second law, the deceleration rate of a tunnel inspection AUV is also related to its mass, the thrust generated by its thrusters, and the force exerted on it by the water flow. Therefore, while ensuring safety and reliability, the time and distance required for deceleration should be minimized to avoid excessive energy consumption.

[0137] F T -F w =ma (4)

[0138] The thrust of a tunnel inspection AUV consists of propeller thrust and water thrust. Propeller energy consumption is primarily determined by propeller power, which in turn is related to the thrust it generates. Propellers are the primary power source for tunnel inspection AUVs. Therefore, to establish an energy consumption model suitable for tunnel inspection AUVs, a water tank experiment was conducted to accurately measure the propeller's cruise thrust and power.

[0139] During tunnel inspection operations, the tunnel environment presents a 1 m / s flow field. During motion, the propeller primarily flows through the wings, while during hovering, the propeller primarily utilizes the propeller, where the flow velocity is also 1 m / s. Therefore, a downstream test was designed. The experimental plan is as follows: First, the test device was installed in a water pool, ensuring that the propeller axis was parallel to the horizontal plane and the propeller outlet was aligned with the water flow direction. Next, the test device was connected to the host computer, and data acquisition and control parameters, such as sampling frequency, voltage, and current, were set. Next, the water pump was turned on and the water flow rate was adjusted, taking into account the flow field velocity at the propeller shaft and the wake coefficient. Next, the propeller power was turned on and the propeller speed was gradually increased. The propeller's cruise thrust and power were observed and recorded, and the corresponding curves were plotted. When the propeller reached maximum speed, the speed was reduced, and the propeller's cruise thrust and power were observed and recorded, and the corresponding curves were plotted. When the propeller stopped rotating, the power supply and water pump were turned off, and the experiment ended. Finally, the collected data was exported for analysis and processing.

[0140] When the propeller is under the action of water flow, the wake effect is taken into account. Combined with the wake coefficient formula of the underwater robot propeller, the wake coefficient is considered:

[0141] ω=0.55C B -0.2 (5)

[0142] Where ω is the wake coefficient, C B is the square coefficient.

[0143] The data obtained from the experiment on the actual forces acting on the tunnel inspection AUV are shown in the following table:

[0144]

[0145] Table 2 Side thrust curve data

[0146]

[0147]

[0148] Table 3 Main thrust curve data

[0149] The force in the table is the combined force exerted on the tunnel inspection AUV by the water flow and the thruster, that is, the actual force exerted on the AUV. Under the action of the water flow, the thruster requires a certain amount of power to offset the force of the water flow. For example, when the thruster is not running, the AUV will be subjected to a force in the opposite direction (that is, the direction of the water flow). Therefore, a certain amount of power is consumed when the combined forward force exerted on the AUV is 0.

[0150] According to the fitted curve, the thrust curves of the main thruster and the side thruster can be obtained. When the quartic function fitting is adopted, the correlation coefficient reaches above 0.999, which proves that the fitting effect is very good. Therefore, the thrust curve formulas of the two thrusters are as follows:

[0151] P zt =-0.0094F 4 +0.3035F 3 -2.2028F 2 +29.419F+353.02 (6)

[0152] P ct =0.1122F 4 -0.2814F 3 -13.337F 2 +116.37F+266.89 (7)

[0153] Among them, P zt 、P ct is the power of the main thruster and side thruster, and F is the combined force of the water flow and the thruster on the AUV.

[0154] According to the relationship between power and energy, the work done by the thruster, that is, the energy it consumes, is the power integrated over time. The thrust generated by the thruster is the force F acting on the tunnel detection AUV minus the thrust F obtained by the water flow. w Then the variable energy consumption model is obtained:

[0155]

[0156] P2=P zt ·n (9)

[0157] Among them, W2 is the variable power consumption, P2 is the propeller power consumption, and n is the number of propellers arranged in this direction.

[0158] The energy consumption of tunnels was summarized and analyzed, and the energy consumption of variable loads and control of AUVs was considered. Energy efficiency indicators were established from two aspects: load and propulsion. This was done to meet the AUV's tunnel inspection mission while achieving energy efficiency and efficient use of energy, thus achieving energy conservation.

[0159] By analyzing the motion state, force state and energy consumption of the tunnel inspection AUV during its mission, a model of the tunnel inspection AUV's energy consumption is established:

[0160] The energy consumption W associated with job planning consists of two parts: variable energy consumption W2 and load energy consumption W1:

[0161] W=W1+W2 (10)

[0162] The load energy consumption W1 is the energy consumed by the task sensor and the surrounding circuits. From the above analysis of the equipment standby power consumption, it can be seen that this part is related to the time t and has a linear relationship. The average value of a large number of tests is as follows:

[0163] W1=P1t (11)

[0164] The variable energy consumption W2 is the energy consumption generated by the propeller when the tunnel inspection AUV is moving. From the above analysis of the AUV motion energy consumption, it can be seen that this part is related to the time t and the propeller thrust curve, as shown in the following formula:

[0165]

[0166] The load energy consumption W1 and variable energy consumption W2 of the variable load energy consumption W during the tunnel inspection AUV operation are substituted with the thruster power P2 to obtain:

[0167]

[0168] Add restrictions on the tunnel inspection AUV during its operation.

[0169] Since the thrust of the propeller is related to the force exerted by the water flow, the relative speed at this time should first be subtracted from the speed of the water flow. The acceleration and deceleration process is related to the mass and the acceleration to be achieved, which can be obtained:

[0170] Constant speed: F T =140(v c -v auv ) 2 (14)

[0171] Acceleration and deceleration: F T =ma (15)

[0172] In a detection process of two adjacent detection points, the total displacement L of the movement is certain, then:

[0173]

[0174] For the speed of the AUV, the acceleration can be integrated to obtain:

[0175]

[0176] At the two detection points, the starting point and the end point are in the detection state, and the tunnel detection AUV is hovering controlled with the initial velocity v0 and the final velocity v f is 0m / s, then:

[0177] v0=v f =0 (18)

[0178] And the thrust generated by the propeller cannot exceed the sum of the maximum thrust that all propellers can generate. According to the arrangement of the propellers:

[0179] F≤F max (19)

[0180] Power on all equipment and sensors to simulate the tunnel inspection AUV using the main push F T = 33N when sailing at a constant speed of 1m / s, the energy consumed in 100s to travel 100m. Figure 5 ;

[0181] The energy consumption models of W1 and W2 are consistent with the experimental results, and the energy consumption models are consistent with the actual situation.

[0182] An electronic device includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0183] A computer-readable storage medium is used to store computer instructions, which implement the steps of the above method when executed by a processor.

[0184] The memory in the embodiments of the present application can be volatile memory or non-volatile memory, or can include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAM bus random access memory (DRRAM). It should be noted that memory of the methods described herein is intended to comprise, but not be limited to, these and any other suitable types of memory.

[0185] The above is a detailed introduction to the energy-saving planning system and method for water tunnel inspection AUV proposed in the present invention, and the principles and implementation methods of the present invention are explained. The description of the above embodiments is only used to help understand the method and core ideas of the present invention; at the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An energy-saving planning method for an energy-saving planning system for water tunnel inspection AUV, The planning system includes a surface monitoring system and an underwater control system; The water surface monitoring system is a graphical control module running on the host computer, which is used to display the status information of the tunnel inspection AUV, set parameters or send instructions; The underwater control system is an embedded computer PC104 module and a drive control module based on STM32 running on the tunnel inspection AUV, which are used to execute specific functional modules and hardware drivers. Data is transmitted between the surface monitoring system and the underwater control system through the communication module; The embedded computer PC104 module is used for the embedded computer system inside the AUV: two PC104 modules are used, each responsible for a different function; one PC104 module serves as a mission controller, performing dead reckoning, thrust distribution, positioning control, and path planning, and receiving and processing information from various sensors; the other PC104 module serves as a data processor, processing the large amount of data information fed back to the tunnel inspection AUV by the side-scan sonar and transmitting it to the mission controller via network signals; The STM32-based drive control module is used for the control and actuator mechanisms within the AUV. It is responsible for generating switch control signals for the tunnel inspection AUV's thrusters, steering gear actuators, and sensors, and communicating with the mission controller. It is characterized by: The method specifically comprises the following steps: Step 1: Analyze the energy consumption of the tunnel inspection AUV and divide the energy consumption into controllable energy consumption and variable load energy consumption; establish an energy consumption model for the tunnel inspection AUV; Step 2: Analyze the motion phases of the tunnel inspection AUV and its corresponding mechanical model; Step 3: Add restrictions on tunnel inspection AUV; Step 4: By analyzing the motion state, force state, and energy consumption of the tunnel inspection AUV during its mission, the energy consumption of the tunnel inspection AUV is modeled to obtain an energy-saving solution with the shortest comprehensive time and reduced control calculation amount; When performing underwater missions, tunnel inspection AUVs need to adjust their speed and direction based on mission requirements and environmental conditions. During speed changes, the movement of tunnel inspection AUVs can be divided into three phases: acceleration, constant speed, and deceleration. The mechanical models and energy conversion mechanisms of these three phases are different, so they need to be analyzed separately. During the acceleration phase, the tunnel inspection AUV converts the battery-generated energy into thrust through its thrusters, or uses the water flow to generate its own kinetic energy. While ensuring mission completion, the tunnel inspection AUV uses the water flow as thrust to reduce the propulsion time of the tunnel inspection AUV, thereby reducing energy consumption during acceleration. F T +F w =in (2) Among them F T is the force exerted by the thruster on the tunnel inspection AUV, F W is the force exerted by the water flow on the tunnel detection AUV, m is the mass of the tunnel detection AUV, and a is the acceleration of the tunnel detection AUV; During the uniform motion phase, the tunnel inspection AUV uses thrusters to maintain its required speed and balance the resistance exerted by the water flow. When the tunnel inspection AUV needs to maintain the same or similar speed as the water flow, it can stop or reduce the operation of the thrusters and use the water flow to drive it forward, thereby saving energy consumption. F T =F w (3) During the deceleration phase, the tunnel inspection AUV reduces its speed by adjusting the thruster direction or shutting down some thrusters, thereby consuming its own kinetic energy. This shortens the time and distance required for deceleration and avoids excessive energy consumption. F T -F w =in (4) According to the relationship between power and energy, the work done by the propeller, that is, the energy it consumes, is the power integrated over time. The thrust generated by the propeller is the force F acting on the tunnel inspection AUV minus the force F acting on the tunnel inspection AUV by the water flow. w Then the variable energy consumption model is obtained: P2=P zt ·n (9) Where W2 is the variable power consumption, P2 is the propeller power consumption, n is the number of propellers arranged in this direction; P zt is the main propulsion power, and F is the resultant force of the water flow and the propulsion force on the AUV.

2. The energy-saving planning method according to claim 1, characterized in that: The specific functional modules include: navigation module, data acquisition module, hardware control module and function algorithm module The navigation module is composed of a variety of sensors, including multi-beam imaging sonar, depth meter, altimeter, DVL, and electronic compass, which are used to provide the tunnel inspection AUV with underwater position, speed, and attitude information and communicate with the mission controller. In addition, the navigation module is also connected to the GPS module and radio module for real-time positioning when on the water surface and for real-time communication and information exchange with the shore-based monitoring system. The data acquisition module obtains real-time data information from various sensors, navigation equipment and cameras, and performs pre-processing and storage to provide a basis for subsequent control decisions; The hardware control module sends control instructions to various actuators, thrusters, and lights, and monitors their working status and feedback information to ensure the normal operation of the tunnel inspection AUV; The functional algorithm module is used to realize the core functions of the tunnel detection AUV.

3. The energy-saving planning method according to claim 2, characterized in that: The energy consumption of tunnel inspection AUV is divided into variable load energy consumption and controllable energy consumption; The variable load energy consumption is divided into variable energy consumption and load energy consumption; the controllable energy consumption is control energy consumption; The load energy consumption is composed of the equipment and line losses that are fully turned on. The variable energy consumption is composed of power consumption that varies with the operating conditions, which is the propeller power consumption; The control energy consumption is composed of the control law power consumption, which is related to the navigation control law algorithm; Since the task has been determined, the power of all load devices has been determined and classified as load energy consumption; Therefore, the load energy consumption can be expressed as: W1=P1t (1) Where W1 is the load power consumption, P1 is the load power, and t is the operation time.

4. The energy-saving planning method according to claim 3, characterized in that: Added restrictions on the tunnel inspection AUV during its operation; Since the thrust of the propeller is related to the force exerted by the water flow, the relative speed at this time should first be subtracted from the speed of the water flow. The acceleration and deceleration process is related to the mass and the acceleration to be achieved, which can be obtained: Constant speed: F T =140(v c -v auv ) 2 (14) Acceleration and deceleration: F T =ma (15) In a detection process of two adjacent detection points, the total displacement L of the movement is certain, then: For the speed of the AUV, the acceleration can be integrated to obtain: At the two detection points, the starting point and the end point are in the detection state, and the tunnel detection AUV is hovering controlled with the initial velocity v0 and the final velocity v f is 0m / s, then: v0=v f =0 (18) And the thrust generated by the propeller cannot exceed the sum of the maximum thrust that all propellers can generate. According to the arrangement of the propellers: F≤F max (19)。 5. The energy-saving planning method according to claim 4, characterized in that: By analyzing the motion state, force state and energy consumption of the tunnel inspection AUV during its mission, a model of the tunnel inspection AUV's energy consumption is established: The energy consumption W associated with job planning consists of two parts: variable energy consumption W2 and load energy consumption W1: W=W1+W2 (10) The load energy consumption W1 is the energy consumed by the task sensor and the surrounding circuits, which is related to time t and has a linear relationship. A large number of tests are performed to obtain the average value as follows: W1=P1t (11) The variable energy consumption W2 is the energy consumption generated by the propeller when the tunnel inspection AUV is moving. It is related to the time t and the thrust curve of the propeller, as shown in the following formula: The load energy consumption W1 and variable energy consumption W2 of the variable load energy consumption W during the tunnel inspection AUV operation are substituted with the thruster power P2 to obtain:

6. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

7. A computer-readable storage medium for storing computer instructions, characterized in that: When the computer instructions are executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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