阅读说明：本技术 一种基于温差能发电驱动的剖面浮标的发电控制方法 (Power generation control method of profile buoy based on thermoelectric energy power generation driving ) 是由 张国成 祁彧 刘继骁 吴新雨 张家利 张力文 孙玉山 于 2021-08-31 设计创作，主要内容包括：本发明的一种基于温差能发电驱动的剖面浮标的控制及其仿真方法,所述控制及其仿真方法包括以下步骤：步骤一、完成海洋温差能驱动的剖面浮标的总体结构设计；步骤二、海洋温差能驱动的剖面浮标的能耗分析方法；步骤三、根据海洋温差能驱动的剖面浮标运动特点,建立运动学和动力学模型,通过直航阻力试验等测试方法,计算得到水动力系数,进而对剖面浮标进行仿真；步骤四、温差能发电驱动的剖面浮标采用基于改进滑模的剖面浮标深度控制和基于虚拟目标垂直面直线路径跟踪控制方法,并通过仿真试验验证控制方法的有效性。本发明解决了传统的海洋环境观测范围不足问题,同时也解决了水下机器人续航力不足的问题。(The invention relates to a control and simulation method of a profile buoy driven by thermoelectric energy power generation, which comprises the following steps of: step one, completing the overall structural design of the ocean temperature difference energy driven section buoy; step two, an energy consumption analysis method of the profile buoy driven by ocean temperature difference energy; thirdly, establishing a kinematics and dynamics model according to the motion characteristics of the section buoy driven by ocean temperature difference energy, calculating to obtain a hydrodynamic coefficient through testing methods such as a direct navigation resistance test and the like, and further simulating the section buoy; and step four, adopting a section buoy depth control method based on an improved sliding mode and a section buoy linear path tracking control method based on a virtual target vertical plane for the section buoy driven by the temperature difference energy power generation, and verifying the effectiveness of the control method through a simulation test. The invention solves the problem of insufficient observation range of the traditional marine environment and also solves the problem of insufficient endurance of the underwater robot.)

1. A power generation control method of a profile buoy based on thermoelectric energy power generation driving comprises a marine thermoelectric energy heat exchanger, a first area and a second area, wherein the first area comprises an energy accumulator, a hydraulic motor and an inner leather bag, the second area comprises a storage battery, a battery management module, a power generator and an outer leather bag, the marine thermoelectric energy heat exchanger is respectively communicated with the energy accumulator, the inner leather bag and the outer leather bag, the energy accumulator, the inner leather bag and the outer leather bag are respectively communicated with each other, a first one-way valve is arranged on a passage of the energy accumulator and the marine thermoelectric energy heat exchanger, a second one-way valve is arranged on a passage of the inner leather bag and the marine thermoelectric energy heat exchanger, and a second electromagnetic valve and a third electromagnetic valve are respectively arranged on two passages connected with the outer leather bag, a first electromagnetic valve and a hydraulic motor are arranged on a passage between the first area and the second area, the output end of the hydraulic motor is in transmission connection with the input end of the generator, the battery management module and the battery are sequentially and electrically connected, the section buoy driven by the temperature difference energy power generation is in communication remote communication connection with the water surface console and the satellite,

the power generation structure and the control method thereof are characterized by comprising the following steps:

determining design indexes and initial design parameters of a profile buoy driven by thermoelectric energy power generation, completing model selection of main equipment, performing design work of each subunit according to performance requirements of the profile buoy, and selecting a proper design method to complete system design of the profile buoy;

step two, completing energy consumption analysis of the ocean temperature difference energy-driven section buoy to obtain energy consumption parameters of the section buoy power consumption equipment driven by the temperature difference energy, and obtaining energy consumption data of the section buoy driven by the ocean temperature difference energy aiming at the power consumption equipment starting state, the working time and the working energy consumption of six stages in the motion cycle process of the section buoy driven by the ocean temperature difference energy;

establishing a fixed coordinate system and a moving coordinate system fixedly connected with the section buoy driven by ocean temperature difference energy, defining a transformation relation between the fixed coordinate system and the moving coordinate system, then establishing a kinematics and dynamics model of the section buoy, establishing a numerical calculation model, performing a straight navigation resistance test, an oblique navigation test and a plane mechanism movement numerical simulation of the section buoy, and calculating to obtain a corresponding hydrodynamic coefficient;

and fourthly, based on two main working modes of the ocean temperature difference energy driven section buoy, adopting an improved sliding mode-based section buoy depth control method for depth control, adopting a virtual target-based ocean temperature difference energy driven section buoy vertical plane straight line path tracking control method for vertical plane motion control, and verifying the feasibility and superiority of the proposed control method through simulation tests.

2. The power generation control method of the profile buoy based on thermoelectric power generation driving as claimed in claim 1, wherein in the step one, the design indexes of the profile buoy based on thermoelectric power generation driving include maximum submergence depth, working time, weight, buoyancy regulating quantity, power generation quantity of a thermoelectric power generation system, communication mode and task sensor, and the initial design parameters of the profile buoy based on thermoelectric power generation driving include overall layout, appearance design, pressure housing design and electric control unit.

3. The power generation control method of the profile buoy based on thermoelectric power generation driving as claimed in claim 1, wherein in step one, after the design index and the preliminary design parameter of the profile buoy based on thermoelectric power generation driving are determined, the underwater robot motion model is established, comprising the following steps:

establishing a space motion coordinate system;

and step two, establishing a space motion mathematical model according to the space motion coordinate system.

4. The power generation control method of the profile buoy based on thermoelectric energy power generation driving of claim 1, wherein in the second step, the working process of the profile buoy driven by ocean thermoelectric energy comprises a motion cycle and a heat cycle in the motion cycle process.

5. The power generation control method of the ocean temperature difference energy driven profile buoy based on the temperature difference energy power generation as claimed in claim 1, wherein in the second step, the energy consumption analysis of the ocean temperature difference energy driven profile buoy specifically comprises:

the ocean temperature difference energy driving system captures ocean temperature difference energy, converts the heat energy into electric energy and stores the electric energy into the battery, and simultaneously converts the ocean temperature difference energy into mechanical energy for driving the buoy to float upwards and submerge downwards, so that the mechanical energy is converted into heat energy by the buoy floating upwards and submerging downwards and is subjected to heat exchange with seawater;

the electric energy in the battery is output to power consumption equipment for use, the power consumption equipment can generate heat energy when working and exchange heat with seawater, and meanwhile, part of the electric energy in the battery is used for controlling an ocean temperature difference energy driving system;

the motion cycle process of the profile buoy driven by ocean temperature difference energy comprises six stages: a water surface floating stage, a submergence starting stage, a submergence stage, a fixed depth drifting stage, a floating up starting stage and a floating up stage,

in the diving starting stage, the section buoy generates buoyancy force to drive energy consumption, the second electromagnetic valve is opened, hydraulic oil in the outer leather bag flows into the inner leather bag under the action of external seawater pressure, and the power of the electromagnetic valve is constant, so that the energy consumption W in the diving starting stage is_dThe following formula is satisfied:

W_d＝P_dt_d (1)

wherein P is_dIs the power of the second solenoid valve, t_dFor the valve opening time, t, of the submerged start-up phase_dIn relation to the driving liquid volume and the liquid flow rate,

in the stage of upward floating starting, the profile buoy generates buoyancy driving energy consumption, the first electromagnetic valve is opened, hydraulic oil in the energy accumulator flows into the outer leather bag under the action of gas pressure in the energy accumulator, and the power of the first electromagnetic valve is constant, so that the energy consumption W in the stage of upward floating starting_dThe following formula is satisfied:

W_a＝P_at_a (2)

wherein P is_aIs the power of the first solenoid valve, t_aFor the valve opening time, t, of the float-up start phase_aIn relation to the driving liquid volume and the liquid flow rate,

in the water surface floating stage, the ocean temperature difference energy driving system finishes the power generation process, the third electromagnetic valve is opened, hydraulic oil in the energy accumulator flows into the inner leather bag under the action of gas pressure in the energy accumulator, and the power of the third electromagnetic valve is constant, so the energy consumption W in the floating starting stage_mSatisfy the following conditionsThe following formula:

W_m＝P_mt_m (3)

wherein P is_mIs the power of the third solenoid valve, t_mFor the time of opening of the valve during power generation, t_mIn relation to the power generation liquid volume and the liquid flow rate,

in the water surface floating stage, the profile buoy driven by ocean temperature difference energy communicates with a water surface console and a satellite, and energy consumption W generated during communication_cComprises the following steps:

W_c＝P_wt_w+P_it_i (4)

wherein P is_wIs the power of the wireless communication module, t_wOperating time, P, of a wireless communication module_iIs the satellite communication module power, t_iIn order to provide the working time of the satellite communication module,

W_mc＝P_mc(t_ss+t_d+t_dd+t_ds+t_a+t_aa) (5)

wherein t is_ssFor the float floating on the water surface, t_ddFor the submergence time of the buoy, t_dsFor buoy fixed depth drifting time, t_aaThe float floating time is shown.

6. The power generation control method of the profile buoy driven by thermoelectric power generation as claimed in claim 1, wherein in step three, a numerical calculation model is established, specifically:

and (3) establishing a section buoy model driven by ocean temperature difference energy by adopting CATIA three-dimensional modeling software, importing the established model into STAR-CCM + software to carry out surface coating treatment on the model, and carrying out surface reconstruction on the coated model by adopting a surface reconstruction technology.

7. The power generation control method of the profile buoy driven by thermoelectric power generation according to claim 1, wherein in step four, in particular, the depth control of the profile buoy based on the improved sliding mode is adoptedDesigning a control law tau, enabling the system to reach a slide film surface within a limited time, namely s (t) is 0, keeping the system to slide in the slide film surface, adopting a section buoy vertical surface linear path tracking control driven by ocean temperature difference energy based on a virtual target, and proposing a vertical force control rate tau_wAnd pitch moment control rate tau_qApplied to the profile buoy to ensure the speed error e of the profile buoy with speed tracking error_uAnd e_wConvergence to zero, position tracking error xi of profile buoy_eAnd ζ_eBut also converges to zero.

Technical Field

The invention relates to a power generation control method of a profile buoy based on thermoelectric energy power generation driving, and belongs to the technical field of underwater robots.

Background

The total area of the sea reaches 3.6 multiplied by 10⁹km²The area covering 71% of the earth is an extremely important component of the global ecosystem and plays an irreplaceable role in stabilizing the global climate. The ocean is also a huge treasury, contains abundant natural resources, particularly biological resources, oil and gas resources, mineral resources and the like, and still has great development potential. Among them, about 20 million organisms are known in the ocean at present, and abundant biological resources provide food support, medical raw materials, and industrial raw materials for human beings. The seabed contains rich oil and gas resources, wherein the oil reserves are about1.1×10¹²t, accounts for about 30% of the global reserves, wherein the reserves of natural gas are about 1.4 × 10¹⁵m³It accounts for about 50% of the global reserves. A large amount of mineral resources are also stored in the ocean, taking deep sea manganese nodules as an example, the deep sea manganese nodules take oxides and hydroxides of manganese and iron as main components, and are rich in various elements such as manganese, copper, nickel, cobalt and the like. The total reserve of manganese nodules in the ocean is estimated to be 3X 10¹³t. To survive and develop, humans must develop oceans, study oceans, and protect oceans. In the 21 st century, human beings will certainly depend on the ocean more, the ocean is taken as a key development object of new resources and new space, and the ocean has extremely important significance for the future development of human beings.

The exploration of oceans begins in early times, and people are aware of complex and changeable marine environments to greatly hinder people from developing production activities along with the continuous deepening of the exploration of oceans in recent modern times. Observing the ocean is a prerequisite for developing the ocean, researching the ocean, and protecting the ocean. Advanced marine environment observation equipment is needed to obtain comprehensive marine environment data, and the marine environment observation equipment is a field which is very important for all the powerful oceans for a long time, so that a great deal of research work is carried out. The observation devices for ships and ocean stations were mainly adopted in the 60 th to 70 th of the 20 th century, and during this period, the observation devices for ships and ocean stations have been developed greatly. At the end of the 20 th century and the 70 s, ocean observation devices mainly including remote sensing technology and underwater vehicles have been developed. After decades of development, a sea, land and air integrated observation network formed by space-based observation equipment, land-based observation equipment, water surface observation equipment, underwater observation equipment and the like is gradually formed, and the future development trend of the marine observation equipment, such as multiple elements, three-dimensional and real-time, is shown. In an ocean, land and air integrated observation network, the underwater detection equipment section buoy is widely applied to the observation work of the marine environment due to the advantages of low cost, long endurance time, wide detection range and the like. The working mechanism of the section buoy is that the size of the volume of the section buoy is changed through the buoyancy adjusting mechanism, so that the buoyancy of the section buoy is changed, the section buoy floats upwards and submerges by depending on the difference value of gravity and buoyancy because the mass of the section buoy is not changed, and marine environment data such as the temperature, salinity and flow velocity of seawater at different depths are obtained through the sensors carried by the section buoy. At present, most profile buoys are applied to networking of an ARGO global marine observation network, so the profile buoys are also called as ARGO buoys. The ARGO global marine observation network plan aims to achieve the purpose of global networking by putting profile buoys in a large scale, covers a larger ocean area as much as possible, completes the observation of the marine environment in a larger space-time, and can be a major breakthrough of the marine observation technology. The plan of the ARGO global marine observation network is proposed by oceanologists in 1998, experiments are carried out in local sea areas in 1999, the ARGO global observation network is distributed in 2004 on the global scale, and currently, more than 4000 ARGO buoys work at the same time, so that the purpose of global networking observation is achieved. However, the horizontal movement of the section buoy adopts a wave following and flow following mode, and the horizontal mobility is lacked, so that the more detailed environmental data sampling work for a specific ocean area cannot be performed. The traditional profile buoy adopts a power supply carried by the profile buoy to supply power, once the power supply is exhausted, the power supply must be replaced, otherwise, the traditional profile buoy cannot work continuously, the profile buoy can be driven by ocean temperature difference energy, the working time of the profile buoy can be prolonged, and the ocean environment observation work in a wider range is completed.

Disclosure of Invention

The power generation control method of the profile buoy based on the thermoelectric energy power generation driving solves the problem of insufficient observation range of the traditional marine environment and also solves the problem of insufficient cruising power of the underwater robot.

A power generation control method of a profile buoy based on thermoelectric energy power generation driving comprises a marine thermoelectric energy heat exchanger, a first area and a second area, wherein the first area comprises an energy accumulator, a hydraulic motor and an inner leather bag, the second area comprises a storage battery, a battery management module, a power generator and an outer leather bag, the marine thermoelectric energy heat exchanger is respectively communicated with the energy accumulator, the inner leather bag and the outer leather bag, the energy accumulator, the inner leather bag and the outer leather bag are communicated with each other, a first one-way valve is arranged on a passage of the energy accumulator and the marine thermoelectric energy heat exchanger, a second one-way valve is arranged on a passage of the inner leather bag and the marine thermoelectric energy heat exchanger, a second electromagnetic valve and a third electromagnetic valve are respectively arranged on two passages connected with the outer leather bag, a first electromagnetic valve and a hydraulic motor are arranged on a passage between the first area and the second area, the output end of the hydraulic motor is connected with the input end of the generator in a transmission way, the generator, the battery management module and the battery are electrically connected in sequence, the profile buoy driven by the temperature difference energy power generation is in communication and remote communication connection with the water surface control console and the satellite,

the power generation structure and the control method thereof comprise the following steps:

determining design indexes and initial design parameters of a profile buoy driven by thermoelectric energy power generation, completing model selection of main equipment, performing design work of each subunit according to performance requirements of the profile buoy, and selecting a proper design method to complete system design of the profile buoy;

step two, completing energy consumption analysis of the ocean temperature difference energy-driven section buoy to obtain energy consumption parameters of the temperature difference energy-driven section buoy power consumption equipment, and aiming at the power consumption equipment starting states, working time and working energy consumption of six stages in the ocean temperature difference energy-driven section buoy motion cycle process to obtain energy consumption data of the ocean temperature difference energy-driven section buoy;

establishing a fixed coordinate system and a moving coordinate system fixedly connected with the section buoy driven by ocean temperature difference energy, defining a transformation relation between the fixed coordinate system and the moving coordinate system, then establishing a kinematics and dynamics model of the section buoy, establishing a numerical calculation model, performing a straight navigation resistance test, an inclined navigation test and a plane mechanism movement numerical simulation of the section buoy, and calculating to obtain a corresponding hydrodynamic coefficient;

and step four, based on two main working modes of the ocean temperature difference energy driven section buoy, adopting an improved sliding mode-based section buoy depth control method for depth control, adopting a virtual target-based ocean temperature difference energy driven section buoy vertical surface straight path tracking control method for vertical surface motion control, and verifying the feasibility and superiority of the proposed control method through a simulation test.

Further, in the first step, the design indexes of the profile buoy driven by the thermoelectric energy power generation comprise maximum submergence depth, working time, weight, buoyancy regulating quantity, power generation quantity of a thermoelectric energy power generation system, a communication mode and a task sensor, and the initial design parameters of the profile buoy driven by the thermoelectric energy power generation comprise overall layout, appearance design, pressure housing design and an electric control unit.

Further, in the first step, after the design index and the preliminary design parameter of the profile buoy driven by the thermoelectric energy power generation are determined, the motion model of the underwater robot is established, and the method comprises the following steps:

establishing a space motion coordinate system;

and step two, establishing a space motion mathematical model according to the space motion coordinate system.

Further, in the second step, the working process of the ocean temperature difference energy driven section buoy comprises a motion cycle and a heat cycle in the motion cycle process.

Further, in the second step, the energy consumption analysis of the profile buoy driven by the ocean temperature difference energy is specifically as follows:

the ocean temperature difference energy driving system captures ocean temperature difference energy, converts the heat energy into electric energy and stores the electric energy into the battery, and simultaneously converts the ocean temperature difference energy into mechanical energy for driving the buoy to float upwards and submerge downwards, so that the mechanical energy is converted into heat energy by the buoy floating upwards and submerging downwards and is subjected to heat exchange with seawater;

the electric energy in the battery is output to power consumption equipment for use, the power consumption equipment can generate heat energy when working and exchange heat with seawater, and meanwhile, part of the electric energy in the battery is used for controlling an ocean temperature difference energy driving system;

the motion cycle process of the profile buoy driven by ocean temperature difference energy comprises six stages: a water surface floating stage, a submergence starting stage, a submergence stage, a fixed depth drifting stage, a floating upward starting stage and a floating upward stage,

starting under divingStage, the section buoy generates buoyancy force to drive energy consumption, a second electromagnetic valve is opened, hydraulic oil in the outer leather bag flows into the inner leather bag under the action of external seawater pressure, the power of the electromagnetic valve is constant, and therefore the energy consumption W in the diving starting stage is_dThe following formula is satisfied:

W_d＝P_dt_d (1)

wherein P is_dIs the power of the second solenoid valve, t_dFor the valve opening time, t, of the submerged start-up phase_dIn relation to the driving liquid volume and the liquid flow rate,

in the stage of upward floating starting, the profile buoy generates buoyancy force to drive energy consumption, the first electromagnetic valve is opened, hydraulic oil in the energy accumulator flows into the outer leather bag under the action of gas pressure in the energy accumulator, and the power of the first electromagnetic valve is constant, so that the energy consumption W in the stage of upward floating starting_dThe following formula is satisfied:

W_a＝P_at_a (2)

wherein P is_aIs the power of the first solenoid valve, t_aFor the valve opening time, t, of the float-up start phase_aIn relation to the driving liquid volume and the liquid flow rate,

in the water surface floating stage, the ocean temperature difference energy driving system finishes the power generation process, the third electromagnetic valve is opened, hydraulic oil in the energy accumulator flows into the inner leather bag under the action of gas pressure in the energy accumulator, and the power of the third electromagnetic valve is constant, so the energy consumption W in the floating starting stage_mThe following formula is satisfied:

W_m＝P_mt_m (3)

wherein P is_mIs the power of the third solenoid valve, t_mFor the time of opening of the valve during power generation, t_mIn relation to the power generation liquid volume and the liquid flow rate,

in the water surface floating stage, the profile buoy driven by ocean temperature difference energy communicates with a water surface console and a satellite, and energy consumption W generated during communication_cComprises the following steps:

W_c＝P_wt_w+P_it_i (4)

wherein P is_wIs the power of the wireless communication module, t_wOperating time, P, of a wireless communication module_iIs the satellite communication module power, t_iIn order to provide the working time of the satellite communication module,

W_mc＝P_mc(t_ss+t_d+t_dd+t_ds+t_a+t_aa) (5)

wherein t is_ssFor the float floating on the water surface, t_ddFor the submergence time of the buoy, t_dsFor buoy fixed depth drifting time, t_aaThe floating time of the buoy is shown.

Further, in step three, the establishment of the numerical calculation model specifically includes:

a section buoy model driven by ocean temperature difference energy is established by adopting CATIA three-dimensional modeling software, the established model is led into STAR-CCM + software to carry out surface wrapping processing on the model, and the surface of the wrapped model is reconstructed by adopting a surface reconstruction technology.

Further, in the fourth step, specifically, profile buoy depth control based on an improved sliding mode is adopted, a control law tau is designed, so that the system can reach a sliding film surface within a limited time, namely s (t) is 0, the system is kept to slide in the sliding film surface, profile buoy vertical plane straight-line path tracking control driven by ocean temperature difference energy based on a virtual target is adopted, and a vertical force control rate tau is provided_wAnd pitch moment control rate tau_qApplied to the profile buoy to ensure the speed error e of the profile buoy with speed tracking error_uAnd e_wConvergence to zero, position tracking error xi of profile buoy_eAnd ζ_eBut also converges to zero.

The invention has the following beneficial effects: the invention

Drawings

FIG. 1 is a process of ocean temperature difference energy driven profile buoy motion cycle and thermal cycle;

FIG. 2 is a design process of a section buoy driven by ocean temperature difference energy;

FIG. 3 is a schematic diagram of the general structure of a profile buoy driven by ocean temperature difference energy;

FIG. 4 is a schematic diagram of the electric control unit of the profile buoy;

FIG. 5 is an energy flow diagram of a section buoy driven by ocean temperature difference energy;

FIG. 6 is a schematic diagram of an ocean thermal energy drive system.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a power generation control method of a profile buoy driven by temperature difference energy power generation, and the power generation structure and the control method thereof comprise the following steps:

the method comprises the steps of firstly, determining design indexes and initial design parameters of the section buoy driven by thermoelectric energy power generation, completing model selection of main equipment, analyzing a working process, determining a total design scheme, developing design work of each subunit according to performance requirements of the section buoy, and selecting a proper design method to carry out system design of the section buoy.

Step two, completing energy consumption analysis of the ocean temperature difference energy-driven section buoy, and obtaining energy consumption data of the ocean temperature difference energy-driven section buoy according to energy consumption parameters of the section buoy power consumption equipment driven by the temperature difference energy, and aiming at a water surface floating stage, a submergence starting stage, a submergence stage, a depth-fixed drifting stage, a floating-up starting stage and a floating-up stage in the motion cycle process of the ocean temperature difference energy-driven section buoy, wherein the energy consumption parameters of each power consumption equipment in the six motion stages are in an on state, working time and working energy consumption;

establishing a fixed coordinate system and a moving coordinate system fixedly connected with the section buoy driven by ocean temperature difference energy, carrying out related description on the motion parameters of the section buoy, defining the transformation relation between the fixed coordinate system and the moving coordinate system, then establishing a kinematics and dynamics model of the section buoy, establishing a numerical calculation model, carrying out a straight navigation resistance test, an inclined navigation test and a plane mechanism motion numerical simulation of the section buoy, and calculating to obtain a corresponding hydrodynamic coefficient;

and step four, completing a profile buoy depth control method based on an improved sliding mode for depth control based on two main working modes of the profile buoy driven by ocean temperature difference energy, completing a profile buoy vertical plane straight line path tracking control method based on the ocean temperature difference energy of a virtual target for vertical plane motion control, and verifying the feasibility and superiority of the proposed control method through a simulation test.

Further, in the first step, the power generation control method of the profile buoy based on thermoelectric power generation driving is characterized in that design indexes of the profile buoy based on thermoelectric power generation driving include maximum submergence depth, working time, weight, buoyancy regulating quantity, power generation quantity of a thermoelectric power generation system, a communication mode and a task sensor, and initial design parameters of the profile buoy based on thermoelectric power generation driving include parameters such as overall layout, appearance design, pressure housing design and an electric control unit.

Further, in the first step, after the design index and the preliminary design parameter of the profile buoy driven based on the ocean temperature difference energy are determined, a motion model of the underwater robot is established, and the method comprises the following steps:

establishing a space motion coordinate system;

and step two, establishing a space motion mathematical model according to the space motion coordinate system.

Further, in the second step, the working process of the profile buoy driven by the ocean temperature difference energy comprises a motion cycle and a thermal cycle.

The motion cycle process comprises six stages, namely a water surface floating stage, a submergence starting stage, a submergence stage, a fixed depth drifting stage, a floating up starting stage and a floating up stage. The water surface floating stage is the initial state of the whole motion cycle, the antenna of the profile buoy is higher than the water surface when the profile buoy is in the water surface floating stage, the transmission of remote control commands and measurement data is realized through the antenna, and meanwhile, the GPS is utilized to finish positioning, so that the navigation position is corrected. And in the submergence starting stage, the profile buoy reduces the buoyancy of the profile buoy, and when the buoyancy is smaller than the gravity, the profile buoy begins to submerge. In the submergence stage, the section buoy is in a low-energy-consumption operation state, and in the submergence stage, only task sensors such as CTD (computer to digital) and the like and devices related to navigation control are turned on to acquire marine environment data and adjust the position of the section buoy in time. When the profile buoy submerges to a preset depth, a fixed-depth drifting stage is started, and the ocean environment at the specified depth can be observed in detail in the stage, so that more comprehensive and accurate data can be obtained. And after the fixed-depth drifting stage reaches the preset time, starting to enter a floating starting stage, increasing the buoyancy of the profile buoy by the profile buoy, and when the buoyancy is larger than the gravity, starting to float by the profile buoy. And in the floating stage, the section buoy is also in a low-energy-consumption operation state, and in the stage, only task sensors such as CTD (China train digital display) and the like and devices related to navigation control are opened to acquire marine environment data and adjust the position of the section buoy in time until the section buoy returns to the water surface again, so that the motion cycle of the section buoy is finished.

The thermal cycle process of the ocean temperature difference energy driven section buoy is as follows: in the submergence stage, the temperature of the seawater is increased along with the increase of the depth of the seawater of the section buoy driven by ocean temperature difference energy, the temperature of the phase change material carried by the section buoy is higher than the temperature of the external seawater, heat is transferred from the phase change material to the seawater, the phase change material begins to solidify until the solidification is complete, and when the temperature of the phase change material is the same as the temperature of the external seawater, the heat is not transferred any more; in the floating stage, the temperature of the seawater is increased along with the reduction of the seawater where the section buoy is located driven by ocean temperature difference energy, the temperature of the phase change material carried by the section buoy is lower than the temperature of the external seawater, heat is transferred to the phase change material from the seawater, when the temperature exceeds the melting point of the phase change material, the phase change material starts to melt until the phase change material is completely melted, and when the temperature of the phase change material is the same as the temperature of the external seawater, the heat is not transferred any more.

Further, in the second step, the energy consumption of the ocean temperature difference energy-driven section buoy is analyzed as follows:

ocean temperature difference energy driving system catches ocean temperature difference energy, converts heat energy into electric energy and stores the battery, and ocean temperature difference energy driving system still converts ocean temperature difference energy into the mechanical energy that drives buoy come-up and dive simultaneously, and buoy come-up dive can be converted mechanical energy into heat energy, carries out heat exchange with the sea water. The electric energy in the battery is mainly output to power consumption equipment for use, the power consumption equipment can generate heat energy when working, the heat energy is exchanged with seawater, and meanwhile, a part of electric energy in the battery is used for controlling the ocean temperature difference energy driving system. The motion cycle process of the profile buoy driven by ocean temperature difference energy comprises six stages, namely a water surface floating stage, a submergence starting stage, a submergence stage, a fixed-depth drifting stage, a floating starting stage and a floating stage.

In the diving starting stage, the section buoy generates buoyancy driving energy consumption, the electromagnetic valve 2 is opened, and hydraulic oil in the outer leather bag flows into the inner leather bag under the action of external seawater pressure. The power of the electromagnetic valve is constant, so the energy consumption W in the diving starting stage_dThe following formula is satisfied:

W_d＝P_dt_d (1)

wherein P is_dIs the power of the solenoid valve 2, t_dFor the valve opening time, t, of the submerged start-up phase_dRelated to the driving liquid volume and the liquid flow rate.

In the stage of floating starting, the section buoy generates buoyancy driving energy consumption, the electromagnetic valve 1 is opened, and hydraulic oil in the energy accumulator flows into the outer leather bag under the action of gas pressure in the energy accumulator. The power of the electromagnetic valve 1 is constant, so the energy consumption W in the floating starting stage_dThe following formula is satisfied:

W_a＝P_at_a (2)

wherein P is_aIs the power of the solenoid valve 1, t_aFor the valve opening time, t, of the float-up start phase_aRelated to the driving liquid volume and the liquid flow rate.

Float on water surfaceIn the floating stage, the ocean temperature difference energy driving system finishes the power generation process, the electromagnetic valve 3 is opened, and hydraulic oil in the energy accumulator flows into the inner leather bag under the action of gas pressure in the energy accumulator. The power of the electromagnetic valve 3 is constant, so the energy consumption W in the floating starting stage_mThe following formula is satisfied:

W_m＝P_mt_m (3)

wherein P is_mIs the power of the solenoid valve 3, t_mFor the time of opening of the valve during power generation, t_mIs related to the power generation liquid volume and the liquid flow rate.

In the water surface floating stage, the profile buoy driven by ocean temperature difference energy communicates with a water surface console and a satellite, and energy consumption W generated during communication_cComprises the following steps:

W_c＝P_wt_w+P_it_i (4)

wherein P is_wIs the power of the wireless communication module, t_wOperating time, P, of a wireless communication module_iIs the satellite communication module power, t_iThe working time of the satellite communication module.

The main control computer of the profile buoy driven by temperature difference energy needs to work continuously, and the energy consumption of the main control computer is related to the average power of the main control computer and the profile motion cycle time.

W_mc＝P_mc(t_ss+t_d+t_dd+t_ds+t_a+t_aa) (5)

Wherein t is_ssFor the float floating on the water surface, t_ddFor the submergence time of the buoy, t_dsFor buoy fixed depth drifting time, t_aaThe floating time of the buoy is shown.

Similarly, the magnetic compass, the CTD sensor, the endothelial capsule displacement sensor and the water leakage monitoring sensor also need to work continuously, the energy consumption of the devices is related to the average power and the section motion cycle time of the devices, and the basic parameters of the element devices are obtained by the calculation formula.

By simulation analysis of the temperature difference energy driving system and simulation analysis of floating and submerging motions of the section buoy driven by the temperature difference energy, the melting time of a phase-change material in the temperature difference energy driving system is 50 minutes, the solidification time is 533 minutes, the submerging starting time is 0.25 minute, the submerging time is 50 minutes, the floating starting time is 0.083 minutes, the floating time is 12.9 minutes, and the power generation process lasts 15 seconds.

Further, in step three, the establishment of the numerical calculation model specifically includes:

and (3) establishing a section buoy model driven by ocean temperature difference energy by adopting CATIA three-dimensional modeling software, and importing the established model into STAR-CCM + software to perform surface covering treatment on the model. And performing surface reconstruction on the wrapped model by adopting a surface reconstruction technology.

The total length of the section buoy is 2.34 meters, the maximum diameter of the main body is 0.22 meter, a rectangular calculation domain is selected according to experience, and the length, the width and the height of the calculation domain are more than 7 times of the length of the main dimension of the section buoy. The grid generation mode is selected as surface reconstruction, a polyhedral grid generator and a prismatic layer grid generator, the polyhedral grid generator has the advantages of high generation speed and good quality of generated body grids, and the prismatic layer grid generator can better simulate a boundary layer and improve the accuracy of numerical simulation. Parameters such as the thickness of a boundary layer, the basic size, the maximum size of the surface and the like are set, and volume encryption processing is carried out on the areas of the two rudder wings, the top and the tail by adopting a volume control method, so that the change of flow fields of the areas can be better captured, and the accuracy of numerical simulation is improved. And generating the volume grids after the parameters are set, wherein the number of the volume grids is 100 ten thousand.

After the volume mesh is generated, a physical model needs to be selected, and then boundary conditions are determined, wherein the boundary conditions are set as follows:

(1) setting the inlet as a speed inlet boundary condition, and giving turbulence intensity, turbulence viscosity ratio and speed;

(2) the outlet is a pressure outlet, the outlet pressure is 0 relative to the atmospheric pressure given pressure, turbulence intensity and turbulence viscosity ratio, namely no other external pressure acts;

(3) the section buoy is set as a wall boundary condition, shear stress is assigned as no slippage, namely no relative motion between fluid at the wall and the wall, the section buoy is assumed to be fixed in numerical simulation, and the fluid motion speed at the wall is 0;

(4) the boundary condition around the calculation field is set as a symmetry plane, and it is considered that there is no normal velocity on this plane.

Further, in step four, specifically, the method for controlling the depth of the profile buoy based on the improved sliding mode is as follows:

the active control force of the profile buoy driven by ocean temperature difference energy in the vertical direction is the buoyancy change caused by the volume change of the outer oil pocket, the interference of ocean current in the horizontal direction is ignored, only the movement in the vertical direction is considered, and the horizontal movement is ignored. Ocean difference in temperature can driven section buoy receives gravity, buoyancy and the common effect of three power of water resistance at the submergence in-process, and the vertical downward (z axle positive direction) of gravity direction, the vertical upwards (z axle negative direction) of buoyancy direction, water resistance and speed direction are opposite, and ocean difference in temperature can driven section buoy receives resultant force F does:

F＝G+B+f (6)

wherein G is the total gravity of the buoy, B is the buoyancy borne by the buoy, and f is the resistance borne by the buoy.

The buoyancy B experienced by the buoy may be expressed as:

B＝-ρ(z)g(V₀-V(t)) (7)

wherein V₀The initial volume of the buoy, v (t) the volume of the outer skin pocket, and ρ (z) the density of the seawater, as a function of depth.

The submarine motion equation of the profile buoy driven by ocean temperature difference energy can be expressed as follows:

when floating on the water surface, the initial buoyancy force on the buoy is equal to the gravity of the buoy, namely mg ═ rho gV₀. Equation (8) can be rewritten as:

order toA＝M^-1A'，B＝M^-1B'， x＝[w z]^TThe above formula can be rewritten as:

assuming a desired dive velocity w_dAt zero, the desired submergence depth z_dFor constant values, derivatives of desired submergence velocity and depthDefining a submarine speed error w_e＝w-w_dError of depth of dive z_e＝z-z_d，

The sliding surface is designed as

The control law τ is designed to allow the system to reach the synovial surface in a limited time, i.e. s (t) 0, and to keep the system sliding in the synovial surface. By derivation of the formula (11), the result is obtained

The synovial membrane approximation rule was designed as follows:

wherein λ₁＞0，α＞0，β＞0，0＜χ＜1，μ＞0。

Substituting equation (13) into equation (12) can yield:

τ＝(CB)^-1[-CAx-λ₁|s(t)|^αsgn(s(t))-λ₂sgn(s(t))] (14)

considering the shake problem in sliding mode control, the symbolic function is replaced by a boundary layer function, and the expression of the boundary layer function is as follows:

further, in step four, specifically, the cross-section buoy vertical plane straight line path tracking control driven by the ocean temperature difference energy based on the virtual target is as follows:

the three-degree-of-freedom kinematic model of the section buoy driven by ocean temperature difference energy on the vertical plane can be expressed as follows:

the three-degree-of-freedom dynamic model of the ocean temperature difference energy driven section buoy on the vertical plane can be expressed as follows:

the positional error of profile buoy tracking is defined as follows:

in which ξ_dAnd ζ_dThe desired position of the profile buoy.

The derivation of equation (18) and the substitution of the kinematic model (16) yields:

the velocity error of the profile buoy tracking is defined as follows:

wherein u is_dAnd w_dThe desired velocity of the profile buoy. The derivation of equation (20) and substitution of the kinetic model yields:

wherein

The aim is to design a robust control law for vertical forces and pitching moments, and the position of the section buoy can track an expected track. The section buoy vertical plane straight line path tracking control flow is shown in figure 1.

The desired position of the profile buoy is defined as:

the desired velocity of the profile buoy is expressed as:

wherein k is_ξ＞0，k_ζ＞0，l_ξ＞0，l_ζ＞0。

If the velocity error e of the profile buoy_uAnd e_wConvergence to zero can ensure the position tracking error xi_eAnd ζ_eAlso convergeTo zero. The model of the profile buoy vertical plane motion can be obtained as follows:

substituting (17) and (18) into (14) can obtain:

whereinIs a non-singular matrix. Assuming the velocity error e of the profile buoy_uAnd e_wConverge to zero to causeAndconverging to zero, one can get:

the next step is to demonstrate the position tracking error xi_eAnd ζ_eConverging to zero, the Lyapunov function is designed as follows:

derivation of the Lyapunov function (21) and substitution of (26) yields:

because k is_ξ＞0，k_ζ＞0，l_ξ＞0，l_ζ> 0, can giveSo the position tracking error xi_eAnd ζ_eConverging to zero. The next step is to demonstrate the velocity error e of the profile buoy_uAnd e_wConverging to zero. Slide membrane surfaces were designed as follows:

wherein λ₁，λ₂Is greater than 0. By deriving equations (29) and (30) and substituting equation (21):

by substituting equation (17) into equation (31), the following can be obtained:

wherein

The synovial membrane approximation rule is designed as follows:

wherein k is₁，k₂，W₁，W₂＞0。

By substituting the formula (34) into the formula (33) and the formula (35) into the formula (32), the vertical force control rate τ can be obtained_wAnd pitch moment control rate tau_qThe expression is as follows:

considering the profile buoy motion models in the vertical plane described by equations (16) and (17), the velocity tracking error is defined as equation (20), and the desired velocity is selected as equation (23). The vertical force control rate τ given by the equations (36) and (37)_wAnd pitch moment control rate tau_qApplied to the profile buoy, ensures the speed error e of the profile buoy with speed tracking error_uAnd e_wConverging to zero. In addition, position tracking error ξ of the profile buoy_eAnd ζ_eBut also converges to zero. The following demonstrates that the definition of the Lyapunov function V₃The following were used:

the derivation of equation (38) can be:

by substituting formula (31) and formula (32) for formula (33):

by substituting formula (36) and formula (37) into formula (38), the following can be obtained:

from the formula (41), when(s)₁,s₂) When the signal is not equal to (0,0),the slip film surfaces represented by the equations (29) and (30) can converge to zero. Satisfies s on the slide film surface₁＝s₂When the ratio is 0, formula (42) and formula (43) can be obtained:

because of lambda₁，λ₂The speed error e of the profile buoy with the speed tracking error is ensured to be more than 0_uAnd e_wConverging to zero. Thereby ensuring the position tracking error xi of the section buoy_eAnd ζ_eBut also converges to zero.