RU2609849C1 - Autonomous drifting profiling oceanologic buoy - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: autonomous drifting profiling oceanologic buoy contains a streamlined sealed rugged housing, made in the form of a cylinder. On the top cover of the body the aerial navigation and communication systems, sensors of electrical conductivity, temperature and pressure are installed. Outside on the bottom cover the expansion container is installed. Inside the housing tank with hydraulic fluid, connected by the hydraulic lines to the expansion container, electric pump and power supply are mounted. The pump is fixed on the inner side of the bottom cover for injection and selection of working fluid into the expansion container from the tank installed inside the housing. In the central part of the housing the electronic control unit and a linear actuator, on which is fixed the power unit with the possibility of moving up and down at a distance of 50-100 mm are mounted.

EFFECT: possibility of increasing the number of obtained oceanologic data.

2 cl, 5 dwg

Description

The technical field to which the invention relates.

The invention relates to the field of underwater robotics, in particular to the technique of studying and developing the ocean, to autonomous and automated underwater vehicles of a drifting, profiling type - buoys.

The level of technology.

Thanks to the ARGO program, autonomous drifting diving (profiling) buoys (“ocean profiling floats” or “Argo Profiling Floats”) have become the main instrument for deep-sea measurements of the thermohaline structure and climate trends in the oceans (Roemmich, D., Owens WB The Argo Project : Global ocean observations for understanding and prediction of climate variability. Oceanography, 2000, 13, No. 2 (NOPP Special Issue), 45-50). A few years after the start of the ARGO program in the late 1990s. the ratio of the number of vertical profiles of salinity, temperature, and water pressure obtained by autonomous profiling buoys and vessels was 5: 1 (Gould, J., and the Argo Science Team, 2004. Argo profiling floats bring a new era of in situ ocean observations. EoS, Transactions of the American Geophysical Union, 85 (19), 11 May 2004). The importance of autonomous buoys for ocean research and monitoring continues to grow, as evidenced by the financing of major new projects, such as AtlantOS (https://www.atlantos-h2020.eu/), for operational oceanography and scientific research of the World Ocean.

Drifting profiling buoys perform several functions, the main of which are as follows:

- carry out measurements of vertical profiles of oceanological characteristics;

- determine the speed and direction of transport in the system of currents on isopycnic surfaces in the water column as quasi-Lagrangian drifters;

- carry out monitoring of underwater noise when equipping them with hydroacoustic equipment;

- determine their geographical coordinates, being on the surface of the water, and transmit measurement data via satellite channels.

A known thermal buoy including a robust cylindrical body comprising an instrument container and a steel bellows abutting against one side wall of a cylindrical body, further comprising a steel spring sandwiched between the second end wall of the bellows and the opposite side wall of the cylindrical the housing, as well as a stopper interacting with the stem rigidly connected to the second end wall of the bellows and hermetically connected to this bellows, the bellows m nshego diameters, the total internal space of the bellows filled easily evaporable liquid in equilibrium with its vapor, and the opposite end rigidly connected to the bellows wall rod passing through their common inner cavity (RU 2137662, 20.09.1999). However, such thermal devices are not reliable enough to change the buoyancy of the buoy due to the fact that the vertical gradients of the water temperature in the ocean are insignificant at moderate latitudes in the cold half-year.

Today, the most reliable are the ARGO buoys, which were created as a result of more than 20 years of work on the development of oceanographic buoy technology by US specialists with the support of the National Science Foundation and the US Naval Research Directorate.

The ARGO buoy has a cylindrical shape. Oceanological meters, including temperature, conductivity and pressure sensors, as well as antennas for navigation and communication systems, are installed on the top cover outside the buoy's hull. In the upper part of the buoy there is also an expansion tank for air, which is pumped out of the body when it ascends to the surface in order to raise the antennas above the water. On the bottom cover outside the buoy housing there is an expansion tank for the working fluid of the hydraulic immersion / ascent system. For ascent, the working fluid is pumped into this tank from a single-cylinder piston pump located inside the buoy body, as a result of which the total volume of the buoy increases and, accordingly, the Archimedean force increases, pushing the buoy up to the surface of the water. For immersion, the working fluid is pumped back inside the piston, while the volume of the buoy decreases, the Archimedean force becomes less than gravity, and the buoy is immersed in the water column. Most of the immersion / ascent cycle, usually up to 10 days, the buoy is under water at the drift horizon, usually set to 1000 m or 2000 m. The buoy's working position is vertical. The design of a single-cylinder piston pump allows you to change the weight of the buoy in the water with an accuracy of 10 ^-3 kg. Such accuracy is necessary for the buoy to reach a given horizon in the water column. The fact is that near the 2000 m horizon, which is often set as the buoy drift horizon, the vertical gradient of water density is usually insignificant, for example, in the North Pacific Ocean it is about 5⋅10 ^-3 kg / m ³ . Under these conditions, the APEX type ARGO buoy, having a volume of 25 liters, sinks by 12.5 meters with an increase in its weight by 10 ^-3 kg. That is, theoretically, an error in adjusting the weight of the buoy of ± 10 ^-3 kg leads in this area to an error of reaching the drift horizon of ≈10 m. In practice, the error of reaching the horizon of 2000 m of the ARGO buoy often reaches 50 m (Laughlin Barker, Santa Clara University Closed - loop buoyancy control for a Coastal Profiling Float Mentor: Gene Massion Summer 2014, found May 10, 2015 at http://www.mbari.org/education/internship/14interns/2014_papers/Barker_Laughlin.pdf). This technical solution was made by us for the closest analogue.

When working with the ARGO buoy, much attention is paid to the accurate balancing of the buoy, taking into account the vertical distribution of the water density and the coefficient of thermal expansion of the aluminum alloy of the buoy hull at characteristic values of the water temperature in the drift area. For profiling in the ocean, the volume of the APEX ARGO buoy varies within 260 cm ³ . The buoy rises slowly, because the Archimedean force is partially compensated by the resistance to the movement of the buoy in the water. It takes 5-7 hours to float a buoy from a horizon of 2000 m. A low buoy ascent rate is necessary to ensure high accuracy in determining salinity. 90% of the buoys of both APEX and AVROR, also operating under the ARGO program, are equipped with temperature, electrical conductivity and pressure meters SBE 41 / 41CP CTD (up to 1000 units annually). Being installed on the top cover of the buoy body, these sensors allow measurements in an undisturbed water environment when the buoy rises to the surface of the water. The CP version of the SBE CTD41 meter appeared in 2008 and is a perfect oceanological instrument providing high accuracy and stability of water salinity data. The conductivity sensor is characterized by an accuracy of determining salinity of water equal to 0.005 practical units of salinity during 3 years of operation. The temperature, electrical conductivity and pressure meter, as well as the oxygen sensor, are switched on only in the lifting areas. In the descent sections, thermohaline characteristics are not recorded, mainly due to the fact that measurements are taken in a satellite track over the buoy and the data quality inevitably decreases.

Thus, due to the fact that the temperature, electrical conductivity and pressure meters are turned off in the sections of the descent of the buoy, the amount of data that could be obtained during the dive / ascent cycle is halved, although the operation of the hydraulic immersion / ascent system is also spent on the descent of the buoy. Consequently, the specific amount of data received per unit of electric capacity of the battery is underestimated, which is irrational. In order to increase the amount of data by 2 times per dive / ascent cycle, the buoy must float up with the sensors, and down with the same sensors, i.e. rotate in a vertical plane 180 ° at the lower and upper points of the trajectory of profiling. In this case, oceanographic measurements will be carried out in an unperturbed medium along the entire path of the buoy profiling.

We have solved the problem of moving the buoy with the sensors forward when profiling in the water column due to the possibility of its rotation by 180 ° at the upper and lower points of the trajectory of the buoy (that is, float with the sensors up, and dive with the same sensors down).

SUMMARY OF THE INVENTION

The technical result of the claimed invention consists in a 100% increase in the volume of oceanographic measurement data by an autonomous drifting profiling buoy in an unperturbed medium during an immersion / ascent cycle by 180 ° turning the buoy in the vertical plane at the upper and lower points of its trajectory.

The technical result is achieved by creating an autonomous drifting, profiling oceanological buoy containing a streamlined sealed strong body made in the form of a cylinder, an antenna for navigation and communication systems, conductivity, temperature and pressure sensors are installed on the top cover of the body, and outside on the bottom cover of the body an expansion tank is installed, a reservoir with a working fluid is mounted inside the housing, connected by hydraulic lines to an expansion tank, an electric pump c, a power supply unit connected electrically to all buoy systems, and an electronic control unit for the buoy systems, while the electric pump is fixed on the inside of the bottom cover and provides pumping and selection of the working fluid along the hydraulic lines into the expansion tank from the reservoir with the working fluid installed inside the housing near the top cover, and in the central part of the housing there is an electronic control unit and a linear actuator on which the power supply is mounted with the ability to move it up and down to a distance of 50-100 mm.

The technical result is also achieved by the fact that an autonomous drifting, profiling oceanological buoy was created, containing a streamlined sealed strong body made in the form of a cylinder, an antenna for navigation and communication systems, conductivity, temperature and pressure sensors were installed on top of the body cover, and on the bottom cover an expansion tank is installed outside the housing; a reservoir with a working fluid is mounted inside the housing; it is connected by hydraulic lines to an expansion tank; a pump, a power supply unit, electrically connected to all buoy systems, and an electronic control unit for buoy systems, while the electric pump is secured from the inside of the bottom cover and provides pumping and selection of the working fluid along the hydraulic lines to the expansion tank from the reservoir with the working fluid installed inside the housing near the top cover, and under the reservoir with the working fluid and above the electric pump, ballast tanks are installed, between which an additional electric sos pumping ballast fluid along hydraulic lines between ballast tanks.

A brief description of the drawings.

In FIG. 1 is a drawing of a general view of an oceanological diving buoy in which the displacement of the center of mass is carried out using an electric linear actuator.

In FIG. 2 is a drawing of a general view of an oceanological diving buoy, in which the center of mass is displaced by an additional electric pump pumping liquid between ballast tanks located in the upper and lower parts of the buoy’s solid body.

In FIG. 3 shows a diagram of a device for ensuring vertical orientation of a buoy when its buoyancy changes with an additional system of longitudinal ballast movement inside the buoy body. The dotted line shows the level of the working fluid in the inner tank and the increased expansion capacity when the buoy emerges.

In FIG. Figure 4 shows the working scheme of a drifting oceanological buoy, in which profiling in the water column is carried out in the position by the sensors forward, with a 180 ° flip (floating up with the sensors up and immersing the same sensors down) in order to provide oceanological measurements in an undisturbed environment.

Detailed Description of the Invention

In the first embodiment (see Fig. 1), an autonomous drifting profiling oceanological buoy contains a streamlined sealed strong body (1), made in the form of a cylinder with hemispherical tips to reduce hydrodynamic resistance. Oceanological meters (3) are installed on the top cover (2) outside the case (1) - temperature, electrical conductivity and pressure sensors, as well as antennas for navigation and communication systems (4). On the bottom cover (5) outside the housing (1), under the plastic cowl (6), an expansion tank (7) for the working fluid of the hydraulic immersion / ascent system is fixed. On the same bottom cover (5), an electric pump (8) is installed on the inside, which provides pumping and selection of the working fluid through the hydraulic lines into the expansion tank (7) from the reservoir with the working fluid (9) located inside the durable housing (1) near top cover (2). In the central part of the robust housing, a power supply unit (10) and an electronic control system for the buoy systems (11) are mounted electrically connected to all buoy systems. Also, a linear actuator (12) is mounted inside the strong housing (1) in its central part, on which the power supply unit (10) is mounted with the possibility of moving it up and down by a distance sufficient to provide a center of mass displacement for turning the buoy by 180 ° the upper and lower points of the trajectory of the buoy.

In the second embodiment (see Fig. 2), an autonomous drifting, profiling oceanological buoy to provide a center of mass displacement and its revolution by 180 ° at the upper and lower points of the buoy trajectory in the central part of the hull (1) under the reservoir with the working fluid (9) and above the electric pump (8), ballast tanks (13) are placed, between which an additional electric pump (14) is fixed, pumping ballast fluid along hydraulic lines between the ballast tanks (13).

Suppose that in the coordinate system associated with the buoy the Z axis is directed upwards, then in order to rotate the buoy in a vertical plane by 180 °, it is necessary to ensure such a movement of the center of mass relative to the center of displacement so that the first is lower than the second when descending: Zm.m> Z .v., and when lifting - vice versa: Zts.m. <Zts.v. Moreover, in a stable position, the angle between the longitudinal axis of the buoy and its vertical axis tends to 0 °, the center of mass and the center of displacement should be located on the longitudinal axis of the buoy: Хц.m. = Хц.в. and Ym.m. = Yv.v.

The internal reservoir with the working fluid of the hydraulic immersion / ascent system is located in the vicinity of the displacement center so that when the buoy emerges, the level of the working fluid in the inner tank drops and, as a result, the center of mass drops, and when the buoy is immersed, the working fluid fills the inner tank and the center of mass rises . When the level of the working fluid in the internal reservoir reaches the position, Zy.p.zh., at which Zц.м. = Zц.в., the buoy is in unstable equilibrium, in which, as a result of local external influence on the side surface of the hull, the buoy turns over , for example, in a turbulent zone in the water column or under the influence of orbital motion in a wave (see Fig. 4).

. Эти условия позволяют провести равноценные по качеству измерения полных вертикальных профилей термохалинных характеристик с помощью стандартного измерителя температуры, электропроводности и давления, например SBE 41/41CP CTD, как на траектории подъема, так и на траектории спуска буя.Under optimal conditions, the buoy should roll over at the moment of the start of the dive or ascent through an infinitely small time interval after changing the sign of its own buoyancy:

. These conditions make it possible to carry out equal quality measurements of the full vertical profiles of thermohaline characteristics using a standard temperature, conductivity and pressure meter, for example, SBE 41 / 41CP CTD, both on the ascent path and on the descent path of the buoy.

, совпал с моментом t_{плавучесть=0} перехода плавучести от положительной к отрицательной, или наоборот, с учетом того, что вертикальные профили плотности воды меняются в зависимости от географического положения буя и сезона. Поэтому мы использовали дополнительную систему продольного перемещения балласта внутри корпуса буя (см. фиг. 3а, 3б).In practice, it is necessary to ensure that the instant of the onset of the state of unstable equilibrium of the buoy,

, coincided with the moment t _{buoyancy = 0} transition of buoyancy from positive to negative, or vice versa, taking into account the fact that the vertical profiles of the density of water vary depending on the geographical position of the buoy and the season. Therefore, we used an additional system of longitudinal ballast movement inside the buoy body (see Figs. 3a, 3b).

Using the control system, we achieved synchronization of the time of the change in the position of the center of mass with the time of the change in the position of the center of displacement, which ensured the buoy to turn 180 ° at the lower and upper points of the trajectory of profiling regardless of the density of water in the water area.

Based on this model, we maximized the amount of oceanological data obtained in one profiling work cycle. At the same time, the volume of these measurements increased by 2 times in comparison with the closest analogue (ARGO buoy).

The device operates as follows.

Before launching the buoy into the water, the working fluid is in the tank (9) and the center of mass is shifted to the top cover (2). With this combination, the buoy has negative buoyancy and is immersed forward by sensors (3). During the period when the buoy is immersed, the sensors accumulate the data of measurements of electrical conductivity (salinity), temperature and pressure in an undisturbed medium. Upon reaching the specified depth, controlled by a pressure sensor (3), the control unit (11) issues a command to the electric pump (8) for pumping the working fluid along the hydraulic lines from the tank (9) to the expansion tank (7) and to the device moving the center masses to the bottom cover (5).

In the first embodiment, the control unit (11) issues a command to the electric linear actuator (12), along which the ballast is moved - the power supply unit (10), which always has a significant mass sufficient to turn the buoy through 180 °. The actuator (12) allows linear ballast movement both up and down over a considerable distance (for example, 50-100 mm).

In the second case, the center of mass is shifted due to the ballast pump (14) pumping ballast fluid along the hydraulic lines between the ballast tanks (13) located in the upper and lower parts of the buoy’s strong body (1). This ballast in the form of ballast tanks (13) and ballast liquid also has a mass sufficient to turn the buoy 180 °.

As a result of the presence in the first and second embodiments of the invention of additional structural elements that move the center of mass, the buoy turns over in a vertical plane by 180 ° and acquires positive buoyancy by increasing the total volume of the buoy. The buoy begins to float to the surface of the water ahead with sensors (3).

When the surface is reached, the buoy determines its coordinates using a satellite navigation system, such as GPS, and transmits the accumulated data over the air. After the end of the radio communication session, the control unit (11) issues a command to shift the center of mass to the top cover (2). The buoy is turned 180 ° and after that the electric pump (8) is turned on to pump the working fluid from the expansion tank (7) into the tank (9). Having received negative buoyancy, the buoy begins to sink and the next dive / ascent cycle begins. Profiling of the aquatic environment each time occurs in the position of the sensors (3) forward, which provides oceanological measurements in an undisturbed environment. Thus, oceanological measurements are carried out in an unperturbed medium along the entire trajectory of the buoy profiling, that is, both during ascent and when diving.

The claimed autonomous drifting, profiling oceanological buoy provides mobility of the vertical position of the center of mass relative to the center of displacement of the buoy as a result of the following.

The longitudinal ballast displacement system inside the buoy body is made using in the first case: a linear actuator that moves the ballast - a power supply unit (10) (see Fig. 3a) and in the second case - a ballast pump (14) pumping ballast fluid between ballast tanks ( 13) located above and below the center of displacement of the buoy (see Fig. 3b).

Thus, the claimed invention, providing a buoy flip in the vertical plane by 180 ° at the upper and lower points of the trajectory of its profiling, allows to increase the amount of obtained oceanological measurement data by 2 times per dive / ascent cycle.

Claims (2)

1. An autonomous drifting profiling oceanological buoy containing a streamlined sealed robust housing made in the form of a cylinder, an antenna for navigation and communication systems, conductivity, temperature and pressure sensors are installed on the top cover of the body, and an expansion tank is installed on the bottom cover of the case, inside the case mounted reservoir with working fluid connected by hydraulic lines with expansion capacity, electric pump, power supply unit, electrically connected to all buoy systems, and an electronic control unit for buoy systems, characterized in that the electric pump is fixed on the inside of the bottom cover and provides pumping and selection of the working fluid along the hydraulic lines into the expansion tank from the reservoir with the working fluid installed inside the housing near the top cover, and an electronic control unit and a linear actuator are mounted on the central part of the housing, on which a power supply is fixed with the possibility of moving it up and down to a distance of 50-100 mm. 2. An autonomous drifting profiling oceanological buoy containing a streamlined, sealed robust housing made in the form of a cylinder, an antenna for navigation and communication systems, conductivity, temperature and pressure sensors are installed on the top cover of the body, and an expansion tank is installed on the bottom cover of the body, inside the body a reservoir with a working fluid is mounted, connected by hydraulic lines with an expansion tank, an electric pump, a power supply unit, electrically connected to everything buoy systems, and an electronic control unit for buoy systems, characterized in that the electric pump is fixed on the inside of the bottom cover and provides pumping and selection of the working fluid along the hydraulic lines into the expansion tank from the reservoir with the working fluid installed inside the housing near the top cover, and under ballast tanks are installed between the working fluid reservoir and above the electric pump, between which an additional electric pump is installed, which pumps ballast fluid through The hydraulic highways between the ballast tanks.

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