KR101260389B1 - A multi-legged seabed walking robot for survey of high current and high turbidity underwater environment - Google Patents

Abstract

Unlike conventional submarine robots that propel thrust by propeller method, multi-joint seabed walking is a new concept that moves with walking legs close to the sea floor by using legs consisting of several joints and is equipped with a means of overcoming a bad watch such as an ultrasonic camera. The robot starts.
Multi-joint seabed walking robot according to the present invention is a streamlined body; A multi-jointed walking leg having a plurality of pairs mounted on the left and right sides of the body and composed of a plurality of joints; Control means mounted in the body and controlling a walking state through the articulated walking leg; Walking leg driving means controlled by the control means for generating a driving signal for driving the articulated walking leg; Sensing means mounted in the body to sense a posture of the body and contact with an external object; And communication means for transmitting and receiving wired and wireless signals with an external device.

Description

A MULTI-LEGGED SEABED WALKING ROBOT FOR SURVEY OF HIGH CURRENT AND HIGH TURBIDITY UNDERWATER ENVIRONMENT}

The present invention relates to a multi-joint seabed walking robot, and more specifically, unlike a conventional seabed robot that obtains thrust by a propeller method, it is able to walk on the sea bottom using a leg composed of several joints, and move and walk on the sea bottom. The present invention relates to a new articulated undersea walking robot capable of overcoming algae while controlling the landing posture by landing on the ground.

The average depth of the sea is 3800m, which occupies 99% of the space where life can live on Earth, and the deep sea occupies 85% of this space, but humans have not yet observed 1% of the deep sea. In addition, the number of species of life that has not yet been found on the earth is estimated at 10 million to 30 million, and only 1.4 million have been found to date. The vast majority of species not yet discovered live in the oceans. This is a testament to the fact that in the last 25 years, a new life has been discovered in the deep sea on average every two weeks. In addition, due to the depletion of terrestrial resources, deep sea oil and gas drilling projects are increasing every year from 2% of total oil production in 2002 to 8% in 2009, and are expected to reach 15% in 2015. In 2009, the Ministry of Land, Transport and Maritime Affairs and four private companies will form a 'undersea hydrothermal deposit development project group' and will start full-scale commercial development in 2012 in Tonga. As such, the oceans are of great exploration value, but dangerous marine environments do not allow humans to easily access them. Unmanned submarine robots are being developed as an alternative to these problems, and they have been widely used all over the world until now, and their scope of use is expanding. Submarine robots can be divided into autonomous unmanned submersibles (AUVs), which mainly explore large areas, and remote unmanned submersibles (ROV), which perform precise operations in relatively narrow areas, and most submarine robots propel propellers. I use it. Propellers have been used as underwater propellers for a long time, and the theory of their propulsion mechanisms is well established and, in certain areas, their efficiency is also high. However, the west coast of Korea has a lot of difficulties in precision operation of the seabed with propeller-propelled submarine robots, which are generally used as a special area where tidal wave difference is big, tide is high, and clock is bad. In addition, when the site is closely investigated deep seas consisting of sedimentary soils, disturbance of the seabed due to propeller flow may be a problem.

There are two different types of submarine robots, one with a crawler and the other with a bridge. Lobster robots have been developed as part of bio simulation studies [Joseph, A. (2004). "Underwater walking", Arthropod Structure & Development Vol 33, pp 347-360.]. Through this, we analyzed the kinematic structure and gait of the crawfish and implemented a central controller based on artificial muscle actuators and command neurons. The robot focuses on biomimetic recognition and gait research rather than actual work. In addition, amphibious six-legged walking robots have been studied for the purpose of investigating shorelines [Tanaka, T., Sakai, H., Akizono, J. (2004). "Design concept of a prototype amphibious walking robot for automated shore line survey work", Oceans '04 MTS / IEEE Techno-Ocean '04, pp 834-839.]. The robot developed a waterproof underwater joint, and improved the robot several times to reduce the weight. However, the focus on expanding land-based robots underwater has not been a positive approach from a hydrodynamic perspective. On the other hand, amphibious robots with six pedals designed to walk and walk using pedals have been developed, but each pedal is a simple form of one degree of freedom and is not a form of a multi-joint multipedal robot [Christina, G., Meyer, N., Martin, B., "Simulation of an underwater hexapod robot," Ocean Engineering, Vol 36, pp 39-47, 2009, Theberge, M. and Dudek, G., "Gone swimming [seagoing robots]", IEEE spectrum, Vol 43, No 6, pp 38-43, 2006.].

Underwater robots, also known as unmanned underwater vehicles (UUVs), are largely divided into autonomous unmanned submersibles (AUVs) and remote unmanned submersibles (ROVs). Autonomous unmanned submersibles are mainly used for scientific investigations or exploration covering an area from hundreds of meters to hundreds of kilometers. Most AUVs developed to date are used for scientific research or military purposes. Remote unmanned submersibles are used for underwater surveys and precision work with positional precision of several tens of centimeters or less. Remote unmanned submersibles are used for various tasks such as submarine cable laying, subsea pipelines and maintenance of subsea structures.

The applications of remote unmanned submersibles are summarized as follows. (1) exploration and salvage of sunken ships and prevention of oil spills due to sunken ships; (2) marine scientific research and marine resource exploration and development; (3) installation of subsea structures, investigation support and maintenance; and (4) military purposes such as mine exploration and mine removal. Is utilized.

Submarine remote unmanned submersibles gain mobility in two main ways. First, the propeller method is effective in the molds such as AUV, but it is not easy to obtain control stability in ROV which requires precise work. This is because the fluid force acting on the ROV in water is nonlinear, and the thrust also has strong nonlinearity such as deadband, response delay, and saturation. In particular, it is difficult to secure posture stability and mobility when exposed to strong currents such as tidal currents on the west coast of Korea, which makes it difficult to obtain positional precision, operational precision, and clear ultrasound images. The direction of algae changes four times a day, and the maximum flow rate of algae in Korea is 3 to 7 knots. In conventional submersibles using propellers, there are problems such as unstable maneuverability and high energy consumption in a strong algal environment.

Second, the caterpillar type propulsion method is difficult to travel irregular seabed terrain or obstacle area and has the disadvantage of disturbing the seabed due to the characteristics of the driving method. The seabed has difficulty in traveling in the caterpillar system because there are always various obstacles such as sunken ships, fishing grounds, ropes, and closed nets, and seabed topography such as reefs and soft ground. In addition, there are many in-situ surveys that need to be conducted while minimizing disturbance in an undisturbed environment in the case of subsea surveys, but there is a problem that it is difficult to use them for this purpose.

The technical limitations or problems of the existing subsea work are summarized as follows.

Safety issues

If divers are involved in the work, there are safety risks from divers and other hazards.

Work time problem

When divers work, the time to work without decompression is limited to 30 minutes at 21m depth and 5 minutes at 40m.

Bird problems

The direction of algae changes four times a day, and the maximum flow rate of algae in Korea is 3 to 7 knots. For divers as well as for underwater robots, algae is the most difficult and dangerous object to overcome. In a conventional submersible using a propeller, there are problems such as unstable maneuverability and high energy consumption inevitably in a strong algal environment.

Clock  Problem

One of the characteristics of the West Sea is the bad clock. Depending on the region and time, there are many places where the clock is only 20-30cm.

Obstacles and Irregular Undersea Issues

In the seabed, there are always obstacles such as sunken ships, fishing grounds, ropes, and waste nets, and irregular seabeds such as reefs, which prevents divers and submarine robots from working and even threatens lives.

Environmental interference problem

A propeller or caterpillar submarine robot inevitably disturbs the seabed. In the case of seabed surveys, there are many surveys that must be conducted in an undisturbed environment.

The biggest limitations and problems of the existing submarine work techniques using robots (unmanned submersibles) can be summarized as strong tides and clocks. In the case of Haemirae (L3.3m × W1.8m × H2.2m), which is a remote unmanned submersible for the subsea operation using the propeller method, it receives about 200kg of resistance in 2 knots of birds, and a 200m diameter 20mm cable has a resistance of about 240kg. Receive. To overcome this, increasing thrust leads to an increase in overall weight and size, which is not a fundamental solution.

Underwater propeller type robots in the related art have difficulty in obtaining stable attitude control characteristics required for subsea operations due to the response delay and nonlinear characteristics of the propeller itself. In particular, the input itself is almost impossible in the strong seas such as the west coast of Korea. In the case of underwater robot, which moves to the endless track, which is another method of movement, it is not easy to maintain the position by being pushed by the birds in the heavy current environment, and it is impossible to control the attitude in the water. There is a problem inevitably accompanied by disturbance of the seabed by the orbit. In addition, the west coast of Korea has a problem that it is impossible to check and work in the subsea environment with the underwater robot equipped only with the conventional optical camera because most of the bad clock environment has a poor turbidity.

One object of the present invention is to overcome the problems of the conventional propeller method or the caterpillar method, the articulated seabed that can overcome the high tidal current through posture control and seabed close walking and explore the seabed environment. It is to provide a walking robot.

Another object of the present invention is to provide a multi-joint seabed walking robot that can work while recognizing the surrounding environment in a seabed with poor visibility, such as the west coast of Korea, and performs the underwater movement function while minimizing the disturbance of the seabed. It is.

Multi-joint seabed walking robot according to an embodiment of the present invention for achieving the above object is a streamlined body; A multi-jointed walking leg having a plurality of pairs mounted on the left and right sides of the body and composed of a plurality of joints; Control means mounted in the body and controlling a walking state through the articulated walking leg; Walking leg driving means controlled by the control means for generating a driving signal for driving the articulated walking leg; Sensing means mounted in the body to sense a posture of the body and contact with an external object; And communication means for transmitting and receiving a signal with an external device.

Preferably, the front of the body is characterized in that the ultrasonic camera is mounted.

Also preferably, the sensing means comprises a posture and a motion measuring sensor.

Also preferably, the sensing means comprises an underwater position tracking device.

Also preferably, it includes a photographing means mounted on the front of the body to take an underwater image, wherein the photographing means is a pan / tilt function underwater camera and lighting device.

Also preferably, the communication means is connected to the shock absorber through the optical fiber and the power cable built-in secondary cable.

Also preferably, the body is characterized in that made of lightweight high strength composite fiber material.

Also preferably, the sensing means is characterized in that it comprises a force / moment sensor installed on the bottom of the body of the subsea robot.

Also preferably, the sensing means is characterized in that it comprises a grounding force sensor which is installed at the tip of the leg of the subsea robot to perform the ground detection.

Also preferably, the walking leg driving means includes a motor driving unit for generating a motor driving signal; First to N-th electric motors operating according to signals of the motor driver; And first to N-th speed reducers operated according to the electric motors and connected to the articulated walking legs to transfer the motions of the respective electric motors.

The articulated undersea walking robot according to the present invention is a submarine robot composed of six legs, which is a completely different concept from propeller propulsion, and lands and moves six legs in close contact with the sea floor and maintains posture using a posture and a motion sensor. While overcoming algae and walking on the sea is effective.

In addition, the multi-joint seabed walking robot according to the present invention is equipped with ultrasonic imaging equipment can be searched in the water with high turbidity, and the front two legs are also used as a robot arm, thereby improving the function.

1 is a schematic conceptual diagram of a seabed exploration system using a multi-joint seabed walking robot according to the present invention.
2 is a perspective view schematically showing a multi-joint seabed walking robot according to an embodiment of the present invention.
3 is a block diagram of a multi-joint seabed walking robot according to the present invention.
4 is a diagram illustrating a simulation state of estimating the distribution of pressure acting on a subsea robot placed in a fluid having a flow rate using a CFD method by using a conceptual design of a multi-joint subsea walking robot according to the present invention.
Figure 5 shows a vector diagram and the link coordinate system of the underwater link of the articulated undersea walking robot according to the present invention.
6 is a view conceptually showing the compensation of the posture for the fluid flow, showing the low flow rate, high flow rate and the rear flow rate state, respectively.
7 is a conceptual diagram of a fluid force response posture compensation of a multi-joint seabed walking robot according to the present invention.
8 is a detailed block diagram of a seabed exploration system using a multi-joint seabed walking robot according to a preferred embodiment of the present invention.
9 is a detailed view showing the joint portion of the robot leg of the articulated undersea walking robot according to an embodiment of the present invention.
10 is a partial side cross-sectional view of a pressure-resistant waterproof joint structure consisting of an electric motor and a harmonic reducer of a multi-joint seabed walking robot according to a preferred embodiment of the present invention.
Figure 11 is a detailed view showing the joint portion of the robot arm combined leg according to a preferred embodiment of the present invention.
12 is a view showing the kinematic structure of the robot leg and robot arm combined leg according to a preferred embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a multi-joint seabed walking robot according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic conceptual diagram of a seabed exploration system using a multi-joint seabed walking robot according to the present invention.

Referring to FIG. 1, the sea floor exploration system 1000 using the articulated seabed walking robot according to the present invention shows a state in which the articulated seabed walking robot 100 reaches 200m below sea level and walks, and the articulated seabed robot ( 100 is connected to the depressor 200 by a secondary cable 240, and the shock absorber 200 is connected to the bus bar 300 by a primary cable 220. The resistance of the primary cable 220 takes up to the shock absorber 200 and is not transmitted to the subsea robot 100.

The seabed exploration system 1000 using the 200m class articulated undersea robot 100 has a depressor 200 to minimize the influence of the fluid force acting on the tether cable to the robot in the heavy current environment. The concept of operation. The subsea exploration system 1000 has two tasks as follows.

Investigation and observation of subsea structures and sinking ships

It moves closely to the sea floor in the heavy current environment up to 2 knots to approach seabed structures, sinking ships, etc., and to investigate and observe the structures existing in the dark clock seabed environment using optical and acoustic equipment.

Robotic arms are used to cut, grind and drill wires, which are necessary for the investigation and observation of subsea structures and sinking ships.

Cheonhae Station  Marine Science Research

By moving to a multi-pedestrian walk within 200m of the seabed, it acquires scientific research data necessary for research on marine physics, chemistry, biology and geology while minimizing disturbance of the seabed.

Samples of organisms, soil, and seawater needed for scientific investigations are taken within 200 meters of the seabed.

In the present invention, to overcome the existing limitations with a new concept of a submarine robot different from the existing propeller type submersible, for this purpose is disclosed a multi-joint subsea walking robot as shown in FIG. The existing limitations mentioned in the prior art are overcome by the following concept.

In terms of safety concerns, undersea robots are used instead of divers in environments where it is dangerous for divers to work on their own.

On working time issues, the diver's diving time limit is overcome by using a subsea robot.

Regarding the algae problem, the robot overcomes the algae by maintaining a posture in which the grounding force is increased by being in close contact with the seabed, and by placing the buffer 200 between the subsea robot 100 and the mothership 300, the algae force applied to the cable is a submarine robot ( Reduce the impact on

Regarding the clock problem, various ultrasonic imaging apparatuses, which are relatively less affected by turbidity, are utilized, and optical cameras are used for proximity checking.

Regarding obstacles and irregular undersea terrain problems, use a multi-legged landing on the sea floor to maintain static stability so as not to be entangled with obstacles.

Regarding the problem of environmental interference, move and work in the way of seabed walking to minimize the disturbance of the seabed.

We define four core technologies for developing multi-joint seabed walking robot according to the present invention, and propose an approach for technology development. The newly proposed submarine robot provides a new concept of submarine robot that moves to walking near the sea floor by using a leg composed of several joints, unlike the existing submarine robot that propels the thrust by a propeller method.

The concept of undersea robots is similar to the way crabs and lobsters move and work on the bottom of the sea, so the robot is named 'Crabster'.

The subsea robot according to the present invention performs a sunken ship exploration and marine science survey in the seabed up to 200m deep offshore in Korea (also performs marine science survey in the seabed up to 6000m depth). In particular, it is able to work in the environment of the west coast where tidal current is strong and visibility is poor, and also it has a walking function without disturbing the environment in the sedimented soil.

Table 1 shows the schematic specifications of FIG. 1, which is an example of the implementation of the articulated undersea walking robot according to the present invention.

As shown in Table 1, the number of legs is four walking legs and two robot arm combined legs.

In addition, the 200m exploration articulated undersea walking robot according to the present invention includes a device capable of detecting a bad watch from the sea floor. The basic specifications (when the legs are folded) are 2.2m in length, 1m in width, 1.1m in height, maximum weight 300kg (including load capacity), 0.5m above ground level, 4 feet of walking legs, 4 DOF legs, 6 DOF legs Two, the maximum specification is a maximum walking speed of 0.5m / sec (1.8km / h), a maximum operating depth of 200m, a maximum bimodulation speed of 2 knots, and a maximum power consumption of 20kW or less. The ability to overcome sea conditions is the maximum working condition Sea state 3 and the maximum survival condition Sea state 4. The bad watch detection capability can be performed in two types, a detection distance of 100m or more and a 10m or more. In other words, it is equipped with a front scanning sonar that can scan the front from the sea floor with a maximum detection distance of more than 100m and an ultrasonic camera that provides a real-time sonar image with a maximum detection distance of more than 10m. The control method is wired remote control method, and the power supply uses a tether cable.

The necessary functions of the combined robot can be summarized again.

function

-Adjust the posture of the body with multi-joint multi-legs by walking on the sea floor and moving the gait.

-Equipped with two robotic arms for working on the sea floor.

-Equipped with ultrasonic imaging equipment to overcome the bad clock.

-Built in turbidity, dissolved oxygen, conductivity, temperature, depth and pH measurement sensor.

-All information of the submarine robot is remotely monitored in real time.

-Posture stabilization and footstep correction function for overturning risk due to disturbance such as irregular terrain, bird, etc.

Withstand pressure Watertightness  system

-Structurally stable pressure and watertight performance at a depth of 200m.

-In case of watertight water tightness such as rotating shaft system, guarantee operation in insulating oil.

-Anticorrosive function against corrosion by sea water and salt.

Toughness

-Operation in Sea State 3, Survive in Sea State 4.

-Move and work in 2 knots of current, survive in 3 knots of current.

-Normal operation in temperatures from minus 10 degrees to imaging 40 degrees, survival in minus 30 degrees to imaging 75 degrees.

responsibility

-Can be used continuously for 24 hours underwater and at sea.

-Scientific research data maintain internationally recognized credibility.

Operational Convenience

-Launching at sea below 3 is possible.

-User graphic interface for operator convenience

-Reduced operator burden by providing some automatic functions

Maintainability

-The subsea robot 100 and its supporting devices are easy to disassemble, assemble and replace.

-Modular production, sufficient spare parts.

-Various buses can be utilized, and easy to pack, move and install.

Scalability

-Secure communication channel and power line of extra channel for additional equipment.

-Robot arm replacement of underwater work tools.

Emergency response function

-When the mechanical connection device between the submarine robot 100 and the bus system 300 of the remote system is broken, the submarine robot 100 transmits its own underwater position by ultrasonic wave over 3 days.

-When the subsea robot 100 is overturned due to excessive seabed steepness or instantaneous current flow or operation mistake, it is possible to recover the posture by itself or with the aid of a remote support device.

Details of the approach to the development of underwater joint mechanism of the subsea robot according to the present invention are summarized in Table 2 below.

According to Table 2, as the main demanding function of the underwater joint mechanism, first, pressure / watertight is required in the mechanical field, and a motor / gear / bearing integrated waterproof joint module was developed. Perform development. In the anticorrosion method, corrosion resistant materials such as aluminum and stainless steel were applied, and oil repellent design of the insulating oil filling method was applied, and the anticorrosive structure was installed by installing a sacrificial anode. In addition, it adopts harmonic drive reducer to achieve zero backlash, performs structural analysis based optimal design, and uses lightweight high strength material.

In the electric field, to provide a submarine robot with a small, lightweight, high-power joint, a low-speed, high-torque BDC motor is adopted, a heat dissipation structure is designed using sea water and filling oil, and a hole center type for joint position feedback. A proximity limit sensor and an electric absolute position encoder are applied. In the control field, compliance controller design is applied to prevent mechanical wear due to impact and to improve safety.

The structure of the articulated undersea walking robot according to the present invention will be described in more detail with reference to FIGS. 2 and 3.

First, Figure 2 is a perspective view schematically showing a multi-joint seabed walking robot according to an embodiment of the present invention. The shape of the articulated undersea walking robot 100 of FIG. 2 is merely an embodiment, and its appearance is deformable.

2, the articulated undersea walking robot 100 is a streamlined body (110); A multi-jointed walking leg having a plurality of pairs mounted on the left and right sides of the body and composed of a plurality of joints; Control means mounted in the body and controlling a walking state and a swimming state in the water through the articulated walking leg; Walking leg driving means controlled by the control means for generating a driving signal for driving the articulated walking leg; Sensing means mounted in the body to sense a posture of the body and contact with an external object; And communication means for transmitting and receiving wired and wireless signals with an external device.

The sensing means is characterized in that it comprises a posture and motion measurement sensor 42, the underwater position tracking device 50, and a force / moment sensor 43 installed on the bottom of the body.

It is mounted on the front of the body includes a photographing means for photographing the underwater image, wherein the photographing means comprises an ultrasonic camera 20 and the pan / tilt function underwater camera 22 and the lighting device (22a, not shown) It is done.

The communication means is characterized in that it comprises an optical communication modem (60).

The communication means is characterized in that connected to the shock absorber through the optical fiber and the power cable built-in secondary cable 240.

The body is characterized in that made of lightweight high strength composite fiber material.

In addition, the sensing means is characterized in that it comprises a moment sensor is installed on the two front front legs of the subsea robot to perform the ground detection.

A plurality of articulated walking legs 121, 122, 123 (not shown), 124, 125 (not shown), and 126 are provided on the side of the body portion 110 of the subsea robot 100, and two are provided on each side thereof. (123, 124, 125, 126), two (121, 122) are provided on the front side. Two articulated walking legs (121, 122) attached to the double front side is a robot arm combined legs to perform the functions of the legs and arms. Each articulated walking leg 121, 122, 123, 124, 125, 126 is composed of a plurality of joints (for example, 121a, 121b, 122a, 122b, etc.).

The articulated undersea walking robot 100 according to the present invention walks undersea with 6 or 4 groups, and two front legs may be utilized as robot arms. The four legs 123, 124, 125 and 126 each have four joint structures actively controlled by an electric motor (Fig. 9), and the front two legs each have six joints and one gripper (Fig. 11). This concept is based on lobster robots, which focus on biomechanical simulation, and a technique in which each leg consists of a joint and a pedal [Christina, G., Meyer, N., Martin, B., "Simulation of an underwater hexapod robot," Ocean Engineering, Vol 36, pp 39-47, 2009.]. In addition, it is a new submarine robot that actively controls posture in response to fluid force.

The leg structure of the articulated undersea robot is as shown in FIG. When the submarine robot moves, it is possible to walk quickly while securing posture stability using six legs. When working or moving things using the robot arm combined legs, support the body or walk with four legs. When the submarine robot moves on four legs, walking stability and speed are relatively lower than when moving on six legs, but all the necessary work and moving functions can be achieved underwater.

The multi-joint seabed walking robot 100 according to the present invention has a streamlined body 110 and a leg shape of a multi-joint structure so as to be suitable for working in a stress-based environment, and detects disturbance due to fluid force and minimizes the effect thereof. To control body and leg posture.

Next, Figure 3 is a block diagram of a multi-joint seabed walking robot according to the present invention.

Referring to Figure 3,

Front-scanning sonar 20 to shoot up to 100m ahead with ultrasound

Ultrasonic camera 20a for capturing a front image up to 10m with ultrasound in real time,

Pan / tilting function underwater camera 22 and lighting device (22a, not shown) that can shoot underwater and rotate and switch angles,

Data storage unit 30 for storing the sensed data and the captured image data during the swimming and walking process,

Posture and motion measurement sensor 42 for detecting the posture of the subsea robot and measuring the state of movement,

Force / moment sensor 43 for sensing the force and moment acting on the walking leg of the subsea robot,

Proximity sensor (44) for detecting the limit of the joint angle,

Speed sensor 48 for sensing the speed and flow rate of the robot,

Underwater position tracking device for tracking and sensing the underwater position of the performing robot in real time (50),

Optical communication modem 60, which handles the signal transmission and reception with the buffer,

A motor driving unit 70 for generating a motor driving signal,

First to Nth electric motors 72-1, ..., 72-N operating in accordance with the signal of the motor driver,

First to N-th reduction gears 74-1, ..., 74-N operating in accordance with the electric motor and transmitting the motion of the motor,

Electric encoders for sensing joint angles (76-1, ..., 76-N),

Limit sensors (78-1, ..., 78-N) for generating a limit signal according to the joint angle,

A control system (10) for transmitting and receiving signals with a buffer and a ground bus through an optical communication modem, receiving a sensing signal sensed during the walking process of the articulated subsea robot (100), and controlling the transmission of data received during walking; And

Power supply unit 80 for supplying power,

.

Each other leg end is equipped with a force sensor or a sensing sensor for ground sensing (not shown).

The articulated undersea walking robot according to the present invention is installed on the sea floor and is connected to the middle of the shock absorber and is connected through the ground bus and the shock absorber. The ground bus receives and stores the photographed image information of the seabed topography through the seabed robot, and transmits a movement command signal to search for a specific area.

The subsea robot moves along the sea floor to a specific area and can walk while moving. The flow rate sensor, the grip force sensor, and the attitude sensor, which detects the disturbance of the seabed according to the current, are detected according to the current, and the attitude of the seabed robot is controlled in response thereto (see FIGS. 6 and 7). At this time, by controlling the posture in the direction of increasing the stability of the posture so as not to be overturned against the resistance and lift caused by the tidal current coming from the front to prevent the accident such as flipping. When walking, it provides a means to secure walking stability by checking the grounding state of the leg through a moment sensor, which is a sensing means installed on the articulated walking leg, and a traction sensor installed on the toe. In order to overcome the bad clock, it is possible to obtain a real-time video image in the sea with high turbidity by mounting an ultrasonic camera as a photographing means. In addition, by using the articulated leg to change the posture to approach the optical camera, you can check the object closer. In this case, the surroundings of the front are brightly illuminated by the lighting device.

Acting on the seabed robot Fluid  Interpretation and modelling

It looks at the fluid force acting on the articulated undersea walking robot according to the present invention. Since water is a fluid having a density of 1000 times that of air, subsea robots operating in the underwater environment have dynamic characteristics that cannot ignore fluid force. In the present invention, a computational fluid dynamics (CFD) method using a numerical calculation tool such as ANSYS is applied.

4 is a view showing a simulation state of estimating the distribution of pressure acting on a subsea robot placed in a fluid having a flow rate by the CFD method using the conceptual design of the subsea robot according to the present invention. Through this process, the fluid force acting on the seabed robot can be calculated and analyzed according to the attitude and the direction of the fluid.

In FIG. 4, the robot arm combined legs 121a, 121b, 122a and 122b, and the remaining right walking legs 124a, 124b, 126a and 126b, and the left walking legs 123a, 123b, 125a and 125b are not shown. It is composed of

Figure 5 shows a vector diagram and the link coordinate system of the underwater link of the articulated undersea walking robot according to the present invention.

Referring to FIG. 5, when walking or swimming with multi-joint multi-foot in water with flow velocity, path planning and control of a joint considering fluid force is necessary, and for this purpose, an essential action must be performed on the leg link. Modeling of fitness. The underwater robot arm kinematic equation can be expressed as Equation (1) by adding a fluid force to the robot arm kinematic equation of the land.

는 관절 토크이다. 유체저항력과 양력은 관절의 각도, 관절 각속도, 유체의 속도, 링크의 형상에 따른 유체력 계수의 함수가 된다. 이를 정의하기 위하여 먼저 링크를 얇은 원판으로 쪼개고 각 원판에 작용하는 유체력을 근사적으로 표현함으로써 이들의 적분에 의해 링크에 작용하는 유체력을 근사화한다. 해저로봇의 링크의 좌표와 속도 및 힘 벡터도를 도 5와 같이 정의하면, j번째 링크에 작용하는 유체저항력은 i번째 좌표에 대해 수학식(2)와 같이 근사적으로 표현할 수 있다.Where M is the inertia matrix with added mass, C is Coriolis and centrifugal force, D is fluid resistance and lift, G is buoyancy and gravity,

Is the joint torque. The fluid resistance and lift are functions of the fluid force coefficient according to the joint angle, joint angular velocity, fluid velocity, and link shape. To define this, first, the link is divided into thin disks and the fluid forces acting on the disks are approximated to approximate the fluid forces acting on the links by their integration. If the coordinates, velocity and force vector of the link of the submarine robot are defined as shown in FIG. 5, the fluid resistance force acting on the j- th link can be expressed approximately as in Equation (2) with respect to the i- th coordinate.

는 j번째 링크의 원판의 속도벡터와 유체 속도벡터 사이의 각도이다. d_pj는 원판을

에 직각인 벡터에 투영한 길이이다.

는 j번째 링크의 길이방향에 직각인 원판의 병진 속도성분이다. 이로부터 i번째 관절에 작용하는 유체력토크는 원판의 위치벡터 ⁱr_j를 고려하여 다음 수학식 3과 같이 표현할 수 있다. Where C _Dj is the two-dimensional fluid resistance coefficient of the j th link,

Is the angle between the velocity vector and the fluid velocity vector of the disk of the j th link. d _pj is the original

The length projected on the vector perpendicular to.

Is the translational velocity component of the disc perpendicular to the longitudinal direction of the j th link. From this, the fluid force torque acting on the i- th joint can be expressed by Equation 3 considering the position vector ⁱ r _j of the disc.

를 관절 각속도 벡터로 표현하면 일반화 토크를 얻을 수 있고, 수학식(1)식의 유체저항력 항 D를 근사적으로 구할 수 있다.
Velocity vector to determine these fluid forces and torques

Is expressed as a joint angular velocity vector, and a generalized torque can be obtained, and the fluid resistivity term D of Equation (1) can be approximately obtained.

Fluid  Optimal Pedestrian Path Planning

If you plan your route to optimize the hydrodynamic forces on the links underwater, you can increase the efficiency of the energy required for walking or swimming. The core technology is to improve the efficiency of the system by optimizing the fluid force because it receives 1000 times as much fluid force in water than in air. In walking, the degree of freedom is taken into account in the planning of the step, and the angle and speed of the joint are planned to maximize the propulsion of the body acting by the fluid force acting on the joint. This problem of fluid force optimum walking path planning can be formulated as follows. That is, a joint that satisfies the following inequality conditions given by Equation (4) below and satisfies the joint constraint given according to the step, and minimizes the fluid force objective function g as shown in Equation 5 acting on the legs moving underwater. Get the path parameters.

This formalized fluid force optimization problem can be solved using commonly known optimization techniques. For example, genetic algorithms or sequential quadratic programming (SQP) can be used.

External force response  Posture Compensation Control

Maintaining stable posture in algae, unlike propeller method, is the main concept of CRABSTER. Therefore, posture compensation control technology to cope with external force such as algae becomes another core technology.

6 is a view conceptually showing the compensation of the posture for the fluid flow, showing the low flow rate, high flow rate and the rear flow rate state, respectively.

7 is a conceptual diagram of a fluid force response posture compensation of a multi-joint seabed walking robot according to the present invention.

As an approach to maintain a stable posture without being overturned or blown over by the current in the sea where the current is present, the attitude compensation method of the crawfish is introduced as shown in FIG. Lobsters adjust their grip by varying their posture depending on the size and direction of the flow rate. If the above-mentioned computational fluid dynamics analysis method obtains the lift and the resistance obtained by body posture, it can be used to derive the conditions to work without overturning on the sea floor. The condition that the robot will not be blown by the current is that the frictional force of the ground tip generated by the weight and lift of the robot is greater than the fluid resistance. That is, the relationship of the following equation (6) can be obtained from FIG.

Where m is the mass of the robot, g is the acceleration of gravity, B is the buoyancy of the robot, f _F is the bottom ground friction force of the robot, f _D is the fluid resistive force f _E is any other external force component, and μ is the ground friction coefficient. , f _L is the lift on the robot. In Equation (6), f _D and f _E are functions of flow velocity and robot posture, so the tide can be overcome by compensating the attitude so that the inequality of Equation (6) is satisfied. In order to implement the posture compensation function in the submarine robot, the flow velocity sensor (or speed sensor), force / torque sensor, posture sensor (or posture and motion measurement sensor), and ground force sensor are installed. Referring to FIG. 7, the articulated subsea robot 100 may be seen to overcome a bird by changing its posture using a multi-articulated walking leg. The articulated submarine robot responds to currents from the front by protruding the body forward.

The articulated undersea walking robot according to the present invention has six legs, and both front legs also function as robot arms. In addition, it is a seabed robot of the concept of moving in close contact with the seabed to overcome the disturbance caused by birds by using the shape and posture of the body and perform the subsea work in a stable posture. The core technologies of the subsea robot according to the present invention are four such as underwater joint mechanism, fluid force analysis and modeling, fluid force optimal walking path planning, and external force response attitude compensation control.

8 is a detailed block diagram of a seabed exploration system using a multi-joint seabed walking robot according to a preferred embodiment of the present invention.

Referring to FIG. 8, in addition to the configuration shown in FIG. 3, the subsea robot 100 includes a switching hub 150 and an optical fiber converter 152 for switching a plurality of signals, and the switching hub 150 includes RS232 and Computer 162 processing input and output signals connected to RS485 device, USB and CAN devices, switching hub 164 connected to a plurality of network cameras, video encoder 166 connected to a plurality of analog cameras, forward Looking Sonar: FLS, 20) or front scanning sonar, ultrasonic camera 20a is connected.

The buffer 200 includes a switching hub 210 for switching a plurality of signals, an optical fiber converter 222, a computer 230 for processing input and output signals and a RS232 connection, and a video encoder having a plurality of analog cameras 242, 243, 244 and 245 connected thereto. 240, and a plurality of network cameras 252 and 254 are connected.

The bus bar 300 includes a switching hub 310 to which a plurality of computers 331 to 339 are connected and to which the optical fiber converters 322 and 324 are connected. The optical fiber converter 322 is connected to the optical fiber converter 222 of the buffer 200, the optical fiber converter 324 is connected to the optical fiber converter 152 of the subsea robot 100.

Through the seabed exploration system including the seabed robot 100, the buffer 200 and the mothership 300 connected as described above to build a system for observing the seabed topography, and controls the seabed robot 100 to the data about the seabed environment Can be secured.

9 is a detailed view showing the joint portion of the robot leg of the articulated undersea walking robot according to a preferred embodiment of the present invention, Figure 10 is an electric motor and a harmonic reducer of the articulated undersea walking robot according to a preferred embodiment of the present invention Partial cross-sectional side view of the pressure-resistant waterproof joint structure consisting of, Figure 11 is a detailed view showing the joint portion of the robot arm combined leg according to a preferred embodiment of the present invention, Figure 12 is a robot leg according to a preferred embodiment of the present invention and Figure shows the kinematic structure of the robot arm combined leg.

9, the joint portion of the robot leg of the multi-joint seabed walking robot according to a preferred embodiment of the present invention is the first joint (125a), the second joint (125b), the third joint (125c) and the fourth joint And 125d. The robot leg 124a is connected to the end of the fourth joint 125d, and the robot leg 124b is connected between the third joint 125c and the fourth joint 125d.

The first joint 125a, the second joint 125b, and the third joint 125c are waterproof assembled by the pressure-resistant waterproof joint structure (see FIG. 10).

Referring to FIG. 10, the first joint 125a, the second joint 125b, and the third joint 125c are waterproof-assembled by the pressure-resistant waterproof joint structure, specifically, the first waterproof body 410. , The second waterproof body 420 and the third waterproof body 430, and the first waterproof body 410 is frameless BLDC motor 72-1 is wrapped by the waterproof O-ring 414, pressure-resistant waterproof housing Inscribed to 418 is mounted via the bearing 412. The speed reducer 74-1 for reducing the driving force of the frameless BLDC motor 72-1 is rotatably connected to the waterproof housing 418 through a bearing 412.

11, the joint portion of the robot arm combined leg according to a preferred embodiment of the present invention is the first joint 125a, the second joint 125b, the third joint 125c, the fourth joint 125d, It consists of the 5th joint 125e and the 6th joint 125f. A gripper 122a-1 is connected to an end of the sixth joint 125f, a robot leg 121c is connected between the third joint 125c and the fourth joint 125d, and a fourth joint 125d. And a robot leg 121b is connected between the fifth joint 125e and a robot leg 121a is connected between the fifth joint 125e and the sixth joint 125f.

The first joint 125a, the second joint 125b, and the third joint 125c are waterproof assembled by the pressure-resistant waterproof joint structure (see FIG. 10). Other joints are also assembled in a pressure-resistant waterproof structure. The feedback of each joint angle can be detected by the electric absolute encoder 76-1, and the joint is prevented by using a limit sensor installed in the joint. In the limit sensor, a hall sensor (not shown) is used in consideration of a watertight waterproof structure.

Referring to Figure 12, looking at the kinematic structure of the robot leg and the robot arm combined leg according to a preferred embodiment of the present invention, four robot legs are connected to the subsea robot body 110, of the subsea robot body 110 Two robotic arms are connected to the front. Roll, pitch and yaw rotations are rotated around X, Y and Z axes, respectively.

To sum up again, the articulated undersea walking robot 100 according to a preferred embodiment of the present invention has a structure that actively performs subsea walking with 28 joints on a total of six legs. Each joint is driven by first to Nth electric motors 74-1, ..., 74-N. The technique of mechanically and electrically designing and controlling the joints of the subsea robot 100 is defined as an underwater mechanism technology. The articulation mechanisms applied on land have been extended or redesigned to be applied in seawater with hydraulic pressure.

The joint mechanism refers to a joint mechanism composed of each of the six legs of the articulated link subsea robot according to the present invention, as shown in Figure 2, each leg is connected to four joints, the front two legs are 6 Connected to the joints of the dog. Joints connected to the two anterior legs each serve as a robot arm.

Each articulation mechanism comprises a first to Nth electric motors 72-1, ..., 72-N for joint driving, a harmonic reducer, i.e., a first to Nth reducer 74-1, ..., 74-N. ), Joint angle sensors (76-1, ..., 76-N), joint limit sensors (78-1, ..., 78-N). The joint drive motor was designed and mounted in a pressure resistant waterproof housing using a frameless BLDC motor to obtain a small, light weight, low speed and high torque. The pressure-resistant waterproof housing was watertight using an O-ring. The harmonic drive reducer is adopted to minimize the backlash of the joint and to obtain the proper reduction ratio. In addition, the absolute angle of the joint can be obtained by installing an electric encoder that provides an absolute angle, that is, a joint angle sensor on the reducer output side of the joint. The joint angle limit sensor is composed of a magnetic type proximity switch, considering the oil drop application for underwater waterproofing. Figure 10 shows such a joint structure.

The electric motor of the sixth joint 125f installed in the robot arm combined leg portion is for operating the gripper.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

10: control system (control means)
20: Forward scanning sonar
20a: ultrasound camera
30: data storage
42: posture and motion measurement sensor
50: underwater position tracking device
60: optical communication modem
70: motor drive part
80: power supply
100: submarine robot
110: body
200: shock absorber
300: Mothership

Claims (10)

Streamlined body;
A multi-jointed walking leg having a plurality of pairs mounted on the left and right sides of the body and composed of a plurality of joints;
Control means mounted in the body and controlling a walking state through the articulated walking leg;
Walking leg driving means controlled by the control means for generating a driving signal for driving the articulated walking leg;
Sensing means mounted in the body to sense a posture of the body and contact with an external object; And
It includes; communication means for transmitting and receiving a signal with an external device,
A pair of front legs can be used as a robot arm combined with six degrees of freedom, and two pairs of rear legs can be used for walking only because of four degrees of freedom. Articulated undersea walking robot. The multi-joint seabed walking robot according to claim 1, wherein an ultrasonic camera is mounted on the front of the body. The multi-joint subsea robot according to claim 1, wherein the sensing means comprises a posture and a motion measuring sensor. The multi-joint seabed walking robot according to claim 1, wherein the sensing means includes an underwater position tracking device. The multi-joint seabed walking robot according to claim 1, further comprising photographing means mounted on the front of the body to photograph an underwater image, wherein the photographing means is a pan / tilting function underwater camera and a lighting device. The multi-joint seabed walking robot according to claim 1, wherein the communication means is connected to the shock absorber through a fiber optic cable and a built-in secondary cable. The multi-joint seabed walking robot according to claim 1, wherein the body is made of a lightweight, high strength composite fiber material. The multi-joint subsea robot according to claim 1, wherein the sensing means includes a force / moment sensor installed between the body and the leg of the subsea robot and a grounding force sensor installed at the toe. delete According to claim 1, wherein the walking leg drive means
A motor driving unit generating a motor driving signal;
An electric motor operated according to a signal of a motor driving unit, and
And a reducer operated according to the electric motor and connected to the articulated walking leg to transmit the operation of each electric motor.

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