OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

HINDUSTAN UNIVERSITY AUTONOMOUS AUV, stagnation condition is clearly captured. Also, UNDERWATER VEHICLE: DESIGN AND boundary layer formation is seen near the walls. IMPLEMENTATION OF THE POSEIDON AUV As the flow advances over the body, the velocity S.Suryakumar1*, Gokulavasan2, Indrajeet Ghosh 3 increases gradually and then reduces in the cap A.Muthuvel4, N.Prakash5, K.Kamalakkannan6 region due to curvilinear nature of the cap 1 BTech Scholor, Hindustan University, geometry. Poseidon presents a cheaper, stronger, [email protected]; 2 [email protected] lighter in weight of 22 kg and compact size of [email protected] 0.7m*0.5m*0.5mas length, width and height of the vehicle and capable of working under 25 m Abstract—POSIEDON is the first Hindustan depth. New advancements include full vehicle University autonomous underwater vehicle (AUV) control of six degrees of freedom, a dual-hull designed and built by a team of 5 undergraduate cantilevered electronics rack and hulls, overhauled students during the academic year of 2014-2015. wire routing for electrical systems, and significant Completed the AUV in a six month design cycle, software for mission reliability and robustness. the vehicle was fully modelled using Solidworks Poseidon sensor suite comprises of inertial software and extensively simulated the structural measurement units (IMUs), two vision cameras, and flow analysis with ANSYS ,STARCCM+ and humidity sensors, water sensors for kill software’s and manufactured almost entirely in switches, a depth sensor and an internal pressure our campus. Grid Independent studies were sensor. Returning features include a vacuum- carried out for the structural and flow analysis. assisted sealing system; hot-swappable battery Various Turbulence models are selected based on pods, unified serial communications, and flexible the literature survey for the flow analysis. Based mission software architecture are installed. In on the Grid independent studies simulation is unstructured mesh, polyhedral mesh was chosen carried out for various speeds for 0.1-0.5 m/sec. as it gives more accuracy for lesser number of During generation of the meshes, attention is cells, thus the computational time is reduced. given for refining the meshes near the AUV so that Testing of AUV is under progress. the boundary layer can be resolved properly. The 1. Introduction typical mesh for AUV and domain. The analysis is Flow over submerged body has been a subject of carried out for 0.25 million grid with 37 N force great number of investigation mainly because of acting on the thruster clamps. The FOS for wider engineering applications. Some examples materials is 3.2 and the yield strength is 172 Mpa are flow over car, buildings, flight-deck of a ship, (the Maximum yield strength) of the material is underwater appended vessels like submarine, 350Mpa hence the design is safe as shown in Fig torpedo, automated underwater vehicle (AUV), 1.1. From the Pressure contour diagram, the remotely operated vehicle (ROV) etc. [1]. variation of the velocity of flow over the AUV is seen at the velocity of 0.5 m/sec. At the bow of the

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

view, side view, bottom view and Isometric view of 2. MECHANICAL DIVISION AUV are show in Figs. From 2.1to 2.4.The Exploded 2.1 SHAPE & SIZE view of the AUV are show in Figs. 5.5 and 5.6. 2.1.1 Hull Design The hull of AUV houses the electrical systems and it is waterproofed. The hull, needs to have enough space for the electrical systems (for future expansion), should have a good accessibility, needs to be corrosion resistant, has to be able to withstand high impact and at the same time needs to be capable of withstanding the water pressure. A cylindrical shape is chosen for the hull because it has a favourable geometry for both pressure and Fig.2.1 Rear View of the AUV dynamic reasons, at the same time it offers also enough room for the electrical systems. The hull is made out of a thick acrylic tube which keeps the hull relatively cheap, corrosion free and able to withstand an impact. The acrylic tube is closed with aluminium plate at one end and another end is covered by hemispherical propylene cap. The cap consists of an aluminium ring which is permanently fixed to the hull with connectors in the aluminium plate. Sealing between the ring and Fig.2.2 Side View of the AUV the plug is ensured by an O-ring, Sealing is provided in the axial direction of the acrylic tube which means that water pressure will ensure more tension on the sealing area when the vehicle is submerged, since the water pressure will press the end caps against the acrylic tube. In this way a webcam, which is mounted inside the hull, can deliver an underwater view. The transparent acrylic tube is also useful to see warning lights of Fig.2.3 Top View of the AUV the central processing unit from outside the hull. The complete assembly of the hull. The AUV has an overall length of 0.56m and a maximum height and depth of 0.5 m. The rear

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

depth, since thrusters must remain powered to keep the AUV submerged. An advantage of this system is that when the thrusters are switched off buoyancy will ascend the vehicle, which means that the vehicle will surface itself when there are electrical problems. Other advantages of this method lay in the economic reasoning, for Fig.2.4 Isomeric view of the AUV example, there are no complex sealing methods 3. WEIGHT AND BUOYANCY needed for depth control. 4. BASIC VEHICLE FRAME DESIGN AND MATERIAL WEIGHT=density Of Material (ρ) × volume of SELECTION CRITERIA Material (v) × acceleration due to gravity (g) 4 .1 MESHING …. (3.1) 4.1.1 Unstructured mesh In unstructured mesh, tetrahedral mesh was BUOYANCY FORCE = density of fluid (ρ) × volume chosen as it gives more accuracy for lesser number of Water displaced × acceleration due to gravity of cells, thus the computational time is reduced. (g) …. (3.2) During generation of the meshes, attention is given for refining the meshes near the clamps so S.no Parts Weight Buoyancy that the load distribution can be resolved properly. (N) (N) The typical mesh for AUV is shown in Fig 6.1. 1 Frame 34.65 24.5 2 Acrylic Hull 27.8 98.3 3 Stainless Steel 82.95 62.7 Hull 4 Thrusters 20 7 5 Battery 20 - 6 Compressed 15 25

air bottle Total 200.4 217.5 Fig 4.1 unstructured mesh on the AUV frames

The AUV buoyancy system is based on a dynamic 4.2.1 Grid independent study diving method. This method requires the AUV to Grid independent test is carried out with 0.15 be slightly positively buoyant, vertically mounted million, 0.25 million and 0.35million cells for 37 N thrusters will then control the depth of the AUV. A force. The difference between the values obtained drawback of this method is the large energy for 0.25 million cells and 0.35 million cells is very consumption the system will need to control less (less than 1%). Hence, 0.25 million cells is

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA considered for further analysis as shown in Table 4.1. Table 4.1 Grid independent study

No. of Grids Yield Sl. FOS Strength No. (Millions) Mpa Fig 4.4 Maximum strain for AUV 1. 0.15 3.2 117 2. 0.25 3.2 117 3. 0.35 3.2 117 4.2 RESULTS AND ANALYSIS The analysis is carried out for 0.25 million grid with

37 N force acting on the thruster clamps. The FOS for materials is 3.2 and the yield strength is 172 Fig 4.5 Maximum displacement for AUV Mpa (the Maximum yield strength) of the material 5. COMPONENT PLACEMENT AND WEIGHT is 350Mpa, hence the design is safe as shown in Fig DISTRIBUTION 4.2. The maximum yield strength, strain and 5.1 AUV symmetry about the three planes. displacement for the AUV frames are shown in The AUV is symmetric about the x-z plane and Figs. from 4.3 to 4.5. close to symmetric about the y-z plane. Although the AUV is not symmetric about the x-y plane it is assumed that the vehicle is symmetric about this plane, so one able to decouple the degrees of freedom. The AUV can be assumed to be symmetric about three planes since the vehicle

operates at relative low speed.

Fig 4.2 Factor of Safety for AUV 5.2 The aligning moment ensures horizontal stability. The AUV remains close to horizontal in all manoeuvres and stabilizes itself, since the centre of gravitation and centre of buoyancy are correctly in right order aligned (i.e. aligning moment). This could be concluded from underwater videos made

during underwater experiments. Fig4.3 Maximum yield strength for AUV

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

5.3 Roll and pitch movement are neglected. orientation for mounting the components of the The roll and pitch movement of the AUV are vehicle. This is done to ensure structural integrity, passively controlled and can therefore be rigidity and for protecting the components neglected, since the AUV stabilizes itself due to the attached to it. aligning moment. Therefore, the corresponding The frame is designed in such a way that even parameters do not have to be identified. when new components is attached to instability Frame consist of fittings so that the components can be attached to it. This reduces the weight and make the AUV to dismantle and assemble easily. All components are placed in such a manner center of mass and Centre of buoyancy acts in a straight line at middle of the AUV. 5.5 Upper Hull: Upper hull consist of two racks. The acrylic hull

assembly protect the electronic components. Fig.5.1 Exploded front view of the AUV Racks are placed vertically for easy mounting and unmounting the circuits. The upper hull consist of Arduino board’s one forward movement camera and sensors. They are connected to eight pin underwater connectors which is fixed to aluminium plate. Front part is made up of poly propelyne fitted with acrylic plate to which camera is attached. For better visibility of camera goggles

is attached. Rubber O-rings are fitted to enclosures Fig.5.2 Exploded Side view of the AUV9. DRAG to ensure its water proof. Poseidon AUV consists of three main parts All connections to the outside of the hull is 1. Frames, made using eight pin connector locater on midcap. 2. Upper hull Mid cap reduces the risk of leak. 3. Lower hull. 5.6 Lower Hull The frame is made up aluminum 6061 [T6 The Lower hull consists of power systems. ANODISED].The upper hull house consists of Batteries are arranged serially and power is electronic components and circuits. Lower hull distributed mutually for all the systems. consists of Batteries. 5.8 Actuators: 5.4 Frame: The actuator system consist of a torpedo The frame is made up Aluminum 6061 [T6 launcher and a grabber system and two servo ANODISED].The frame consist of positions and motors.

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

5.9 Torpedo Launcher: seawater and other special environmental use Torpedo and markers are custom designed. requirements. Torpedo launching is achieved by spring 6. The 12V requirement of the operating voltage mechanism using servo motor based upon PWM is easy to acquire from the lithium battery. signals. Torpedo is designed in such a way that it Thrusters run up to 28000 rpm and it develops 3.8 travels a long distance and hit the target. kg upward thrust which draws little current from 5.10 Active Grabbers: battery. 2 NUS sponsored thrusters used for the One metallic grabber is used to grab the forward motion. Thrusters run upto 4000 rpm. recovery object. One separate servo motor is used Thrusters work based upon automation coded by to drop the marker in the bin based up on PWM relay. signals. Metallic grabber is used for better holding. 5.12 External Enclosures: 5.11 Thrusters: Aluminum plates are used as an external Propulsion is given by 4 brushless motor. 2 KZ- enclosures which is non corrosive. This attached to 3800 underwater thruster is a power unit that can hulls with the help of nuts so this makes the provide thrust for underwater equipment assembly and disassembly easy. Rubber O-rings (instruments) or underwater robot, specially are used with aluminum plates to make to designed for ROV, AUV, underwater vehicle, water waterproof. Thus it safeguards the boards inside or underwater leisure equipment’s, aquaculture the hull. Holes are drilled on plates for connecting industry, underwater cleaning equipment and so the entire system to the battery hull. on, with high efficiency, large thrust, and small size, use flexible and easy to control of features. 6. CENTRE OF GRAVITY & BUOYANCY Use a both-way water-cooling brushless ESC The Centre of gravity of the AUV is (electronic speed controller), 30-60A, via PWM (Xg, Yg, Zg)= (0.0m, 0.05m, 0.0m) signal to control KZ-3800. The Centre of Buoyancy of the AUV is 1. Meet the 50m water depth work environment. (Xb, Yb, Zb)= (0.0m, 0.16m, 0.0m) 2. The 50mm diameter 4 blades ducted propeller 7. CALCULATION AND COEFFICIENT OF DRAG provides thrust more than 3.8KG (Forward). 7.1 Computational domain 3. Control propeller rotating direction can The computational domain is modelled, based on effectively provide thrust of forward or reverse. the specifications given in Fig. 7.1. 4. Haven't gear reducer, use the motor to drive directly, reduce intermediate links, can improve the transmission efficiency and to reduce equipment failure rates. 5. The full set used aluminum 6061, surface anodized, able to meet including fresh water, Fig 7.1 Specifications for Computational Domain

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

7.2 Assembly of AUV and Domain Fig 7.3 Unstructured mesh - magnified view near The assembly of the AUV and Domain is done in the wall STAR-CCM+. The two models are imported into the 7.3 RESULTS AND ANALYSIS OF BARE AUV software and the AUV volume is subtracted from 7.3.1 Introduction the Domain volume. Thus, the two separate Three dimensional numerical analysis of the flow volumes become one volume with the domain as over Autonomous Under-Water Vehicle (AUV) is the negative volume. carried out with the general purpose Reynolds 7.2.1 Unstructured mesh Averaged Navier-Stokes Equations (RANSE) solver In unstructured mesh, polyhedral mesh was STAR-CCM+. For the analysis the DARPA SUBOFF chosen as it gives more accuracy for lesser number model has indicated in Chapter 4 is taken for the of cells, thus the computational time is reduced. analysis simulating the towing tank testing carried During generation of the meshes, attention is out by Roddy, R. F. [34]. Steady analysis is carried given for refining the meshes near the AUV so that out both with unstructured polyhedral and prism- the boundary layer can be resolved properly. The layer meshes with AKN k-ε turbulence models for typical mesh for AUV and domain is shown in Fig bare AUV. 7.2 and a magnified view near the solid wall of For all the cases, the maximum residual from AUV is shown in Fig 7.3 continuity, x-momentum, y-momentum and z- momentum is restricted to 10-4+3 as convergence criteria. Initially, 300 iterations are carried out with first-order upwind scheme and relaxation factor for velocity as 0.3 and pressure as 0.1 to guard against divergence of the solution. Later, till the convergence criteria are met, iterations are carried out with second-order upwind scheme with velocity relaxation factor as 0.5 and pressure Fig. 7.2 Section view of AUV and Domain with relaxation factor as 0.3 to obtain higher accuracy unstructured mesh and also to accelerate the convergence. Following data are used for the analysis:

• Liquid = H2O (Water) • Density (ρ) = 1000.0 kg/m3 (for water) The value of turbulent kinetic energy at the inlet is calculated as follows

… (7.1) Where,

Ti – turbulent intensity = 0.0515 J-s/kg-m

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

The value of dissipation rate (ε) for k-ε model and specific dissipation rate (ω) for k-ω model at the inlet are calculated from:

7.3.2Grid independent study Grid independent test is carried out with 0.35 million, 0.5 million and 0.67million cells for 0.5 Fig 7.4 Velocity contour for AKN k-ε turbulence m/sec velocity. AKN k-ε turbulence model is used model for the test. The difference between the values obtained for 0.5 million cells and 0.67 million cells is very less (less than 2%). Hence, 0.67 million cells is considered for further analysis as shown in table 9.1. Table 7.1 Grid independent study

Sl. No. No. of Grids Drag Force Fig 7.5 Pressure contour for AKN k-ε turbulence (Millions) (N) model From the velocity contour diagram, the variation 1. 0.35 15.38 of the velocity of flow over the AUV is seen. At the 2. 0.50 9.738 bow of the AUV, stagnation condition is clearly 3. 0.67 9.860 captured. Also, boundary layer formation is seen

near the walls. As the flow advances over the Table 7.2 Drag force for various speed body, the velocity increases gradually and then reduces in the cap region due to curvilinear nature Sl. No. Velocity Drag Force of the cap geometry as shown in Figure 7.5. The (m/sec) (N) simulation is ran for AKN k-ε turbulence model 1. 0.5 9.86 with various speed is shown in Table 7.2. 2. 0.4 6.40 7.3.4 Pressure contour diagram 3. 0.3 3.58

7.3.3 Velocity contour and vector diagram The velocity contour diagram for AKN k-ε turbulence model is shown below.

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

Fig.7.6 Pressure contour for AKN k-ε turbulence 8. ELECTRICAL AND PROGRAMMING DIVISION model POWER BUDGET AND TYPE OF BATTERY From the Pressure contour diagram, the variation 8.1 Electrical Requirement: of the velocity of flow over the AUV is seen. At the 1. NIVIDIA JETSON TK1. bow of the AUV, stagnation condition is clearly 2. Arduino mega 2056. captured. Also, boundary layer formation is seen 3. OPENROV sensor board near the walls. As the flow advances over the 4. Ultra sonic sonar MX7078 body, the velocity increases gradually and then 5. Motor driver and controller. reduces in the cap region due to curvilinear nature 6. BMS for power distribution. of the cap geometry as shown in Figures from 7.6 7. Thrusters. to 7.8. 8. Battery. 9. Some MOSFET N-type 10. Switching controller. 8.1.2 Microprocessor Board

Fig. 7.7 Pressure contour on the starboard side

Fig.8.1 NIVIDIA JETSON TK NVIDIA’s latest and most advanced mobile processor, the Tegra® K1, creates a major Fig. 7.8 Pressure contour on the bow side discontinuity in the state of mobile graphics by 8. VEHICLE SPEED bringing the powerful NVIDIA Kepler™ GPU Relative low speed, so lift forces can be neglected. architecture to mobile and delivering tremendous The AUV operates at relative low speed, i.e. max. visual computing capabilities and breakthrough 0.5 m/s, which means that lift forces can be power efficiency. neglected. The low speed was verified during underwater experiments (wet tests)

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

• Input Voltage (limits) -6-20V • Digital I/O Pins 54 (of which 14 provide PWM output) • Analog Input Pins -16 • DC Current per I/O Pin -40 mA • DC Current for 3.3V Pin- 50 mA

• Flash Memory 256 KB of which 8 KB used Fig.8.2 Logics by boot loader The NVIDIA Tegra K1 mobile processor is designed • SRAM- 8 KB from the ground up to create a major discontinuity • EEPROM- 4 KB in the capabilities of mobile processors, and • Clock Speed- 16 MHz delivers the industry’s fastest and most power 8.4 Points to note: efficient implementation of mobile CPUs, PC-class • Its control the thrusters by the help of graphics, and advanced GPU-accelerated bulletproof controller by means of PWM. computing capabilities • With the help of PWM it will

automatically flow the current rates by

the help of image processing.

• The navigation system (IMU) will help to

locate the position of our AUV.

• It’s have some sensors like as pressure,

Gyro and magnetic compass.

• It will have calibration of 100m with the Fig.8.3 Arduino mega range of 600 kHz. The Arduino Mega2560 can be powered via the 8.5 Battery USB connection or with an external power supply. The board can operate on an external supply of 6 We are using three battery two for thrusters, one for microcontroller and processer. We are using to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the LIPO battery for save environment underwater. 8.6 Battery Rating- board may be unstable. If using more than 12V, 1.11.1V/4200MA X 2 IN SERIES FOR THRUSTERS= the voltage regulator may overheat and damage 22.2v the board. The recommended range is 7 to 12 2.11.1V/4200MA FOR MICROPROCESSER. volts. 8.3 Data: • Microcontroller - AT mega 2560 • Operating Voltage- 5V • Input Voltage (recommended)- 7-12V

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

9. NAVIGATIONAL DESIGN Items Voltage(V) Amp(A) The design of softy for vehicle control architecture NIVIDIA JESTON TK1 5V/2.5V 2A comprises of different modules and number of MEGA 5V 0.5A components for handling various situation of the OPENROV(IMU) 5V 0.4A AUV. These modules use the sensor data and the HYDROPHONE (5-12)V >=0.5A data processed from the image to control the THRUSTERS 12V 1A vehicle according to their need. ACTUATOR 5V 0.4A 9.1Architecture SERVO MOTOR 5V 0.4A The architecture of softy consists of many levels in WATER SENSOR 5V 0.2A charge of maintaining and controlling the AUV. PRESSURE SENSOR 5V 1A Each level has its own importance in the decision making of the AUV. At the lowest level we have the hardware components which is instrumental in making the right action and feeding the right information to the vehicle. It’s followed by the detection level which is used to make out how the

environment is, and with the help of navigational Fig.8.3 Arduino with thruster system it detects what tasks to perform and 8.7 MOSFET: follows to the task level. At task level with the necessary algorithms decisions are taken and are send to the corresponding hardware 9.2 Navigational System For the AUV to take a decision it has to know where it is at that point of time. Navigational Fig.8.4 MOSFET system with the help of combinations of hardware helps to know the know it. Poseidon AUV is built with a low cost IMU device which consists of 3-axis magnetometer for detection of heading, 3-axis accelerometer to detect roll, pitch and yaw, 3 axis gyroscope to detect the orientation and pressure sensor for knowing the depth with 1cm precision. Softy performs a robust calculation to obtain different set value which are then used for building 8.1Navigation Architecture the map. The array of images are processed for Here load means the thrusters where they would finding the objects which makes the localization be connected. more accurate and help in faster decision makin

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

• The hydrophone will find some pinger 9. SENSORS position or any obstacle position by the help of camera and send pulse to controller to move or change position.

9.1 Sensor Specifications: Fig.13.4 Noise controller Fig.13.1 Turnigy sensors 9.2 Ultrasonic sensor (MX7078): The ultrasonic sensor (MX7078) is implemented in • OPENROV IMU the POSEIDON to find the pinger position by o 3-axis magnetometer for catching the frequency and sound of the detection of heading (regardless transmitting pingers. Which will attached to the of orientation) mega processer and help to indicate the pingers. o 3-axis accelerometer to detect roll and pitch o 3 axis gyroscope to detect rotational rate • MS5803-14BA Pressure sensor o Senses down up to 130m depth

o Precision to about 1cm of depth Fig. 9.5 Ultrasonic sensor o Integrated temperature sensor • It’s having the three pin wiring. precise to about 0.1C • It’s having the range of 0-7m range of pinger and sonar reflictor.

Fig. 13.2 IMU

9.6 Analog voltage output sensor

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

9.3 Presser Sensor: It is use for finding the presser in water by which we can find the depth and by IMU the processor 10. ENDURANCE AND RANGE OF AUV COVERAGE: can adjust the POSEIDON. It will help him to collide Our design is such that, which have minimum with water ground. weight compared with Buoyancy and vehicle have perfect frame. 10.1 Power budget/consumption: Due to design and material selection POSEIDON AUV has less power wastage and perfect use of power. The AUV will work for 30 minutes continuously in under water if 50% power used by Thruster. But it consume 30% only in the real time. 11. TYPE OF CONTROLLER

The design of softy for vehicle control architecture Fig 9.7 Pressure Sensor Layout comprises of different modules and number of 9.4 The outer diagram: components for handling various situation of the

AUV. These modules use the sensor data and the data processed from the image to control the vehicle according to their need. For recovery we have attached to the completion

Fig. 9.8 Pressure Sensor outer diagram 9.5 The inner diagram:

Fig. 9.9 Pressure Sensor inner diagram Fig.11.1 Control System.

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

Fig. 11. 5 Sensor

12.1 Thrusters: Fig. 11.2 Power Distribution KZ-3800 underwater thruster is a power unit that By the help of rs232 cable data communication will can provide thrust for underwater equipment conducted. (instruments) or underwater robot, specially designed for ROV, AUV, underwater vehicle, water or underwater leisure equipment’s, aquaculture industry, underwater cleaning equipment and so on, with high efficiency, large thrust, small size, use flexible and easy to control of features.

Fig. 11.3 Microcontroller

Fig. 15.6 Thruster The propulsion or thrust of the AUV is delivered by four trolling motors, two horizontally mounted and two vertically mounted. The horizontal motors

ensure motion in the surge and yaw directions*. Fig 11.4 Microprocessor The vertical motors ensure stability (in the roll and pitch directions) and motion (in the heave direction). The position of the motors on the AUV can be seen in Fig. 5.2.

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA

13. OBSTACLE AVOIDANCE algorithm to perform in order find the required Objects are the main key for the AUV to know what it obstacle. is heading up to or what the task that it has to 14.2 Buoy dashing perform is. Processing of image from the two camera When the AUV attains its normalized position at a placed on the AUV are used for detecting them. One depth in water, it then searches for the colour of the camera is placed in the front of the top hull at buoy through the front camera. the centre of AUV. This one is used to detect various This task algorithm uses image segmentation objects like the buoy, L shape, hearten cut-out. The based on HSV colour space. HSV colour space is other camera is placed at the bottom of the AUV in also consists of 3 matrices, HUE, SATURATION and the second support rod used to detect bins. In the VALUE. In Open CV, value range for HUE, task of ball dropper, this camera is used to find the SATURATION and VALUE are respectively 0-179, 0- bowl placement and position the AUV such that the 255 and 0-255. HUE represents the colour, ball drop exactly in it. The detection is one of the SATURATION represents the amount to which that most computationally expensive levels and since not respective colour is mixed with white and VALUE all the modules are required at any given moment, represents the amount to which that respective but still have to be working in order to accumulate colour is mixed with black. evidences, priorities are assigned by the algorithm The module searches for the colour of either red, based on the current mission. yellow or green which is defined as per the 14. CAMERA BASED IMAGING WITH LIGHTS competitions requirements. So for the processing, each stream of image from 14.1 Processing of image from camera the camera is first converted from RGB to HSV colour space. For the conversion to occur first the Poseidon uses two of LOGITECH C170 cameras image is obtained in greyscale followed by with has a 1024x768 resolution with maximum thresholding. We could get certain small patches 30fps.One of these placed at the front of the AUV all over images due to noise in thresholding, which obtain stream of images at 10 fps for processing is eliminated by morphological opening. i.e., and making the corresponding action. And during dilation, followed by the erosion with the same the task of ball dropping the bottom camera is structuring element. We then use the HSV values mostly used at 10 fps for detecting the bowl. to find the area in the image to matches it. When Intel's Open CV on the top of the on-board the match is found, AUV is then reset to the processor ,Jetson TK1 from NVIDIA is used to appropriate location and orientation, and starts to perform image processing of feeds from both move towards it and finally passes over the buoy. camera followed by executing the corresponding 14.3 L space passing algorithms and then transferring the control to the For this task, we will be using haar cascade Arduino for performing the action. Different task classifiers which will be detecting the L shaped have combinations of different image processing rods. These classifiers are trained with lot of

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA positive and negative images. These images are converted to *.vec file using opencv create samples function which is bundled with opencv. These vec files are then used to train the classifier by opencv_ train cascade function to produce the final xml file. These trained classifiers are then used for detecting and passing the L shaped gate. 14.4 Camera:

The camera will do the image processing to the complete the objectives. Fig. 15.1 Launching Layout

15.2 Ball dropping programming

Camera on the bottom of the AUV is used for this task. It searches for bin to which the ball has to drop. The stream from the camera is obtained in Fig 14.1 Camera the form of greyscale. Ball dropping algorithm then It is Logitech c500 which is HDCAM and have quick find blur the image to reduce the noice in it, frames, which help to have good processing in followed by hough transformation function to find complete the objective. It is 1.3mp cam have use the circular patterns in the image. Once detected with USB. the algorithm repositions the AUV itself such that, 15. LAUNCH AND RECOVERY when the ball is dropped, it falls in the bowl which 15 .1 Torpedo launching programming is pre induced in the algorithm. This task too uses the same mechanism of training and using the classifier for detecting the hearten 15.3 Octagon exit shape. When detected, control is sent to the After dropping the ball the front camera in the launch function through the serial line for the AUV is used to track the bottom of the octagon release of the torpedo. and move towards it. Then with the help of bottom camera it centres the mark such that when the AUV raises it comes out thought the octagon as whole. 15.4 Path finder At certain position AUV is in need to find the path that is kept below. The bottom camera is used to identify the rectangular orange path with the help of canny edge detection and contour algorithms .It

4th National Conference of Ocean Society of India OSICON-15 22-24 March 2015 CSIR-National Institute of Oceanography, Goa, INDIA follows it in the front direction with is decided by 2. Elgar desa, R. Madhan and P. Maurya, the magnetometer from the IMU to reach the “Potential of autonomous underwater corresponding next task. vehicles as new generation ocean data platforms”, Current Science, 2006, Vol. 15.5 Kill Switch/Recovery: 90, No. 9. 10th May 2006. We have added water sensor with the help of 3. Pankajakshan, R., Remotigue, M.G., Arduino ,when the water will goes upto the level Taylor, L.K., Jiang, M., Briley, W.R. and of start/stop if any error found, which help to Whitfield,D.L, “Validation of Control- react underwater and start the our AUV. Surface Induced Submarine Maneuvering 15.6 Recovery algorithm Simulations Using UNCLE”, 24th Symposium on Naval Poseidon is implemented with a recovery system, Hydrodynamics,Fukuoka, Japan, July 8-13, such that in the situation of error or incorrect 2002. movement, the navigational system with imaging 4. Thomas.C. Fu et al., “PIV measurements is used to recover to the last know “good path” of the cross-flow wake of a turning which is determined by the localization algorithm. submarine model (ONR body –1)”, IMU plays a major role in recovery as it is one of NSWCCD-50-TR-2002 / 019 the important input to the recovery algorithm. Hydromechanics Directorate Research and Development Report. CONCLUSION 5. Yamamoto, I., Aoki, T., Tsukioka, S., In this project, analysis is carried out for POSEIDON Yoshida, H., Hyakudome, T., Sawa, T., model of AUV with commercial code STAR-CCM+. Ishibashi, S., Inada, T., Yokoyama, K., Both Structural and Flow Analysis is carried out for Maeda, “Fuel cell system of auv bare AUV propeller interaction for various drift ‘Urashima”, IEEE oceans/techno-ocean angles. In the analysis, AKN k-ε model (buffer 2004. layer turbulence models is used for the CFD 6. Scott Kanowitz et al., “Subjugator: the analysis The Drag coefficient, the FOS, stress, development of an autonomous strain, etc. are presented. underwater vehicle”, Machine Intelligence Laboratory,University of REFERENCES Florida, Gainesville, Fl 32611. 1. Charles C. Eriksen et al., “Seaglider: A 7. Yamamoto et al., “New discovery of long-range autonomous underwater marine system development”, special vehicle for oceanographic research”, IEEE lecture, blue earth ’06,Jamstec, Pacifico Journal of Oceanic Engineering, 2001, Vol. Yokohama, Japan, 2006. 26, No.4, October 2001. 8. Stevenson, Peter, Furlong, Maaten, Dormer, David, “AUV design: shape, drag

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