Drones, ROV and Gliders -What is a drone? A drone, in technological terms, is an unmanned aircraft. Drones are more formally known as unmanned aerial vehicles (UAVs) or unmanned aircraft systems (USAs). Essentially, a drone is a flying robot that can be remotely controlled or fly autonomously through software-controlled flight plans in their embedded systems, working in conjunction with onboard sensors and GPS.

-The history of drones The first pilotless radio-controlled aircraft were used in World War I. In 1918, the U.S. Army developed the experimental Kettering Bug, an unmanned "flying bomb" aircraft, which was never used in combat. The first generally used drone appeared in 1935 as a full-size retooling of the de Havilland DH82B "Queen Bee" biplane, which was fitted with a radio and servo-operated controls in the back seat. The plane could be conventionally piloted from the front seat, but generally it flew unmanned and was shot at by artillery gunners in training. The term drone dates to this initial use, a play on the "Queen Bee" nomenclature.

De Havilland DH82B "Queen Bee" biplane

Aircraft specifications:

Power Unit: One 130 hp de Havilland Gipsy Major 1

Wing Span: 29 ft 4 in (8.94 m)

All-up Weight (A.U.W): 1,825 lb. (828 kg)

Max Speed: 104 mph (167 kph)

Ceiling: 14,000 ft (4,267 m)

Range: 300 miles (483 km)

Military drone use solidified in 1982 when the Israeli Air Force used UAVs to wipe out the Syrian fleet with minimal loss of Israeli forces. The Israeli UAVs acted as decoys, jammed communication and offered real-time video reconnaissance.

-Modern story of drones 2001: In the aftermath of 9/11, the CIA began flying armed drones over

Afghanistan as part of the war against the Taliban. The first CIA drone-based kill operation took place in February 2002, when an unmanned Predator drone was used to target a suspect thought to be Osama bin Laden. However, it turned out to be an innocent man named Daraz Khan who was out collecting scrap metal.

2006: Recognizing the potential of non-military, non-consumer drone applications, the FAA issued the first commercial drone permits. These permits lifted some of the limitations placed on consumer drones flown for recreational purposes. In doing so, it opened up new possibilities for companies or professionals who wanted to use drones in assorted business ventures. At first, barely any commercial drone permits are requested. However, that number soon ramped up.

2010: The French company Parrot released their Parrot AR Drone, the first ready-to-fly drone which can be controlled entirely via Wi-Fi, using a smartphone. The drone was almost immediately successful, both critically and commercially, receiving the 2010 CES Innovations award for Electronic

2013: In December 2013, Amazon released a concept video showcasing

founder Jeff Bezos’ dream for a drone-based delivery system. In an interview on 60 Minutes, Bezos described the possibility of using the technology to make half-hour deliveries.

2016: Already one of the best drone makers on the marketplace, DJI’s

Phantom 4 introduced smart computer vision and machine learning technology. This allowed it to avoid obstacles and intelligently track people, animals, or objects. The resulting UAV was a major milestone for drone photography and consumer drones in general.

- How drones work? While drones serve a variety of purposes, such as recreational, photography, commercial and military, their two basic functions are flight and navigation. To achieve flight, drones consist of a power source, such as battery or fuel, rotors, propellers and a frame. The frame of a drone is typically made of lightweight, composite materials, to reduce weight and increase maneuverability during flight. Drones require a controller, which is used remotely by an operator to launch, navigate and land it. Controllers communicate with the drone using radio waves, including Wi-Fi.

-Technology, features and components. Drones contain a large number of technological components, including:

Electronic Speed Controllers (ESC)

Flight controller

GPS module

Battery

Antenna

Receiver

Cameras

Sensors, including ultrasonic sensors and collision avoidance sensors

Accelerometer, which measures speed

Altimeter, which measures altitude

Any discussion about drone features is closely tied to the type and use case of

the drone, including recreational, photography, commercial and military uses.

Examples of features include:

Camera type, video resolution, megapixels and media storage format

Maximum flight time, such as how long the drone can remain in the air

Maximum speeds, including ascent and descent

Hover accuracy

Obstacle sensory range

Altitude hold, which keeps the drone at a fixed altitude

Live video feed

Flight logs

-Electronic Speed Controllers (ESC) The term ESC stands for, an electronic speed control is an electronic circuit used to change the speed of an electric motor, its route and also to perform as a dynamic brake.

Components used in ESC

Solder pads for the 3-BLDC motor phases Negative (-) LIPO connections Positive (+) LIPO Connection Servo signal or input of the PWM signal GND reference of PWM Signal Solder jumper, for altering the direction of Rotation (CW/CCW) Solder jumper, for varying the type of the PWM input signal state LED.

- Flight controller A flight controller (FC) is the brain of the aircraft. It's basically a circuit board with sensors that detects orientation changes of your drone. It also receives user commands, and controls the motors in order to keep the quadcopter in the air.

Flight controllers are continuously evolving with their processors becoming faster to keep up with evolving flight controller software’s Flight controllers are usually titled to include the main microprocessor’s model as this gives the pilot a basic idea of the flight controllers’ capabilities. The most common microprocessor models used are the STM32 F1, F3, F4 and F7 chips. Essentially, the higher the number after the ‘F’ the faster the microprocessor will be and the more functionality it will have.

- GPS module

The primary purpose of the 12 visible satellites is to transmit information back to earth over radio frequency (ranging for 1.1 to 1.5 GHz). With this information and some math, a ground-based receiver or GPS module can calculate it position and time.

-Battery

The lithium battery packs used to power quadcopters have two common chemistries: Lithium polymer (LiPO) and lithium polymer high voltage (LiHV). The primary difference between the two is that a LiPO cell has a fully charged voltage of 4.2V compared to a LiHV cell which has a voltage of 4.35V at full charge. A LiPO has a resting or nominal voltage of 3.7V versus a LiHV which has a storage voltage of 3.8V. In regards to the performance of the two packs, a LiHV battery will initially provide more power but abruptly drops in voltage when discharged whereas a LiPO has a more linear discharge making it easier to qualitatively gauge the remaining flight time.

-FPV Antenna An antenna converts electrical power into electromagnetic waves and vice versa. In FPV, antennas (or antennae) enable wireless communication between the video transmitter (VTX) and receiver (VRX). Antennas in your FPV system are critical elements that determine the range and signal quality.

FPV Antenna Anatomy

Active Element – conductive material that transfers and receives radio wave signal in the air

Coaxial Cable – a special shielded cable that carries signal from the connector to the antenna element without emitting radio signals. They are used to extend the length of the antenna

Connector – used to connect the antenna to a video transmitter or receiver.

-Radio Control System (RCS) A radio control system is made up of two elements, the transmitter you hold in your hands and the receiver you put inside your drone. Dramatically simplifying things here, your drone transmitter will read your stick inputs and send them through the air to your receiver in near real time.

-What types of sensors do drones use? 1. Gyroscope The most basic of drone sensors, gyroscopes are cheap and basic enough to be integrated into even cheap mini-drones. Despite the very simple scientific principles that govern how gyroscopes work, they are still highly essential tools that are used for navigation in high-end aircraft and space shuttles. In practically all drones, gyroscope technology is heavily employed to help maintain a stable hover.

2. Barometer Barometers are sensors that measure air pressure. In drones, this air pressure information is used to determine the drone’s altitude. To ensure their best performance, barometers need to be periodically using air pressure readings at the local sea level. Barometers are found in almost all drones and are mostly used to aid in maintaining a stable altitude. Autonomous drone missions were changes in altitude are essential also make use of the readings from the onboard barometer.

3. Accelerometer -Accelerometers are used to determine position and orientation of the drone in flight. These small silicon-based sensors play a key role in maintaining flight control. The movement of these small 'diving boards' changes the amount of electrical current moving through the structure, indicating a change of position relative to gravity.

- Another technology used in accelerometers is thermal sensing, which offers several distinct advantages. Because of the sensitivity of these sensors, they play a role in stabilizing on-board cameras that are vital for applications like filmmaking. By controlling up and down movement, as well as removing jitter and vibration, filmmakers are able to capture extremely smooth looking video.

4. GPS GPS technology has played a huge role in allowing drones to fly autonomous missions. It’s not a feature that can be found in all drones but is a pretty standard inclusion for prosumer-grade models. By comparing the actual position of the drone with its targeted position, the PID controller determines which way the aircraft should move and instructs the drone motors with the appropriate commands.

5. Magnetometer In cases where determining the drone’s heading using only GPS location is not appropriate, a drone needs to have a magnetometer. As its name implies, a magnetometer measures the strength and direction of a magnetic field. Using this principle, a drone can always determine the direction of the magnetic North and adjust its trajectory accordingly.

6. Rangefinder There are different types of rangefinders found in drones but all of them perform a simple task: to determine how far away from the ground the drone is. If it sounds like a rangefinder’s function would be redundant with that of the barometer, then you’re right: a rangefinder is basically an alternative to a barometer that has a more limited scope but is much more accurate. The main drawback of using a rangefinder is that it only works when the drone is hovering close to the ground.

7. Inertial Measurement Unit (IMU) An IMU is not exactly a separate sensor of the drone but is instead a collaboration of several sensors. In most cases, a drone’s IMU consists of accelerometers, gyroscopes, and magnetometers, each set of which works in all three axes of movement. 8. Engine Intake Flow Sensors Flow sensors can be used to effectively monitor air flow into small gas engines used to power some drone varieties. These help the engine CPU determine the proper fuel-to-air ratio at a specified engine speed, which results in improved power and efficiency, and reduced emissions.

-Altimeter The True Terrain Following enables the drone (UAV) to accurately follow the terrain during the flight, based on data received from the laser altimeter. In True Terrain Following mode, the drone flies at low and constant AGL altitudes (up to 1 meter) without a need to import precise Digital Elevation Model (DEM) height-map into UgCS.

Underwater Drones

Robot ROV’s “ROV” stands for remotely operated vehicle. ROVs are unoccupied, highly maneuverable underwater robots that can be used to explore ocean depths while being operated by someone at the water surface. Remotely operated vehicles, or ROVs, allow us to explore the ocean without actually being in the ocean. ROVs range in size from that of a small computer to as large as a small truck. Larger ROVs are very heavy and need other equipment such as a winch to put them over the side of a ship and into the water.

Wave Gliders The most travelled drones on the planet are Wave Gliders, developed by California tech firm Liquid Robotics, which have covered more than 1.4 million miles of ocean so far. Each drone consists of a surfboard-sized "float" and a wing-shaped "sub" that hangs up to 26 feet (8 meters) under the water. The drones use wave motion and solar power to travel thousands of miles at sea without fuel, with applications in environmental monitoring, defense and maritime surveillance, and offshore oil-and-gas operations.

Ocean Gliders Autonomous ocean gliders, or underwater gliders, like the Slocum glider shown here, can convert small changes in buoyancy into forward motion. They are used extensively for scientific research at sea, such as remote water sampling, environmental monitoring, or acoustical surveillance over months and thousands of miles of ocean.

1. ROV’s These underwater robots are controlled by a person typically on a surface vessel, using a joystick in a similar way that you would play a video game. A group of cables, or tether, connects the ROV to the ship, sending electrical signals back and forth between the operator and the vehicle. Most ROVs are equipped with at least a still camera, video camera, and lights, meaning that they can transit images and video back to the ship. Additional equipment, such as a manipulator or cutting arm, water samplers, and instruments that measure parameters like water clarity and temperature, may also be added to vehicles to allow for sample collection. First developed for industrial purposes, such as internal and external inspections of underwater pipelines and the structural testing of offshore platforms, ROVs are now used for many applications, many of them scientific. They have proven extremely valuable in ocean exploration and are also used for educational programs at aquaria and to link to scientific expeditions live via the Internet.

ROV parts

I. Tether A typical work class ROV has a tether cable installed between the vehicle and the TMS (tether management system), to transmit electrical power, optical signals and mechanical payloads through a light and highly flexible and robust cable. ROV tether cables are exposed to repeated bending at small diameters and low tension, followed by occasional snap loads. High performance polymer yarn handles hydrostatic pressure at great depths, and is resistant to fatigue and friction damage. It is also chemically stable in seawater, oils and other fluids used in the oil & gas industry.

II. Thrusters

An underwater thruster is a configuration of marine propellers and hydraulic or electric motor built into, or mounted to an Underwater Robot as a propulsion device. These give the robot movement and maneuverability against sea water resistance. The main difference between underwater thrusters and marine thrusters is the ability to work under heavy water pressure, sometime up to full ocean depth. III. Frame The Catalina frame is composed primarily of 1/2" (nominal) PVC pipe and fittings. These are inexpensive, easy to cut and glue, waterproof, totally corrosion resistant, and widely available in hardware stores and online sources. The purpose of the frame is to support, align, and protect the major underwater components of the ROV. These are: 1 camera, 3 lights, 4 thrusters, 2 floats, and various wires. We will start by describing several specialized parts of the frame, then conclude by explaining how to put it all together.

The Brain of ROV

Introduction -Voyager II is an ROV based on Asgard. To make good use of space in Asgard, the ROV MAKER Team came up with its own control board instead of using single-board computers available on the market such as raspberry pi. The entire endeavor is called the Baroque project by the ROV MAKER team. - Having surveyed potential hardware solutions, the team narrowed down the choices to: (1) multimedia performance and (2) data routing delay. The team eventually chose the data routing delay and used the MIPS-based router for the Baroque control board. - The Baroque board adopts router chipset and its hardware has two versions: the ROV Baroque board and the reel Baroque board. The on-board PLC (Power Line Control) module allows the ROV Baroque board and the reel Baroque board to communicate for as long as 100 meters. On the ROV tube side, you can save more space if co-working with ESC board. On the reel side, the Baroque board provides WIFI and RJ45 as two interfaces to connect a Notebook to an ROV. - To maximize the efficiency of the electronic speed controller (ESC), ROV MAKER has also developed its own ESC control board, supporting up to 4 ESCs. The ESC control board also integrate power monitor ICs. The Baroque board can monitor the voltage and current through I2C. The ESC control boards helps save much space in the Asgard Ball module.

ROV Baroque Board The ROV Baroque Board works as the control board of Voyager II. By executing relevant software and controlling the peripheral hardware, the board makes Voyager II the best underwater robot it can be. The working voltage of the ROV Baroque board is between 5-18 Voltage. The board has built-in OpenWrt work as the Operating System and is installed with node.js and Janus Gateway software module. But the ROV client-server software of VoyagerII is not built-in. The ROV Baroque Board: Front View

The ROV Baroque Board: Back View

Application: ROV-REEL Configuration The Baroque control board integrates the Power Line Communication (PLC) module, which uses a power line and can transmit network data farther than the conventional Ethernet line. Thanks to the PLC on board, the ROV Baroque control board and the Reel Baroque boards can build a local network by twisting a pair of neutral buoyancy lines. The transmission is capable of traveling as far as 100 meters.

2. Wave Gliders -The Wave Glider harvests energy from ocean waves for propulsion. With this energy source, Wave Gliders can spend many months at a time at sea, collecting and transmitting ocean data. -The vehicles host sensor payloads such as: atmospheric and oceanographic sensors applicable to ocean and climate science, seismic sensors for earthquake and tsunami detection, and video cameras and acoustic sensors for security and marine environment protection purposes. -Wave Gliders are used for defense, maritime surveillance, commercial, oil and gas, and science and research applications. Examples include: -Commercial/Oil and Gas – atmospheric, seismic, and environmental monitoring -Defense - Anti-submarine warfare and Intelligence, Surveillance and Recognizance -Maritime Surveillance – surface vessel detection for coastal and border security -Scientific research – weather monitoring, climate change, deep-sea seismic detection, ocean acidification, environmental monitoring, bio-geophysical research and fish/ecosystems monitoring

Wave Gliders Parts

I. Weather station and marker light A weather station is a device that collects data related to the weather and environment using many different sensors. Weather stations sensors may include a thermometer to take temperature readings, a barometer to measure the pressure in the atmosphere, as well as other sensors to measure rain, wind, humidity and more.

II. Solar panels

Solar panels are a silent, maintenance free, convenient and cheap way of keeping your glider batteries fully charged. For practical reasons they are not usually fitted to the glider structure although you occasionally see them taped to turbo engine doors or on the top of the cockpit coaming.

III. Active radar reflector Active radar reflectors are increasingly fitted to small vessels to replace passive radar reflectors. They have the advantage of being small in size and of low weight, and so are easily positioned towards the highest point of the vessel, including the mast-top of a wave glider. They are basically a very simple concept – received radar signals are detected, amplified and immediately retransmitted.

IV. ADCP Option

Acoustic Doppler Current Profilers (ADCP) are hydro-acoustic instruments that are used to measure water velocities or currents over a specific range or water depth. ADCPs utilize the Doppler effect to measure water velocity in discrete layers – essentially sending a sound signal of a specific frequency into the water column and measuring the sound signal return. The change in return frequency is proportional to the water velocity. ADCPs can be deployed many ways, up-looking, down-looking and side-looking.

V. AIS Receiver AIS receivers allow you to receive AIS transmissions from nearby vessels and output the data in either serial, USB or TCP/IP format (or a combination of the above).

1. Dynamic Model Applications 1.1. Having a good dynamic model can save time and money by providing a

sufficient way to develop control and estimation schemes in simulation rather than traditional trialand-error methods. In addition, the model can serve as a platform for testing different sea-state conditions.

1.2. Control is generally separated into classical or frequency domain and modern

or time domain control. Either method relies on a good dynamic model for development and testing. The general types of control methods seen are as follows:

• Adaptive Control: Identifies parameters using a sensor network and modifies the controllers gains as necessary. • Geometric Control: A coordinate free formulation of control algorithms. • Hierarchal Control: Decision making is split up in a hierarchy order. • Intelligent Control: Uses probability such as fuzzy logic, Bayesian probability and machine learning for control. • Optimal Control: Used to optimize a cost function. For example, if the most important state of the wave glider is position, this can be given a higher weighting. • Robust Control: The controller is robust to small errors or disturbances. • Stochastic Control: These are Bayesian driven control algorithms that assumes a stochastic noise in the dynamic model.

3. Ocean Gliders -An Ocean glider is a type of autonomous underwater vehicle (AUV) that employs variable-buoyancy propulsion instead of traditional propellers or thrusters. It employs variable buoyancy in a similar way to a profiling float, but unlike a float, which can only move up and down, an underwater glider is fitted with hydrofoils (underwater wings) that allow it to glide forward while descending through the water. At a certain depth, the glider switches to positive buoyancy to climb back up, and the cycle is then repeated. - The typical up-and-down, sawtooth-like profile followed by a glider can provide data on temporal and spatial scales unattainable by ordinary AUVs and much more costly to sample using traditional shipboard techniques. A wide variety of glider designs are in use by navies and ocean research organizations and typically cost around US$100,000.

Ocean Glider Parts

I. Engine The overall principle of glider engine concept is to change the glider volume and therefore to change glider buoyancy. The principle of volume change is either realized by pumping a low viscosity hydraulic oil back and forth between an internal and an external bladder or by pushing seawater in or out of a cavity. Unlike floats, glider cycle up and down through the water column in a saw tooth pattern, because their wings and their body lift are converting the vertical motion also into horizontal motion, both as the vehicle ascends and descends.

II. Hull

The hull of a glider is another important part. It is needed to provide a streamlined hydrodynamic shape, to resist external 5 pressure and therefore to protect the electronics. Furthermore, it is needed to determine drag and compressibility which have an impact on important operational parameter such as duration and, consequently, cost of a deployment, especially for electric powered gliders.

Navigation To navigate from one waypoint to the next a glider has to follow a certain track underwater. This targeted underwater movement, called flying, is characterized by two parameters. The glide angle and the heading. To be able to adjust these parameters the live performance of the glider has to be monitored constantly. Therefore, glider navigation includes both monitoring performance and subsequent adjustment of glide angle and heading.

Communication Glider frequently come to the sea surface to communicate with mission control by using the Iridium satellite phone system. Antennas can be housed in a tail fin (Slocum), in a tail string (Sea glider) or in a wing (Spray). They are raised above the surface 20 while the vehicle is communicating or obtaining a GPS fix. In high sea-states, however, loss of performance of communication systems can occur, but glider typically have enough internal memory for message buffering and data storage.

Energy The amount of energy carried by a glider affects how long the glider can stay out in the water before it must be recovered and therefore it determines mission length and duration. Since the major part of the available energy is consumed by the buoyancy pump (~70 %), the depth of the dives and the stratification of the ocean are critical parameters. This means glider batteries last longest when dives are deep, slow, and occur in water that has little change in density.

BIBLIOGRAPHY

https://internetofthingsagenda.techtarget.com/definition/drone https://www.elprocus.com/electronic-speed-control-esc-working-applications/

https://www.getfpv.com/learn/new-to-fpv/all-about-multirotor-fpv-drone-flight-controller/

https://www.getfpv.com/learn/new-to-fpv/all-about-multirotor-fpv-drone-battery/

https://oscarliang.com/best-fpv-antenna/#what-is-fpv-antenna

http://dronenodes.com/drone-transmitter-receiver-fpv/

https://3dinsider.com/drone-sensors/

https://www.fierceelectronics.com/components/how-many-sensors-are-a-drone-and-what-do-they-do

https://www.youtube.com/watch?time_continue=311&v=YW_VR3Yx0DE&feature=emb_logo

https://www.droneshowsoftware.com/software

https://www.worldfishing.net/news101/industry-news/fish-farm-drones-assist-in-wreck-recovery

https://oceanexplorer.noaa.gov/facts/rov.html

https://www.nexans.no/eservice/Norway-no_NO/navigate_331785/ROV_umbilical_and_tether.html

https://en.wikipedia.org/wiki/Underwater_thruster

https://www.rovmaker.com/2019/11/18/a-quick-guide-to-the-baroque-control-board-the-brain-of-rov/

https://en.wikipedia.org/wiki/Liquid_Robotics

https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/glider_handbook/media/gfh_ch09.pdf

https://www.sciencedirect.com/topics/engineering/radar-reflector

http://www.rowetechinc.com/blog/adcp_application_summary/

https://shop.marinetraffic.com/ais-receivers.html

https://www.researchgate.net/publication/329628268_Design_and_Experimental_Analysis_on_Autonomous_Control_System_of_Wave_Glider

https://en.wikipedia.org/wiki/Underwater_glider

https://www.ocean-sci-discuss.net/os-2016-40/os-2016-40.pdf