Quadcopter for Aerial Surveillance Edmund Nhlanhla Moyo, Student No: 215078937, Department of Electrical and Electronic Engineering Technology University of Johannesburg, Johannesburg, South Africa Abstract—In this document, we will discuss how an Unmanned Aerial Vehicle (UAV) system is implemented and used to capture aerial real-time data. A focus shall be given to the selection of the most important component of the system, the flight controller, and its sensors. The UAV system will be designed for stable flight for accurate data capture. The project’s unique feature shall be the inclusion of a sense and avoid system to allow for the drone to avoid collisions with obstructions. Keywords—Aerial Vehicle, Real-Time Data, Flight Controller, Sense and Avoid. I. i. INTRODUCTION Background remaining stationery in the air, as well as its VTOL capabilities, are its main benefits [3]. Due to this, the quadcopter can operate in almost any situation, including inside or in confined locations with restricted agility. Many of the characteristics of a quadcopter may also be found in a traditional helicopter with one main rotor and one tail rotor. The conventional helicopter needs a complicated hub to make it feasible to spin the motor axis to produce a translating action, but the quadcopter has no moving elements other than the rotating motors and propellers. The quadcopter is also more adaptable in terms of where to set the centre of gravity and less susceptible to vibrations. Flying inside buildings is safer since the rotors can be covered more readily and are considerably smaller [3]. As was previously mentioned, the standard quadcopter design contains only the propellers as moving elements. The only method to create a lateral motion is to tilt the entire frame because the motors and their propellers are fastened to it. The quadcopter does not need a tail rotor to regulate yaw motion, in contrast to a typical helicopter. The quadcopter features four motors with a clockwise and counterclockwise rotation of two each. There will be a moment near the yaw axis if the clockwise and counterclockwise motor pairs spin at different rates [3]. Unmanned aerial vehicle (UAV) development began at the turn of the 19th century when the majority of the first prototypes were intended to be airborne missiles or remotely piloted weapons [1]. Unmanned aerial vehicles (UAVs) now have a far larger range of uses and are no longer just used for military objectives. Recent technology advancements have opened new possibilities and increased the accessibility of these flying machines for public usage. UAVs are now ii. Objectives routinely flying today on regular basis, guarding the borders, keeping an eye on agriculture, and recording or The goal of this project was to design and implement a photographing TV either provides information or augmented quadcopter, often known as a four-rotor aircraft, that could fly reality toys for kids. All these opportunities provide a broad steadily while being controlled manually by radio. The range of UAV enhancement options [1]. primary focus of the project is to design a system that can The advancement of technology has also made it possible for achieve impeccable flight stability using advanced control enthusiasts and other amateurs to become ardent drone pilots. systems techniques. The aim is also to use an Ardupilot PX4 Most civil applications, like search and rescue, or other Cube Orange flight controller to control the flight of the cutting-edge applications benefit from some form of computer quadcopter and to configure the controller with my own aided autonomous or automated flight, even though most configuration and drone code. Another aspect of the project is hobbyists and other enthusiasts buy drone systems for the to also capture aerial data using the drone. The PX4 Cube enjoyment of flying the craft around the yard, taking quality Orange flight controller is a very versatile microcontroller aerial videos, or competing in First Person View (FPV) racing. board that can be used for professional flight [4]. Therefore, The operator can put up a "flight plan" in a control centre the user must configure and set it specifically for the application to have a commercial UAV fly from one GPS appropriate mission. This report's goal is to outline the waypoint to another, then return home, or travel to a GPS project's proposal as well as the measures that are to be taken waypoint, snap a 360-degree photo, then travel back to its to implement the project. starting point [2]. The quadcopter is a common type of drone, mostly due of its distinctive features. The quadcopter's hovering capability or PJEELB3 ELECTRICAL PROJECT REPORT 2022 iii. Problem Statement Many of the present environmental issues facing the globe are a result of industrialization. For instance, industrialization is responsible for climate change, dangerous air pollution levels, the depletion of fishing supplies, poisons in rivers and soils, an abundance of garbage on land and in the seas, the loss of biodiversity, and deforestation [5]. Innovations are advancing more quickly, more effectively, and more broadly than ever before as the Fourth Industrial Revolution (4IR) picks up speed. Additionally, technology is getting more interconnected, and we are witnessing a fusion of the digital, physical, and biological worlds. By influencing the economies, values, identities, and prospects for the next generations, new technologies are facilitating societal transformations [5]. There is a need for advanced, reliable, and cost-effective systems to collect aerial data and deliver packages. Drones can also be used in precision agriculture where they are able to do crop spraying and dusting thus increasing productivity in the agricultural sector. After all, food security is one of the major concerns as the Fourth Industrial Revolution looms. It is apparent that there is a need for stable flight for accurate real-time data capture, error-free data transmission in precision agriculture, and crash-free landings in drone delivery. The need for stable flight is especially important for the drone pilot, who needs to be able to accurately fly their drone to the exact location of the target, as inaccuracies might result in the loss of the drone, injuries to people or animals, or worse still, fatalities. motor situated on the same diagonal rotates either clockwise (CW) or counterclockwise (CCW) in the same direction (CCW) [7]. When driving a car, we can move forward, backward, to the left, or to the right, but when discussing a flying system, we wouldn't use the same terminology. Yaw, roll, and pitch are terms used in the flying system [7]. Before learning about a quadcopter's flight dynamics, it is important to grasp its three primary angular motion parameters: yaw, roll, and pitch. Figure 1: Three axis of drone movement [11] II. LITERATURE REVIEW i. Components for unmanned aerial vehicles We need to attach several sophisticated electrical gadgets to construct a dynamic unmanned aerial vehicle [6]. Many smart electronic components, including a brushless DC motor, a PX4 Cube Orange Multi-Rotor controller, an ESC (electronic speed controller), and a 5500 mah Lithium Polymer battery, have been employed in this application. All those electrical components and their behavior will be covered in this section. This part also includes an in-depth discussion of the flight dynamics that the flight controller is responsible for. This chapter also covers the design of the control systems of the drone. ii. Flight Control Mechanics The relative thrust of each of the four motors is changed to regulate the quadcopter's mobility. We are employing Xshaped quadcopters in this instance. In this quadcopter, the III. i. THE QUADCOPTER Actuators Here, a brushless DC motor (BLDC) has been employed. A brush placed across the shaft of a DC motor switches the coils' power direction [5]. The coils and magnets of a DC motor are utilized to drive the shaft. These brushes are absent from brushless motors. The motor, which is mounted to the mounting, has coils in the middle. They have many magnets fixed to an exterior cylinder that is connected to the spinning shaft. The coils are so secured. It indicates that a brush is not necessary because the wires may reach them directly [8]. Compared to a DC motor, a brushless DC motor rotates at a significantly greater speed and consumes less power (at the same speed). Additionally, there is no power loss because of brush transfer. We can see a 1000KV BLDC motor with three input wires in the figure below. These three wires will be connected to an electronic speed controller (ESC) [5]. Each brushless motor has a Propeller installed on top of it. There are several sizes and forms of propellers. We are employing propellers with dimensions of (15*5.5), which means that their diameter is 15 and their pitch is 5.5 inches. Pitch provides an effective area whereas diameter provides an area. The propeller will produce more thrust and be able to lift more weight if we use one with a greater pitch for a similar diameter, but it will also need more electricity. More velocity and agility are offered by a high RPM, but less weight can be lifted [8]. ii. HD Camera A camera shall be used to view and capture real-time data using the drone. The camera of choice is the Run Cam Nano 3. vi. Circuit Diagram Below is the full circuit diagram of the Quadcopter: Electronic Speed Controllers (ESC) Since brushless motors are three-phase, they cannot be used with DC power. To keep the motor spinning, ESC continually provides three frequency impulses with distinct yet adjustable phases. Both the battery input and the motor's three-phase output are present. Using pulse width modulation, the controllers connected and disconnected the motor about 2000 times per second (PWM). In place of a mechanical switch, a MOSFET transistor is employed as a switch. Motors cannot notice the changeover because it happens so quickly [7]. When a 24 V battery is attached, the motor only operates at half speed since it only recognizes the battery as 12 V half the time. The motor inductance, which maintains the motor current flowing continuously, is likewise impacted by the switching speed. The battery current will be equal to 50% of the motor current since the battery is only supplying that current 50% of the time. The internal circuit diagram of the ESC and its current (Amps) response over time are shown in the figure below. iii. v. Figure 2: The layout of the Unmanned Aerial Vehicle [3]. An inclusion of Detect and Avoid system shall be included to give the project an interesting twist. The drone shall be wired and configured to detect and avoid possible obstructions. Using the circuit diagram and components the actual quadcopter is as depicted in the figure below. Radio and Reciever A transmitter serves as a user's controller. The user can only control the quadcopter using this transmitter. The foundation is radio communication. The drone has a receiver attached to it, and the receiver has an antenna that it uses to communicate with the transmitter. This entire conversation is wireless. A signal is sent from the transmitter to the receiver, which then delivers it to the flight controller. Here, we are utilizing a transmitter and receiver from FLYSKY. This transmitter has a range of 1500 meters, however, if it is used in an area with a lot of magnetic interference, its range will be reduced. iv. Power Plant Figure 3: The complete quadcopter as built. Quadcopters frequently employ lithium polymer (LiPo) batteries due to their lightweight design and high current rating. Here, 3 Cell LiPo batteries were utilized. LiPo batteries have a single-cell capacity of up to 3.6 V. The 2200mAh LiPo battery has a voltage of 11. V (3 cells), a discharge rate of 30C, and a capacity [7] vii. Specifications of aircraft The aircraft specifications are as follows: • Max Flight time/Endurance = 30 minutes • Max speed 300km/hr • Max payload = Up to 1Kg • Range = 1500m • • • Vertical take-off & landing capability practically take off and land anywhere) Hovering capability Max altitude 100m IV. (can METHODOLOGY AND TASKS Like any other robust project, a comprehensive methodology must be followed to ensure successful completion. This includes a thorough planning phase. In fact, the planning phase is the most important phase of the project. A lot of time is spent figuring out which components exactly are to be used and what their sizing should be. The next phase is the execution phase. In this phase, the connection of components is implemented. The flight controller is also configured to the desired specifications. The final phase is the testing phase. This is where the system is checked and tested to ensure that it is working as intended. The testing phase is also where the system is debugged and tweaked. The actual flight is also performed in this phase. The last phase is the analysis phase. This is where the data is analyzed. This phase is also where the results are presented and a comprehensive conclusion to the project is drawn. Figure 4 below gives a summary of the process steps V. RESULTS AND OUTCOMES The results of flight test conducted at the James and Ethel Park, Johannesburg are shown in the figure below. Figure 5: The flight path of the quadcopter during the successful test. Figure 6:The graph depicting altitude vs time. Figure 4: The block diagram of the formulated methodology. Figure 7: The graph depicting voltage vs time It was also important to understand the flight dynamics surrounding vertical take-off and landing so that we are able to include a sense and avoid system and how to configure it in our flight controller and Ground Control Station. We also wanted to determine the behavior of the Brushless DC motors and their relative power consumption when used to hover. The flight controller we used is the PX4 Cube, which is a sophisticated autopilot system. Astounding results were achieved from the Vertical Take Off and Landing/Hover Test bench as the system is optimized for sensing and avoiding obstacles and gathering data. REFERENCES Figure 8: The graph depicting current vs time. VI. PERFORMANCE AND DATA ANALYSIS From the results above, in the tests, the maximum altitude achieved is 45m and this is achieved after a climb of 2 minutes. Caution was being taken not to push the parameters to their rated maximum. As expected, the battery voltage experienced an exponential decrease. The full charge voltage is found using the formula below: Voltage = No of battery cells * 3.8 = 8 * 3.8 =30.4v The flight commenced with a nominal voltage of 28v and ended at a voltage of 25v. This was done so as not to reach the critical voltage of the cells as this would have potentially caused a crash. [1 ] [2 ] [3 ] [4 ] [5 ] [6 ] [7 ] A fairly constant current output was maintained throughout the test. This is also important during hovering to maintain the balance of the aircraft. [8 ] CONCLUSION The objectives of the project explore a lot of aspects in the fields of electrical, electronic, and aeronautical engineering. The first part of the project is to achieve stable flight using advanced control systems. The second part of the project is to use brushless DC motors to replace traditional DC motors for propulsion. The third part of the project is to achieve remotecontrolled flight using a radio control transmitter and receiver. The fourth part of the project is to develop a quadcopter drone that is capable of aerial data collection using an HD camera. [9 ] J. Halgasik, “Flight Control For System Unit for Small UAV Aircraft,” Czech Technical University, Prague, 2014. 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