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Autonomous Drone Charging Station 1

ECE 4512: Design I April 25, 2018

design document for

Autonomous Drone Charging Station

submitted to:

Dr. Bryan Jones

ECE 4512: Senior Design I

Department of Electrical and Computer Engineering

413 Hardy Road, Box 9571

Mississippi State University

Mississippi State, Mississippi 39762

April 25, 2018

Prepared by:

S. Thomas, H. Fowler, D. Giles, Z. Armstrong, and T. Hubbard

Faculty Advisor: Professor Mehmet Kurum

Industrial Advisor: Josh Weaver

Department of Electrical and Computer Engineering

Mississippi State University

413 Hardy Road, Box 9571

Mississippi State, Mississippi 39762

email: {jst212, hgf26, dg704, za59, alh798}@ece.msstate.edu

LIST OF ABBREVIATIONS

DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING



FAA - Federal Aviation Administration

GSM - Global System for Mobile Telecommunication

ADCS - Autonomous Drone Charging Station

IPR - Ingress Protection Rating

I2C - Inter-Integrated Circuit

TX - Transmit

RX - Receive

iOS - iPhone Operating System

SIM - Subscriber Identity Module



Executive Summary

Today, industries are wanting to remotely operate drones from central locations. However, companies must

abide by FAA regulations stating that a drone must be kept in visual line-of-sight during operation. To

perform remote operations, companies need a supervisor to observe any active drones at the remote

location. With continuous operation of drones, a problem arises. Drones have a short battery life and need

to be charged regularly. This causes the supervisor to shift their focus away from any active drones to the

ones that need charging which violates FAA regulations. With the Autonomous Drone Charging Station

(ADCS), manually charging a drone is no longer a burden to the supervisor. The ADCS provides continuous

drone flight for remote operations by autonomously charging the drone when it lands while also serving as

a protective container. Below, Figure 1 shows a visual representation of the ADCS system.

Figure 1 - Autonomous Drone Charging Station

The ADCS must demonstrate durability, reliability, and convenience. For communication reliability, the

ADCS’s location must fall within at least 45 miles of a single cellular tower to ensure a connection between

the ADCS and the device requesting its services. As for durability, the ADCS must maintain functionality

through water splashes and solid particles larger than a grain of sand. It must also lift a load of up to 300

lbs. Convenience is another constraint, as the web application for the project must be able to deliver

commands to and retrieve status reports from the ADCS at any time.

To provide communication between the ADCS and a device requesting its services, a cellular module was

installed inside of the ADCS. When a request from the web application is sent to the ADCS, the cellular

module receives the request and sends it to the microcontroller that controls the ADCS. The microcontroller

processes the command and acts accordingly. An “open” command causes the doors for the ADCS to open

and the 300 lb-rated actuator begins raising the platform on which the drone will land and charge. A “close”

would perform the opposite, giving the drone a protected place to charge once it lands. To begin the

charging process, the ADCS must test each charging plate to see if there is contact with a compatible leg

of the drone. Once the two contacts are found, the plates are polarized appropriately and the charging

commences. As for status report request, the microcontroller will gather key information about the ADCS

and send it back to the web application, providing the user with the state of the station.

Because the ADCS houses drones up to 3.5ft. in diameter, it accommodates larger drones than other

competitors. Implementing inductive charging would significantly improve the project by eliminating the

need of charging plates. This would free up the processing power used to find the charging contacts of a

drone and reduce the weight of the platform, therefore lightening the load on the actuator. The ADCS’s

success would bring about true continuous operation, simultaneously saving time and money.



TABLE OF CONTENTS

1. 39

2. 207

2.1. 197

2.2. 199

2.3. 1910

3. 1911

3.1. SYSTEM OVERVIEW 11

3.2. Error! Bookmark not defined.2

3.3. Error! Bookmark not defined.8

4. Error! Bookmark not defined.26

4.1. Test Certification - Lift Load2426

4.2. Test Certification - Drone Charging2527

4.3. Test Certification - Drone Sensing 325

4.4. Test Certification - Application 32

4.5 Test Certification - Drone Size 34

4.6 Test Certification - Laser Sensor 36

4.7 Test Certification - Remote Operation 37

4.8 Test Certification - ADCS Complete System 38

5. 2539

6. 2539





1. PROBLEM STATEMENT

1.1 Historical Introduction

Unmanned aerial vehicles (UAVs) first appeared in 1849 when Austria planned an airstrike on the city of

Venice using balloons equipped with 30 pound bombs. Five decades later, Nikola Tesla contributed to the

development of UAVs by providing them with radio control. The more commonly known term “drone”

would come about in 1935 when the U.S. created a military UAV known as the DH-82B Queen Bee, which

was used for target practice. Fast-forward to 2013; Amazon CEO Jeff Bezos announced that Amazon will

invest research into drones for shipping, fueling the expansion of commercial drones [1].

As technology advances, drones and their usage have dramatically changed through the years. The growing

market for drones will impact a number of industries including private security, law enforcement, real

estate, construction, mining, agriculture, and utilities. Outlook for the growth of the commercial drone

sector will grow at a compound rate of 19 percent between 2015 and 2020 [1]. With the popularity of

commercial drones on the rise, the need for drones to accomplish multiple remote tasks from a central

location becomes a necessary factor. By doing so, this will eliminate the need for traveling to the work site

and maximize the pilot’s production from his/her fixed location.

With the usage of drones changing from viewer visual line-of-sight to remote operations and scheduled

autonomous flights, a challenge arises: abiding by the Federal Aviation Administration (FAA) regulations.

To abide these regulations pilots are required to have visual line-of-sight of the drone at all times [3]. For

remote operation of drones to take place, two modes of operation are plausible. The first mode calls for an

observer at the remote location to keep visual line-of-sight of the drone(s) at all times. Therefore, the pilot

can remain at a central location and operate a drone remotely. The second mode of operation requires the

drone to have collision avoidance technology, which can be expensive for small companies. By

implementing the latter mode of operation, the FAA will grant a waiver allowing autonomous flight;

therefore, an observer’s presence is no longer essential.

Because these remote tasks may run for extended periods of time, the demand for improved battery life

increases. Today, the average flight time of a drone is roughly 15 minutes until the battery needs changing

or plugging in for charging by hand. This can become an obstacle for observers who need to keep visual

line-of-sight of the drones. When dealing with multiple drones, charging and observation of drone activity

become two separate tasks. This presents the issue of the observer having to watch the drone while it is in

operation and also attempt to change the battery of the other drones all at once. These actions do not fall

within the regulations of the FAA and doing both simultaneously is simply not feasible. With the

Autonomous Drone Charging Station (ADCS), the hassle of companies manually charging drones will

become obsolete. By allowing the ADCS to charge the drones autonomously, the observer’s sole job

becomes monitoring the drone’s activity. This, in turn, will permit FAA-approved continuous operation.

1.2 Market and Competitive Product Analysis

The market for commercial drones has exploded within the past five years because of the increases in

funding, advances in technology, and decreases in cost. Contributing around 64 million dollars, 3DR is one

of the largest U.S. companies to invest in commercial drones. Since 2017, the drone market has amassed a

worth of around two billion dollars, making it a heavily rewarded investment [1]. Industries such as

agriculture and surveillance would benefit significantly from remote operation. For example, agricultural

companies are using drones to help monitor crop growth and increase crop production. Drone agriculture

revenue today accumulates to 500,000 dollars and is projected to grow to four million dollars by 2024 [4].



Unfortunately, autonomous charging stations have not reached the mainstream market. Only a handful of

companies have developed autonomous charging stations for drones, creating little competition. To remedy

this, companies such as Skysense and The Dronebox have developed charging stations that automate the

process of charging a drone, allowing for continuous flight time. These companies aided in solving these

problems but have yet to fully meet the needs of the industry. Products of these competitors limit consumers

by placing restrictions on drone size; for instance, the Dronebox and Skysense charging stations support

only quadcopter drones that have an average wingspan of one foot and five inches. The Dronebox charging

station also requires the consumer to buy their custom drone and does not allow for much modification [2].

As a result, companies would have to conform to these restrictions, which costs consumers more money.

The market’s situation has created a need for our product, the ADCS. The ADCS team’s charging station

will allow consumers to use their own drone of choice, and the only requirement is that the maximum size

of the drone be approximately five feet and six inches. The ability to modify the drone and use different

sizes offers a large variety of missions that can be completed, compared to competitors, and saves the

consumers money. Our product will allow the use of any type of drone meeting the previously stated size

constraint. The ADCS will allow companies to operate remotely from a central location and, at the same

time, serve as a protective container for the drone.

1.3 Concise Problem Statement

The problem with continuous remote drone operation is that drones have a short battery life and the drones

need to be charged. Since the major objective of autonomous flight is eliminating human interaction, the

drone must charge autonomously. As stated earlier, companies using drones must abide by the FAA

regulations stating a drone can only be operated as long as the drone is within eyesight [3]. However,

companies can receive a waiver to operate these drones without the need of keeping the drone in line-of-

sight. In 2015, 1,000 permits were granted, and this number more than tripled in 2016 with 3,100 permits

granted [1]. This raises two points: the need exists for remote operations and fully autonomous flight, and

the FAA is more than willing to allow it now.

Drawing the big picture, the main service of the ADCS is to provide continual drone flight for remote

operations by autonomously charging the drone and serving as a protective container. The core functions

of the ADCS are to sense when the drone is near and open the roof to allow it to land. After the drone has

landed, the ADCS needs to know the landing pad can descend and the roof can close without damaging the

drone. Finally, the ADCS must be able to charge the drone autonomously, swiftly, and effectively. These

requirements must be met in order for this project to work.

1.4 Implications of Success

The ADCS will make continuous drone operation at any common geographic location possible by allowing

companies to charge their drone remotely and autonomously. If the ADCS becomes a standard for remote

drone operations, the ADCS may be able to acquire FAA permits for all charging stations, no longer

requiring pilots to apply for this permit. This allows companies with autonomous drones to use the ADCS

and the drone in unison without the need for an observer. If the companies do not have an autonomous

drone, or do and still want an observer to watch the drone, the ADCS still meets FAA regulations.

After the market has accepted the product and begun to use the ADCS, drones will be more useful with the

increase in battery life through the ADCS. Another additional benefit of this product is in the field of

security. Monitoring large crowds is hard for someone on the ground, but seeing everything through a

bird’s-eye view can help spot malicious activity. This idea currently cannot be implemented because of the

limitations of drone batteries. The ADCS will fix this problem by setting up multiple charging stations



around the city, and when the drone starts to lose power, it can locate the nearest charging station. With a

massive setup of drones and charging stations, then a whole city could potentially be kept safe with eyes in

the sky.

2. DESIGN REQUIREMENT/CONSTRAINTS

The main goal of the Autonomous Drone Charging Station (ADCS) is to provide continual drone flight for

remote operations by autonomously charging the drone and serving as a protective container. Today, FAA

regulations limit remote drone operation by requiring the pilot to have visual line-of-sight of the drone. To

allow remote drone operation that abides by FAA regulations, users of the ADCS must meet one of two

regulations: have an observer at the remote location who has visual line-of-sight of the drone at all times,

or meet waiver requirements by outfitting the drone with collision avoidance technology. In either case, the

ADCS will allow autonomous operation of drones by eliminating the need for human interaction. A drone

can simply land and start charging. The remainder of this document is divided into two sections: the

technical constraints and the practical constraints. The technical constraints lay out the details the ADCS

design must follow to ensure it allows drones to charge autonomously and be protected while inside the

station. The practical constraints present the conditions and regulations within which the ADCS must

operate.

2.1 Technical Design Constraints

On the following page, Table 2.1 contains the five technical design constraints that must be met upon

completion of this system.

Table 2.1 Technical Design Constraints

Name Description

Communication The ADCS must be within 72.4 kilometers of a

cellular tower, depending on the tower’s

technology, and communicate via the cellular

network.

Maximum Load The ADCS will have a lift component that must

lift a maximum load of 60 pounds.

Drone Charging The ADCS charger will be controlled by a

microcontroller which delivers a voltage of ±12

with a ±5% variability.

Application The ADCS must provide information to the user’s

smartphone regarding the station’s status. Some

examples would be battery life, roof open or

closed, etc.

Drone Size The ADCS will support drone size up to 3’5”.



2.1.1 Communication

An application on the user’s phone will be used to control the ADCS through cellular network. The ADCS

must be within 3G coverage of any local cellular carrier tower. With cell towers coverage gets deterred at

certain ranges; therefore, we want to keep the ADCS relatively close, within 45 miles, of a cell tower. Based

on this requirement, the placement of the ADCS must be considered accordingly. Because of how the ADCS

remotely operates, distance is not an issue when positioning the station. As long as these requirements are

met, the station should function properly.

2.1.2 Maximum Load

The ADCS will contain two mechanisms: retractable doors and a floor lift. As for the retractable doors, the

force required to open and close the ADCS will be less than lifting the platform up and down. The lift will

require a greater force. The metal frame of the lift must be capable of raising the platform containing the

drone and any other hardware components placed on the platform. To be more specific, the lift must be able

to raise and lower a maximum load of 60 pounds in order to function properly. The 60 pounds accounts for

the charging hardware and the weight of a drone. The 60 pound constraint will allow any weight drone be

used with the ADCS.

2.1.3 Drone Charging

Autonomous drone charging is one of the key functions of the ADCS. Properly charging the drone’s

batteries with the correct voltages will be crucial. The ADCS will be able to charge any Li-Poly/Li-Ion

battery with the cell range of 2 - 4. Theses batteries require a specific voltage range to charge that is

between 3.3 volts and 4.2 volts. Exposure to any voltages outside this range will cause damage to the

drone’s battery and could result in failure of the battery by not allowing it to hold a charge or possibly

explode. In order for the ADCS to be a successful product, it must deliver the required voltage range of

whatever drone battery is being used. This can all be done by using precautions when charging the drone's

battery.

2.1.4 Application

The application for the ADCS will operate on a website which allows all devices that can access the world

wide web to be used. The application is necessary to command the station to open the roof and retrieve

battery data from the ADCS. The user should be able to use this application from any location and maintain

consistent communication with the ADCS as long as the user abides by the operating location constraints.

Also, every five seconds the application will request a report from the ADCS regarding its status. Each

report will consist of two major components: the station’s battery life and the state of the station. The state

section of the report will describe to the user if the ADCS’s roof is open or closed, if the charging platform

is raised or lowered, and if charging is taking place.

2.1.5 Drone Size

The size of the ADCS will be able to contain drones as large as the average hexacopter (3’5” wingspan).

Competitors’ autonomous charging stations limit consumers by only supporting smaller drones, which sizes

average around one foot and five inches. Having a larger drone creates more real estate for attachments that

can be installed and room for an extra battery. This, in turn, allows the drone to carry heavier loads, operate

for longer periods of time and take on tasks that require more complex hardware that smaller drones simply

cannot hold.



2.2 Practical Design Constraints

Table 2.2 contains the five practical design constraints.

Table 2.2 Practical Design Constraints

Type Name Description

Economic Cost The ADCS’s $1500 price tag will make it a competitive

product on the charging station market.

Ethical Legality The ADCS users must comply with FAA regulations

unless permitted otherwise.

Health and Safety Safety The ADCS must be safe for the drone to interact with in

order to avoid damage to the drone.

Manufacturability Parts Availability The ADCS must be large enough to accommodate drone

sizes for up to 3’5” diameter.

Sustainability Durability The ADCS must be able to handle most weather

conditions including rain, hail, snow, and high winds.

2.2.1 Economic

The goal of the ADCS is to create a universal charging station. With the prices of drones increasing due to

high demand, the charging station needs to be economically efficient. Other drone charging station

companies include a drone, and customers must purchase the company’s drone, along with the charging

station, instead of using his or her own drone. Another economic problem with other charging stations is

requiring user’s drones to have fully autonomous software. A customer will pay more because of the

software integrated into the drone and charging station. The ADCS will have just autonomous charging

software, but a person can fully pilot his or her own drone when the drone battery charges to a sufficient

load. The ADCS materials for construction and software should not cost more than $1,500 in total.

2.2.2 Ethical

FAA regulations state that drones must be in visual line-of-sight of the pilot or observer. The ADCS has no

built-in capabilities to determine if the drone is within sight of the user, but the pilot needs to be aware of

these rules to avoid potential fines.

2.2.3 Health and Safety

As engineers, safety is crucial when designing a product and must be the highest priority, not only to the

users but to their property as well. Multiple sensors will be added to the ADCS to ensure that when the

drone is being lowered, and the roof is closing, the drone will not be crushed. To control and monitor these

operations, the user will have an application installed on their phone. The application should be consistent

and rarely miss updates from the ADCS so that the user knows exactly what is happening.



2.2.4 Manufacturability

The ADCS itself is to be around 6x6x4 (l*w*h) in feet, making it a universal charging station for drones

that meet the size constraints. The construction constraints of the ADCS have been determined to fit almost

any reasonable sized drone from a simple quadcopter to a larger scale octocopter. The supported drone size

range will be anywhere from one foot to three feet in diameter and one to two feet in height.

2.2.5 Sustainability

The ADCS must withstand moderate weather environments. Since there are many parts in the ADCS that

are sensitive to water, the station needs to be water resistant when the roof is closed. In the case where the

ADCS is left in the open environment, it should be able to keep rainwater out as long as there is no flooding

of water greater than one inch. Since the ADCS could be placed anywhere, the outside layer of of the ADCS

needs to be strong enough to be able to stop objects that may fall across it. Also, when temperatures become

abnormally low or high, the performance of most electronic devices tends to slow down or halt, causing

undesired functionality.

2.3 Appropriate Engineering Standards

Along with technical and practical constraints, the ADCS must abide by the engineering standards

contained in Table 2.3 on the following page.

Table 2.3. Appropriate Engineering Standards

Specific Standard Standard Document Specification/ Application

GSM (Global System for

Mobile

Communications)

Sans Institute InfoSec Reading

Room Paper

The application must follow the

standards such as sending 128-bit

random number (RAND) and

checking that the appropriate

response was given back.

IPR (Ingress Protection

Rating)

International Standard EN 60529 The ADCS must be able to withstand

solid objects up to one square

millimeter and protect against water

splash from all directions.

2.3.1 GSM

The ADCS requires long-range communication to the user since the station could potentially be hundreds

of miles away from the user. The best way to communicate to the station is using a mobile chip that talks

to the application using GSM. GSM, also known as Global System for Mobile Communication, was created

in 1991 and has been thoroughly tested since then. It is currently the leading standard for cellular

communication.



2.3.2 IP44 Environment Resistance

The drone and circuitry will be enclosed within the ADCS. Since the ADCS will be exposed to the open

environment, it must possess a certain level of tolerance to the elements in order to protect these

components. The IP44 standard states that the product must protect against splashes of water from all

directions and solid material up to one square millimeter.

3. APPROACH

The Autonomous Drone Charging Station (ADCS) will serve to provide continual drone flight for remote

operations by autonomously charging the drone while also serving as a protective container. The ADCS

will contain a floor lift, retractable cover, direct contact charging, and system of sensors. By use of a mobile

application, the user can send commands to the ADCS to lift and open for the enclosed drone to ascend for

operation. With the return of the drone, the ADCS will receive and lower the drone to safety and commence

autonomous charging. Use of the ADCS will eliminate the need for human interaction when charging the

drone’s battery or the need to physically plug in the battery for charging. Design constraints have been

established to create a baseline for component, sensor, and software usage, which are discussed in the

following sections.

3.1. System Overview

For the ADCS to be a fully autonomous charging station, several systems will be utilized to eliminate

human interaction during its operation. A mobile application will be used to send commands through use

of GSM. The GSM will then transmit that input to a microcontroller to notify the ADCS to take actions for

operation. The microcontroller will send back information gathered by sensors to inform the user of the

battery life of the ADCS, the drone’s landing status, and whether or not the ADCS can enclose the drone.

Below, Figure 3.1 shows an overview of the ADCS and functionality of the different subsystems that make

up the ADCS.



Figure 3.1 – ADCS Overview

3.2. Hardware

The ADCS is composed of several hardware systems that include the microcontroller, battery, linear

actuators, and wireless communication module. These hardware systems are discussed in further detail in

the following sections.

3.2.1 Distance Sensor

The distance sensor will sit at the bottom of the ADCS and measure the height of the platform as it rises

and falls. When placed in the ADCS, the sensor must face upward so there is a direct path between itself

and the bottom of the platform. It must reside in a section of the ADCS where no internal objects obstruct

this path because it can only measure the distance of the object immediately in front of it. The sensor

(Adafruit VL53L0X) can measure a minimum height of 50mm (1.97 in.) and stops measuring at a maximum

of 1200mm (3.94 ft.). Since we are measuring heights that fall within the 762mm to 914mm (2.5 to 3 ft.)

range, this sensor works out perfectly for the project. Its accuracy falls within +/- 3 to +/- 12% of the actual

height, depending on the surface it is pointed towards. A limit switch would sound ideal in this situation,

but for status purposes, which tie in with the smartphone application, a laser sensor is capable of providing

more detailed feedback. An example of needing more feedback would be when the ADCS needs to report

the progress it has made in raising the platform. Another example would be if the platform suddenly stopped

raising and the laser sensor can provide the height of the platform for troubleshooting purposes. Also, where



a bump switch works in a binary fashion, the laser sensor offers a more customizable approach when

adjusting the height. See Table 3.1 below for sensor comparison and detail.

Table 3.1 - Distance Sensor Evaluation

Distance

Sensor

Sensor

Type

Input Voltage

Range

Distance

Measurements (min-

max)

Prog. Language/

Comm. Protocol Accuracy Cost

Adafruit

VL53L0X Laser 3-5V 50-1200mm I2C

+/- 3% to +/-

12% of actual

height

$14.95

Adafruit

VL6180X Laser 3-5V 5-200mm I2C

+/- 3% to +/-12%

of actual height $13.95

Ultrasonic

Sensor HC-

SR04

Sonar 5V 20-4000mm C/C++ +/- 3mm $3.95

The VL53L0X laser distance sensor is a quarter-sized device and uses I2C for communication. The surface

it utilizes to measure the height of the platform can play a role in its accuracy. Because the sensor uses

reflection to measure distance, darker surfaces can produce less-accurate readings due to their light

absorbing properties. If the laser is able to point at a bright and highly-reflective surface, it will provide a

more accurate reading when measuring the height. Although the sonar sensor may have appeared to be a

better choice, its distance measuring capabilities were a slight overkill for what we need for the project.

3.2.2 Microcontroller

The Arduino Mega2560 will control the ADCS. Two reasons show the valuable importance of the Megafor

the project. One reason the team chose the Mega is that everyone in the group is familiar with the Arduino

software, so that makes explaining things to one another very easy. The number of I/O pins and analog pins

prove why the Mega presents efficiency for the ADCS. The ADCS will have three motors for raising and

lowering and for opening and closing. Relays will be used to control these motors and will require two

relays to control one motor and therefore a total of six relays will be needed. This means there will also be

six I/O pins needed to operate the relays. Along with the motor controls the charging patches will be using

16 relays and thus another 16 I/O pins will be needed. Based on this requirement, it was crucial that we

selected a microcontroller that had a sufficient number of pins to meet the 22 I/O pins needed for these two

subsystems. It was clear that the Arduino Mega2560 was the best microcontroller of choice meeting this

requirement while also having more than enough pins left over for other smaller subsystems. Table 3.2

shows a comparison of microcontrollers that were considered in the use of the ADCS.



Table 3.2 - Microcontroller Comparison Table

Microcontroller Software # of I/O pins # of analog

pins

Arduino Uno R3 Arduino

Software 14 6

Arduino

Mega2560

Arduino

Software 54 16

3.2.3 Battery

To power the ADCS, one 12VDC/120Ah (voltage direct current / amp hour) battery will be powering the

ADCS to provide around 14 charging cycles for charging the drone. The cycle can be justified with the

math in later discussion of the batteries. The ADCS will be operating several mechanical and electrical

components when the drone is ready to land. During flight of the drone, the ADCS will not need to be in

full power operation.

Table 3.3 - ADCS Power Supply Summary

Battery

(ADCS)

Output

Voltage

Life

Expectancy Cost Rechargeable Count

12VDC/120Ah

Deep Cycle

Battery [6]

12 VDC 120 Ah $219.99 Yes 1

The battery life expectancy is large due to the combination of a smart circuit only fully powering up the

mechanics of the ADCS when the drone is ready to enter/exit the ADCS.. Table 3.4 will summarize the

component’s amp-hour while ADCS is idle, and Table 3.5 will summarize the component’s amp-hours

while the ADCS is at full operation.



Table 3.4 - ADCS Battery Consumption (Idle)

Battery Rating = 120 Ah (12VDC/40Ah rechargeable Deep Cycle Battery)

Component (5V Max.)

(Operating at 5V) Drain for Each Component Total Drain

Arduino Uno Rev 3 (1) [X2] 50mA 50mA

Electron (v005) (1) [X4] 250mA 250mA

Total Current Drain: 300mA

Table 3.5 - ADCS Battery Consumption (Full Operation)

Battery Rating = 120 Ah (12VDC/40Ah rechargeable Deep Cycle Battery)

Component (quantity) [source]

(Operating at 12V) Drain for Each Component Total Drain

RF Receiver (1) [13] 200uA 200uA

Electron (v005) (1) [14] 250mA 250mA

Linear Actuators (3) 3A 9A

16 Module Relay Input (1) 20mA 20mA

16 Module Relay Output (2) 4A 8A

Total Current Drain: 17.3402 A

Life Expectancy of Battery Bank at 100% Drain: 6.92 hrs.

Since the horizontal actuator runs the longest, that will be how long the ADCS takes to run a half-cycle.

The time it takes for the horizontal actuator to fully extend will be 163.64 seconds. By multiplying the time

by two, this gives the total time (full-cycle) it takes for the ADCS to run at full operation. Multiplying the

current draw (17.3402A, from table 3.6) and the time that it approximately cycles through full operation



(328 seconds), the total Ah consumption would be 0.7879 Ah. This leaves the other running time of the

ADCS as idle. With the assumption that the ADCS charges one drone at a time, the Ah consumption would

be 0.7879Ah plus the power consumption while idle (7.68Ah). This calculation allows the ADCS to have

approximately 14 charging cycles for a drone.

Table 3.6 - Linear Actuator Operating Times

Motions Lift/Lid Displacement Total Time to Operate

Vertical Actuator (Lift) 7” 31 second

Horizontal Actuator (Lid) 36” 163.64 seconds

* linear actuators move the platforms 0.22” per second

When working with the different amp hours, the discharge characteristics can differ at different max

voltages. Figure 3.2 shows the different discharge characteristics at specific voltage for a 55 amp-hr battery.

This shows the possibilities of run time at different battery voltages that the drone may have.

Figure 3.2 - Discharge Time for Different Loads

The drone will need to be equipped with its own small 3.7VDC battery to provide power for an Arduino

Mini that will communicate to an RF transmitter. The RF transmitter will be running when the drone has

landed and when in flight, so it needs to be on its own power supply so that it does not diminish the life of

the drone’s battery. The RF transmitter battery will be hooked up to the same circuit that helps charge the

drone’s battery so the 3.7V batteries can all stay charged. Table 3.7 will summarize what onboard battery

the drone will need to keep power to the RF transmitter.



Table 3.7 - Drone Onboard Power Supply

Battery

Output

Voltage

Life

expectancy Cost Rechargeable Count

405585 3.7 VDC 3000 mAh $9.99 Yes 2

The 405585 Lithium Polymer Battery was chosen because it has a slim design and has a high life

expectancy. The other useful aspect to the 405585 is that the battery is rechargeable and can be connected

directly to the Arduino mini.

3.2.4 Motors

Along with autonomously charging drones, the ADCS must also serve as a protective container. This

becomes necessary in the case that the ADCS is left at the remote operation. Leaving the ADCS in the open

environment means the drone will need to be kept safe within the ADCS. To make the ADCS a protective

container while still keeping its ability to serve as an autonomous charging station, two mechanical systems

must be installed: a lift to receive, lower, and raise the drone for its mission and a retractable cover to open

and enclose for the drone’s protection. Motors will be required to make these mechanical systems work.

After research, it was determined that linear actuators will be the motor of choice for achieving the

mechanisms of these systems. As for the retractable roof, the force required to push and pull the doors open

will be less than the lift. The motors will only have the load of the doors, but the lift must raise a maximum

of 300 pounds. The 300 pounds account for the metal frame of the lift and the platform the lift will raise

containing the drone and metal patches. To meet this design constraint, it proved crucial to pick the motor

capable of lifting 300 pounds. Table 3.8 outlines noteworthy linear actuators that were considered.

Table 3.8 - Linear Actuator Motor Comparison

DC Motors (by

company name)

Operational

Voltage

Typical

Operation

Current

Speed Max Load Cost

ECO-Worthy 12V 3A 0.22”/sec 330 lb. $70.99

Progressive

Automations 12V 4A 0.27”/sec 330 lb. $149.99

WindyNation 12V 5A 0.39”/sec 225 lb. $78.99

The ECO-Worthy linear actuator met the 300-pound constraint by over 30 pounds. Another specification

that stood out was it needed only three amps of current to operate, making it the lowest current needed for

operation out of the three linear actuators. Although speed was not a concern for the ADCS’ lift, the slow

speed of only 0.22 inches per second made the ECO-Worthy linear actuator less desirable than what was



expected. This specification led to further research in finding a desired linear actuator capable of a faster

speed.

Further research showed that a high speed linear actuator is costly. WindyNation’s linear actuator proved

to be the most cost-efficient in terms of speed but missed the maximum load constraint by 75 pounds and

resulted in requiring the most current needed for operation. With further research, Progressive Automations’

linear actuator met the maximum load constraint by 30 pounds but only increased speed by .05 inch per

second and is the most costly.

After consideration, the ECO-Worthy linear actuator was the motor of choice for being the most cost-

efficient while also meeting the maximum load constraint.

3.2.5 Wireless Communication Device

The wireless communication device that will be in the ADCS is the Particle Electron. The reasons for

choosing this wireless communication device are its convenience to the developer and the user, and it was

donated by Dr. Kurum. Since this device was donated, the team only looked for communication modules

that would be easier to use than the Electron in both server support and microcontroller setup. Since the

Electron has a built-in microcontroller, there is hardly any setup time. Also, most of the other

communication modules used third party SIM cards, requiring the user to pay for a specific carrier. Since

the Electron has its own custom SIM card, this device can connect to most major carriers around the world

with a low-cost data plan. Through serial communication, the Electron will send commands to and receive

acknowledgements from the Arduino.

Table 3.9 - Wireless Communication Device Evaluation

Communication Module SIM card Custom

Servers? Standard Price

Particle Electron Custom Yes GSM Free

2691 Adafruit 3rd party No GSM $80

Interlogix NX-591NE-GSM 3rd party No GSM $150

3.3. Software

The ADCS uses multiple software packages to implement many of the hardware processes. The software

portion can be broken down to application system and microcontroller system. The main processes are

application state, transmission state, controller state, sensor state, charging state, and status state. Figure 3.3

shows the high-level software design.



Figure 3.3 - High Level Software Design

3.3.1 Application

The application system of the ADCS is a crucial element because it is the user interface between the station

and the user. Without the application, the user would no longer be able to send the ADCS commands as

well as get information back. Two common mobile application operating systems are iOS (Apple) and

Android (Google). For a prototype, it would be easier to write code for one operating system for now and

add compatibility for both later.

Table 3.10 - Application Specifications Table

Operating

System IDE Language App quality [5] Users [6]

iOS (Apple) Xcode Swift or Objective C 68.5 12%

Android (Google) Android Studio Java 63.3 87%

Table 3.10 shows the different aspects of using iOS and Android. iOS uses Swift for its programming

language, which was developed specifically for iOS and is less prone to errors, while Android uses Java.

Although the amount of Android users is significantly larger than iOS, the ADCS team is choosing iOS

development because of the familiarity of programming in Objective C. Since Apple developed Swift, a

programming language specifically for iOS devices, it has a large amount of support while also having

added built in security.

The application will send http requests to the Particle Electron cloud servers. Those servers will then send

data through GSM to the communication device. GSM uses user data header (UDH), which is a protocol

that specifies the bit order for all packets being transmitted [15]. When the communication device needs to

contact the application, it sends a request to the server. If the app is not responding, then it will sit in the

server until it gets a response from the app.

3.3.2 Application State

The application will act as a user interface to control the ADCS and show its status. As stated above, the

application will use http requests to send data to the Particle Electron servers. For security, the app will

have a login page that will only allow access to the ADCS that the user owns. After the user has logged in,



they will have access to the menu page where they can record the size of the drone, control the ADCS, or

view the status of the ADCS. When sending commands to the ADCS, the http request will be a POST

request. If the user is wanting a status update of the ADCS, such as the battery percentage, then a GET

request is sent to the servers. The reason for these differences comes from how the server is setup to handle

the requests. Using a POST request indicates that the servers must contact the communication device for

the data, while using a GET request indicates that the data exists on the server. To make things easier,

values such as battery life are stored as variables on the server. So instead of contacting the communication

device for the information, the app only asks the server, allowing it to be more responsive. If a request to

the server does not get a response, then an error message will appear telling the user to try to resend the

request.

3.3.3 Microcontroller

The microcontroller is the head of the ADCS because of all the processes it manages as well as the data it

stores. The main method of communication between the microcontroller and the other devices is serial data

transfer because most of the team is more familiar with it. Since user commands will be coming from the

communication device, the microcontroller will prioritize the data it is sending before any of the other

devices. Below, Figure 3.4 demonstrates the communication process.

Figure 3.4 - Communication Between Microcontroller and Cellular Module

The microcontroller will initially be waiting for commands from the communication device. Once it

receives a command, it will perform the code associated with it. These are some commands that the

microcontroller can receive and should be able to handle:

Open ADCS: This command will tell the microcontroller that the ADCS needs to be fully open. First the

microcontroller will talk to the 16 mod charging relays to see if they are charging the battery. If they are,

then the microcontroller will tell the communication module that opening the ADCS failed. If the drone is

not being charged, then the microcontroller will tell the roof to open. It will then check the sensors to make

sure that the roof is open, and if the check passes, it will tell the platform to raise. Once the sensors show

that the lift is fully raised, the microcontroller will tell the communication device that the ADCS is open



and wait for more commands. If any unexpected events happen that cause the ADCS to not fully open, then

a failure will be sent to the communication device along with an integer value that maps to a specific error.

Close ADCS: This command will tell the microcontroller that the ADCS needs to be fully shut. First, the

microcontroller will tell the sensors to check if the drone is on the platform. If the drone is not on the

platform, or if it is in a spot where it could be damaged from the ADCS closing, then the microcontroller

will tell the communication device that it failed to close. If the sensors determined that the drone was in a

good position, then the microcontroller will tell the platform to lower. After checking the sensors, if the

platform is lowered, it will then close the roof and then check with the sensors if it did close. If everything

has closed, then the microcontroller will tell the communication device that the command was a success

and wait for more commands. If any unexpected events happen that cause the ADCS to not fully open, then

a failure will be sent to the communication device along with an integer value that maps to a specific error.

Check Battery: This command will tell the microcontroller to check what the battery voltage is. The

microcontroller will use the programmable multimeter and run a simple check to see what the power is.

Once this is found, a numeric value that is related to the power level will be sent to the communication

device as a success. If any unexpected events happen that cause the ADCS to not fully open, then a failure

will be sent to the communication device along with an integer value that maps to a specific error.

3.3.4 Linear Actuator/Motor State

The linear actuator and motors control the roof and platform. The order in which the roof closes or opens

needs to be in line with the sensors and when the platform raises or lowers. If a wrong step is taken, then

the drone could be crushed between the two doors of the roof or between the roof and the platform. In the

linear actuator and motor state, it is crucial in making sure the components are moving properly. When the

motors are given the signal to control a specific part, this state needs to do a continuous loop of moving and

checking to make sure everything is okay. This state is also in control of the speed at which the motors

move, so setting the motors to go faster and slower will be done here. If no initial speed is given to the

motors, then the default one is set. Since the motors are only connected to the microcontroller, there will

be no direct contact with the sensors. This means two things: the motors must be able to swiftly stop moving

when given a command, and stop commands will take top priority over other transmitted data. This state is

also in charge of relaying any error messages that the linear actuators and motors give.

3.3.5 Distance Sensor State

The following figure, Figure 3.5, provides a more visual explanation of the role of the distance sensor in a

sequential cycle. The sensor will initially start off in a wait state in which it waits for the ADCS platform

to rise. In code, a fixed maximum height is set, and when the reading from the sensor reaches or slightly

exceeds that value, a signal is sent back to the microcontroller letting it know that the platform has reached

the appropriate height, stopping the raising process. The sensor will then proceed to another wait state. In

this state, the sensor waits for the platform to be lowered to the minimum height specified in the code. Once

the minimum height criteria have been met, the sensor will send a signal back to the microcontroller letting

it know to stop the lowering process. Once this is complete, the sensor will enter its initial state again and

the cycle will continue to repeat itself until the ADCS is powered down.



Figure 3.5 - Sensor State Flow Chart

NOTE: Sensor is measuring height during “Wait” states.

3.3.6 16 Mod Relay Charging State

When charging the drone, the key element to know is how much voltage to give to the drone battery. If too

much voltage is given to the battery, then it can explode, and if too little is given, the battery might not ever

hold a charge again. When the drone lands, it will be on small square charging pads, and a voltage sensor

to determine which two pads the drone lands on. Once the voltage meter realizes what pads the drone has

landed, the relays will receive voltage flow through the certain pads and into the drone telling which pads

have become energized. If the drone is only on one pad, then it will tell the communication device that the

drone needs to be moved until it is on two pads. Figure 3.6 shows how the polarity of each pad gets added

and how the voltage is regulated.



Figure 3.6 - Charging State Flow Chart

3.3.7 Battery State

The battery state allows the user to accurately know the battery life of the ADCS. Displaying the battery

life is not as crucial as some of the other processes, but it is very much needed because if the battery is

almost dead, the user needs to know that it should be charged. The method of measuring the battery power

uses a programmable multimeter writing to the microcontroller in order to send battery information back to

the web application. Figure 3.7 shows what happens if the microcontroller requests a battery power reading.



Figure 3.7 - Battery State Flow Chart

3.3.8 Usage Cases

3.3.8.1 Sunny Day

For ideal conditions, Figure 3.8 shows a simple process that will take place to get the drone up in the air.

The user will open the app and send a request to open the ADCS. Once the communication device receives

the request, it will send a command to the microcontroller to open the doors.



Figure 3.8 - Typical Open Operation

3.3.8.2 Rainy Day

Below, Figure 3.9 shows a rainy-day case where operations do not work out perfectly. When the drone is

ready to be charged, it will land on the ADCS platform. If the drone is not in the correct position for the

platform to lower, then a failure signal will be sent to the user letting them know to reposition the drone.

Once the drone is in the right position, the microcontroller tells the motors to lower the platform and then

sends a signal that the command succeeded.

.

Figure 3.9 - Typical Closing Operation



4. EVALUATION

The following sections evaluate the test results, how they were set up, and why they were set up with

specific conditions. While some experiments were tested separately, others were tested in combination with

one another. Table 4.1 shows the design constraints that must be met in order for the ADCS to properly

function. Since these constraints are so crucial to the project, a majority of the tests were designed for the

subsystems that relate to them.

Table 4.1 Technical Design Constraints

Name Description

Communication

The ADCS must be within 45 miles of a cellular

tower, depending on the tower’s technology, and

communicate via the cellular network.

Maximum Load The ADCS will have a lift component that must lift

the platform and all hardware on the platform.

Drone Charging

The ADCS charger will be controlled by a

microcontroller which delivers a voltage of 3 volts

to 4.2 volts for any size battery.

Application

The ADCS must provide information to the user’s

smartphone regarding the station’s status. Some

examples would be battery life, roof open or closed,

etc.

Drone Size The ADCS will support drone size up to 3’5” in

diameter.

4.1 Test Certification - Lift Load

The lift will be tasked with lowering the drone into the ADCS so it can be stored and then raising it so it

can take off. The key aspect to the lift is that it stops when fully lowered and it raises flush with the top of

the ADCS. The tests are discussed further below.

4.1.1 No Load Test

The first test was created to make sure that the lift is functioning properly and that it reached the needed

height of 29 inches to be flush with the top of the ADCS. Before applying a load on the lift, a test needed

to be conducted to determine this best placement of the motor used to operate the lift from the lowest

starting position. To determine the best placement of the motor, the motor was placed at different starting

angles. Power was given to the motor and a recording of the amperage being pulled was recorded. Table

4.2 shows the results from the test.



Table 4.2 Starting Angle of Motor Current Draw (No Load)

Starting Angle 90° 60° 20°

Max Current Draw 0.65 A 1.3 A > 3 A

These results were helpful in showing that starting angle position of the motor proved to be a factor in the

current draw that it would take to start lifting. The motor used to drive the lift had a rated maximum current

draw of three Amps. These test results show the current draw of the motor with no load on the lift.

Additional weight would result in a higher current draw and it needed to be less than three amps that the

motor could handle. Therefore, selecting a starting angle that left sufficient current draw for a load was

critical. As the Table 4.2 shows, at 90° the lowest current draw was reached and second lowest was at 60°.

The 20° position was automatically excluded based on the fact that the motor was already at its maximum

current draw and any additional weight would exceed the limit of the motor’s rating. Furthering the

selection of the motor starting angle, the 90° starting angle was excluded because it was not able to meet

the height of 29 inches. This resulted in selecting the 60° starting position which only pulled one Amp and

met the height requirement of 29 inches. With this current draw at this angle left us an additional current

draw of two amps with added weight which would be more than sufficient for the load needing to be lifted.

4.1.2 Max Load Test

A second test was created to show how much load the lift could withstand when reaching maximum amount

of current drawn from the motor. Once the motor reaches the max current draw from the load of the lift, the

motor will not perform properly or can even fail. Since the motor would not work with a 90° angle, stated

in the previous section, switching to a 60° angle would suffice for lifting the desired load. The team

determined the max load the lift would encounter, with charging hardware plus drone, would not exceed

30 pounds. Along with the 60° angle, an additional 60 pounds was added to the lift during our max load

test. The success from the test shows that the lift can provide lift support for double the desired weight, and

the initial current drew 1.8 amps. Since the motor’s max current draw is 3 amps, the test shows that the load

can increase on the lift and shows that the motor would continue to work properly.

4.2. Test Certification - Drone Charging

The most crucial part of this drone is to make sure that the ADCS can charge the drone swiftly and

efficiently. When the drone lands and the drone sensing technology gives the “OK” to charge, then the

charging tech must be able to consistently charge it safely. If any problems occur, the ADCS needs to be

able to perform the correct error handling, and tell the user what error the occured. The tests are further

discussed below.

4.2.1 Normal Condition Test

In normal conditions the drone will have landed on the patches of the ADCS and charging will commence.

With an onboard battery monitor, the ADCS will control the charging and battery life of each battery

ensuring proper charge.



Figure 4.1 - Drone Charging from patches

We will know when the drone is charging because we will be able to monitor the voltage using a voltage

sensor. If the voltage sensor shows any voltage, then the ADCS know the user’s drone is charging.



Figure 4.2 - Current draw of drone charging Figure 4.3 - No current draw of drone charging

4.2.2 Non-Charging Plates Test

When the drone has landed and the ADCS is charging, the arduino then asks the microcontroller to detect

the two contacts of the drone. By doing this the ADCS only has to power on two relays. This is important

because constantly powering all of the relays costs energy which lowers efficiency.

Figure 4.4 - Current draw of all relays on



Figure 4.5 - Current draw of only two relays on

4.3 Test Certification - Drone Sensing

When the drone lands into the ADCS, two of the pads will be used to charge the drone. The problem is to

find which of those two pads are being used, and to see how close they are to the edge of the ADCS. If the

charging plates indicate that the drone is not correctly in the box, then an error must be sent to let the user

know. The tests are further discussed below.


In normal situations, the drone will land in the middle of the ADCS and begin charging. This test simulates

a good landing where the drone’s contacts are touching two plates and there is no bridge created by those

contacts. While performing this test, the arduino was able to figure out which plates the drone’s contact

were on.

Figure 4.6 - Drone landing in most optimal position



4.3.2 Bad Drone Position Test

In bad situations, when the drone is approaching the ADCS there may be conditions where the drone can

not land as accurately as wanted so the drone lands a foot or more off to the side.

Figure 4.7 - Drone landing with one contact hanging off patches

If this situation occurs, then the ADCS will notify the user that drone cannot charge and needs to be

repositioned.

4.3.3 Plate Shorting Test

In worst case situations, when the drone lands and the contacts fall between two plates a short is formed in

the circuit. When checking for drone position, a current sensor needs to recognize large spikes in current

and turn off power to the plates immediately. This test simulates a bridge between two plates.



Figure 4.8 - Drone contacts touching more than one patch (possible short)

While performing this test, the arduino was able to sense the high spike in current, turn off the plates, and

send a message to the user telling them to reposition the drone.

4.4 Test Certification - Application

The application allows a remote user to control the ADCS. Since it is displaying status updates to the user,

it also needs to be fast as well as handle faulty responses.

4.4.1 Speed Test

To ensure that the user has quick access to the ADCS, the application needs to be as fast as possible. Burp

suite is used to check the round trip time (RTT) of the requests and responses. Figure 4.8 is a picture of

where the RTT can be found. Table 4.3 shows the average response time from the web application and the

ADCS.



Figure 4.8 - RTT Location

Table 4. 3 Command Test

Commands/Checks Average Round Trip

Time

Open Approx. 1 sec

Close Approx. 1 sec

Check Charge Approx. 2 sec

Check Signal Approx. 2 sec

Check Drone Approx. 2 sec

4.4.2 Faulty Request Test

Since some packets can get dropped when communicating through GSM, the web application needs to

validate the data that it receives from the ADCS. A faulty response was sent to the application from the

ADCS to simulate a packet being dropped through bad connection/tampering. Figure 4.10 shows the error

that the application generated when it received a false response.



Figure 4.10 Generated Errors

4.5 Test Certification - Drone Size

One of the major selling points of the ADCS is its ability to accept multiple sized drones. With this,

customers can have their own drones with different modifications on them. Since the size of the drone is

an unknown variable, extensive testing with different sizes and different drone legs will be done to ensure

compatibility with a wide range of drones.

4.5.1 Multiple Size Drone Test

Since the patches use 8.5” by 8.5” square sheet metal, the minimal distance between contacts on the legs of

any drone must be at least 12.5”. This is important because if the drone lands and both contacts reside on

the same patch, no charging will occur since the polarity on each contact has to be opposite of the other to

do so.



Figure 4.11 – Distance between the contacts on the legs of the drone is too small. No charging will

take place.

4.5.2 Pad Charging Anywhere Test

A drone may not always land in the center of the platform because of imperfections in flight and landing

positions of a drone. The platform will have 16 charging plates, setup in a 4x4 grid, allowing the drone to

land in an area roughly over 1156 square feet. Whether the drone lands in the center, corners, or sides of

the platform, it is capable of receiving a charge. As long as both contacts of the drone are touching two

separate plates on the platform, the ADCS can find the drone contacts and allow proper charging.



Figure 4.12 - Drone is getting charge no matter the orientation of the contacts in respect to the

patches

4.6 Test Certification - Laser Sensor

The ADCS utilizes a laser sensor, the VL53L0X Time of Flight Distance Sensor, to measure the height of

the platform so the microcontroller knows when to stop the lifting and lowering process. Though a bump

switch would have seemed more ideal in this situation, the laser sensor is more robust when adjusting the

stopping height of the platform. This sensor was selected because its measuring capabilities fall perfectly

within the requirements of the project. To test the sensor, it was initially set up according to the code and

schematic provided by the Adafruit website. Sensor accuracy was tested using a sheet of paper to act as the

object being measured and a ruler. Based on the results, the readings from the sensor fell within ±10mm of

the actual height of the sheet of paper. This proved to be sufficient for our project. It was determined that

if the object being measured fell outside of the maximum height the sensor was capable of measuring, a

reading of “Out Of Range” was given. Also, because the sensor measures whatever object is directly in

front of it, errors can occur if a foreign object obstructs the direct line of measurement. Such errors would

be the lift failing to stop at a specified point due to the inability of the sensor to monitor height. Since the

actuators possess a current limiter, the failure of this device would not be detrimental to the ADCS, but the

lift would fully extend or descend with no control of its height. This would also affect the status report of

the drone if one is requested. To remedy this issue, a timeout is placed in code so that if an acknowledgement

is not sent back within a certain amount of time, then the system knows that something has gone wrong

with the sensor. This malfunction would then be recorded in the status report, notifying the user of this

occurrence.

4.6.1 Laser Accuracy/Distance Test (Test the accuracy and the distance of the lasers.)

Table 4.4 on the following page shows the accuracy of the laser sensor when performing test at three

different heights.



Table 4.4 - Laser Accuracy Test

Height in Code

(HC) Test #1 Test #2 Test #3 Average of Test

(± of HC)

100mm 98 102 104 ±1.33

300mm 300 305 297 ±0.67

500mm 501 502 498 ±0.33

4.7 Test Certification - Remote Operation

Remote charging presents the is ADCS’s most important function, and it will control the ADCS from

anywhere as long as the user has access to the internet. Remote charging means that the user might not be

able to physically see the station, so there is a need for proper error handling. The tests below discuss this

further.


Two tests show that the ADCS can be remotely operated. The first request to control the ADCS was sent

over wifi. The next one was sent through mobile data. Table 4.4 below shows that remote operation works

for both methods.

Table 4.5 - Remote Application Test

Method Requests Sent Requests Succeed

Mobile Data 25 25

Wifi 25 25

4.7.2 Status Update Test

To ensure that the user receives the most recent data, certain tests need to prove that the ADCS sends

constant data back to the application. When the application goes inactive, the ADCS will still need to send

data back to the cloud, When the application turns on, the ADCS can receive the most relevant data from

the cloud. The test done proves battery status changing ,and watching battery status changing proves the

web application works properly.

4.7.3 Error Test

To prevent damaging the drone and the ADCS, error handling must be implemented. Upon an error, the

user also needs to be notified so that they can take precautionary actions. During this test an error was

created from the ADCS to check and see if the application received it. Figure 4.13 is taken from the web

application after the error is created. After generating an error, it took about 10 seconds for it to be seen on

the web application.



Figure 4.13 - Error Test Web Application

4.8 Test Certification - ADCS Complete System

These last tests ensure that the ADCS functions properly. The tests below are in depth and use all of the

findings from the previous tests to make sure that the ADCS functions properly when there are unexpected

occurrences.

4.8.1 Full Normal Condition Test

The team tested a situation where the ADCS opened, the drone landed in the middle, then the ADCS closed

and began charging. The entire test took about three minutes and was fully successful.

4.8.2 Full Error Simulation Test

For this test the team tested a situation where the ADCS opened, but the drone did not land on the charging

pads. The system worked as expected because the application told the user that the drone was not in the

correct position. We then repositioned the drone and checked the position again. The application noticed

that the drone was in the correct position, lowered the ADCS and then began charging. Figure figure

4.14shows the web application telling the user to reposition the drone.

Figure 4.14 - Drone Reposition Test



5. SUMMARY AND FUTURE WORK

The purpose of ADCS was to create a charging station for drones that would allow for continual drone

flight for remote drone operations. At the end of the semester we successfully created a working prototype

that a user could communicate to through the use of a web application. This communication was crucial

and gave the user the ability to control the ADCS with commands that opened and closed the ADCS and

also send commands to start and stop charging of the drone. Statues of the battery life of the ADCS and

whether the ADCS was opened or closed was also in the web application. With our success the ADCS

eliminates the need for human interaction with changing or charging of the battery of a drone. Drones can

land on the ADCS and charging can commence all while being protected inside the ADCS.

The future work and and improvements of the ADCS would include a better way of powering the system

of the ADCS. As of now, the ADCS is powered by a 12 volt deep-cycle battery which would require needed

human visits to change the battery or charge it. We would like to introduce solar power to the ADCS system

that would allow the charging of the 12 volt deep-cycle battery, making the ADCS more sustainable. Work

to come would include making a PCB and enclosing the ADCS container with walls and roof that would

ensure the protection of the drone.

6. ACKNOWLEDGEMENTS

We wish to acknowledge Dr. Mehmet Kurum and Dr. Bryan Jones of Mississippi State University and

Raytheon of Forest, Mississippi along with Shane Morrison for their continued support and feedback

regarding this project. Our team enjoyed working with each of you as you all provided wealthy knowledge

in working with this project.

7. REFERENCES

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[2] "Apple Vs Android — A comparative study 2017 – AndroidPub", AndroidPub, 2018.

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[3] "ECO-WORTHY 14"(350mm) Stoke Linear Actuator 1500N 12V 5.7mm/S |Eco-worthy",

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14350mm-stoke-linear-actuator-1500n-57mms-p-432.html. [Accessed: 22- Feb- 2018]

[4] "WindyNation 12 Volt, 225 lbs Linear Actuator + AC to 12 VDC Power Supply + Wireless

Remote Control DPDT Switch + Actuator Mounting Brackets", Web, 2018. [Online]. Available:

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Linear-Actuator-AC-to-12-VDC-Power-Supply-Wireless-Remote-Control-DPDT-Switch-

Actuator-Moun/-/1455?p=YzE9Mjg=. [Accessed: 22- Feb- 2018]

[5] "Mini Medium Force Linear Actuator | ActuatorZone", Actuatorzone.com, 2018. [Online].

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[6] 2018. [Online]. Available: https://www.walmart.com/ip/12-V-40-AH-Deep-Cycle-

Battery/187182099?wmlspartner=wlpa&selectedSellerId=1685&adid=22222222227071941530

&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=c&wl3=182839343998&wl4=aud-

310687322322:pla-

286554537481&wl5=9060111&wl6=&wl7=&wl8=&wl9=pla&wl10=112550064&wl11=online

&wl12=187182099&wl13=&veh=sem#read-more. [Accessed: 22- Feb- 2018]

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[12] LAPTOP, "405585 3000mAh 3.7V Lithium Polymer Battery Li ion Lipo Rechargeable

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2500mAh-Li-ion-Rechargeable-Accumulator-For-Mobile-Power-

Bank/32515193445.html?src=google&albslr=110852476&isdl=y&aff_short_key=UneMJZVf&s

ource=%7Bifdyn:dyn%7D%7Bifpla:pla%7D%7Bifdbm:DBM&albch=DID%7D&src=google&a

lbch=shopping&acnt=708-803-3821&isdl=y&albcp=653153647&albag=34728528644&slnk=&t



8. APPENDIX: PRODUCT SPECIFICATION

Documents

Autonomous Drone Charging Station - IMPRESS Labimpress.ece.msstate.edu/wp-content/uploads/2018/06/ADCS-Design... · Autonomous Drone Charging Station (ADCS), the hassle of companies