Birthday Drone

Final report - ME271E

Luke Asperger, Tatiana Mowry, Coline Nantermoz, Zach Blum

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Table of contents

Executive Summary 3

Renders in different configurations 3

Summary of Performance Specifications 4

Summary of the mission 4

Summary of the scaled delivery demo 4

Mission 5

Systems Engineering 8

Project Objective Statement 8

Mission Need Statement 8

Functional Flow Diagram 8

Functional Breakdown Structure 9

Requirements Discovery Tree 10

Work Flow Diagram 11

Work Breakdown Structure 11

Gantt Chart 11

Hazard Analysis Write-up (SHARP) 12

Configuration 15

Four Designs 15

Selecting Final Configuration 17

Robot Constraints 18

Sizing Optimization 18

Description of final configuration 18

Critical Performance Specs 19

Wing design in XFLR5 20

Wing geometry 20

Elevator and fin geometry 20

Results 21

Delivery mechanism design 23

Demo 25

Mission and Waypoints 25

Actuators’ control 26

PID tuning 26

Screengrabs 26

Final Design 28

3 View Drawings with dimensions (in inches) 28

Renders of hybrid aerial robot in different flight configurations 29

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Delivery Mechanism 30

Sized and selected components 33

Performance Specifications 34

Future Directions 36

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Executive Summary

Renders in different configurations

Figures 1 and 2 below show the final aerial robot design in different configurations.

Figure 1: Render of final robot while hovering

Figure 2: Render of final robot in forward flight

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Summary of Performance Specifications

Figure 3: Chart of Key Robot Parameters

Summary of the mission

Our project’s mission was to safely deliver a birthday cupcake onto an empty table at a specified

time, because it would be a valuable addition to a special occasion.

Summary of the scaled delivery demo

In order to test our delivery mechanism, we attached it to the bottom of our quadcopter.

At Stanford’s Lake Lagunita, we manually piloted the drone off of the ground to a hover, then

had the autopilot fly the drone to selected waypoints in a relatively square path. Once it returned

to the starting location, we switched to manual flight to land the drone, released the package by

activating the delivery mechanism, and finally took off and landed at the takeoff site.

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Mission

In the beginning of the project, we started with four main ideas about potential missions.

The first idea was to design a drone that would be capable of safely transporting and delivering

a fragile item made out of glass, by minimizing sudden motion and orientation changes during

transport. The second idea was to deliver a food item at a precise, predetermined time and

location. The third idea was to increase ease of assembly for products made up of multiple

parts, by having the drone lay each individual part of an assembly in a location convenient for

assembly. The fourth idea was, in order to reduce the need for human action, we would design

an aerial robot capable of identifying a predetermined package from a row of boxes and

autonomously picking it up for delivery.

In order to select which mission idea to pursue, we constructed a tradeoff chart, shown

below in Figure 4.

Figure 4: Tradeoff Chart for Mission Ideation

The items in the leftmost column of the chart represent depictions of the mission ideas

discussed above: identifying one out of many packages, carrying fragile items, delivering food,

and aiding in assembly. The top row represents the criteria used to judge each of these ideas.

The box highlighted in blue--time needed--represents the criterion with highest weight, and

signifies the time needed to actually construct a drone and delivery mechanism capable of

performing the given task. The other criteria represent complexity of the mission idea,

probability of us succeeding in building a working drone to perform the given task, cost of the

materials needed to build the mechanism for the drone, utility of the mission, how “cool” the

mission seemed to us, and if the mission was safe to perform. After ranking the ideas on each

of the categories (from 1 to 3, with 1 being bad at the given criterion and 3 being great), the idea

that succeeded (highlighted in red) was delivering food, at a precise, predetermined time and

location.

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After we had narrowed down the mission to the delivery of food, we further ideated to

decide what food item we wanted to deliver. While the initial idea had been to deliver a box of

pizza, we all very much enjoyed the idea of delivering a birthday cake/cupcake as a surprise on

someone’s birthday, because the delivery would not only be useful in that it would provide the

guests of a party with food, but also because it would be an enjoyable surprise addition to the

party. Ultimately, we decided on the following as our overall mission: our project’s mission was

to safely deliver a birthday cupcake onto an empty table at a specified time, because it would be

a valuable addition to a special occasion.

After specifying our mission statement, we then needed to devise a delivery scenario in

which our delivery would be useful and appropriate. We envisioned Stanford students

celebrating a birthday on Meyer Green on Stanford’s campus, and one of the guests would like

to surprise the person whose birthday it is with a cupcake. The student wants to get the

cupcake delivered from Sprinkles in the Stanford Shopping Center. Because the streets

between Stanford Shopping Center and Meyer Green are congested, and the student would like

to add an element of surprise to the party, the student requests in advance that the cupcake be

delivered by drone at a specific time. Taking this as an example use case, we then needed to

determine appropriate takeoff and landing locations. Because Meyer Green is already a

relatively open space with tables, we kept this as our landing location. We then looked and

found that there was an open plaza behind Sprinkles in the shopping center, which would serve

as an acceptable takeoff location. The sample takeoff and landing locations are shown below in

Figure 5a and Figure 5b.

Figure 5a: Takeoff location in plaza behind

Sprinkles in Stanford Shopping Center.

Figure 5b: Landing location on Meyer Green

Because there are no major obstacles in this path from Sprinkles to Meyer Green, we

determined that the optimal path would be to simply fly straight from Sprinkles to Meyer Green,

at its cruise altitude of between 50 and 100 feet. This path is about 1.14 miles one-way. This

delivery scenario path is shown below in Figure 6.

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Figure 6: Sample delivery scenario flight path from Sprinkles to Meyer Green.

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Systems Engineering

Project Objective Statement

The goal of the project objective statement is to clarify what the project is about, and to

balance resources, time and result considerations. Our project objective statement is:

“Surprise someone on their birthday by delivering a cupcake using a drone at the specified time,

using commercially available off-the-shelf components in 7 weeks.”

Mission Need Statement

The Mission Need Statement is a concise description of the functions that the project’s

result will have to perform. It is intended as a reference throughout the project. Our Mission

Need Statement is:

“Safely deliver a birthday cake onto an empty table at a specified time.”

It highlights our deliverable: an aerial robot capable of delivering a cupcake, the required

performance: we are focusing on delivering at a precise time and location, and the main

constraint: security, both of the user(s) and of the cupcake (it shouldn’t be damaged).

Functional Flow Diagram

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In summary, before the mission begins, we will receive the order and calculate the

logistics for completing the mission. After inspecting the robot to ensure it is ready for takeoff, it

will launch and fly to the destination. The drone will place the cake on a table and play the

happy birthday song. Then, it will takeoff, and fly back to base and land there.

Functional Breakdown Structure

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In summary, performing the mission will consist of four main functions. The drone will be

provided power which will be distributed and regulated throughout the flight. In performing the

flight, the rotors and wings will provide propulsion and lift, and we will monitor the payload and

use controls to ensure that the drone remains stable. In order to provide guidance and

navigation, we will calculate the route and time needed to complete a certain delivery, and

Mission Planner will aid in autonomously flying to the desired location. The delivery will use an

actuator to release the cake onto the table, and will confirm the delivery before taking off again.

Requirements Discovery Tree

There

are two main branches of our Requirements Discovery Tree: performing the mission technically

and performing the mission with constraints. Performing the mission technically will require a

combination of providing power to guide and navigate during the flight, and actually delivering

the cake. In performing the mission with constraints, we deal with development constraints

(such as the timeframe and risk of the project) and constraints on the design (including weight,

wingspan, speed, and hover time).

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Work Flow Diagram

Work Breakdown Structure

Gantt Chart

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Hazard Analysis Write-up (SHARP)

The main hazards were from flying objects, the fast propellers, and the LiPo batteries.

To mitigate risks, we performed a short trial run before our Lake Lag flight by carefully stepping

through our mission steps. We discussed where to land and release the box and one team

member held the robot and carried it through the mission as a dry run. We also took precautions

to make sure no one would be hurt: we stored our batteries carefully, we used the arming

system and a safety switch on the robot, and we ensured that the drone would not be too close

to others

During the actual mission, the robot ran out of battery and fell to the ground. Fortunately,

this was a hazard that we had forseen and no one was near the robot when it fell. To identify

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even more hazards in the mission, we could perform more trial runs to see if they are

consistent. We could also talk to other teams to learn about any problems they encountered.

Section A : Identify the general hazards

Hazard Conditions or Processes:

- Moving equipment / parts

- Electrical

- Heat / hot surfaces

- Needles / sharps

- Falling objects

Section B: Outline the Procedure

Sequence of Steps and Tasks

Hazard Hazard Control Measures

Gather stuff to take to Coyote Hill

Battery should be in pouch Checklist: safety glasses, fire extinguisher, water, sunscreen, drone and controller, charged batteries

Load the payload on the drone Check the CoM

Battery should not be connected, but attached to the top of the drone

Connect the battery. Push the safety button

After this step, everyone should be behind the pilot

Arm the motors Propellers turning Make sure no one else is flying. Tell the other groups we’re arming

Take off in manual mode Watch the stability at low altitude, land if it’s too wobbly

Put in autopilot mode Make sure it is far away enough

Test the delivery mechanism: land / drop payload

Take off and return without payload

Check the PID constants

Land back at start Make sure everyone is out of the way

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Summary of PPE:

- Appropriate street clothing (long pants, closed-toed shoes..)

- Safety glasses

Section C: Question your methods

What if the payload wobbles too much?Then switch to manual mode and tweak the PID

constants

Risk rating: it is likely but no injuries / minor (if the payload actually detaches and falls) →

medium

What if we lose sight of the quadcopter? Then, land the quad wherever it is, locate it on Mission

Planner and pick it up. Don’t forget to bring the fire extinguisher

Risk rating: it is possible but minor, and a risk of fire is really rare but would be moderate to life

impacting → medium

What if a bird comes close to the quadcopter? Then land

Risk rating: rare and minor → low

Everything is in the low - medium range → we just have to ensure we are following best

practices.

Section D: Perform a trial run

Try delivery mechanism separately: lab checkoff this week

Try to fly quadcopter separately indoors / outdoors: already done

Fly indoor with manual control: next week lab checkoff

Fly outdoor and land on a table top / target: final goal

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Configuration

Four Designs

Tilt Rotor Design: This design consisted of 4 propellers arranged in a trapezoidal shape. The

propeller motors are attached to rods that can rotate via stepper motors in the body of the robot.

Weighing in at 5.42 kg with a wingspan of 1.2 meters, this configuration can achieve a range of

46.0 km.

Multi-Rotor Design: This configuration was designed to work well in forward flight as well as

hover. It could take advantage of an existing quadcopter base for the hover rotors and the

cruise rotors would activate for forward flight. It achieved a range of around 60 km.

Plane Design: This design maximizes range, and ends up with a final range of 96km. That’s

why it has many rotors for forward flight, and is very light (the cupcake(s) are kept in the bay,

which would open thanks to a trap door). We named it the plane design because it is very

aerodynamic, however, the vertical takeoff and landing would consume a lot of battery.

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Tilt Body Design: This design includes four propellers along the wings, and the body tilts in

order to transition between hover and cruise. The final total mass for this design was 2.8365 kg,

with a wingspan of 1.17m. This configuration achieved a maximum range of about 38.1km.

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Selecting Final Configuration

Criteria

Configuration Payload Safety (25)

Material Cost (20)

Range (10)

Aesthetics (10)

Delivery Feasibility (20)

Design Simplicity (15)

Tilt body 1 3 2 3 3 3

Tilt rotor 3 2 2 3 3 2

Multi-rotor 3 1 3 3 3 2

Plane 3 1 3 3 2 2

There were a number of factors we considered when selecting our configuration. The

most important consideration was payload security. Because we are delivering a cupcake, we

needed a design that would minimize changes in orientation, which was something that the tilt

body would not be able to do well.

Additionally, we needed to keep the material cost down and the design complexity down

because delivering a cupcake is not a task that you can easily justify an overly expensive robot

for. The added motor and propeller costs were major downsides to the multi-rotor and plane

designs. The mechanism for tilting the rotors is fairly straightforward, so we believed the tilt rotor

design would be both relatively cheap and feasible from a design perspective.

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Robot Constraints

One of the biggest constraints that the tilt-rotor design puts specifically on the robot is on

the length of the body. We needed to make sure that there would be room for the propellers to

rotate without interfering with the wings of the robot. An exact check of this constraint would

have required calculating angles and comparing the the three dimensional geometry of the

body. However, we were able to come up with a much simpler and sufficiently accurate check

that only looked at the body length and made sure it was at least as great as twice the propellor

diameter plus the chord length.

𝑏

𝐴𝑅+ 𝑑𝑝𝑟𝑜𝑝 ≤ 𝑙𝑏𝑜𝑑𝑦

The second constraint we threw in was that the wingspan had to be less than 1.2 meters. This

was because we wanted to make sure that it would be able to fit on a standard sized picnic

table when delivering a cupcake.

Sizing Optimization

The constraints enumerated above were added to the matlab optimization, so all the designs

MATLAB gave us fit within those constraints. The parameters we optimized for were cruise

velocity, wingspan, aspect ratio, taper ratio, and propeller diameter. The goal of our optimization

was range, as this will allow us to deliver the cupcake from locations as far as possible.

Description of final configuration

The final configuration of our robot is a tilt-rotor design similar to the design in the foam board

prototype shown below. The propellers are arranged in a trapezoidal geometry to minimize air

flow disturbance between the propellers during forward flight. The propellers are fixed to axels

that rotate via servo motors in the body of the plane.

The exact propeller placement could be optimized further. However, that is beyond the scope of

this class. The wingspan is 1.2 meters, as specified by the sizing optimization. In this prototype,

the body is simple shaped as a rectangular prism using the length, width, and height

measurements spit out by MATLAB, but further optimization would yield a more aerodynamic

body.

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Critical Performance Specs

A full chart of our performance specifications is located at the end of our report. However, a few

key highlights of the parameters spit out by our MATLAB optimization are listed in the following

chart.

Parameter Final Value

Total Mass 5.42kg

Battery Mass Fraction 0.61

Body Length 0.39m

Body Width 0.31m

Body Height 0.15m

Cruise Velocity 20m/s

Range 46km

Propeller Diameter .22m

Taper Ratio .8

Wingspan 1.2m

Aspect Ratio 7.5

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Wing design in XFLR5

Wing geometry

Wingspan Area MAC Aspect ratio Taper ratio Root to tip sweep

1.2 m 0.2 m2 0.167 7.31 0.68 5.71o

We used NACA 23012 airfoils. At first, we wanted to use high performance, low Re, high

lift airfoils, comparable to the ones found on sailplanes, but, as those airfoils were very

cambered, the pitching moment was always negative. Thus, we got back to the conventional

NACA 23012. To make it stable (negative slope of Cm), we had to tweak the center of gravity of

the plane. This corresponds to what happens in reality as well: our delivery mechanism +

cupcake is heavy (200g) so its position (and the one of the battery) determine the position of the

center of gravity. Flying with a badly positioned CG leads to inevitable crashes, as we

experienced during indoors flying tests.

We also added twist to prevent stalling at the tips.

Elevator and fin geometry

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Results

To Have a pitching moment Cm of 0, we choose an angle of attack 𝞪 = 11.0o. This results in a

CL of 1.14, comparable with the one we obtained in the midterm (1.13).

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The CL/CD ratio of 13.8 is not optimal but stays quite good, and brings us enough lift.

xCG = 0.094m ; xNP = 0.11m ; MACwing = 0.167m → SM = 10%. Our plane is really stable to

disturbances in pitch.

The lift profile at 𝞪 = 11.0o is given by:

We reran the midterm analysis using the polars from NACA23012 instead of 23112 and the right

Reynolds number and we got slightly more range with a slightly higher lift.

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Delivery mechanism design

After we had specified our mission objective, we then needed a way to actually deliver

our cupcake. We designed some rudimentary prototypes during our ideation phase to come up

with four different delivery mechanism designs. The first design was a claw that would grip the

sides of the cupcake box so the robot could land on a table, release the box, and then fly off.

The second idea worked in conjunction with the first: the box would be “spring loaded” and

would open by itself when the claw released it. This would be achieved by elastic bands pulling

the sides apart. The third idea was a trapdoor that would be manually operated by the receiver.

The user would open a hatch on the robot, releasing the cupcake box. The fourth idea was to

have a series of parachutes mimicking balloons that were attached to the box. The box would

then be dropped safely onto the table while the robot was hovering. After defining our four

ideas, we refined our prototypes to determine which idea we liked best.

Criteria Total

Mechanism Feasibility (35%)

Reliability (25%)

Cool Factor (15%)

Cost (10%) Effect on Aerodynamics (15%)

Claw 3 3 2 3 3 2.85

Claw + Spring Loaded Box

2 3 3 2 3 2.55

Trapdoor 3 3 2 3 2 2.7

Balloons 2 1 3 2 2 1.9

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We then needed to choose our ideal delivery mechanism. In order to choose which

design would work best, we created a trade-off chart to weigh our options. We wanted to stress

the design feasibility, so that column was given the largest weight of 35%. Given our limited

time, we wanted a feasible design that was reliable, so reliability was also strongly weighted.

We considered additional factors, such as material cost, excitement factor, and effect on the

robot’s aerodynamics. Our trapdoor design was not particularly exciting and the parachute idea

lacked reliability. The spring-loaded box really just worked in conjunction with another delivery

idea, so we decided to go forward with our best design: the claw.

We designed the claw to that the mechanism would grip the box on opposite sides. The

cupcake box has a lip to prevent the box from slipping out while the robot is in flight. The claw

sides move away from each other to release the box and snap closer together to hold the box.

We originally planned to use linear actuators to push the claw sides apart, but, ironically, the

actuators did not arrive in time to include them in our delivery drone. Instead, we relied on the

servo motors included in our kit. When the servos activate, they push against one of the claw

sides, expanding the claw. We wanted to ensure that the claw would only expand in a linear

fashion, so one claw side is mounted to a short, linear track. This ensures that the claw sides do

not rotate relative to each other. When the servos deactivate, rubber bands pull the two sides

closer together so the box is secure. This passive way of holding the box is both safer and

energy efficient. We only need to activate the servos when needed, and if the servos fail, the

box is still securely held.

Our mechanism design works for both the analytical model and our demo version. The

mechanism we designed and built would indeed hold a small cupcake, so we did not scale it for

our analytical model. It would be possible to upscale the mechanism to allow more room for a

larger cupcake, but that would also require further calculations regarding the weight of the

payload and the increased drag from the larger box. Leaving the mechanism’s size the same

allowed us to see how our design fared in actual flight conditions when we flew outdoors for the

demo video.

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Demo

Mission and Waypoints

In the actual mission, our robot would take off from the bakery, fly to the delivery

location, land and release the box, and then return to the bakery. We mimicked this series of

events in our demo. The robot would be completely autonomous in the actual mission, but we

performed takeoffs and landings manually in case there were any errors on our robot’s altitude

sensor. Our demo approximated the mission: we took off manually, we switched to autopilot, the

robot flew waypoints around Lake Lagunita, and we switched back to manual and landed the

robot. This represented the robot flying from the bakery to the party location. In our demo, we

released the box, took off again and landed a short distance away, and the “partygoers” enjoyed

the cupcake. This mimicked leaving the cupcake box at the party and returning to the bakery.

Our waypoint path just needed to represent the elapsed time between taking off at the

bakery and landing at the party. The path is just a simple loop that takes the drone back to the

concrete slab so we could land at the “party.” This showed that the drone could fly at a

consistent speed in autopilot so the arrival time would be accurate. The waypoints used in the

Lake Lag flight are shown in the figure below.

The drone started in the rightmost location and flew to each of the other locations in order

(counterclockwise) before returning to the takeoff location.

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Actuators’ control

On our delivery mechanism, we had two servos that needed to be actuated so that they

would rotate and push the claw linearly (while the pins slid in their slots), in order to open the

claw mechanism and drop the package. The servo motors were set up so that they used power

from the UBEC and were each connected to a different port in the PixRacer. After testing that

the servos worked while using a servo tester, we continued to modify the PWM values in

Mission Planner until we were satisfied with the minimum and maximum angle through which

the motor’s arm sweeps (and thus the distance that the linear mechanism will be pushed).

Then, we configured the channels on our transmitter to correspond to the channels used on the

PixRacer for the servos. Importantly, we set it up so that one switch on the transmitter

corresponded to sending a PWM signal to both servo channels on the PixRacer. This allowed

us to only need to toggle one switch in order to activate both servos at the same time.

PID tuning

We originally set up the PID constants for the drone using the recommended initial

values provided to us. Because we were strategic in adding the delivery mechanism to the

center of the drone and using the location of the battery as a way to counteract any

discrepancies of the center of mass caused by the delivery mechanism, we were able to keep

our center of mass almost exactly the same after adding the delivery mechanism as before it

was added. Thus, we were fortunate in that we did not need to conduct any additional PID

tuning, after the initial PID constants were set.

Screengrabs

Takeoff Landing and Releasing Box

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Landing Again Cupcake Delivery

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Final Design

3 View Drawings with dimensions (in inches)

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Renders of hybrid aerial robot in different flight configurations

Cruise Configuration

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Hover

Configuration

Delivery Mechanism

3D Render

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Exploded View

3

View Drawings of Delivery Mechanism

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Sized and selected components

Propellers: Our MATLAB optimization yielded .22m as the optimal propeller diameter for our

robot. This is about 8.6 inches, so a good option on sizing would be the Aeronaut Carbon

Electric 8.5 x 7 propellers, which can be found in the UIUC propeller database

ESC’s: Based on our power requirements, at hover we expect each motor to consume around

400W. Calculating our current requirements from a voltage of 14V, we will need ESC’s that can

handle up to around 40 amps. A suitable option is sold by robotshop at the following link.

https://www.robotshop.com/en/t-motor-40a-air-multirotor-esc.html

Motors: Our hover RPM is just under 12,000, so given a typical LiPo battery of 11-14V, that

means we need a motor with a Kv rating of about 1000Kv. A suitable option can be found at the

following link:

https://www.robotshop.com/en/brushless-rotor-motor-1000kv-15a.html

Batteries: We need 496 Watt-hours of battery capacity. Assuming we run all batteries in

parallel, this means we need around 35 amp-hours of capacity (at 14V). The following battery is

1 amp-hour and weighs just under 90 grams. If we use 35 of them, we will come in just under

our allotted battery weight of 3.2 kg, so this seems like a perfect choice to suit our purposes.

https://www.venompower.com/collections/venom-drone-batteries/products/venom-50c-3s-

1000mah-11-1v-fpv-drone-racing-lipo-battery-xt60-ec3-deans-plug

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Performance Specifications

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Future Directions

We learned many lessons through this aerial robot design project. First, we learned that

delivering a package on time is still an issue with current delivery methods, and drones may be

able to fix this. We learned this in a very ironic fashion: we ordered linear actuators from

Amazon to build our delivery mechanism, and the actuators never arrived due to delays in the

delivery. We also learned the importance of prototyping and iteration. Our first delivery

mechanism prototype was relatively inconsistent and the claw tended to bend when actuated,

rather than move linearly. To combat this, we lasercut the claw again with the inclusion of an

additional pin and slot, to further constrain the motion to the linear direction. This iteration

worked much better and more consistently than did the original version. Further, we also

learned the importance of positioning the battery and delivery mechanism exactly correctly so

that the center of mass would be positioned as expected. There were a few instances during

testing of the drone and delivery mechanism in the d.school in which our pilot attempted to take

off, and the drone’s center of mass was very far towards the back, resulting in the drone

accelerating backwards into a wall. Finally, we learned the importance of making sure to check

a battery’s charge before performing a flight. After two flights during our final waypoints and

delivery checkoff, we decided to fly it a third time without checking the battery’s charge levels.

At the very end of that final flight, the battery ran out of charge and plummeted from the sky and

crashed. If we had checked our battery’s charge before every flight, this would not have

happened.

Using these lessons learned and the process of constructing our drone, we can

extrapolate the mission of delivering a birthday cupcake to many other cases. The main

takeaways from our construction of a robot to delivery a cupcake is that future drone delivery

applications can incorporate the idea that the purpose of drone delivery is not only to deliver the

package and return, but also to provide an experience. Our birthday drone was not only

delivering a cupcake but also adding an element of joy, fun, theatricality, and surprise that

cannot be rivaled by other means of delivery. Additionally, our mission included the concept of

determining in advance what would be the optimal time to takeoff so that the delivery would land

on time. This is an important component that future drone delivery services will need to master.

Further, the importance of being able to deliver to a specific location using a specified path will

be crucial to future drone delivery.

Finally, in order to optimize our aerial robot, there are multiple potential areas for future

development. First, we could actually construct our ideal robot, using the optimized wing and

airfoil design from XFLR5. This would drastically improve the range over our current

quadcopter. Further, we could automate takeoff and landing, so that it does not have to be

manually controlled. Because waypoints and GPS may not be accurate enough to land a drone

on a table, we may need to add some detection systems on the bottom of the drone to be able

to land at a specified target region.

Ultimately, this project allowed us to gain experience in prototyping a working delivery

mechanism to deliver a package to a user. We also were able to optimize the wing and airfoil

design of an ideal robot that would maximize the ability to deliver a cupcake over a large range.