Quadrotor OM

SPRING SEMESTER REPORTIndoor Quad-rotor Control

M.E. Team Number 01Members:

ECE DEPARTMENT:

Jigar Patel: Team Leader

John Chung: Software/Hardware Engineer

Matthew Kishe: Team Webmaster/Test Engineer

ME DEPARTMENT:

Adam Sobiewski: Team Leader/Treasurer

Andrew Silva: Sponsor Liaison

Gabriel Morales: Mechanical Engineer

SPONSOR

ContentsI. Function Analysis..............................................................................................................2

II. Project Specifications........................................................................................................2

III. Operation Procedures...................................................................................................3

Hardware Assembly.............................................................................................................3

Firmware.............................................................................................................................7

IV. Addition Assembly Required.........................................................................................9

V. Troubleshooting................................................................................................................9

VI. Future Repair/Replacement..........................................................................................9

VII. Spare Parts.................................................................................................................10

Table of

FiguresFigure 1: Propeller Guard........................................................................................................2

Figure 2: Support Arm.............................................................................................................2

Figure 3: Protective housing....................................................................................................3

Figure 4: Landing gear and motor assembly...........................................................................4

Figure 5: Main frame Assembly1..............................................................................................5

Figure 6: X-frame Configuration1.............................................................................................5

Figure 7: PDB mounting1.........................................................................................................5

Figure 8: ESC cable connections1............................................................................................6

Figure 9: PX4 mounted onto the bottom of the frame.............................................................6

Figure 10: Cable connection for hardware...............................................................................7

Figure 11: QGC PX4FMU CONFIG/SCAN Screenshot.................................................................8

Figure 12: Installation instructions for protective housing.......................................................9

Page 1 of 12

I. Function AnalysisThe protective housing is comprised of eight (8) total parts consisting of four (4) support

arms and four (4) propeller guards, both shown below. The propeller guards enclose

each motor assembly to prevent it from coming into contact with any obstacle in the

event of a crash. The propeller guards are connected to the main quadcopter frame via

support arms. The support arms are designed to transfer the load from the propeller

guard through the center of mass of the quadcopter.

FIGURE 1: PROPELLER GUARD

FIGURE 2: SUPPORT ARM

II. Project SpecificationsThe protective housing shown below is expected to withstand any indoor obstacle impact

or crash resulting from flight failure to prevent damage to any of the quadcopter’s

components. In addition, the added weight of the protective housing is not likely to

decrease flight time by a substantial amount.

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FIGURE 3: PROTECTIVE HOUSING

Furthermore, the protective housing will protect the users from harm during handling of

quadcopter. In addition to disconnecting the battery, the protective housing will keep the

users hands and fingers outside of the propeller’s spinning radius. Eyes and hand

protection is still a requirement while handling the quadcopter.

III. Operation Procedures

Hardware Assembly3DR provides a well described guide for the hardware assembly of the quadcopter. This

manual can be found at the following link. The following are used in the assembly of the

quadcopter:

3DR Quad D Frame

o 2 fiberglass plates

o 1 fiberglass PX4

o I fiberglass accessory plate

o 4 aluminum arms (2 black-back, 2 blue-front)

o Fiberglass landing gear (legs)

o Power distribution board (PDB)

o 4 880kV motors

o 4 propellers (11” X 4.7”)

o 4 electronic speed controllers (ESCs)

o Misc. Parts (washers, nuts, screws, and spacers)

PX4FMU

PX4IO

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PX4FLOW

PPM sum receiver

Telemetry Module

Cables for connecting all the modules together

Refer to the site for detailed instructions on how to unbox and assemble a quadcopter.

Below are a summary of the steps for putting together the quadcopter.

a. Start with putting together the landing gear onto the arms with spacers in

between the legs, do this for all four arms (See Figure 4)

Parts used:

o Two M3X25mm screw (green)

o Two M3 metal washer (pink)

o Two M3X18mm spacers

o Four M3X5mm screws (blue)

b. Mount the motors onto the end of the arm. Insert the motor cables into the side of

the arm, do this for all four arms (See Figure 4)

Parts used:

o Two M3X5mm screws (blue)

o Two M3 lock washers (orange)

FIGURE 4: LANDING GEAR AND MOTOR ASSEMBLY1

c. Once all four arms are done, assemble the main frame top and bottom plates

(See Figure 5)

Four M3X30 mm screws (blue)

Four M3X25 mm screws (green)

Eight M3 metal nuts (pink)

Four M3 lock washers (orange)

Four M3X08 mm spacers

1 Image from http://store.3drobotics.com/products/3dr-quad-frame-kit-electronics

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Four 3X5mm screws (red)

FIGURE 5: MAIN FRAME ASSEMBLY1

d. Mount the PDB onto the four spacers in the middle of the bottom plate. Make sure

that the front arrow on the PDB matches the copters convention and

configuration type (‘X’ frame configuration). (See Figure 7)

FIGURE 6: X-FRAME CONFIGURATION1 FIGURE 7: PDB MOUNTING1

e. Connect the ESC cables to the respective motor cables. See Figure 8 to obtain the

correct directions for the motors. Directions are shown in Figure 6.

NOTE: Do not secure the ESCs until the directions have been verified

(this step is explained in the next section)

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FIGURE 8: ESC CABLE CONNECTIONS1

f. Mount the PX4FMU and PX4IO onto a plate and use spacers to attach it to the

bottom plate.

FIGURE 9: PX4 MOUNTED ONTO THE BOTTOM OF THE FRAME

g. Use double sided tape or Velcro to stick the RC receiver, and telemetry receiver

onto the top of the copter and use M3X8mm nylon screws to mount the PX4FLOW

onto the bottom of the accessory plate.

h. Use the figure below to make all the cable connections to the PX4FMU/IO board

(See

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FIGURE 10: CABLE CONNECTION FOR HARDWARE2

i. Once all the components are correctly connected move to the firmware section to

flash the firmware.

FirmwareThis section talks about setting up the PX4FMU along with the carrier PX4IO board. Make

sure you have an empty Micro SD card. First step is to install the firmware using

QGroundControl (QGC).

a. QGroundControl (QGC) Software

Download the most recent version of QGroundControl which can be downloaded

by clicking here and then follow these steps to get ready for your first flight

b. PX4FMU Firmware

In QGC click on the CONFIG then on the big green SCAN button. Click on the

flash/upgrade firmware button to load the firmware onto the PX4FMU.

2 High resolution image http://pixhawk.org/_media/airframes/x5/buildlog_q_x5_26.jpg?cache=

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FIGURE 11: QGC PX4FMU CONFIG/SCAN SCREENSHOT

c. PX4IO Firmware

Hold down the safety switch while powering on the PX4 to renter the boot loader

mode. If done correctly the red led on the IO board will flash rapidly. Let the FMU

boot normally, it will automatically upgrade the processor firmware.

d. Airframe Setup

Once the firmware is flashed onto the board the first thing to do in QGC is to

make sure the right Airframe has been selected. This is done by clicking on the

AIRFRAME CONFIG button on the left toolbar and following the onscreen

instructions.

e. Sensor Calibration

Next is the sensor calibrations which is done by clicking on the SENSOR

CALIBRATION from the left toolbar. Follow the on-screen instructions to calibrate

all the sensors (i.e. Magnetometer, Gyro meter, and Accelerometer)

f. RC Calibration

After the sensors are calibrated, the remote controller (RC) needs to be calibrated

to set the min and max values for the RC inputs. This is done by clicking on the

RC CALIBRATION button from the left toolbar and following instructions.

g. Manual Mode flight Test

Once all the previous steps are successfully completed a manual mode flight test

is to be performed. The USB will not provide sufficient power to spin the motors

and thus the battery should be connected to the system and the USB shall no

longer be connected. Follow the steps below to enter Manual Mode:

1. Make sure RC calibration is done first

2. Start QGC (optional)

3. Connect PX4 board to the battery

4. Connect PX4 board to USB (for data collection if telemetry is not

connected)

5. Turn on the RC transmitter

6. Hold down the safety switch (blinking red light should now be solid red

indicating ready to arm status)

7. Hold the RC throttle stick to the bottom left (this is the method for arming

the copter)

8. You should hear the audio alarm for “ARMED”

9. Release the safety switch

10. The servos should now move

If you are having trouble make sure the Throttle and Yaw channels are not

reversed and also make sure that the ESCs are calibrated.

h. Telemetry on PX4

Plug in the telemetry to the board using a 3DR Radio adapter cable to the UART2

port of the board.

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IV. Addition Assembly Required This section talks about the

installation of the protective

housing. Twenty-four (24)

M3x25.4mm screws and M3 nuts

are required for installation. Pre-

drilled holes and support arm and

propeller guard should be lined

up and secured using a screw

and nut. The arrows and solid

sots in Figure 2 illustrate where

each screw and nut should be

placed.

V. TroubleshootingMost of the troubleshooting requires research since there are many stages at which

troubleshooting may occur. Primary sites referred to were the manufactures’ sites. (i.e.

PX4, 3DR etc.)

VI. Future Repair/ReplacementThis section talks about the future repairs and replacements which are specific to the

future goals of the project. Major code modifications and replacements are anticipated to

implement the Velocity based flight control. This involves modifications to the PX4

firmware. Specific files that need to be modified are listed below:

The multirotor velocity controller folder contains the source code that needs

modifications to implement the velocity controller. (Filename:

mc_vel_control_main.cpp)

The PX4 depends on a RC script file to initialize all the sensors, IO board, Inter

Process Communication (IPC), PX4 Flow, MavLink (communication protocols) and

the controller module. This file needs to be updated onto the SD card for the

initialization.

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FIGURE 12: INSTALLATION INSTRUCTIONS FOR PROTECTIVE HOUSING.

The PX4 also requires configuration to set the controller to recognize the vehicle

type, and to set the parameters to be used by the quadcopter. i.e PWM cutoff

frequencies.

In addition to the controls listed above, spare parts for each component of the protective

housing will be fabricated in case of failure of one piece. The parts were designed to be

easily interchangeable if a piece were to fracture. Prior to each flight, all screws, nuts,

and components of the protective housing, as well as the entire quadcopter system,

should be checked for any issues to prevent catastrophic failure during flight.

VII. Spare PartsThis section provides the specs and descriptions of the required spare parts needed to

minimize downtime in case of crashes. Click here to buy these parts.

TABLE 1: SPARE PARTS LIST

Part Name Specifications Description Images

Propellers 11 X 4.711 X 4.7P

Used for flying the copter, the letter P which stands for pusher is used for the clockwise rotating arms. While the propellers without the P are used for the counter-clockwise rotating arms.

SpacersM3 X 24mmM3 X 08 mmM3 X 18 mmM3 X 30 mm

Black nylon spacers of varied lengths.*NOTE: have lots of these on hand, easy to break hard to find.

Legs N/A

Legs break easily specially when learning flight and landing. Having spares or re-designing legs will be helpful.

BatteryLiPo Battery 3S3300 mAh

Lithium Polymer battery 20C discharge rate

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Dean Connectors

MaleFemale

Dean connectors are widely used all through the copter components. The motor board, ESCs, batteries all use male/female dean connectors.

ESCs 20A-BEC

Electronic Speed Controllers (ESCs) a spare set would be helpful (4 ESCs)

Motors 880 kVSpare set of motors (4 motors)

Arms3DR Aluminum Arms

Spare arms needed in case of crashes, blue is for front, black is for the back.

Support Arms

Protective Housing Support Arms

Spare arms are essential in the event of a crash resulting in a compromised arm. Fabrication takes 24 hours to cure.

Propeller Guards

Protective Housing Propeller Guards

Due to long and tedious fabrication time, spare propeller guards are essential in the event of a crash resulting in a fracture.

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