preliminary design review - university of colorado boulder · preliminary design review team scout:...

PRELIMINARY DESIGN REVIEW Team Scout: Austin Anderson, Geoff Inge, Ethan Long, Gavin Montgomery, Mark Onorato, Suresh Ratnam, Eddy Scott, Tyler Shea, Marcell Smalley

October 15, 2013 Scout Preliminary Design Review 2013 1

OVERVIEW 1) Background

2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot

6) Single Board Computer

7) Sensors

8) Interface

9) Mass/Power/Cost Summary

10) Testing

11) Future Work


BACKGROUND AND PURPOSE

• Autonomous search and rescue multicopter

• Capable of exploring dangerous urban environments

• Reduce risk to human life

• Map the environment

• Navigating through doorways is a critical capability



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot

6) Sensors


8) Interface


10) Testing

11) Future Work


REQUIREMENTS

1.1 The sensor suite shall measure its relative position to the wall/doorframe/ground while it is 0-1 m from the wall at an

altitude of 1-2 m

1.1.1 The sensor suite relative position measurement shall be accurate to within ±3 cm

1.2 The sensor suite shall mechanically integrate with the multicopter to form Scout

1.2.1 The sensor suite shall be less than the 1.5 kg maximum payload capacity of the multicopter

1.2.2 Scout shall have an endurance of 10 minutes

1.2.3 The sensor suite shall utilize regulated power from an additional battery

1.3 The sensor suite and control system shall communicate and send proper signals to control the multicopter

1.3.1 The control system shall actuate the motors of the multicopter to achieve the desired motion

1.4 Scout shall maintain controlled flight with error no greater than ±6 cm from its desired position

1.4.1 Scout shall be capable of hover, with a designated orientation, at altitude of 1-2 m

1.4.2 Scout shall be capable of maneuvering at a speed between 0.2 – 2 m/s

1.5 Scout shall be capable of comparing its onboard data with the RECUV indoor flying lab

1.5.1 Scout shall be capable of mounting IR trackers, used by the flying lab

1.5.2 Scout’s data shall be stored I such a way that it can be compared to the flying lab’s data



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


PROJECT OBJECTIVES

• Level 1 Objective: Sensing

• Design a sensor suite capable of integrating with a multicopter platform

• Sensor Suite shall measure relative position* of targeted objects with an error of no more ± 3cm when located 0-1 m from the targeted object.

• Level 2 Objective: Motion

• The control system must control the relative position of the platform to ± 6 cm of a commanded position

• Scout must maintain controlled hover

• Scout must achieve controlled dynamic motion

• Level 3 Objective: Doorway Searching & Maneuvering

• Search for doorway, measuring 0.9m X 2.0m, through lateral movement along wall

• Navigate and maneuver through a doorway upon detection

*from the sensor to a specified point on the doorway


Power up and maintain

hover at 1-2 m above the

ground.

Begin Searching for

doorway 0-1 m away from

wall

Determine when a 0.9 m

by 2 m doorway is present

and stop searching.

Maneuver through the

doorway and cease

operation.

Side View

Top View

Floor

Doorway Wall

Floor

Doorway

Wall

CONCEPT OF OPERATIONS


FUNCTIONAL BLOCK DIAGRAM


BASELINE DESIGN

Multicopter: Arducopter RTF X8

Control: APM 2.6 running Arducopter

autopilot Sensor:

Hokuyo URG-04LX-UG01

Sensor:

MaxBotics MB1043

Command/Data Handling:

BeagleBone Black

APM mounted

directly on

multicopter

upper surface

Ultrasound placed on

lower mounting .

Faces floor

CDH mounted on

lower mounting.

Facing upward

2D Laser mounted on

upper mounting facing

platform's path

October 15, 2013 10

Sensor Data Telemetry Data Logic Command AutoPilot Command

GPIO, RS 232, Digital USB, MAVLink, Digital Voltage Command

Ultrasonic Sensor (MB1043)

Laser Sensor (URG-04LX-UG01 )

BeagleBone Black

APM 2.6 Autopilot 3DR RTF X8

Acquires vertical position measurement

Acquires lateral position measurement

Processes position and telemetry data and sends “stick” command to APM

Processes input from Beaglebone and sends commands to motors

Autonomously flies through the doorway using

APM voltage commands

SCOUT INTERFACE SUMMARY


IDENTIFICATION OF CRITICAL PROJECT ELEMENTS

Critical Purchases

• Multicopter Selection • Dictates mass budget/payload capacity

• Determines mounting locations

• Imposes restrictions on the autopilot system used

• Autopilot Selection • Imposes limitations on what sensors can be used

• Control capabilities of the multicopter

• Sensor Selection • Dictates communication protocols (ex: RS232)

• Imposes limitations on how quickly position can be established



Design Challenges

• Sensing • Have an accuracy and resolution of at least ±3 cm

• Limits how quickly position can be established

• Software

• Synchronized data processing and communication (sensors/microcontroller and

autopilot/microcontroller)

• Design for difference in sensing rates and autopilot command rate

• Sufficient memory for data storage and programming code

• Control laws may need to be translated (Simulink/LabVIEW to C)

• Electrical • Signal/Connector compatibility between all sensors and autopilot

• Minimize power conversion losses (voltage regulators)



• Stability • Determine multicopter and autopilot sensitivities to center of gravity location

• Design and test mounting/weight distribution strategies (SolidWorks)

• System Integration • Components purchased, designed, and tested with foresight on the other

components with which they must integrate

• Very important properties: mass and power budgets, signal compatibility and software languages



• Testing Facility • Testing performed in RECUV’s indoor flying

laboratory (Construction completed Spring 2014)

• Alternate Testing Plan

• Mechanical department’s high speed camera used with a grid placed on the path of the multicopter

• Grid has known interval quantities to find the position

• Recording will be used for requirement verification

• Verification

• Must verify both sensor requirements and control requirements are both

under the required ±3 cm independently



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


MULTICOPTER SELECTION - RTF X8

Width = 0.5 meters

Uses an Open Source Autopilot

Maximum Payload of 1.5 kg

Flight Endurance = 10 - 15 min

Pros

Very large payload capacity (1.5 kg) allows for a variety of design options

Open source autopilot allows for alterations to be made if the multicopter is modified in the design process

Mounting areas available on multiple regions of the platform

The included APM 2.6 autopilot system is one of the best available

30 minute assembly time

Width (0.36 meters) allows for easy maneuverability through doorway

Low cost, within the $3,000 budget

Cons

Moderate flight endurance (10 – 15 minutes)


RTF X8 - FEASIBILITY ANALYSIS

• Flight Endurance at Max Payload Capacity: 10 – 15 min • Exceeds the customer requirement of 10 minutes (Requirement 1.2.2)

• Mounting Capability: Variable surface • Top of platform, bottom of platform and possibility of gimbal integration for

sensors/control system from protruding struts (Requirement 1.2)

Bottom Surface Top Surface

Autopilot

Mounting


RTF X8 - FEASIBILITY ANALYSIS

• Cost: ~$1,200 • Total available budget for multicopter and autopilot of $3,000

• Width: 0.36 meters • Doorway width defined to be 0.91 meters

0.36 m 0.28 m 0.28 m

2.03

m



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


PERFORMANCE SUMMARY

66.42 mm [2.61 in]

40.6

4 m

m

[1.6

in

]

Command Rate = 100 HZ

Mass = 17g

Power = 500mW

Open source – 100% modifiable

Active community, many

developers

Pros

Light weight (17g)

Could be programmed using Arduino IDE

Strong community support

Cons

Not plug-and-play. Needs pre-flight tuning.


Rate Control Loop:

Calculates necessary

motor commands to bring actual

rates closer to commanded rates

Command:

Radio controller

roll, pitch, yaw,

throttle and

climb rates

Altitude Control Loop:

Calculates necessary motor

commands to bring actual throttle

and climb rate closer to those

commanded

Motor

Commands

yield new

aircraft state

Current rates and altitude

measured by the onboard Inertial

Measurement Unit (IMU)

Multicopter

Control

SOFTWARE FUNCTIONALITY: APM 2.6 AUTOPILOT


Size and Complexity of Arducopter Software

• Arducopter takes up 94.5% of the board’s programmable memory. Leaving only 14,332 bytes

• Incorporating additional software into a package not completely understood is extremely risky

• While Arducopter software could be modified to incorporate our CDH algorithms, understanding the autopilot code in its entirety is not feasible for the scope of this project

Limited Processing Power

• ATMEGA 2560 8-bit CPU processor capable of operating at 16MHz

• Only has 8kb of static random access memory (SRAM)

AUTOPILOT LIMITATIONS



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


SCOUT’S SENSOR MANIPULATION

Laser range finder scans

environment and reports 638

ranges at 10Hz

Designed algorithm

computes relative

position of Scout to each point in the

scan.

Using relative

position,

designed

algorithm

determines

desired

position

Designed algorithm

calculates

rates and throttle

that will result in the desired position

Arducopter autopilot uses

commanded rates and

throttle to drive motors

Motors on platform actuate and Scout

begins to move


ALTERNATIVE SOLUTION: SEPARATE BOARD FOR SENSOR DATA

MANIPULATION Pros

Eliminates risk of insufficient

processing power, and memory

Reduces risk of creating bugs within

software.

Could provide extra hardware

capabilities (communication ports)

Cons

Adds additional interface between

microcontroller and APM 2.6.

Additional cost to project

Additional mass and power

requirements


PERFORMANCE SUMMARY

• Interface = GPIO(92), UART, USB(x1)

• Mass = 40g

• Power Usage = 2.5W

• Processor Speed = 1GHz

• RAM = 512MB

• Cost = $45

BeagleBone

Pros

Very low power usage (2.5W)

Low cost with $45

High processing power and memory

Low mass (40g)

Able to run Linux distributions

Strong community support

Cons

Moderate available ports


DATA HANDLING

• Validation of design

• Must record relative position data to verify sensing meets requirements

• Commanded position must also be stored to verify control requirements are met

• Debugging code

• Storing commands sent to APM will help in debugging software

Data to be stored

•

•

•

•

•

Maximum Data Storage

• Data stored at 100Hz (same rate as autopilot main loop)

• Storage occurs for entire 10 minute flight endurance

• Each number stored as double precision floating point

(

)

BeagleBone Black’s microSD slot



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


URG-04LX-UG01 OVERVIEW

How it works:

● Uses an infrared light source used for area scanning

● Measures a maximum distance of 4000 mm

● Has a sweep function that provides a scan area of 240o that outputs the measured distance every 683 steps (0.352o)

2-D sensing area of the URG

Non-Radiated Area: 120o


MANEUVERING WITH THE 2D LASER

• The URG will receive the diffused IR

laser when pitched assuming the

wall has a roughness greater than

785 nm

• Using the accelerometers to obtain

pitch, the distance to the wall can

be calculated

Pitch Concern • The 2D laser will use a

sweep function in order

to detect a doorway

• The laser will record

distances along a wall

until a noticeable gap

occurs in the data


ALTERNATIVE DESIGN OPTIONS

Sensor Shielding

• Develop physical shields around the sensor that doesn’t reduce its functionality, but protects it from Vicon’s infrared signals

Vicon Notch Filtration

• Use physical filter over camera system to filter out sensitive wavelengths

Notch Filter

Other Sensors

• IR Sensors

• Use IR sensors that operate at different wavelengths to be outside the range of operation from the Vicon system

• Imaging

• Projects a grid of lasers on the wall and captures an image to determine distance

• Not susceptible to interference with Vicon system

Using a grid to process distance

TiM3xx IR Sensor


RANGE (URG-04LX-UG01)

• Sensor suite measures relative position 0-1 m from wall

• The URG has a detection distace of 20 mm to 4000 mm. (Requirement 1.1)

• Sensor suite measures relative position to a doorframe while manuevering through

• The URG can determine position from 20 mm to 4000 mm with a 240o field of view (Requirement 1.1)

• Sensor suite relative position measurements accurate to within ±3 cm

• At a distance of 20 mm to 1000 mm the URG is accurate to ±30 mm* (±3 cm). (Requirement 1.1.1)

• Sensor suite capable of distinguishing a doorway from a wall

• The URG has the ability to determine position at every point (638 steps) in a field of view of 240o

Doorway Wall

Sensor Field of View

*at 1000 mm to 4000 mm the URG is

accurate to ±3% of measurment October 15, 2013 Scout Preliminary Design Review 2013 33

SENSOR FUNCTIONALITY: MB1043

How it works

● Transducer converts electrical energy into high frequency ultrasonic sound waves, above 1800Hz

● Sound waves traverse until they hit an object, at which point they bounce back in the form of an echo

● Echo sensor recieves echo, and calculates the distance to the object from time of flight of the sound waves

● MB 1043 uses RS 232 communication protocol to interface with processor

● Due to interference from propwash, sensor is suited for vertical hight rangefinding as opposed to wall detection

Outbound

Sound

Waves

Reflected

Sound

Waves Target

Object

MB 1043


RANGE (MB 1043 HRLV)

• The sensor suite shall measure its relative position while it is

1-2 m above ground. • The ultrasound has a detection distance of 30cm to 5000mm (Requirement

1.4)

• The sensor suite shall be capable of continual accurate

measurements to maintain hover of ± 6cm • Ultrasound sensor takes measurements at a rate of 10Hz with 1mm

accuracy (Requirement 1.4)


VERTICAL RANGE FINDING

• Statically mounted underneath Scout facing downward to measure vertical distance to ground

• Pitch and roll angles calculated by accelerometers will be used to determine Scout’s height in non-level states

• Can then calculate vertical distance to Scout using a rotation matrix, roll and pitch angles and the distance measured by the sensor

Measured

height

Actual

height



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


ELECTRICAL INTERFACE (SBC & AUTOPILOT)

• The Single Board Compter and APM can communicate through bidirectional USB ports

• This can be done using the MAVLink Protocol

• SBC running Linux distribution(Angstrom/Ubuntu) could be installed with MAVLink drivers

• This has been done on the Rasberry Pi / BeagleBoneXM / Odroid / AsctecAtomBoard proving feasibility

BeagleBone

Autopilot

USB HOST

USB Client Ports


RS232 , GPIO

URG-04LX-UG01

BeagleBone Black

MB 1043

500mA 3.1mA

RS232 , GPIO

5V DC

ELECTRICAL INTERFACE (SBC & SENSORS)

MECHANICAL INTERFACE

• Ensure a mounting design capable of supporting electrical components on multicopter can be developed

• If a simple mounting set-up is capable of meeting minimum mounting requirements, then it is feasible that at least one suitable mounting design can be developed for this project

• At this stage of the design a simple model would be useful for requirements related to

• Mounting area for components • Satisfaction of the system’s mass budget • Preservation of multirotor's flying qualities • Visibility for sensors


SIMPLE MOUNTING MODEL INVESTIGATED

• Top Plate

• Hokuyo URG-04LX-UG01 (2D laser sensor)

• Bottom Plate:

• BeagleBone Black SBC

• MaxBotics MB1043 (Ultrasound Sensor)

• Samsung Li-Ion battery

Assumptions

•Plates made of polycarbonate (typical engineering plastic)

•Plates will be of length (L), width (W) and thickness (t) equal to 5 mm for both (factor of safety FS = 1.74)

•Both plates are connected to the multirotor via 4 stainless steel bolts (r = ¼ inc) each

2-D

Laser Ultrasonic

Beagle

Bone

Battery

Length 50 [mm] 50 [mm] 86 [mm] 67 [mm]

Width 40 [mm] 50 [mm] 56 [mm] 36 [mm]

Area 2050

[mm2] 2500 [mm2] 4816[mm2] 2412 [mm2]


MOUNTING LOCATIONS

Use of pre-existing

holes to attach

plates

Ultrasonic Sensor

Autopilot

Single Board

Computer

Bottom View

Battery

2D-Laser Sensor


MOUNTING AREA

• The top plate must at least cover a base equal to the autopilot’s area. Atop,plate = 2699 mm3 > A2D-Laser = 2050 mm3

• For the bottom plate, area is dictated by the dimensions of the battery, single board computer, and mounting bolts. Abottom,plate = 12,823 mm3

Area division of lower plate

BeagleBone

Black (SBC)

Battery

115 mm

112 mm

Note: Ultrasonic

does not contribute

since is on opposite

side Bolts


PREVIOUS MOUNTING

• Example of RTF X8 with

go pro camera and

additional sensors on

the bottom

• Previous examples of

similar equipment

mountings suggest

sufficient area is

available

Arducopter platform provides sufficient space for

attaching mounting plates


MOUNTING MASS

Component Mass [g]

Upper Plate 16

Lower Plate 77

Bolts 781

TOTAL 874

Total conceptual mounting weight < Remaining payload

Weight of simple mounting mechanism does not exceed

available payload (Requirement 1.2.1)

Mass [g]

Max Payload 1500 Sensors -164

BeagleBone -40 Battery -98

Remaining PL 1198

Conceptual Mounting Mass Remaining Payload Calculation


FLIGHT CHARACTERISTICS

• Mounting mechanism must not disrupt the aircraft’s flying characteristics by changing its c.g.

• Following equation describes c.g. for a rigid body of various subcomponents (i)

= 0

• Location of mounted components does not

adversely affect CG location—ensuring

acceptable flight characteristics


Sensor Visibility

• Placement of upper 2D laser 4.5 inches above the multicopter’s centered horizontal plane provides clearance of all structures resulting in 360o field of view

• With the ultrasound facing downwards relatively over the multicopter’s geometric center, the sensor is roughly 29 cm clear of each propeller

• Assuming inviscid propwash, the ultrasound has a cone of 32.71o of unaffected air during a hover of 1m

Mounting mechanism allows sufficient field of view for all sensors


Unobstructed View


2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


POWER

• Multicopter’s battery will provide power to the Multicopter and Autopilot

• Multicopter’s Battery: Lithium Polymer, 305g, 4000 - 4999mAh

• BeagleBone: 2.5 W (5V, 500mA)

• Hokuyo: 2.5 W (5V, 500 mA)

• Sonar: 0.016 W (5V, 3.1 mA)

• Total: for 10 min duration

• These components will be powered by an additional battery separate from the multicopter’s battery

RTF X8 Battery


SELECTED ADDITIONAL BATTERY

Samsung Li-Ion 18650 Rechargeable Battery • Capacity: 2800mAh

• Voltage: 7.4V → 20.72 Wh

• Dimensions: 67 mm x 36mm x 18mm

• Weight: 98g

• Max. charge current: 1.75A

• Max. discharge current: 5A

• Cut off voltage: • Over-Charge Protection: 8.7V

Over-Discharge Protection: 4.6V


MASS FEASIBILITY SUMMARY

• Maximum Payload Capacity: 1500 g

• Payload Margin: 1500 g – 672.3 g =

Remaining Payload for:

• Stand-offs, Material Changes, Wiring

1.5 kg

677 g

Payload Mass • CDH: 40 g

• Hokuyo: 160 g

• Sonar: 4 g

• Battery: 98 g

• Mounting: 375 g

• Total: 677.3 g


COST FEASIBILITY SUMMARY

Main Project Budget ($5000)

• Single Board Computer: BeagleBone $45

• 2D Laser Sensor: URG-04LX-UG01 $1175

• Ultrasonic Sensor: MB 1043 HRLV $35

• External Battery: Samsung LI-Ion 18650 $25.99

Total Cost:

Multicopter/Autopilot Budget (Additional $3000)

Multicopter: RTF X8

• Autopilot: APM 2.6 (Included with Multicopter)

Budget Margin: $5000 - $1285 =

Remaining budget for:

• Mounting, Wiring, Repairs, Backup Units

$5,000

$1,285

$3,000

$1,200 Secondary Margin: $3000 - $1200 =

Remaining budget for:

• Repair Kit, Spare Parts, Backup Units



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface


10) Testing

11) Future Work


TEST FACILITY

• Large open space ideal

for flying Scout safely

• Room for Vicon test

equipment to be

assembled

• Can serve as a base of

operations for the Scout

team


VICON EQUIPMENT

• Infrared cameras mounted on truss or tripods flood the test environment with IR light

• Infrared reflectors attached to Scout reflect IR, and are tracked by infrared cameras

• Software uses predefined geometry of cameras to calculate position and orientation of Scout


HIGH SPEED CAMERA

• Mechanical department’s high speed camera provides an alternative method of testing

• Would be used in conjunction with a calibration grid to measure position of Scout.

Example of a calibration grid,

used for object tracking with

high speed cameras


Requirements for Testing

• Scout requires an indoor test facility, where it can be flown and tested safely

• The RECUV lab provides a controlled environment where Scout can be tested

• Scout requires test equipment to precisely measure its position and orientation

• Vicon Bonita 10 infrared motion capture system with millimeter level precision

• Mechanical department’s high speed camera with calibration grid (off-ramp)

• Scout must be capable of synchronizing onboard position and state sensor data with

that collected by the indoor flying lab

• Time stamping data acquired by Scout and test equipment

• Sending Scout’s real time data via wireless communication (off-ramp)

(Requirement 1.5.2)



2) Requirements

3) Baseline Design

4) Multicopter

5) Autopilot


7) Sensors

8) Interface

9) Mass/Power/Cost Budget

10) Testing

11) Future Work


MULTICOPTER FUTURE CONSIDERATIONS

Baseline Design Known Feasibilities

• Meets the budget requirements set by customer

• Interfaces with APM autopilot and allows for mounting of the BeagleBone, Sensors, and additional batteries

• Meets width and velocity requirements

• Can support the weight of the payload

Future Feasibility Considerations

• Study the sensitivity of the multicopter to center of gravity shifts

• Characterize the vibrations generated by the multicopter

• Study structural aspects and durability from drawings in SolidWorks

Arducopter RTF X8


• Baseline Design Known Feasibilities

• Control purchased Multicopter

• Maintain controlled flight

• Satisfies mass, power and cost requirements

• Future Considerations

• Determine how to pull feedback data from APM to BeagleBone

• Determine sensitivity to changes in center of gravity

• Altering open source code if changes to Multicopter are made

Commands to

Multicopter Commands from

BeagleBone

Feedback to

BeagleBone

AUTOPILOT FUTURE CONSIDERATION

AMP 2.6 Autopilot


• Baseline Design Known Feasibilities

• Capable of communicating with both sensors and APM

• Operates faster than sensors send data to BeagleBone to feasibly produce commands

• Contains enough memory to store data for duration of operation

• Satisfies mass, power and cost requirement

• Future Considerations

• Develop Code

• Simulate Data Processing

• Translating control laws into usable code

• Plan for difference between 10 Hz sensor data and 100 Hz APM cycle speed

Sensor

Inputs

Feedback

from APM

Output to

APM

SBC FUTURE CONSIDERATION

BeagleBone Black


SENSING FUTURE CONSIDERATIONS


• Able to detect distances both vertically and laterally while maintaining accuracy requirements

• When experiencing dynamic motion, sensor data can be manipulated to determine position

• Sensors meet cost, mass, and power constraints

• Sensors can mount to the multicopter platform and transmit distance data to BeagleBone


• Determine whether the 2D laser scanner can interface with the indoor flying lab

• Managing power and regulating it in order to provide power to the sensors with minimal voltage loss

• Research the best communication protocol and how to most efficiently transmit the sensor data

BeagleBone Black


MECHANICAL FUTURE CONSIDERATIONS


• Mounting design can easily meet cost and payload capacity requirements

• Center of Gravity location is not affected enough to alter flight characteristics

• All of the mission components can be mounted on the platform


• Vibration dampening and mitigation • Platform’s structure may cause vibrations interfering and/or damaging sensors • Mounting must dampen out frequencies • Starting point spring-mass dampener approximation

• Static and dynamic structural analysis • Detailed breakdown of static forces on mounting and required structural strength • Craft’s path in space must be related to applied loads.

• Thermal effects involving motors and electronic components • Layout satisfy temperature ranges of electrical components

• Center of gravity modeling in CAD • Find exact position of craft’s center of mass before and after mounting


REFERENCES

1Hee Jin Sohn; Byung-Kook Kim, "A Robust Localization Algorithm for Mobile Robots with Laser Range Finders," Robotics and Automation, 2005. ICRA 2005. Proceedings of the 2005 IEEE International Conference on Robotics , pp.3545,3550, 18-22 April 2005

2Steux, B.; El Hamzaoui, O., "tinySLAM: A SLAM algorithm in less than 200 lines C-language program," Control Automation Robotics & Vision (ICARCV), 2010 11th International Conference on , pp.1975,1979, 7-10 Dec. 2010

3Bachrach, A.; de Winter, A.; Ruijie He; Hemann, G.; Prentice, S.; Roy, N., "RANGE - robust autonomous navigation in GPS-denied environments," Robotics and Automation (ICRA), 2010 IEEE International Conference on , pp.1096,1097, 3-7 May 2010

4“Laser Scanners, TiM3xx / TiM31x / Indoor / Short Range” , SICK Sensor Intelligence., https://www.mysick.com/ecat.aspx?go=FinderSearch&Cat=Gus&At=Fa&Cult=English&FamilyID=344&Category=Produktfinder&Selections=53789 [Cited 10 October 2013]

5“Mid range distance sensors, Dx35 / DS35 / IO-Link” , SICK Sensor Intelligence., https://www.mysick.com/ecat.aspx?go=FinderSearch&Cat=Gus&At=Fa&Cult=English&FamilyID=402&Category=Produktfinder&Selections=75114 [Cited 10 October 2013]

6“AT: Samsung Li-Ion 18650 Cylindrical 7.4V 2800mAh Flat Top Rechargeable Battery w/ PCM Protection” , All-Battery.com, Total Power Solutions, http://www.all-battery.com/SamsungLi-Ion18650_7.4V_2800mAhwithPCM-31444.aspx [Cited 13 October 2013]

7“BeagleBone Black” , beagleboard.org, http://beagleboard.org/Products/BeagleBone%20Black [Cited 7 October 2013]

8“URG-04LX-UG01 Product Information”, Hokuyo Automatic Co., http://www.hokuyo-aut.jp/02sensor/07scanner/download/products/urg-04lx-ug01/, [September 23, 2013]

9“MB1043 HRLV-MaxSonar®-EZ4? Product”, MaxBotix, http://www.maxbotix.com/Ultrasonic_Sensors/MB1043.htm, [September 27, 2013]

10“3DR RTF X8,” 3D Robotics UAV Technology, http://store.3drobotics.com/products/apm-3dr-x8-rtf, [cited 22 September 2013]

11“APM 2.6 Set (external compass),” 3D Robotics UAV Technology, http://store.3drobotics.com/products/apm-2-6-kit-1, [cited 25 September 2013]

12“Laser Grid GS1,” GhostStop Ghost Hunting Equipment, http://www.ghoststop.com/Laser-Grid-GS1-p/laser-lasergrid-gs1.htm, [cited 10 October 2013]

13“Notch Filters,” Thor Labs, http://www.thorlabs.us/NewGroupPage9.cfm?ObjectGroup_ID=3880&, [cited 10 October 2013]

14“X8 Motor Out Test,” YouTube.com, http://www.youtube.com/watch?v=cdS6Cy5aOvk, [cited 4 October 2013]


https://www.mysick.com/ecat.aspx?go=FinderSearch&Cat=Gus&At=Fa&Cult=English&FamilyID=344&Category=Produktfinder&Selections=53789




http://www.all-battery.com/SamsungLi-Ion18650_7.4V_2800mAhwithPCM-31444.aspx







http://beagleboard.org/Products/BeagleBone Black

http://www.hokuyo-aut.jp/02sensor/07scanner/download/products/urg-04lx-ug01/







http://www.maxbotix.com/Ultrasonic_Sensors/MB1043.htm

http://store.3drobotics.com/products/apm-3dr-x8-rtf







http://store.3drobotics.com/products/apm-2-6-kit-1









http://www.ghoststop.com/Laser-Grid-GS1-p/laser-lasergrid-gs1.htm











http://www.thorlabs.us/NewGroupPage9.cfm?ObjectGroup_ID=3880&

http://www.youtube.com/watch?v=cdS6Cy5aOvk

QUESTIONS?


APPENDIX


DESCRIPTION OF QUALITATIVE TRADE VALUES

• Integration Capability: • Values for this category indicate how easily the source code of the autopilot can be viewed

and manipulated. An • Extreme in this category indicates that the source code is readily available and easily manipulated. • High suggests that the source code is somewhat scattered, but still easily manipulated. • Medium indicates the source code is heavily scattered, and somewhat difficult to modify. • Low indicates the source code is difficult to locate and difficult to modify. • Locked suggests the source code is unavailable and impossible to modify.

• Documentation: • Values in this category indicate how easily it is to find information regarding the source

code, as well as the activity of the development community. • Very good: Indicates that the documentation is thorough and easily understandable,

and the community is well versed an active. • Good: Suggests the documentation exists, but may not be thorough, and the

community is active but amateur. • Medium: Some documentation of code missing, community is active but amateur • Low: Little documentation of how the code functions, community is small • Very Low: No documentation of how the code functions, community is small or

unexistant


WEIGHTING SCALE

• Mounting Capability • A high ranking (very good) in this category will mean that multiple surfaces are available

for mounting, and are not restricted by other components of the multicopter.

• A poor ranking (very low) in this category will mean that only one area is available for mounting, and it may not allow for all of the components necessary for the mission.

• Durability • Methods of Analysis

• Arm thickness, length and material composition

• Platform and propeller materials

• Customer reviews

• All of these parameters were taken into account in order to give an overall score for durability

• A very good score in this section would mean that each component performed very well

• A very low score would mean that almost, if not all of the components performed poorly


WEIGHTING TABLE

Trade Parameters Score 5 Score 4 Score 3 Score 2 Score 1

Width < 0.3m 0.3 - 0.4m 0.4 - 0.5m 0.5 - 0.6m 0.6m <

Mounting Capability*

Very Good Good Medium Low Very Low

Durability* Very Good Good Medium Low Very Low

Flight Endurance > 25 min 20 - 15 min 15 - 10 min 10 - 5 min 5 min >

Payload Capacity > 1.4 kg 1.4 - 1.1 kg 1.1 - 0.8 kg 0.8 - 0.5 kg 0.5 kg >

Cost < $500 $500 - $850

$850 - $1150

$1150 - $1500

> $1500

Trade parameters with

corresponding score

ranges

Only parameters that

evaluate ability to satisfy

mission requirements

included

Not included in trade

study:

• Velocity

• Assembly time

• Height and length

dimensions

* Reasoning for qualitative descriptions given in appendix


MULTICOPTER SELECTION

• All capable of completing mission

• Narrowed selection down to the top three (highlighted in blue)


FURTHER RESEARCH AND ELIMINATION

− Width = 0.35 meters

− Uses a Naza–M Closed Source Autopilot

− Maximum Payload of 1 kg

− Flight Endurance = 10 – 15 min

− Width = 0.61 meters

− Used an Open Source Autopilot

− Maximum Payload of 0.8 kg

− Flight Endurance = 25 min

• Trade study was perfomed on 9 different multicopters, top 3 analyzed

further

• Used highest weighted parameters for further analysis

• Performed low in payload capacity (highest weighted category)

• Closed source autopilot adds unnecessary design complications

SteadiDrone QU4D DJI Phantom


Trade parameters with

corresponding score ranges

Only parameters that

evaluate ability to satisfy

mission requirements included

Not included in trade study:

• Included Sensors

• Included Components

• Default Sensing Resolution

AUTOPILOT SELECTION

* Reasoning for qualitative descriptions given in appendix


Integration

Capability* Extreme High Medium Low Locked

Weight 8 - 17g 18 - 27g 28 - 36g 37 - 45g 46 - 55g

Power 250 – 320

mW

321 – 390

mW

391 – 460

mW

461 – 530

mW

531 – 600

mW

Cost $149 - 228 $229 -

307 $308 - 386 $387 - 465

$466 -

544

Command Rate 341 – 400 Hz 281 – 340

Hz

221 – 280

Hz

161 – 220

Hz

100 – 160

Hz

Documentation* Very Good Good Medium Low Very Low


AUTOPILOT SELECTION


• Narrowed selection down to the three top performing

(highlighted in blue)


DOWN SELECTION OF FINAL AUTOPILOTS

PX4FMU AeroQuad 32

• Untested use onboard chosen platform

• Command Rate = 200Hz

• Scientifically astute developer community

• Incredible documentation, all well

organized

• Untested use onboard any well

performing platform

• High power draw (500mW)

• Command rate = 100Hz

• Large developer community

• Integration with best multicopter (with highest payload capacity) was

top priority


TRADE PARAMETERS


Power Consumption < 1W 1-2W 2.1-3W 3.1-4W > 4.1W

Integration Easy Moderate Average Challenging Difficult

Range Overdoes

Required Range

Exceeds

Required

Range

Meets

Required

Range

Meets Some of

Required Range

Meets Little

of Required

Range

Accuracy <±10 mm ±11-20 mm ±21-30 mm ±31-50 mm >±50 mm

Resistance to Disturbances

Very Good Good Medium Low Very Low

Usable Surfaces Very Good Good Medium Low Very Low

Weight < 10g 10 -70g 70 - 130g 130 - 200g > 200g

Field of View >100o 45o-99o 20o-44o 5o-19o <5o

Resolution <1 mm 6mm 50mm 10 cm >20 cm

Cost < $100 $100 - $300 $300 - $600 $600 - $1300 > $1300

Documentation Very Good Good Medium Low Very Low

Qualitative Trade Parameters:

• Integration – defined by the

difficulty to mount and

interface with microcontroller

(with the knowledge of the

team)

• Resistance to Disturbances –

defined by the sensors ability

to overcome disturbances

such as dust particles,

propeller wash, and vibrations

• Usable Surfaces – defined by

the surfaces the sensor is

accurate on (i.e. carpet,

stucco wall, etc..)

• Documentation – defined by

the completeness of

documentation


SENSOR SELECTION • Did a trade study of different types of sensors, but not

one sensor could complete the mission alone.

• A combination of sensors needed to be chosen

• The top two sensors can be seen, which happen to

work well in combination.

MICROCONTROLLER/SBC SELECTION


Available Ports Extreme (>2 USB,

GPIO,>1 UART)

High (USB, GPIO ,

UART)

Medium (USB,

GPIO/UART) Low (USB)

Very Low

(Requires

Expansion)

Mass 20g – 40g 41g – 60g 61g – 80g 81g – 100g >101g

Power 2W-4W 5W-6W 7W-8W 9W-10W >11W

Processor Speed 1743Hz - 1535Hz 1534Hz - 1327Hz 1326Hz - 1118Hz 1117Hz - 909Hz 908Hz - 700Hz

Memory 2051MB – 1744MB 1743MB – 1436MB 1435MB –

1128MB

1127MB –

820MB 819MB – 512MB

Cost $35 - $64 $65 - $94 $95 - $124 $125 - $154 >$155

Documentation* Very Good Good Medium Low Very Low

* Reasoning for qualitative descriptions given in appendix Not included in trade

study: Operating System

Support October 15, 2013 Scout Preliminary Design Review 2013 77

MICROCONTROLLER/SBC SELECTION


• Narrowed selection down to the three top performing

(highlighted in blue) October 15, 2013 Scout Preliminary Design Review 2013 78

FURTHER RESEARCH AND ELIMINATION

Odroid X2 Rasberry Pi


• Weight = 90g

• Power Usage = 5W

• Processor Speed = 1.6GHz

• RAM = 512MB

• Cost = $35


• Weight = 82g

• Power Usage = 20W

• Processor Speed = 1.2GHz

• RAM = 1GB

• Cost = $182


PREVIOUS SOLUTIONS

• Scout must be capable of determining its relative position to objects in its environment

• Robotics community has addressed this problem via simultaneous localization and mapping (SLAM) algorithms

• SLAM imposes its own challenges:

• Processing the range data is computationally intensive and is usually done off board the vehicle

• When data is processed onboard, it generally occurs on powerful microcontrollers boasting 32bit CPU capable of clocking at GHz speeds, with at least 512Mb random access memory (RAM)

A map generated by an autonomous

land rover, using laser range data and

a SLAM algorithm

NEEDED ADAPTATIONS TO SUITE PROJECT: • Mapping an environment is out of the scope of this project:

• SLAM is so computationally intensive because it “stiches” thousands of scans together to create

a seamless map of the environment October 15, 2013 Scout Preliminary Design Review 2013 80

INTERFACE FEASIBILITY


FLIGHT CHARACTERISTICS

• Assuming mass symmetric placement of autopilot, sensors, electrical components and mounting change in c.g. only occurs along vertical axis.

• The following relation becomes the result:

• To avoid the propellers of the craft, yupper = 11.43 cm

ylower = 0.92 cm


Payload 0.75 kg 1.5 kg

SIZING (MB1043 HRLV)

● The weight of the MB 1043 sensor is 4.3g

● Additional 5g of weight on Scout is feasible according to mass budget

● Small, 0.20cm x 0.22cm x 0.155cm, can be placed under Scout, takes up minimal space.

A 19.9 mm

B 22.1 mm

K 16.4 mm

J 15.5 mm

DETECTION OF DOOR

• The sampling frequency of the URG is 10 Hz.

• Moving at 0.2 m/s the sensor will detect a point every 20 cm in between sweeps. Since the doorframe is ~.9 m wide this gap can be detected.

• Using the diagram shown below and knowing

and

m the minimum detected door thickness would be 0.28 cm

Doorframe

SIZING (URG-04LX-UG01)

● The fact that only one is needed cuts down additions the the mass budget.

● The weight of the URG sensor is approximately 160g

● (Add note on how we are in the weight budget and if it is feasible to add 160g)

● (Add note on mounting surface that we can put it on)

*all units in mm

Payload 0.75 kg 1.5 kg

preliminary design review - university of colorado boulder · preliminary design review team scout:...

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