Remote Control Multi-Copters

Slides from a short talk I gave to my local amateur radio club in late 2013 describing the basics of quadcopter flight dynamics, radios and operating considerations.

Transcript

1. Remote Control Multi-Copters Erik O’Shaughnessy - KF5WUT erik.oshaughnessy@gmail.com 1 Thursday,3 October, 2013
2. Multi-Copter Definition A radio controlled model using multiple rotors for: Lift Propulsion Attiude Control Has three or more rotors Electrically powered with Lithium Polymer (LiPo) batteries 2 Thursday,3 October, 2013
3. Why Fly Multi-Copters? Simplicity Robustness Novice Friendly Fun! 3 Thursday,3 October, 2013
4. Multi-Copters - Why Now? Inexpensive High Capacity Batteries Inexpensive Flight Control Electronics Expanding Interest in High Performance Flying Platforms for: Video Capture Robotics Autonomous Flight Operations 4 Thursday,3 October, 2013
5. Anatomy of a Multi-Copter Air Frame Flight Control Board Battery Electrical distribution network Electronic Speed Controllers Electric Motors & Propellers Flight Control Input Receiver FC BAT RX CCW 1 CW 2 CW 3 CCW 4 5 Thursday,3 October, 2013
6. Flight Dynamics Lift is achieved via thrust from all rotors Pitch is achieved by differential thrust from front to back Roll is achieved by differential thrust from left to right Yaw is achieved by differential thrust from diagonally opposed rotors FC BAT RX CCW 1 CW 2 CW 3 CCW 4 6 Thursday,3 October, 2013
7. Equipment RC Transmitter Flight Simulator Quadcopter Model Batteries and Charger Spare Parts and Tools 7 Thursday,3 October, 2013
8. Operations Flying Locations Large open spaces without trees, people and animals are best Club fields, usually require membership in AMA for liability Indoors - Requires skill and/or small model Example Flight Durations Blade mQX ( 3.7VDC, 600mAh ): 8 to 15 minutes DJI FlameWheel 450 ( 11.1VDC 2200 mAh): 8 to 12 minutes 8 Thursday,3 October, 2013
9. Operations - Hazards Never Fly Model Towards Yourself or People Loss of Orientation Flying Model Out of Line of Sight (LOS) Overhead Obstacles Wind, Water Animals and Fire Ants 9 Thursday,3 October, 2013
10. RC Radios Ground to Air One “Channel” Per Flight Control Input Air to Ground Model Telemetry First Person Video Transmitted to Ground Station 10 Thursday,3 October, 2013
11. RC Radios - Analog Operating frequencies: 27 MHz, 50 MHz, 72 MHz and 75MHz Modes: AM Pulse Position Modulation (PPM) Pulse Code Modulation ( PCM ) Requires active pilot coordination to prevent unintended inputs 11 Thursday,3 October, 2013
12. RC Radios - Digital Operates from 2.4000 GHz to 2.4835 GHz Popular Digital Protocols: DSM2, DSMX and F. A. S. S. T. DSM2 and DSMX are Direct Sequence Spread Spectrum F.A.S.S.T. uses Frequency Hopping Spread Spectrum TX is bound to RX, RX then ignores inputs from unknown TX Takeaway: 100s of TX can operate simultaneously without pilot coordination 12 Thursday,3 October, 2013
13. FPV - First Person Video Real-Time Video Feed Transmitted from the Model to a Ground Station FPV has two practical benefits to the pilot: Ability to fly the model even if it has left line of sight Pilot remains oriented regardless of model attitude 13 Thursday,3 October, 2013
14. FPV - Example Video Frame 14 Thursday,3 October, 2013
15. FPV - Flight Equipment Video Camera On Screen Display (OSD) Module UHF Transmitter and Antenna Optional Second Battery To Power FPV Components GPS Receiver, Compass, Altimeter 15 Thursday,3 October, 2013
16. FPV - Ground Equipment UHF Antenna and Receiver Video Distribution To: FPV Video Goggles Video Display Digital Video Recorder Head Tracker for Controlling the FPV Camera Gimbal 16 Thursday,3 October, 2013
17. FPV - Video Transmission Commercially Available Video TX/RX typically operate at: 910 MHz 1.2 - 1.3 GHz 5.8 GHz To Be Continued... 17 Thursday,3 October, 2013
18. FPV - Considerations Added Cost Match Range of Control and Video Links Extra Weight of FPV Gear Reduces Flight Time Increased Risk of Losing the Model Beyond Visual Range Operating is Not Allowed by AMA Rules 18 Thursday,3 October, 2013
19. Lithium Polymer (LiPo) Batteries Composed of “cells”, each cell contributes ~3.7 VDC LiPo Battery Operational Dimensions: mAh, S and C mAh: the capacity in milliamp/hours ranges from 300 mAh to 5000+ mAh S is the number of cells 1S, 2S, 3S up to 10S or more C is the recommended maximum discharge rate 10C is 10x the capacity of the battery, bigger is better. 19 Thursday,3 October, 2013
20. LiPo Batteries - Safety Multi-cell LiPo batteries require a balanced charger to ensure equal charging between cells. LiPo’s heat up on discharge, swelling is sure sign of discharging too quickly LiPo’s can burst and combust vigorously, always charge in a safe place: on concrete, away from combustibles fire-proof charging “bag” which can contain the LiPo if it bursts Protect LiPo batteries from physical damage, do not drop! 20 Thursday,3 October, 2013
21. LiPo Batteries - Connectors XT-60 - hexTronic 60 amp keyed connector EC3 and EC5 - 60 and 120 amps keyed connectors Deans Ultra Connectors - 50 amp keyed connector RC Car LiPo’s commonly use: Tamiya connectors Traxxas connectors Most common discharge connectors: EC3, Deans and XT60 21 Thursday,3 October, 2013
22. Selected Web Reading oddcopter.com openpilot.org getfpv.com wattflyer.com electrichelicopterfun.com 22 Thursday,3 October, 2013
23. RC Abbreviations AMA - Academy of Model Aeronautics - http://www.modelaircraft.org/ FPV - First Person Video, flying using video transmitted from model ESC - Electronic Speed Controller, takes PWM input to control rotor speed BNF - Bind and Fly, model comes assembled and includes a RX RTF - Ready to Fly, model comes assembled and includes a TX and RX PNP - Plug and play, model may require assembly and does not include radios or batteries ARF - Almost Ready to Fly, model requires assembly and does not include radios or batteries 23 Thursday,3 October, 2013
24. Remote Control Multi-Copters Erik O’Shaughnessy - KF5WUT erik.oshaughnessy@gmail.com 24 Thursday,3 October, 2013
25. FC BAT RX CCW 1 CW 2 CW 3 CCW 4 25 Thursday,3 October, 2013