User Manual

22/06/2016 MicroduinoQuadcopterTutorialMicroduinoWikipedia
4/15
Duringtherotation,itwillformanantitorqueoppositetotherotationduetoairresistance.Yawingrotationisrealizedbyusingthe
reversetorque.Whentheaircraftsuspends,thespeedofthefourmotorsisthesame,whichcanoffsettorqueinbothhorizontaland
verticaldirection,andachievebalance.Whenthespeedofthefourmotorsisdifferent,unbalancedantitorquewillcausehorizontal
rotationandtheaircraftwilldeviatefromtheroute.Asthepictureshows,byincreasingthespeedofthemotor1and2,and
decreasingthatofthemotor3and4,theclockwiseantitorquegeneratedbythemotor1and2willbelargerthanthecounter
clockwiseantitorquegeneratedbythemotor3and4,causingclockwiserotationoftheaircrafthorizontallyandgeneratingno
verticaldisplacementwhenthereisnochangeinthethrustupside.
PitchandRollMotion
PitchmotionreferstotherotationintheYaxisdirectionwhiletherollmotionreferstotherotationintheXaxisdirection.
Asthepictureshows,byincreasingthespeedofthemotor1anddecreasingthatofthemotor2,andkeepingthesameofthe
variablequantityaswellasthespeedofthemotor3and4:Thethrustoftheheadislargerthanthatoftherear.Theunbalanced
torquemakesthebodyrise.Similarly,therollmotionisrealizedbyreducingthespeedofthemotor1andincreasingthatofthemotor
2,generatingatorqueforward.
Theprincipleoftherollandpitchmotionisthesameduetosymmetryinthemiddle.Bykeepingthespeedofthemotor1and2
unchanged,andchangingthespeedofmotor3and4,it'llgenerateunbalancedtorqueandmaketheaircraftrotatearoundtheXaxis
direction.
ControlProcedure
Theremotecontrollersendsoutcontrolcommand,suchastakeofforflyingleft.Thecontrolsignalisreceivedwirelessly.
Aremotecontrolsignalreceivingmodulereceivesacontrolsignal,whichisconvertedintoPWM,PPMorothersignalsand
thentransmittedtotheflightcontroller.
Microcontrollerusestheremotecontrolsignalandthesensor'svalue(thecurrentstateoftheaircraft,suchasacceleration,
directionandotherinformation)tocontrolthefourmotorandachievethedesiredactionthroughthePWM.
Sincethefourmotorcombinationcontrolcanonlyreachtosixdirections,whichisanunderactuatedsystem.Soherewemusthave
aflightcontrollertocontrolthewholesystem.
Intheflightcontrollers,sensorssuchasgyroscopeandacceleratoraredispensable.Microcontrollercancalculatedatafromthetwo
sensors,getthecurrentaircraft'sattitudeandthenadjusttherotationratewithalgorithmssuchPIDtokeepthestability.Sureyoucan
addanelectroniccompasstogetthedirectionoraGPSmoduletogetthegeographiclocation.Simplyspeaking,thequadcopteris