What is a flight controller?What is a flight controller?


Flight con­troller — (aka: brains, flight board, com­put­er, con­troller) is a device that ensures the flight of the copter, con­trol­ling gas, roll, pitch and yaw (throt­tle, pitch, roll, yaw).

pitchpitchyawyawrollrolldrone flightdrone flight


In gen­er­al, the flight con­troller per­forms the fol­low­ing func­tions:

  • Col­lects infor­ma­tion from sen­sors (installed on it or exter­nal: com­pass, GPS, gyro­scopes, etc.);
  • Sets/calculates its posi­tion in space accord­ing to sen­sors;
  • Col­lects infor­ma­tion about exter­nal con­trol actions (devi­a­tions of the stick by the pilot or the next step of the program/autopilot algo­rithm);
  • Cal­cu­lates dis­crep­an­cies and Pro­por­tion­al-Inte­gral-Deriv­a­tive (PID) coef­fi­cients, in accor­dance with the firmware / pro­gram of autopi­lot or man­u­al con­trol;
  • Sends con­trol / cor­rec­tive sig­nals to actu­a­tors (speed con­trollers).

Principle of operation

The flight con­troller com­mands the speed con­trollers via pulse-width mod­u­la­tion (PWM / PWM), where the con­troller mode is set by the dura­tion of the puls­es, or via the Inter-Inte­grat­ed Cir­cuit (IIC / I2C) ser­i­al inter­face, where the con­troller mode is set by dig­i­tal sig­nals: the first deter­mines the device address , the sec­ond — sets a val­ue from 0 to 255. The PWM method is most often used.

The simplest scheme of a quadrocopterThe simplest scheme of a quadrocopter

Operation of the flight controller and controlsOperation of the flight controller and controls

What are there?

Flight con­trollers from var­i­ous man­u­fac­tur­ers are wide­ly rep­re­sent­ed, such as Mul­ti­Wii, Ardupi­lot, 3DRobotics (Pix­hawk), Hov­er­Fly Pro (Open­Pilot and Copter­Con­trol), CopterControl3D (CC3D Rab­bit Flight Con­troller), Mikrokopter, etc. Most of them have “open source”, which means soft­ware the abil­i­ty to change any para­me­ter of the flight con­troller, up to writ­ing your own pro­gram / firmware for con­trol­ling the copter. The qual­i­ty and cost of such “brains” are usu­al­ly low­er, and there are incom­men­su­rably more oppor­tu­ni­ties for exper­i­men­ta­tion, as well as oppor­tu­ni­ties for mak­ing mis­takes.

types of flight controllerstypes of flight controllers

Which is better?

There is a sim­ple rule — the more expen­sive the flight con­troller, the more sta­ble and reli­able the mul­ti­copter will be. The fact is that lead­ing man­u­fac­tur­ers use high-qual­i­ty hard­ware com­po­nents and high-qual­i­ty soft­ware for con­fig­u­ra­tion and man­age­ment. These man­u­fac­tur­ers include DJI with the Naza‑M V2 con­troller, its light­weight ver­sion — NAZA‑M Lite, as well as pro­fes­sion­al WooKong‑M and A2.

DJI controllerDJI controller

Of the advan­tages, it should be not­ed: a fair­ly con­ve­nient loca­tion of con­nec­tors for con­nect­ing the nec­es­sary devices and relat­ed periph­er­als; reli­a­bil­i­ty of con­nec­tors; plas­tic case, for pro­tec­tion against exter­nal influ­ences. There is also built-in vibra­tion decou­pling to pro­tect sen­si­tive sen­sors locat­ed on the board from harm­ful vibra­tions of the flight con­troller body, which inevitably occur dur­ing the oper­a­tion of the pow­er plant. Thus, we can say that this is a fin­ished prod­uct, max­i­mal­ly pre­pared for out-of-the-box flights.

Almost all “famous” con­trollers have copies, some­times of quite good qual­i­ty, which some­times can­not leave you indif­fer­ent when build­ing, for exam­ple, a back­up device. One way or anoth­er, this choice is rather from a series of “reli­gious”. In any case, when choos­ing a flight con­troller, remem­ber that this is the “brain” of your sys­tem, and most impor­tant­ly when fly­ing — safe­ty (and the miser pays twice).


By Yara