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).
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.
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.
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.
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).