What are FCs?

In the world of R/C hobbyists, multi-rotors is the latest addition. While controlling a model plane or a boat, the pilot has an absolute control and does it meticulously. But this is not the case with the multirotors and here’s when flight controllers comes to our rescue. A FPV Drone Flight Controller(FC) is the very core of a quadcopter and controls most of the onboard electrical components with the support on an arduino-like microprocessor and an series of sensors. Let’s give you an exclusive insight of flight controllers.

In order to catch up with the pace of all so evolving flight controller software, the flight controllers are also continuously adapting with the changing times. The inclusion of the main microprocessor’s model makes sure the pilot has a basic understanding about the flight controller’s capabilities. The most common microprocessor models used are the STM32 F1, F3, F4 and F7 chips. The higher number after F usually indicates a faster microprocessor with extensive functionalities.

image credits : oscarliang

In order to program a FPV Drone Flight Controller, it is connected with the help of a micro USB to the computer and flashed with firmware that is specific to the chosen FC configurator software. The firmware configures the board with the program and settings that is essential to oversee and manage the quadcopter. The USB interface enables connection between the FPV Drone Flight Controller and its configurator thereby allowing the user to modify and change the boards settings that reflects on the receiver configuration, failsafe setup, rates, PID’s, and flight modes. For all FC’s, it is usually recommended to flash the latest firmware that is within the reach as it will provide enhanced flight characteristics and therefore it will eventually minimize the amount of software issues.

image credits: oscarliang

A drone frame with equally spaced holes, houses a FPV Drone Flight Controller. The standard orientation is a spacing of 30.5mm by 30.5mm between hole diameters on a 220 sized quadcopter. Many flight controllers use mounting holes that are larger than 3mm diameter to enable the accommodation of rubber grommets that helps in isolating the FC from motor vibrations.
A gyro is a microchip, which can sense the angular velocity at which a quadcopter rotates in the roll, pitch and yaw axis. And then with the help of calculus mathematics and the given gyro inputs, the FPV Drone Flight Controller is able to estimate and quantify the distance a quadcopter has rotated and whether such a rotation is accelerating or decelerating. Another sensor chip performing a similar function is the accelerometer.

Added advantage: One can also calculate the precise angle of the quadcopter from the horizon as the accelerometer is capable enough to detect the constant acceleration of gravity.
The whole cornerstone of a FPV Drone Flight Controller is the PID control loop in the software used to stabilize the quadcopter while flying. PID expands into proportional, integral and derivative which are calculus terms analogous to the magnitude, area under observation, and gradient of a curve respectively.

In addition to the above mentioned sensors, we also have GPS, barometer and current sensors to provide some enhanced features to enable more telemetry data and flight capabilities. A GPS helps in identification of a quadcopter’s rough position, height and ground speed. Barometer helps in estimating the air pressure whereas a current sensor helps in displaying the battery consumption and the amount of instantaneous current drawn.
A broth is only as good as its key ingredients, similarly a quadcopter will be as good as its components. Choose mutually compatible components that suits your purpose and is completely ideal for your application.

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