XAircraft X650 QuadCopter(QuadRotor) Flight Controller Architecture Design

XAircraft has designed several flight controllers for internal research and development and testing without sell
since 2007.

In the R&D process, in order to achieve standardization and scalability in flight control, we repeatedly modified the architecture design. The picture below shows the final design of flight control architecture which we we called "standard flight control system".

The master control chip ARM of standard flight controller provide 100MPIS processing power to meet the requirements of complex and high-speed control. Flight controllers support 7 exptend modules, two of them are built-in input signal capture module(input module) and control signal output module (output module).

Input Signal Capture Module(Input Module) Features:

• Support 12-channel remote control signal capture.

• Each capture channel has 1us pulse width identification ability.
• Compatible with any type and frequency remote control, such as Futaba, JR, Spektrum, etc.

• Support two or more remote control devices to capture the signal at the same time, on some special occasions, often requires two people to execute a remote control mission, as one person control flight, another control camera mount, requires two remote control devices to work simultaneously.

• Detect the pulse width of remote control input signal, for some advanced remote control, this feature can be used as control protection and signal stability testing.

Meanwhile, users can adjust parameters and check the working condition of input signal capture module by using
XAircraft Flight Control Management(Parameter Adjustment) Software and XAircraft USB-Link PC Connector.

Control Signal Output Module (Output Module) Features:

• 12-channel output capability.

• Each channel output control accuracy: 1us

• Support the general and high-speed digital steering engine, 12 channels are divided into 3 groups, each pulse signal can be arbitrarily adjusted.

• Support High-Speed (UltraPWM mode) Electric Speed Control Device(UltraPWM ESC), low-speed mode are also available.

Although the X650 is a quadrotor (Quadcopter) products, but it equipped with the standard flight control can support up to 12 rotor, usually retaining four output channels for the camera mount, means the X650 flight control can drive 8 rotor(8 propeller) without need to purchase a new flight controller.


Except the two built-in modules, XAircraft standard flight control module also has 5 extend ports, they are PortA to PortE, one of them used for AHRS (Attitude and Heading Reference Systems) which provides Pitch & Roll Angle and heading. As the flight control get the AHRS attitude and heading signals, like 30 degrees tilt, 18 degrees yaw, the flight control algorithms adjust the aircraft's attitude to achieve a smooth flight.

AHRS module is a standard configuration on X650.

The remaining extend port can also be used to connect other modules, such as GPS Module, Range Finder Module, LED Module(indicate aircraft status), Power Monitor Module and so on.

There is a special interface called the connector port (Link Port) in flight controller. All devices connected to the port are called connectors (Linker). Player can set the parameters of flight control Via USB-Link, or upgrade firmware for the flight control.

USB-Link is a standard configuration on X650. Users can also install the Bluetooth device (Bluetooth-Link), OSD-Link and so on. We actively cooperate with several universities in China to improve the control instruction of this interface. It will be announced to help the secondary development of flight control system.