QuadcopterFlightSimulator
Quadcopter Flight Simulator in C and Three.js
This is a basic quadcopter simulator built using Three.js as a fun weekend project. The simulator solves the nonlinear dynamics of a quadcopter, taking into account the equations of motion of the body, the dynamics of the four rotors and the battery charge. The included controller uses a simple proportional control in ACRO mode, controlling angular rates based on linearized dynamics, without any thrust compensation.
🚀 Getting started
The easiest way to run the simulator is from your web browser The simulator will render a 3D quadcopter model, and you can control it using a keyboard (WASD for roll/pitch, arrows for thrust/yaw).
🤔 Assumptions and Limitations
As this is a weekend project, several assumptions were made to simplify the model:
- No electrical transient in the brushless motors
- Effect of temperature is neglected
- Constant friction torque
- Propeller thrust and torque approximated with fixed-point performance (J=0)
- Secondary aerodynamic effects are neglected (propeller cross-flow, P-factor, propeller wakes, vortex ring, ground effect, rotation rates, influence of the frame…)
- Coriolis effect is neglected
These assumptions have a strong influence on the accuracy of the simulation. Note that this simulator is a basic implementation and may not be entirely accurate or realistic. It is intended for experimental purposes only.
📑 References
[1] A. Gibiansky, “Quadcopter dynamics, simulation and control”, Blog, 2012
[2] E. Gopalakrishnan, “Quadcopter flight mechanics model and control algorithms”, Master Thesis, Czech Technical University, Prague, 2016
[3] L.F.M. Mendoza et al., “Trajectories generation for unmanned aerial vehicles based on obstacle avoidance located by a visual sensing system”, Mathematics 2023, 11(6), 1413
Other useful resources:
- Brushless motor model: https://electronics.stackexchange.com/questions/39387/how-are-current-and-voltage-related-to-torque-and-speed-of-a-brushless-motor
- Brushless motor calculator: https://www.ampflow.com/motorCalculations/
- LiPo battery voltage chart: https://blog.ampow.com/lipo-voltage-chart/
- ESC PWM control: https://www.controleng.com/understanding-the-effect-of-pwm-when-controlling-a-brushless-dc-motor/
- APC propeller data: https://www.apcprop.com/technical-information/file-downloads/
- Control system: https://wilselby.com/research/arducopter/controller-design/
- ACRO mode: https://docs.px4.io/main/en/flight_modes_mc/acro.html
- Arduino PID controller implementation: https://www.youtube.com/watch?v=4vpgjjYizVU