Drone control

Drone project

This project is intended to be a rather simple core drone stabilizer application based on Teensy and the prop shield.

Intended to be expanded with an outer control loop with a non-realtime sensor, e.g. GNSS, camera or laser scanner.

Propeller - motor performance

Measured with the app below, using the motor 3508-700KV Turnigy Multistar 14 Pole Brushless and a 14x5.5 carbon propeller. The ESC is a Hobby-wing x-rotor 40A controller.

Time responce

With 11 V supply (3 lipo cells). From 1.1ms to the ESC (idle) to 1.9ms almost full throttle. The ESC update frequency is 400 Hz.

With 11 V supply (4 lipo cells). note that 30 amps is not sustainable, the motor gets hot fast.

Trust

Transfer gain measurement from ESC pulse width to trust. The Hobby Wing controller is calibrated to 1ms=off, 2ms=full power.

Normal size propeller (14x5.5) for the motor. The translation for ESC pulse to trust is almost linear. The trust increases with the square of the rotation speed, but drag increases with power 3 of the rotation speed, so end result is almost linear.

Data for the graph above is

% Measurement from esc,motor,propeller test
% file created 2020-10-04 17:49:57.982360
% 1: esc value (motor 1) 0=1ms, 1024 = 2ms
% 2: rps (motor 1) a rotations per second)
% 3: rps (motor 1) b rotations per second)
% 4: Motor voltage (volt)
% 5: total current (amps)
% 6: trust force (gram force)
% 7: CCV (rotation direction)
% 8: Temperature motor (deg C)
% 9: Temperature ESC (deg C)
100 8.27 8.27 11.3 0.1 10 0 38.8 33.3
200 18.89 18.91 11.3 0.4 54 0 28.8 27.9
250 24.78 24.78 11.3 0.7 92 0 27.2 28.0
300 30.11 30.16 11.3 1.2 136 0 27.8 27.6
300 30.17 30.12 11.3 1.2 136 0 26.2 27.9
350 35.65 35.65 11.1 1.7 192 0 27.2 28.2
400 40.33 40.54 11.2 2.5 246 0 26.3 28.7
450 44.49 44.47 11.3 3.6 300 0 27.4 28.4
500 49.34 49.33 11.3 4.5 371 0 26.8 28.5
550 54.00 54.01 11.4 5.8 440 0 27.9 29.2
600 58.11 58.07 11.2 7.2 523 0 27.0 29.3
650 61.94 61.71 11.0 9.0 600 0 27.0 30.0
700 65.24 65.20 11.0 10.3 660 0 27.6 29.8
750 68.22 68.67 11.2 12.5 730 0 29.2 30.6
800 71.01 71.14 11.3 14.4 806 0 31.7 30.3
850 73.87 73.89 11.5 16.7 870 0 32.1 29.1
900 76.76 76.62 10.8 18.7 930 0 33.0 31.3

Motor test app

MATLAB simulation

Simulink model of hexacopter.

Sim mechanics simulated hex-drone hoovering.