3-Degrees-of-Freedom Helicopter

This laboratory experiment is intended to test different controller designs on a multivariable system to gain a deeper understanding of applied control engineering.

The System

The helicopter shown in the schematic figure possesses three rotational degrees of freedom. The angle of rotation θ (travel) is the angle describing the rotation of the system around the e3-axis (violet). The elevation angle (elevation) is the inclination of the carrier arm φ (yellow) to the horizontal and thus between the axes e1 and e3. The angle of inclination α (pitch) describes the actual inclination of the two rotors (blue) to the horizontal (between the axes e2 and e3). The two driving rotors can be controlled independently of each other, and their input voltages are the manipulated variables of the system.

schematic illustration of a helicopter with three degrees of freedom

Figure: Schematic illustration of the helicopter

Since the system is unstable without control, a stabilizing controller is needed, realizing efficient trajectory tracking and robust disturbance rejection while considering constraints in the inputs and states. The designed controllers can be tested "online" on the real system. The results of the conducted experiments, including a video of the experiment, can be accessed online.


In this video you can see the designed controllers on the reals system.

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Video: 3-DoF Helicopter in Action

Challenges for the Teaching

  • Stabilization of the 3-DoF Helicopter during maneuvers
  • Robustness against disturbances (attacking forces, motor voltage pulses)