Control of a 2-dof helicopter

Helicopters are widely used air vehicles in emergency cases and in transportation sector owing to their capability of rapid landing on and taking off from limited and different types of terrains. The performance of helicopter control is directly related to the control of pitch and yaw angles. Any motion of the helicopter in pitch angle causes an undesired deviation in yaw angle, and in the same way the changes of yaw angle affects the pitch angle. Two-degrees-of-freedom (2-dof) helicopters are widely used test platforms in control labs due to their helicopter-like high nonlinearity and the coupling between its axial motions. Their computer assisted structure provides a rapid prototyping environment for testing the designed control approaches. Thus, the challenging dynamics, encountered in helicopter controlling, can be safely investigated via a more simplified system, and the controller systems which can handle these dynamics can be designed. The control of 2-dof helicopters is doable through the adjustment of rotation speed of the two electrical motors. This thesis presents an introduction to the used 2-dof helicopter including its Lagrangian modeling and then the experimental applications of several control techniques are demonstrated by utilizing this test setup with detailed design procedures. The first of applied control approaches is fuzzy control which has a linguistic structure. Second control scheme is backstepping technique which is a good implementation of Lyapunov stability criterion. Third control approach investigated is sliding mode control known with its robustness against disturbances and parameter uncertainties. Fourth method is a technique that is based on the passivity of the system. The last control technique placed in content is called passivity based sliding mode control obtained by defining the sliding mode control law under the circumstance that the passivity of the system is ensured.