Periodic motion stabilization of a virtually constrained 3-DOF underactuated helicopter using second order sliding modes

Second order sliding mode control is developed to solve the tracking control problem to induce periodic behavior in a 3-DOF underactuated helicopter laboratory prototype. Virtual constraints approach for motion planning is considered prior the controller design in order to achieve the control goal. Both state feedback design and dynamic output feedback design with sliding mode velocity observers, running in parallel, are proposed. Performance issues of the proposed controller are illustrated in a numerical study.