This paper presents the application of two nonlinear control techniques—backstepping and sliding-mode—to an autonomous micro helicopter, the Quadrotor, as part of the *OS4* project at the Autonomous Systems Lab (EPFL). The authors describe the Quadrotor's architecture, dynamics, and control challenges, emphasizing its underactuated and dynamically unstable nature. They derive a detailed dynamic model of the Quadrotor, including gyroscopic effects and rotor dynamics. The paper details the implementation of both control techniques on a test bench and through simulations, demonstrating their effectiveness in stabilizing the Quadrotor's orientation and trajectory. The backstepping controller is shown to perform well even under relatively high perturbations, while the sliding-mode controller, though less stable due to its switching nature, also achieves stabilization. The authors conclude by highlighting the potential for further development towards a fully autonomous indoor Quadrotor.This paper presents the application of two nonlinear control techniques—backstepping and sliding-mode—to an autonomous micro helicopter, the Quadrotor, as part of the *OS4* project at the Autonomous Systems Lab (EPFL). The authors describe the Quadrotor's architecture, dynamics, and control challenges, emphasizing its underactuated and dynamically unstable nature. They derive a detailed dynamic model of the Quadrotor, including gyroscopic effects and rotor dynamics. The paper details the implementation of both control techniques on a test bench and through simulations, demonstrating their effectiveness in stabilizing the Quadrotor's orientation and trajectory. The backstepping controller is shown to perform well even under relatively high perturbations, while the sliding-mode controller, though less stable due to its switching nature, also achieves stabilization. The authors conclude by highlighting the potential for further development towards a fully autonomous indoor Quadrotor.