Control Design and Simulation Validation for High-Force Aerial Physical Interaction with a Tilting and Center-of-Mass-Shifting UAV

Unmanned aerial vehicles capable of physical interaction with the environment are increasingly relevant for inspection and maintenance where human access is hazardous or costly. The Aerobull platform, an H-shaped coaxial octocopter developed at DTU, addresses the force–attitude coupling that limits conventional multirotors by combining tiltable rear rotors with an internal shifting-mass mechanism. During contact, the centre of mass is displaced forward, enabling the rear rotors to reorient thrust horizontally. This thesis extends Aerobull's simulation-based control framework along three axes: sensing, control, and simulation infrastructure. The previous contact model is replaced by four distributed uniaxial load cells, enabling a passive orientation strategy on inclined surfaces and mitigating the lateral sliding of the earlier architecture. A dual-mode high-level controller is developed to manage both free-flight navigation and force regulation during pushing, coordinated with a platform controller commanding the shifting-mass displacement upon contact; the overall framework is validated on flat and inclined surfaces, including under wind disturbances. A feedforward compensation for the pitching moment of a future Cartesian end-effector is also integrated into the allocation pipeline. A super-twisting sliding mode controller is adapted from a planar formulation to the full six-degree-of-freedom Simscape model. Finally, a co-simulation pipeline coupling Simulink with PX4, ROS 2, and Gazebo is built to bring the control loop closer to real-flight conditions. Simscape results demonstrate stable 20 N pushing on flat and 15° inclined surfaces under aerodynamic disturbances, with pitch deviations below 0.3° during end-effector loading of 3 N·m. The Gazebo pipeline validates the free-flight behaviour and achieves preliminary force tracking, identifying the tilt servo transient and load-cell signal quality as the main open points before hardware transfer.