Position Tracking Control of Nonholonomic Two-Wheeled Drones on a Wall Based on Input-Output Linearization

This paper presents a novel position tracking control law for two-wheeled drones moving on a wall based on an input-output linearization method developed for two-wheeled mobile robots. We first derive the dynamics of two-wheeled drones that move vertically while maintaining contact with a wall. These dynamics reflect the constraints imposed by the wall, with the attitude represented on the special orthogonal group SO(3). Next, we design a position tracking control law based on input-output linearization, where body velocity and angular velocity are treated as inputs, and the forward position of the drones is chosen as output. However, since the two-wheeled drones' inputs are rotor thrusts, as with conventional drones, body velocity and angular velocity cannot be directly commanded. To address this issue, we augment the control architecture with a control loop that calculates the rotor thrusts to drive the actual body velocity to the target body velocity. Finally, we conduct numerical simulations and experiments to verify the effectiveness of the proposed control method.