Robust visual servoing using adaptive sliding mode control and quaternions for a quadrotor UAV tracking a dynamic target

HERMAN CASTAÑEDA CUEVAS (2023)

Quadrotor unmanned aircraft vehicles are being used nowadays more than ever in dangerous

and complicated environments that include on-sea structure inspections, density-forest analy-

sis, search-rescue operations, and precision agriculture activities, among many others. Given

its extended use in multiple scenarios, the need for proper control and robustness against

complex environments is highlighted, resulting in a reluctant adoption of quadrotors for fully

autonomous operations. This is especially true in applications where local positioning is re-

quired such as target tracking operations, object picking, indoor navigation, between others.

Most of the time these operations are executed using an onboard camera, as such, keeping

the objective inside the eld of view is a major problem when external perturbations affect

the aircraft. To propose a solution to this problem, this thesis presents a robust image-based

visual servoing -control- design for a quadrotor unmanned aerial vehicle performing visual

target-tracking operations in the presence of turbulent winds. Visual data, extracted by the

analysis of critical image features, is processed to control the positioning and heading of

the aerial vehicle. The image acquisition algorithm considers a virtual camera approach,

which produces an image insensitive to the roll and pitch movements. The previous image

operations and the quadrotor modeling are performed using the quaternion rotational repre-

sentation, which avoids many of the well-known Euler angle singularities. Additionally, a

novel adaptive non-singular fast terminal sliding mode strategy is introduced to minimize the

visual servoing error. Unlike other sliding mode methods, the proposed approach reduces

the complexity of the system due to the reduction of control parameters, while providing

practical nite-time convergence, robustness against bounded external disturbances as well

as model uncertainties, non-overestimation of the control gains, and chattering attenuation.

Furthermore, the stability of the system in a closed loop is guaranteed through the Lyapunov

stability analysis. Finally, the proposed control algorithm is extensively tested using the

Gazebo/ROS simulator which provides a close-to-real-life insight into the performance of

the system comparing it to the same scenario using the Euler angles representation.

Maestría en Ciencias de la Ingeniería

Tesis de maestría

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS INGENIERÍA Y TECNOLOGÍA AERONÁUTICAS AERONAVES