  In this paper, the problem of coordinated transportation of heavy payload by
a team of UAVs in a cluttered environment is addressed. The payload is modeled
as a rigid body and is assumed to track a pre-computed global flight trajectory
from a start point to a goal point. Due to the presence of local dynamic
obstacles in the environment, the UAVs must ensure that there is no collision
between the payload and these obstacles while ensuring that the payload
oscillations are kept minimum. An Integrated Decision Controller (IDC) is
proposed, that integrates the optimal tracking control law given by a
centralized Model Predictive Controller with safety-critical constraints
provided by the Exponential Control Barrier Functions. The entire payload-UAV
system is enclosed by a safe convex hull boundary, and the IDC ensures that no
obstacle enters this boundary. To evaluate the performance of the IDC, the
results for a numerical simulation as well as a high-fidelity Gazebo simulation
are presented. An ablation study is conducted to analyze the robustness of the
proposed IDC against practical dubieties like noisy state values, relative
obstacle safety margin, and payload mass uncertainty. The results clearly show
that the IDC achieves both trajectory tracking and obstacle avoidance
successfully while restricting the payload oscillations within a safe limit.
