Strict Passivity Analysis of UAV Swarm Cooperative Payload Transportation Systems with Time Delays

This paper investigates strict passivity analysis for continuous-time unmanned aerial vehicle (UAV) swarm cooperative payload transportation systems with time delays arising from onboard processing and state acquisition. The UAVs are assumed to have identical dynamic characteristics and to be interconnected through a structurally sparse topology. By exploiting the block-diagonal structure of the subsystem matrices and the sparsity of the structural connectivity matrix (SCM), two necessary and sufficient strict passivity conditions that are mathematically equivalent to the conventional lumped criterion are derived without requiring high-dimensional matrix inversion. Furthermore, two sufficient conditions based on single-UAV parameters are developed to reduce the computational burden for large-scale swarms. Numerical studies based on UAV model parameters and generic subsystem matrices demonstrate the computational advantages of the proposed conditions. For a 14-UAV system, the conventional lumped criterion requires 2069.1 s, whereas the aggregate computation times of the two single-UAV-based conditions are 0.589 s and 0.336 s, respectively. These results demonstrate that the proposed structural decomposition framework can substantially improve the efficiency of strict passivity verification for large-scale UAV swarm systems.