Structural and dynamic analysis of airborne towed detection coil array system

To address the challenges of nonlinear dynamics and attitude stability control in airborne towed detection coil array systems, this paper proposes a high-fidelity dynamic modeling and “steady-state design-dynamics” integrated analysis method. The method first employs the lumped mass method to discretize the cable system and combines six-Degree-of-Freedom (6-DOF) rigid body theory to model the detection coils, constructing a complete rigid-flexible coupled dynamic model. Furthermore, a steady-state flight configuration is designed based on static equilibrium theory. After validation through field flight tests, the unstretched lengths of all cables are back-calculated using the displacement method and a progressive analysis approach, thereby precisely resolving the difficulties in system design and determining simulation initial conditions for the complex model. Simulations under three typical severe disturbance conditions indicate that: under constant velocity increment, a gentler acceleration strategy with a lower peak and more dispersed duration more effectively suppresses attitude disturbances and tension impacts; a rear aerodynamic membrane enhances dynamic maneuvering stability, but subject to the coupling effects of membrane self-weight and environmental airflow disturbances, it faces constraints regarding static attitude offset and increased structural loads; the severity of lateral disturbances is primarily dominated by the perpendicular crosswind component; and in complex maneuvers such as turning, the geometric configuration of the tower structure endows the system with self-stability, although high-speed maneuvers still significantly increase lateral swing amplitude and structural loads.