Remote payload transportation using an aircraft-towed flexible cable system

We demonstrate the concept of using a cable towed beneath an aircraft to transport payloads without landing. The cable is modelled using a lumped parameter approach and the equations of motion are derived using Kane's method. Full three-dimensional dynamic coupling is preserved between the aircraft dynamics and the motion of the cable and payload. The system is controlled via aircraft maneuvering and prescribing the reel acceleration of the cable. A simulated payload transportation operation is numerically represented as a nonlinear optimal control problem and solved using a direct transcription technique implemented in Matlab. Numerical results are presented for a typical payload transportation operation.