Dynamic Coupling of the KC-135 Tanker and Boom for Modeling and Simulation

Current Automated Aerial Refueling (AAR) research requires precision modeling and simulation of the refueling process between a KC-135 tanker aircraft and an unmanned aircraft. In order to meet this requirement, both steady-state and dynamic interactions between the tanker aircraft, the refueling boom, and the receiver aircraft must be accurately represented. Boom orientation and motion is known to change the trim of the tanker aircraft, which in turn influences the formation flying and station keeping tasks involved in current Air Force AAR concepts of operation. This paper describes the development of the coupled equations of motion for the refueling boom, which model its motion and its dynamic interactions with the tanker. For the purposes of this investigation, and to validate the boom model dynamics, the coupled boom model is first implemented as a boom-only simulation. The coupled model is compared to two existing boom-only models: one of which has been used for aerial refueling improvement studies, and the other is currently being used for boom operator training. Steady-state and dynamic responses to control inputs to the boom are calculated by the coupled boom model, then compared to those calculated using the existing models.