Präzise Rendezvousregelung für Luft- und Bodenfahrzeugsysteme
- Precise rendezvous control of aircraft and ground vehicle systems
Engels, Stefan; Moormann, Dieter (Thesis advisor); Abel, Dirk (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2019
A major focus of current aerospace research is enhancement of energy efficiency. In order to reach this goal, one potential solution is to reduce the weight of the aircraft. As a result, the aerodynamic lift required is reduced as well as coupled drag and necessary thrust. One possible approach to weight reduction is to eliminate the landing gear from the aircraft. In doing so, however, the take-off and landing processes have to be supported by a ground based system such as a ground vehicle. From a flight dynamics and automatic control point of view, the landing process is a significantly more challenging task compared to take-off. At the moment of touchdown, the position, velocity and roll, pitch and yaw angle of aircraft and ground vehicle must be coordinated. In order to achieve this, the translational and rotational degrees of freedom of both systems must be aligned to comply with determined thresholds; i. e. they will have to be synchronized. The reduction of remaining deviations to touchdown is defined as rendezvous. For technical reasons including enhanced reaction speeds and repeatability, but also with regards to economic efficiency, an automation of the rendezvous control system will be necessary. In this thesis, the fully automated landing of an aircraft on a ground vehicle is discussed. The automatic control focus will thereby be on the aircraft. The complete landing process is split into two phases: During the approach phase, aircraft and ground vehicle are guided to the start of a previously determined rendezvous area with adequately matching position and velocity. During the subsequent landing phase, both systems need to be precisely synchronized such that the rendezvous can be successfully completed when the aircraft touches down on the ground vehicle - in spite of any atmospheric disturbances. Because aircraft and ground vehicle usually have heterogeneous dynamics, the presented concept includes a distribution of tasks with respect to their dynamics. Within the scope of this thesis, the presented control system concept is designed and implemented for a typical combination of aircraft and ground vehicle. For validation purposes, the control system is evaluated by means of simulations including various atmospheric disturbances. In conclusion the concept is verified by experimental flight tests.