Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

Improved guidance, navigation & control software

The primary aim of the FASTWing project is the development of an alternate textile wing concept with an increased aerodynamic efficiency to reach a glide ratio greater than five. Another goal is the implementation of a lightweight guidance platform, which has to provide autonomous flight control. In a concept trade off several design concepts for FASTWing system have been discussed. The result of the concept trade off favours the concept of a large parafoil.

The autonomous flight control will be provided by the Parafoil Guidance, Navigation and Control (PGNC) software being implemented in the avionics system. To keep the effort to a minimum, for FASTWing already existing PGNC software should be adapted. Thus the FASTWing PGNC software is based on GNC algorithms used in PTD (Parafoil Technology Demonstrator) and X-38 project.

The Basic Software (BSW) of the avionics system acts as application service between the hardware (onboard computer, sensors etc.) and the application software (PGNC software). In coordination with NLR the interface between the BSW and the PGNC software has been defined. The application side of the BSW has been documented in terms of an Interface Control Document (ICD). Based on the interface definition the already existing PGNC software has been adapted for FASTWing.

To verify accurate operation of the PGNC, the software has been tested first in the development environment (Windows) and second in the avionics system environment (VxWorks). Therefore, based on the simulator for the X-38 parafoil flight control software, a closed loop simulator has been developed for the Windows environment to simulate a FASTWing mission. Due to the BSW/ASW software architecture concept, the PGNC software tested on the Windows platform is fully transportable to the Avionics System of the flight hardware for use in flight tests.

Closed loop testing under Windows with the goal of verifying numerical stability and robustness of the control algorithms has been completed in late 2003. Following the first release of the flight application software, the integration and real time testing on the flight hardware was completed in September 2004. Flight Readiness was certified.

In addition to the onboard software, a ground station console was developed providing real time visualization and data display to the ground operator. Furtheron, the flight control team provided a mission planning tool that allows to adapt the mission quickly in case of changing meteorological conditions.

The first flight of the parafoil guidance system took place 21-Apr-2005 and the second flight was done on 02-May-2005. Post flight analyses has proven that on both flights the parafoil guidance software has worked well without any anomaly.

For each flight a detailed post flight analysis has been performed which analyzed - on the basis of flight data recorded on board - the performance of the onboard software with special focus on sensor data acquisition and processing, plausibility of mission management decisions, dynamic response of the guidance and control function. Flights were then reproduced on the simulator to allow an improvement of the system models used for the design of the guidance and control software.

The results have shown that in addition to the flawless performance in flight the significant advantage of the applied control development concept is the flexibility w.r.t. configuration changes. With the very limited amount of flight test data available from deployment tests with different load masses it was possible to design a control system, which allowed clearing the system for autonomous operations after only two remote controlled flights.

The applied design concept and the resulting flight control software can be used on any parachute landing system. Most obvious applications are the autonomous delivery of personnel and cargo for the military. Space applications include the landing on extraterrestrial bodies with an atmosphere.

It is of particular value that the guidance system does not require a square parachute. Any parachute with directional capability such as a modified round canopy can be used.

Civilian applications include smart air rescue systems which have a built in capability to actively avoid obstacles of hazardous areas in case of a required bail out of the crew.

Verwandte Informationen

Reported by

EADS Space Transportation
See on map
Folgen Sie uns auf: RSS Facebook Twitter YouTube Verwaltet vom Amt für Veröffentlichungen der EU Nach oben