Parafoil test vehicle ALEX - Further development and flight test results

Jann, Thomas; Doherr, K.-F.; Gockel, W.

doi:10.2514/6.1999-1751

Cited by 13 publications

(11 citation statements)

References 2 publications

(1 reference statement)

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“…It aimed to identify behavior of a small (200lbs) and extensively instrumented parafoil-based system and to investigate GNC-concepts for the autonomous landing. 29,30 Three and four degree of freedom models were developed and parameters of these models were identified during this study.…”

Section: Introductionmentioning

confidence: 99%

“…22,[29][30][31][32][33] The Parafoil Technology Demonstrator program was set up and conducted under ESA to demonstrate feasibility of guiding a large-scale parafoil autonomously to a predefined point and to perform a flared landing within a specific range. Another objective was to enable further investi-gation into the flight dynamics of the parafoil systems.…”

Section: Introductionmentioning

confidence: 99%

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Development of Control Algorithm for the Autonomous Gliding Delivery System

Kaminer

Yakimenko

2003

17th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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Abstract. The paper considers the development and simulation testing of the control algorithms for an autonomous high-glide aerial delivery system, which consists of 650sq.ft rectangular double-skin parafoil and 500lb payload. The paper applies optimal control analysis to the real-time trajectory generation. Resulting guidance and control system includes tracking this reference trajectory using a nonlinear tracking controller. The paper presents the description of the algorithm along with simulation results and ends with guidelines for the further implementation of the developed software aboard the real system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of Control Algorithm for the Autonomous Gliding Delivery System

Kaminer

Yakimenko

2003

17th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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“…A number of efforts have applied aerodynamic parameter identification to airdrop systems [4][5][6][7][8][9][10][11]. Jann et al describe the development of a highly instrumented parafoil and payload research platform, ALEX, incorporating a Global Positioning System (GPS) receiver, magnetometers, rate gyros, accelerometers, air data probes, and video cameras to address the problem of generating enough data for system identification [4].…”

mentioning

confidence: 99%

“…Jann et al describe the development of a highly instrumented parafoil and payload research platform, ALEX, incorporating a Global Positioning System (GPS) receiver, magnetometers, rate gyros, accelerometers, air data probes, and video cameras to address the problem of generating enough data for system identification [4]. With this system, they performed an extensive investigation into the problem of aerodynamic parameter identification for parafoil and payload systems [5][6][7].…”

mentioning

confidence: 99%

“…In this case, the system identification procedure described here could be used to develop an approximate model based on GPS alone which could then be refined with whatever additional sensor information is available. Depending on the available sensor data, this refinement could be performed using similar methods to the existing airdrop identification methods mentioned previously [4][5][6][7][8][9][10][11]. Another possibility is that the model made from GPS data using the proposed procedure could be simply augmented to capture unmodeled dynamics observed in the additional sensor channels using more general system identification techniques such as those recently developed by Majji et al [15,16].…”

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confidence: 99%

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Specialized System Identification for Parafoil and Payload Systems

Ward

Costello

Slegers

2012

Journal of Guidance, Control, and Dynamics

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There are a number of peculiar aspects to parafoil and payload systems that make it difficult to apply conventional system identification procedures used for aerospace systems. Parafoil and payload systems are unique because typically there is very little sensor information available, the sensors that are available are separated from the canopy by a complex network of flexible rigging, the systems are very sensitive to wind and turbulence, the systems exhibit a number of nonlinear behaviors, and the systems exhibit a high degree of variability from flight to flight. The current work describes a robust system identification procedure developed to address the specific difficulties posed by airdrop systems. By employing a two-phase approach that separately considers atmospheric winds estimation and aerodynamic coefficient estimation, a nonlinear, 6-degree-of-freedom dynamic simulation model is generated using only Global Positioning System data from the flight test. The key to this approach is the use of a simplified aerodynamic representation of the canopy, which requires identification of only the steady-state response to control input to completely define the dynamic model. The proposed procedure is demonstrated by creating a simulation model using Global Positioning System data from actual flight tests. To validate the procedure, the dynamic response of the simulation model is then compared to inertial measurement unit data that were not used in any way to develop the simulation model, with excellent results.

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Estimation of attitudes from a low-cost miniaturized inertial platform using Kalman Filter-based sensor fusion algorithm

Kumar

Jann²

2004

Sadhana

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Due to costs, size and mass, commercially available inertial navigation systems are not suitable for small, autonomous flying vehicles like ALEX and other UAVs. In contrast, by using modern MEMS (or of similar class) sensors, hardware costs, size and mass can be reduced substantially. However, low-cost sensors often suffer from inaccuracy and are influenced greatly by temperature variation. In this work, such inaccuracies and dependence on temperature variations have been studied, modelled and compensated in order to reach an adequate quality of measurements for the estimation of attitudes. This has been done applying a Kalman Filter-based sensor fusion algorithm that combines sensor models, error parameters and estimation scheme. Attitude estimation from low-cost sensors is first realized in a Matlab/Simulink platform and then implemented on hardware by programming the micro controller and validated. The accuracies of the estimated roll and pitch attitudes are well within the stipulated accuracy level of ±5 • for the ALEX. However, the estimation of heading, which is mainly derived from the magnetometer readings, seems to be influenced greatly by the variation in local magnetic field.

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Parafoil test vehicle ALEX - Further development and flight test results

Cited by 13 publications

References 2 publications

Development of Control Algorithm for the Autonomous Gliding Delivery System

Development of Control Algorithm for the Autonomous Gliding Delivery System

Specialized System Identification for Parafoil and Payload Systems

Estimation of attitudes from a low-cost miniaturized inertial platform using Kalman Filter-based sensor fusion algorithm

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