Modeling and Robust Attitude Controller Design for a Small Size Helicopter

This paper addresses the design and application controller for a small-size unmanned aerial vehicle (UAV). In this work, the main objective is to study the modeling and attitude controller design for a small size helicopter. Based on a non-simplified helicopter model, a new robust attitude control law, which is combined with a nonlinear control method and a model-free method, is proposed in this paper. Both wind gust and ground effect phenomena conditions are involved in this experiment and the result on a real helicopter platform demonstrates the effectiveness of the proposed control algorithm and robustness of its resultant controller.Comment: 6 page

An experiment to compare the combined array and the product array for robust parameter design

The paper reports a robust parameter design experiment, where we have used Taguchi's product array and a combined array simultaneously. This was done as part of a research project dealing with experimental design to optimise the process of sheet metal spinning. We found that the classical analysis of the product array identified a control factor, which has an influence on the variance of the response. There were no indications of this effect in the combined array. A confirmation experiment supports the finding that this factor in fact is a control factor. It seems that its effect on the variance is due to several two- and three-factor interactions that were not large enough to be found in the combined array. In the authors' opinion this shows that the use of a product array and the classical analysis provides robustness against imprecise model assumptions. --Robust parameter design,noise factor,design factor,signal to noise ratio,product array,combined array,interaction plot

Screening interacting factors in a wireless network testbed using locating arrays

Wireless systems exhibit a wide range of configurable parameters (factors), each with a number of values (levels), that may influence performance. Exhaustively analyzing all factor interactions is typically not feasible in experimental systems due to the large design space. We propose a method for determining which factors play a significant role in wireless network performance with multiple performance metrics (response variables). Such screening can be used to reduce the set of factors in subsequent experimental testing, whether for modelling or optimization. Our method accounts for pairwise interactions between the factors when deciding significance, because interactions play a significant role in real-world systems. We utilize locating arrays to design the experiment because they guarantee that each pairwise interaction impacts a distinct set of tests. We formulate the analysis as a problem in compressive sensing that we solve using a variation of orthogonal matching pursuit, together with statistical methods to determine which factors are significant. We evaluate the method using data collected from the w-iLab.t Zwijnaarde wireless network testbed and construct a new experiment based on the first analysis to validate the results. We find that the analysis exhibits robustness to noise and to missing data

Eliciting probabilistic expectations with visual aids in developing countries : how sensitive are answers to variations in elicitation design ?

Eliciting subjective probability distributions in developing countries is often based on visual aids such as beans to represent probabilities and intervals on a sheet of paper to represent the support. The authors conducted an experiment in India that tested the sensitivity of elicited expectations to variations in three facets of the elicitation methodology: the number of beans, the design of the support (pre-determined or self-anchored), and the ordering of questions. The results show remarkable robustness to variations in elicitation design. Nevertheless, the added precision offered by using more beans and a larger number of intervals with a predetermined support improves accuracy.Economic Theory&Research,Information Security&Privacy,Markets and Market Access,Statistical&Mathematical Sciences,Crops&Crop Management Systems

Retrospective Evaluation of the Five-Year and Ten-Year CSEP-Italy Earthquake Forecasts

On 1 August 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP) launched a prospective and comparative earthquake predictability experiment in Italy. The goal of the CSEP-Italy experiment is to test earthquake occurrence hypotheses that have been formalized as probabilistic earthquake forecasts over temporal scales that range from days to years. In the first round of forecast submissions, members of the CSEP-Italy Working Group presented eighteen five-year and ten-year earthquake forecasts to the European CSEP Testing Center at ETH Zurich. We considered the twelve time-independent earthquake forecasts among this set and evaluated them with respect to past seismicity data from two Italian earthquake catalogs. In this article, we present the results of tests that measure the consistency of the forecasts with the past observations. Besides being an evaluation of the submitted time-independent forecasts, this exercise provided insight into a number of important issues in predictability experiments with regard to the specification of the forecasts, the performance of the tests, and the trade-off between the robustness of results and experiment duration. We conclude with suggestions for the future design of earthquake predictability experiments.Comment: 43 pages, 8 figures, 4 table