the paper represents the second part of a study related to the development of an actuators control system for a morphing wing application, and describes the experimental validation of the control designed in the first...
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ISBN:
(纸本)9789898425003
the paper represents the second part of a study related to the development of an actuators control system for a morphing wing application, and describes the experimental validation of the control designed in the first part. After a short presentation of the finally adopted control architecture, the physical implementation of the control is done. To implement the controller on the physical model two Programmable Switching Power Supplies AMREL SPS 100-33 and a Quanser Q8 data acquisition card, were used. the inputs of the data acquisition were two signals from Linear Variable Differential Transformer potentiometers, indicating the positions of the actuators, and six signals from thermocouples installed on the SMA wires. the acquisition board outputs channels were used to control power supplies in order to obtain the desired skin deflections. the control validation was made in two experimental ways: bench test and wind tunnel test. All 35 optimized airfoil cases, used in the design phase, were converted into actuators vertical displacements which were used as inputs reference for the controller. In the wind tunnel tests a comparative study was realized around of the transition point position for the reference airfoil and for each optimized airfoil.
the Escota Company aims at the formalization and improvement of the decisional process for preventive maintenance in a multi criteria (MC) environment. According to available pieces of knowledge on the infrastructure ...
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ISBN:
(纸本)9783540856399
the Escota Company aims at the formalization and improvement of the decisional process for preventive maintenance in a multi criteria (MC) environment. According to available pieces of knowledge on the infrastructure condition, operations are to be evaluated with regards to (w.r.t.) technical but also to conformity, security and financial criteria. this MC evaluation is modelled as the aggregation of partial scores attributed to an operation w.r.t. a given set of n criteria. the scores are expressed over a finite scale which can cause some troubles when no attention is paid to the aggregation procedure. this paper deals withthe consistency of the evaluation process, where scores are expressed as labels by Escota's experts, whereas the aggregation model is supposed to deal with numerical values and cardinal scales. We try to analyse this curious but common apparent paradox in MC evaluation when engineering contexts are concerned. A robustness study of the evaluation process concludes this paper.
Scene Transition Nets (STN) are graphical modeling tools and simulators for discrete-continuous hybrid systems. Designers have previously built complex STN models of large-scale systems on the basis of a single aspect...
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ISBN:
(纸本)9789898425751
Scene Transition Nets (STN) are graphical modeling tools and simulators for discrete-continuous hybrid systems. Designers have previously built complex STN models of large-scale systems on the basis of a single aspect. However, many large-scale systems consist of several sub-systems designed for different purposes and based on different aspects. In addition, these subsystems are complexly intertwined with each one another. For verifying the behavior of such complex systems in simulations, it is necessary to construct multiple STN models of the subsystems, integrate them by taking into account the relationships among the subsystems, and simulate them in parallel. Kawata has proposed "multi-aspect modelingh using STNs in order to realize above-mentioned modeling concepts. However, the interaction of the sub-STN models with other models is difficult according to the basic STN concepts. this shortcoming interferes withthe practical implementation of multi-aspect modeling. the authors overcome this shortcoming by enabling the sharing of the state variables of the actors (actors correspond to tokens in Petri nets). Called "actor-link", the simple concept enables to construct complex layered and parallel structures of STNs and perform multi-aspect modeling. the experimental results for the modeling and simulation of certain complex industrial systems demonstrate the effectiveness of the proposed method and simulation tool.
the well-known electro-mechanical analogy that equates current, voltage, resistance, inductance and capacitance to force, velocity, damping, stiffness and mass has a shortcoming in that mass can only be used to simula...
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ISBN:
(纸本)9783540856399
the well-known electro-mechanical analogy that equates current, voltage, resistance, inductance and capacitance to force, velocity, damping, stiffness and mass has a shortcoming in that mass can only be used to simulate a capacitor which has one terminal connected to ground. A new model that was previously proposed by the authors that combines a mass with a pulley (MP) is shown to simulate a capacitor in the general case. this new MP model is used to model the off-diagonal elements of a mass matrix so that devices whose effective mass is coupled between more than one actuator can be represented by a mechanical system diagram that is topographically parallel to its equivalent electric circuit model. Specific examples of this technique are presented to demonstrate how a mechanical model can be derived for both a serial and a parallel robot with both two and three degrees of freedom. the technique, however, is extensible to any number of degrees of freedom.
Autonomous machines promise more flexibility and robustness changes in their environment compared to manually programmed solutions in industrial applications. However, the autonomous planning of actions involves discr...
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ISBN:
(纸本)9783030924416
Autonomous machines promise more flexibility and robustness changes in their environment compared to manually programmed solutions in industrial applications. However, the autonomous planning of actions involves discrete as well as continuous properties, which results in a np-hard planning problem. Especially for multiple machines and long planning horizons the design of domains requires a lot of fine tuning and thus manual effort. Modularization and reuse of existing domain knowledge with formalized models is one solution to this issue. However, the models of different projects tend to be misaligned, in particular when several parties contributed to the project, which deteriorates the performance. In this paper, we present two domain optimization and extension algorithms, which adapt the models to facilitate planning. the first algorithm handles inconsistent units, or even misaligned pieces of sub-information. It automatically generates conversions and allows to call operations with a wider range of input types. the second algorithm aligns models from different sources with varying modeling views. After this reformulation, we can compose models more efficiently to a larger domain. For both optimizations, we rely on the formal set-based models that we also use in our previously presented hierarchical planning algorithm. Our hierarchical approach allows an almost linear scalability withthe length of the plan. However, it comes with non-optimality effects due to the imposed intermediate goals that depend on the quality of the model. the optimization algorithms of this paper allow to adapt and extend the model so that valid shortcuts reduce these suboptimalities. We conduct experiments on a task and motion assembly problem, demonstrating scalability for up to 62 parts and plans with over 1000 steps, which either result in discrete state or high-level position changes, with planning times of less than 15 min. Our experiments also include the successful plan execution o
In this paper a new and efficient algorithm to solve a closed-form direct kinematics solution of the general 6-6 planar Stewart platform is presented. the main idea is to compute the reduced Groebner basis under degre...
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ISBN:
(纸本)9781424447947
In this paper a new and efficient algorithm to solve a closed-form direct kinematics solution of the general 6-6 planar Stewart platform is presented. the main idea is to compute the reduced Groebner basis under degree lexicographic ordering for the closed-form equations by using computer algebra firstly. Secondly, select 10 Groebner bases from the obtained 41 ones and construct a 10times10 Sylvester's matrix, which is relatively small in size. A 20th degree univariate equation is obtained from the determinate of the matrix and all 40 sets closed-form direct kinematics solutions are obtained. the proposed algorithm is simple and reduces greatly the computation burden than the existed methods. the process also shows that there exist many different resultants that will lead to the same univariate equation. the same results can be obtained by using the continuation method. Finally a numerical example is given to verify the algorithm and its results without extraneous roots agree withthe original equations.
Sleep disorders affect a great percentage of the population. the diagnostic of these disorders is usually made by a polysomnography, requiring patient's hospitalization. Low cost ambulatory diagnostic devices can ...
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ISBN:
(纸本)9789898425027
Sleep disorders affect a great percentage of the population. the diagnostic of these disorders is usually made by a polysomnography, requiring patient's hospitalization. Low cost ambulatory diagnostic devices can in certain cases be used, especially when there is no need of a full or rigorous sleep staging. In this paper, several methods to extract features from 6 EEG channels are described in order to evaluate their performance. the features are selected using the R-square Pearson correlation coefficient (Guyon and Elisseeff, 2003), providing this way a Bayesian classifier withthe most discriminative features. the results demonstrate the effectiveness of the methods to discriminate several sleep stages, and ranks the several feature extraction methods. the best discrimination was achieved for relative spectral power, slow wave index, harmonic parameters and Hjorth parameters.
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