The aim of the present work is to investigate the bilinear modeling of a tubular fixed-bed reactor, with an adiabatic ammonia reactor as an illustrative example. Through orthogonal collocation technique and bilinear a...
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The aim of the present work is to investigate the bilinear modeling of a tubular fixed-bed reactor, with an adiabatic ammonia reactor as an illustrative example. Through orthogonal collocation technique and bilinear approximation, a bilinear model is obtained from nonlinear partial differential equation describing; the dynamics of the reactor. Furthermore a low order bilinear model is also developed. The validity of the bilinear model over the linear one is established via simulation. It is shown that this bilinear model is more accurate in matching the dynamics of the reactor at much wider range around the operating point. The methods suggested here are helpful for the modelization of similar complex proceccess and other tubular fixed-bed reactors such as methanol reactors.
Summary form only given. The main theme of the article is to discuss how to associate a value with information in the context of control. It concludes with a discussion of some differences between control and communic...
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Summary form only given. The main theme of the article is to discuss how to associate a value with information in the context of control. It concludes with a discussion of some differences between control and communication. Two issues are time delays and computational requirements.< >
The phenomenon of transmitting the electric fields from their primary bioelectric sources through biological tissues towards measurement sensors is known as the volume conduction. It is a basis for the operation of ma...
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The phenomenon of transmitting the electric fields from their primary bioelectric sources through biological tissues towards measurement sensors is known as the volume conduction. It is a basis for the operation of many biosensors used for the measurement of bioelectromagnetical phenomena. An electroencephalograph (EEG) used for the recording and monitoring the bioelectrical activity of brain is an excellent example of such devices. Due to the volume conduction an overlapping of the contribution to each electrode channel from neighbouring bioelectrical sources is present. As a result raw EEG scalp potentials are characterized by weak spatial resolution. Owning to described reasons raw, multichannel EEG recordings tend to provide an unclear image of the brain activity. In this study the influence of applying 2D window function to the neighbourhood of each electrode before removal of common reference locally is examined. The Local Spatial Filters focus on removing the common signal of electrodes in a specific neighbourhood of the electrode of interest. The performance of algorithm is examined in the task of eliminating source overlapping from EEG-based BCI system recordings and compared with classic approaches such as Common Average Reference (CAR), Surface Laplacian (SL) and Common Spatial Pattern (CSP). For the better evaluation of performance of proposed approaches performance, their effectiveness is tested during the classification of the dataset IVa provided for the “BCI Competition III” organized by the Berlin Brain-Computer Interface group.
The LQ regulators with state or output feedback, designed for nonzero plant initial conditions and zero external excitations and applied to the systems with nonzero excitations are considered. In the case of the LQ re...
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The LQ regulators with state or output feedback, designed for nonzero plant initial conditions and zero external excitations and applied to the systems with nonzero excitations are considered. In the case of the LQ regulator with output feedback, zero external excitations and nonzero plant initial conditions it is shown that the regulator is optimal or suboptimal if its initial conditions are adequate or nonadequate to those of the plant, respectively. It is shown that the LQ regulators with state or output feedback applied to systems with nonzero excitations retain their optimality properties which however concern only the transients generated by the excitations. Additionally, a necessary condition of regulation for MIMO plant is formulated and proved.
Over the last four years efforts have been devoted towards the development and validation of mechanical test result models relating to a range of alloy steels. Several neural-network based models have been developed, ...
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In this paper a new concept of set invariance, called D-invariance, is introduced for dynamical systems described by delay difference equations. We will be interested in the definition and computation of such invarian...
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In this paper, the full channel attitude controller is investigated for the high speed aircrafts’ cruise phase. Taking the complexity of dynamic system into consideration, the back-stepping method is introduced to re...
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ISBN:
(纸本)9781665426480
In this paper, the full channel attitude controller is investigated for the high speed aircrafts’ cruise phase. Taking the complexity of dynamic system into consideration, the back-stepping method is introduced to reduce the difficulty of controller design, thus it would be much easier to directly design nonlinear controller for subsystem. Besides, one of the problems in designing the control law based on back-stepping is the inevitable "explosion of terms", a novel tacking differentiator based on sigmoid function (STD) is introduced to alleviate the problem, which endows the STD with superior advantages comparing to the traditional differentiator. Furthermore, the observer is applied in outer-loop and inner-loop to estimate the "total disturbance" and some immeasurable state. The estimated value will be the compensation controller integrated into the robust adaptive control law. Lastly, to illustrate the feasibility and superiority of the controller proposed, a series of comparative simulations with nominal and positive/negative perturbation are carried out on a high speed aircraft’s full channel attitude model.
Flight data collected by the flight data recorder (FDR) are a series of parameters which can be used to reflect flight state and performance. Once an aircraft behaves abnormally, the flight data will certainly change....
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ISBN:
(数字)9781728101996
ISBN:
(纸本)9781728102009
Flight data collected by the flight data recorder (FDR) are a series of parameters which can be used to reflect flight state and performance. Once an aircraft behaves abnormally, the flight data will certainly change. Then the flight anomaly can be detected if anomalous features are captured. Clustering methods are usually used to distinguish the abnormal data from the normal massive data. Most state-of-the-art clustering methods are oriented to the data sets that have equal length which requires the isometric division of flight sequences. However, the actual sampling rates of flight parameters are different, and the duration of each flight is diverse. A huge challenge is presented for fleet-level anomaly detection. In this work, an improved Density Based Spatial Clustering of Applications with Noise (DBSCAN) approach is proposed by integrating Dynamic Time Warping (DTW) to address this issue. Two types of actual flight data sets from fleet data that have unequal length are utilized to verify the proposed method. Experimental results indicate that the improved DBSCAN algorithm can detect potential abnormal flight behaviors in both climbing stage and descending stage.
Robotic rehabilitation devices that utilize embedded systems, such as the Stretchbox - a device de-signed for hand rehabilitation through the actuation of rollers stretching a rubber band by BLDC motors-demand control...
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ISBN:
(数字)9798350393965
ISBN:
(纸本)9798350393972
Robotic rehabilitation devices that utilize embedded systems, such as the Stretchbox - a device de-signed for hand rehabilitation through the actuation of rollers stretching a rubber band by BLDC motors-demand controllers that are safe, scalable, and understandable at a high level. Behavior trees satisfy these requirements and have found broad applications in robotics and some pioneering applications in the medical sector. Despite their widespread use, there has been an absence of behavior tree frameworks for micro controllers programmed with MicroPython, which is an attractive language for embedded systems and the chosen platform for the Stretchbox's high-level controller. This paper introduces a behavior tree implementation for MicroPython tailored as a high-level controller for the Stretchbox device. The implementation includes standard behavior tree nodes, specialized nodes, and classes designed for interfacing with micro controller peripherals and for Blue-tooth communication with the tablet-based user interface. This system provides a comprehensible and straightforward method for controlling the Stretchbox device for rehabilitation, establishing a well-defined hierarchy for event management. Furthermore, the solution is designed to be extensible, allowing for adding new therapeutic behaviors and integrating extra devices. As an open-source library, the implementation facilitates the adoption of behavior trees in other MicroPython- based projects. The detailed explanation of the approach in applying behavior trees to the Stretchbox serves as a practical demonstration of how behavior trees can be effectively used in controlling rehabilitation devices.
In this paper, a new method for the dynamic analysis of robot is developed from the Lagrange-Euler equation. This new method can solve those problems which needs too much amount of calculation when dynamic analysis of...
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In this paper, a new method for the dynamic analysis of robot is developed from the Lagrange-Euler equation. This new method can solve those problems which needs too much amount of calculation when dynamic analysis of robot is performed with Lagrange-Euler method. When it is used in the dynamic analysis of open chain robot with 6 degree-of-freedom, the whole calculating process, including the calculation of the homogeneous transformation matrices needs only 1,436 multiplications and 1,092 additions.
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