Swarm robotic which search target with swarm intelligence are controlled in a coordinated way, the robot's own common knowledge and his group experience guide his behaviors. In essence, the group experience is the...
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Unmanned aerial vehicles (UAVs) are widely used in military and civilian applications. The safety of UAV has been paid more and more attention. Prognostic and Health Management (PHM) of UAV can realize the fault predi...
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Unmanned aerial vehicles (UAVs) are widely used in military and civilian applications. The safety of UAV has been paid more and more attention. Prognostic and Health Management (PHM) of UAV can realize the fault prediction during flight and make an appropriate response according to potential faults. Therefore, the safety and reliability of UAV are improved. However, the existing PHM research on UAVs has the following two challenges: a) the number of fault samples in historical flight data is small, and it is impossible to cover multiple fault modes of UAVs to meet the demand of modeling and verification, b) the actual flight verification of the UAV PHM technology cannot be carried out directly through actual flight test. Aiming at the above problems, this paper proposes a fault data generation method based on the Hardware-In-the-Loop Simulation (HILS) technology. We construct a UAV model and its corresponding fault models by analyzing fault features of UAV flight control system. It can simulate the actual faults and generate flight data with multiple fault modes, thereby available data are provided to support PHM research. Besides, PHM algorithms implemented on airborne PHM modules can be verified via this platform in real-time. The experiment results show that the HILS platform has a good performance for fault injection.
The paper discusses an approximation model developed for linear hyperbolic DPS with two state variables and two collocated boundary inputs, expressed in classical, finite-dimensional state-space framework. Using the m...
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The paper discusses an approximation model developed for linear hyperbolic DPS with two state variables and two collocated boundary inputs, expressed in classical, finite-dimensional state-space framework. Using the method of lines approach with the backward difference scheme, the original PDEs are transformed into a set of ODEs and expressed in the form of the state-space equations with matrix-valued state, input and output operators. The eigenvalues and the steady-state solutions of the approximation model are analyzed. The considerations are illustrated with a parallel-flow double-pipe heat exchanger. Steady-state and frequency-domain responses obtained from its original PDE model are compared with those calculated from its ODE approximations of different orders.
Different ues of expert systems in process control are discussed. The paper concentrates on expert systems for closed single loop control. Motivation for this is given and a prototype experiment is described. The expe...
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Different ues of expert systems in process control are discussed. The paper concentrates on expert systems for closed single loop control. Motivation for this is given and a prototype experiment is described. The experiment is evaluated and an expert control architecture is proposed. The system can be compared with a real-time operating system. An implementation based on YAPS and object-oriented programming is described.
A digital elevation model (DEM) is convenient for representing the continuously varying topographic surface of the Earth, and it is a common data source for terrain analysis and other spatial applications. In the mean...
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A digital elevation model (DEM) is convenient for representing the continuously varying topographic surface of the Earth, and it is a common data source for terrain analysis and other spatial applications. In the mean time, the utility of visual digital terrain is widespread. Thus, methods used for displaying visual digital terrain based on DEM data were to be researched carefully. The paper presents a method of reading the USGS standard format DEM data and gives two ways of displaying the digital terrain's surface. Triangle mesh is a common and widely used method and has its own merits in displaying, while constructing surface using NURBS curve is another important way. Their difference and similarities was noted. Examples of these two displaying methods were also presented.
We propose a new algorithm for feedback nonlinear synthesis. The algorithm computes suboptimal solutions, with bounds on suboptimality, to the Hamilton-Jacobi-Bellman equation. For systems that are modeled with polyno...
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We propose a new algorithm for feedback nonlinear synthesis. The algorithm computes suboptimal solutions, with bounds on suboptimality, to the Hamilton-Jacobi-Bellman equation. For systems that are modeled with polynomials the computations can be done efficiently via semidefinite programming. To illustrate the strength of the proposed method, we compute smooth stabilizing feedback controllers for several problems.
With the wide application of manipulator, the working environment of the manipulator has become more and more complex. The performance of the manipulator is also constrained by parameter uncertainty, actuator fault, a...
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In this paper an approach to continuous-time nonlinear block-oriented dynamic system identification containing unknown time delay is presented. In the presented approach the excitation being a step or step-like signal...
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In this paper an approach to continuous-time nonlinear block-oriented dynamic system identification containing unknown time delay is presented. In the presented approach the excitation being a step or step-like signal is generated from D/A converter equipped with zero-order hold filter. Data used for model identification are sampled step or step-like responses. Parameters of the corresponding models are obtained by an optimisation algorithm utilizing ideas of randomized search. The presented discussion is illustrated by simulation experiments devoted to model identification of Wiener, Hammerstein, Hammerstein-Wiener and Wiener-Hammerstein systems.
A standard approach to estimate the frequency function of a linear dynamical system is to use spectral estimation. Traditionally, this is done by smoothing in the frequency domain using a window function. This method ...
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A standard approach to estimate the frequency function of a linear dynamical system is to use spectral estimation. Traditionally, this is done by smoothing in the frequency domain using a window function. This method has proved to be successful in most cases and is widely used. However, if the frequency response has fast variations as e.g. a peak that is local in frequency, the loss of resolution caused by smoothing might result in unacceptable errors. In this paper a wavelet based method for improvement of existing smoothing techniques is proposed. The method combines standard frequency domain smoothing with wavelet thresholding. Through simulations, this approach seems to give better frequency estimates than those obtained with traditional methods.
In order to solve the problems of long cycle and the difficulty of test, this paper proposes a method of power-in-the-loop motor simulator. Firstly, the topology of the motor simulator is proposed, composed of an inte...
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