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A direct self-repairing controller based on adaptive sliding mode control technique designed for the quadrotor helicopter with actuator faults is studied in this paper. Without any fault diagnosis, such adaptive sliding mode-based fault-tolerant control is implemented to track the desired output signal, when any actuator of the quadrotor loses effectiveness. Moreover, the Lyapunov stability theory...
The strapdown guidance technology, which can improve the system reliability and reduce cost efficiently, has been paid great attention and developed quickly. However, the detecting information of strapdown seeker can't be used to proportional navigation directly because it is coupled with missile attitude, so the method of Line-of-Sight (LOS) rate extraction for strapdown seeker is investigated. Background...
Scandate cathode is the most promising cathode type which can be utilized in THz devices. There is a wide transition region in the I-V characteristics of scandate cathode. The low slope and dual slope in the I-V characteristics according with Child-Langmuir law will be discussed in this paper.
Environment perception is an important research issue for both unmanned ground vehicles and robots. To improve the capacity of perception, a visualized acoustic saliency feature extraction (VASFE) method based on both the short-time Fourier transform (STFT) and the Mel-Frequency Cepstrum Coefficient (MFCC) for environment sound signal processing is proposed in this paper. Sound signal is visualized...
Atmospheric turbulence is one of important factors to affect UAV flight smoothly. To reduce the influence of atmospheric turbulence, active disturbance rejection controller is designed in this paper. Firstly, mathematical models are built for UAV movements and atmospheric turbulence. Secondly, the altitude controller and the lateral deviation controller with linear state equations are designed. Finally,...
Cognitive radio technology has been widely researched to improve the spectrum usage efficiency. Dynamic spectrum access is the most promising approach to fully utilize the scarce spectrum resources. In this paper, we consider the situation where multiple channels are owned by several primary users and propose two new dynamic spectrum access schemes which are scheme with equal detection probability...
Solution of the problem of fault accommodation in nonlinear dynamic systems is related to constructing the control law which provides full decoupling with respect to fault effects. Existing conditions are formulated and calculating relations are given for the control law.
According to characteristics of perpendicularity error evaluation of planar lines, particle swarm optimization (PSO) is proposed to evaluate the minimum zone error. The evolutional optimum model and the calculation process are introduced in detail. Compared with conventional optimum methods such as simplex search and Powell method, it can find the global optimal solution, and the precision of calculating...
This paper proposes a new mathematical QoS model called LRD_Q_Model for long range dependence (LRD) multimedia flows on the basis of network calculus theory. In LRD_Q_Model, the packets of a LRD flow are regulated by the Fractal Leak Bucket model at the edge nodes of networks and scheduled by the weighted fairness queuing (WFQ) model at each router of the transmission path. We give the service curve...
As the extension of the least significant bits (LSB) steganographic algorithm, steganographic algorithm embedding in two least-significant bits (Two-LSBs for short) has some characteristics, such as visual imperceptibility, higher capacity and easy realization. A new steganalysis method is introduced to detect the existence of hidden message that are randomly embedded in LSB and the second significant...
Partial occlusion is a difficult problem in computer vision since whether the object is changed or occluded is ambiguous, especially when distinguishing it only from the object boundary. In this paper, we proposed a novel idea to solve this problem by taking shape matching as a morphing processing. A mass-spring model is constructed from the point set which is sampled from a template (or reference)...
In this paper, an improved adaptive fault estimation algorithm is proposed for a class of polytopic linear parameter varying (LPV) systems. The conventional adaptive fault estimation design method suffers from low performance of the fault estimation and a strict equation constrain, so a novel fast adaptive fault estimation (FAFE) design method proposed in this paper not only enhances the performance...
A hybrid mechanism is a configuration that combines the motions of two characteristically different electric motors by means of a mechanism to produce programmable output. In this paper, by means of establishing mathematic model for the influence of output accuracy of a planar hybrid five-bar mechanism affected by manufacturing error of link length, the sensitive coefficient of manufacturing error...
This paper presents a novel approach to improve the OOV (Out-of-vocabulary) phrase translation by combining lexical information and web mining. We first retrieve the top relevant anchor words with source OOV phrase from search engine, and then search the translation with expanded query ??source OOV phrase + anchor word?? from mixed-language web pages. Finally, a ME (Maximum Entropy) model is employed...
Based on the analysis of existent evaluation methods for spatial straightness errors, an intelligent evaluation method is provided in this paper. The evolutional optimum model and the calculation process are introduced in detail. According to characteristics of spatial straightness error evaluation, ant colony optimization (ACO) algorithm is proposed to evaluate the minimum zone error. Compared with...
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