A new concept of a synchronous detector for Giant Magneto-Impedance（GMI） sensors is presented. This concept combines a lock-in amplifier, with outstanding capabilities, high speed and a feedback approach that ensure...
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A new concept of a synchronous detector for Giant Magneto-Impedance（GMI） sensors is presented. This concept combines a lock-in amplifier, with outstanding capabilities, high speed and a feedback approach that ensures the amplitude detection with easily adjustable gain. The synchronous detector is capable of measuring high-frequency and very low amplitude signals without the use of diode-based active rectifiers or analog switches. In comparison with most of the commercially available diode-based peak detectors, the linearity of the synchronous detector is generally better, especially for low level amplitudes. The synchronous detector has been used for the amplitude measurement of single frequency sine signal and for the demodulation of amplitude-modulated signal. It has also been successfully integrated in a GMI sensor prototype. Magnetic field measurements in open-and closed-loop of this sensor have been conducted. The measured sensitivity was about 1.02 V/Oe in open-loop while it was 0.12 V/Oe in close-loop. The above research provides technical accumulation for the design of sensor nodes based on GMI sensor wireless sensor networks.
In this paper, a new unscented Kalman filter(Unscented Kalman filter, UKF) for nonlinear system with both one-step randomly delayed measurements and colored measurement noises is proposed. Firstly, the first-order Mar...
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In this paper, a new unscented Kalman filter(Unscented Kalman filter, UKF) for nonlinear system with both one-step randomly delayed measurements and colored measurement noises is proposed. Firstly, the first-order Markov sequence model is used to whiten colored noise, at the same time, an independent and identically distributed Bernoulli variable is used to model the delay of measurement data transmission, then the model of nonlinear one-step randomly time delay system with colored noise whitening is established. Secondly, filter recursion formula of UKF under the above model is proposed through unscented transformation(Unscented transformation, UT) to calculate the posterior mean and covariance of the nonlinear state based on the Bayesian filter framework. The proposed new UKF method can effectively deal with the issue that traditional UKF is failure under the condition of one-step randomly delayed measurements and colored measurement noises. The efficiency and superiority of the proposed method are illustrated in a numerical example for a target tracking problem.
Remote sensing hyperspectral imaging can obtain rich spectral information of terrestrial objects, which allows the indistinguishable matter in the traditional wideband remote sensing to be distinguished in hyperspectr...
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Remote sensing hyperspectral imaging can obtain rich spectral information of terrestrial objects, which allows the indistinguishable matter in the traditional wideband remote sensing to be distinguished in hyperspectral remote *** image has the characteristics of "combining image with spectrum". Making full use of spectral information and spatial information in hyperspectral image is the premise of obtaining accurate classification results. At present, most of hyperspectral data feature extraction algorithms mainly utilize local spatial information in the same channel and spectral information in the same spatial location of different channels. However, these methods require a large amount of prior knowledge, it is difficult to fully grasp the hyperspectral data of all spatial and spectral information, and the model generalization ability is poor. With the development of deep learning, convolutional neural network shows superior performance in all kinds of visual tasks, especially in the two-dimensional image classification, and could get a high classification accuracy. In this paper, an image classification method based on three-dimensional convolution neural network is proposed based on the structural properties of hyperspectral data. In the proposed method, first the stereo image blocks of hyperspectral data are intercepted, then multi-layer convolution and pooling operation of extracted blocks by convolutional neural network are implemented to obtain the essential information of hyperspectral data, finally the classification of hyperspectral data is completed. The experimental results show the proposed method could provide better feature expression and classification accuracy for hyperspectral image.
The traditional wired seismograph has disadvantages such as cumbersome cable, complicated wiring, crosstalk and noise between adjacent transmission lines. In addition, the dynamic range of the instrument is small, and...
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The traditional wired seismograph has disadvantages such as cumbersome cable, complicated wiring, crosstalk and noise between adjacent transmission lines. In addition, the dynamic range of the instrument is small, and the observation of seismic signals is not intuitive, which can not meet the needs of high-precision seismic exploration. In order to solve these problems, the design of distributed three component seismic data acquisition system based on Lo Ra wireless communication technology is proposed. The system uses Lo Ra long-distance wireless communication technology and 24 bit Σ-Δ ADC, which realizes long-distance wireless communication and large dynamic range seismic data acquisition. Besides, the system has manmachine interaction interface, which can observe the parameters of seismic waveform in real time and adjust sampling rate directly. The whole circuit has the advantages of simple design, high precision and good stability. To sum up, the design has certain practical value and application prospect.
This paper concers the H∞ control for singular systems with time-varying ***,an augmented LyapunovKrasovskii functional（ALKF） is constructed by adding some integral terms which are dependent on the singular matrix ...
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This paper concers the H∞ control for singular systems with time-varying ***,an augmented LyapunovKrasovskii functional（ALKF） is constructed by adding some integral terms which are dependent on the singular matrix to the quadratic ***,to handle the derivative of the ALKF,a modified relaxed integral inequality is *** a result,a sufficient condition with a state feedback controller is derived to ensure the closed-loop system to be regular,impulse free and asymptotically stable with H∞ ***,a numerical example is given to verify the effectiveness and the superiority of the proposed method.
This paper presents a two-stage position control strategy based on the differential evolution(DE) algorithm for a planar second-order nonholonomic manipulator,which has one passive joint and this passive joint is not ...
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This paper presents a two-stage position control strategy based on the differential evolution(DE) algorithm for a planar second-order nonholonomic manipulator,which has one passive joint and this passive joint is not the first joint(planar APA manipulator for short,where m≥1,n≥0).An offline DE algorithm is used to calculate all link target angles corresponding to the target *** to these target angles,a Lyapunov function is constructed to design the controllers A for the control stage 1,which are used to control all active links to their target *** to the constraint equation of the planar APA manipulator,an oscillatory trajectory is planned for the first active link based on the online DE *** the first active link tracks the oscillatory trajectory,it will back to its target angle ***,the passive link will be jointly controlled to its target angle ***,the other Lyapunov function is constructed to design the controllers B for the control stage 2,which are used to control the first active link tracks the target trajectory and control the remaining m+n-1 active links maintain in their target *** results of a planar AAPA manipulator demonstrate the effectiveness of the proposed control strategy.
A control method is proposed to suppress stick-slip vibration of drillstring system based on tracking control with zero steady-state error and state observer in this paper. A multiple degree-of-freedom(DOF) model of d...
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A control method is proposed to suppress stick-slip vibration of drillstring system based on tracking control with zero steady-state error and state observer in this paper. A multiple degree-of-freedom(DOF) model of drillstring dynamic is presented first, which considers high-order modal of stick-slip vibration. Then, state observer is constructed to estimate the states of drillstring system, whose states are usually difficult to measure in the top of drillstring system. Finally, combing state feedback control and internal model principle, a tracking control with zero steady-state error is proposed to ensure the speed of rotary table and bit are consistent. The proposal only need top measurement, can eliminate multiple torsional modes, and has a strong robustness. Simulations show the effective of the proposal.
The measuring instrument selects the network analyzer, combines the direct current source and the Helmholtz coil to form the GMI effect test system. PC program written in Lab VIEW, network analyzer and DC current sour...
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The measuring instrument selects the network analyzer, combines the direct current source and the Helmholtz coil to form the GMI effect test system. PC program written in Lab VIEW, network analyzer and DC current source is controlled by the host computer. The host computer can process and plot the impedance data collected by the network analyzer, and save the data and images locally. The test system by measuring the commercial Vitrovac6025 strip material, found that the material all showed a strong GMI effect at different frequencies. By comparing the measured data of the network analyzer and the impedance analyzer measured in the same frequency band, we found that the two are consistent, which verifies the accuracy and reliability of the test system.
In this paper, we combined the quorum sensing mechanism of bacteria with the Repressilator oscillator to describe the rhythmicity of bacteria. It is found that the transmission of signal molecules between cells produc...
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In this paper we consider a problem in task execution for multi-robot trajectory planning with collision avoidance in a shared working environment. Consider two or more robots generating trajectories towards their res...
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ISBN:
(数字)9781728169040
ISBN:
(纸本)9781728169057
In this paper we consider a problem in task execution for multi-robot trajectory planning with collision avoidance in a shared working environment. Consider two or more robots generating trajectories towards their respective goal positions. The collision may occur if their trajectory coordinates are intersecting at a point or follow the same path segment simultaneously. The central planner is introduced to control robot motion in the collision state and to reduce the complexity of the multi-robot path planning system. The global path for every robot is generated by the $\mathrm{A}^{*}$ algorithm in a grid-based environment. The path has presented a sequence of optimal grid numbers and later transformed into Cartesian coordinates for smooth trajectory generation. The central planner takes an optimal grid sequence for every robot to analyze the collision state according to its cost value. It regenerates the trajectories to minimize the complexity cost value and replaces the previous trajectory based on minimum cost value. In the collision state, the central planner allows one robot at a time to pass along the conflict path segment and hold others in queue at a safety offset distance until the previous robot passes safely. The algorithm has been applied to robots working in a shared environment in complex maps and the simulations is performed with MATLAB to calculate the efficiency of this approach for handling collision states in a multi-robot path planning system.
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