In an electro-hydraulic servo control system,the force servo system is an important ***,due to the nonlinear characteristic of hydraulic systems,traditional control methods cannot achieve satisfactory control *** deal...
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In an electro-hydraulic servo control system,the force servo system is an important ***,due to the nonlinear characteristic of hydraulic systems,traditional control methods cannot achieve satisfactory control *** deal with this issue,a load velocity compensation algorithm based on the structural invariant principle is proposed in this ***,the theoretical analysis of the hydraulic and cylindrical force control system is presented,and the mathematical model of the force control system is *** the open-loop frequency response characteristics of the system are analyzed,in which the Bode diagram shows that the bandwidth of the system is obviously expanded after adopting the load velocity compensation ***,apractical hydraulic and cylindrical force servo system is introduced to validate the feasibility of the proposed controller,the experimental results demonstrate that the proposed method can improve the performance of force control and eliminate the influence of load stiffness on the dynamic characteristics of the system through a set of comparative experiments with different elastic loads.
This paper investigates the mean square and almost sure stability of a class of neutral stochastic differential delay equations with highly nonlinear coefficients. We first examine the regularity of the solution to th...
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This paper investigates the mean square and almost sure stability of a class of neutral stochastic differential delay equations with highly nonlinear coefficients. We first examine the regularity of the solution to the highly nonlinear neutral stochastic differential delay systems. Then the explicit stability conditions are obtained by the Lyapunov functional and semi-martingale convergence theorem. Especially, the explicit stability conditions of pure delay neutral stochastic differential delay equations are obtained. It is revealed that the delay term in the drift can contribute to the mean square and almost sure stability.
Non-dominated sorting is widely used in multi-objective evolutionary algorithms. There are many approaches to non-dominated sorting, but they are computationally expensive when the number of objectives or the number o...
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Non-dominated sorting is widely used in multi-objective evolutionary algorithms. There are many approaches to non-dominated sorting, but they are computationally expensive when the number of objectives or the number of fronts becomes relatively large. This paper proposes an efficient non-dominated sorting approach based on a dominance ranking graph created in this paper. The approach takes advantages of both the dominated and non-dominated relationships, it is able to efficiently handle the case of large number of objectives/fronts. Experimental results show that the proposed algorithm outperforms its several popular variants in most of the tests.
This paper investigates the stabilizability of positive time-delay system. The nonnegative constraint makes the design of a control law different from a general system. Firstly, a method to calculate the L_1 gain of a...
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This paper investigates the stabilizability of positive time-delay system. The nonnegative constraint makes the design of a control law different from a general system. Firstly, a method to calculate the L_1 gain of a positive time-delay system is presented. Then, the design of a state feedback controller and a high-gain observer is presented by taking full advantage of the characteristics of the positiveness of the system. Finally, the observer and feedback controller are combined to stabilize the system and improve dynamic performance. A numerical example illustrates the provided method is effective.
To address the problem of data fusion between monocular camera image with 3 D data from laser detection and ranging(LADAR)sensor,this paper proposes a novel simplified scheme based on the planar feature method,which c...
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To address the problem of data fusion between monocular camera image with 3 D data from laser detection and ranging(LADAR)sensor,this paper proposes a novel simplified scheme based on the planar feature method,which can meet the accuracy requirements of the joint calibration with fewer checkerboard calibration plate(CP)positions than traditional ***,a mathematical model of the joint calibration is established to obtain the calibration ***,the selection of positions and orientations of the CP are introduced and the corresponding influence to the calibration is ***,the calibration result is optimized by using a nonlinear Levenberg-Marquardt(LM)optimization approach,and the distance residual method is utilized to estimate the ***,experimental results conclude that the minimum number of positions required to meet the joint calibration accuracy in the proposed method is 5,which is less than 12 in traditional methods.
With the booming installed capacity of permanent magnet synchronous generator (PMSG) for wind energy generation, the grid becomes weaker and the oscillation events are frequently observed in weak-grid-tied large-scale...
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ISBN:
(数字)9781728155081
ISBN:
(纸本)9781728155098
With the booming installed capacity of permanent magnet synchronous generator (PMSG) for wind energy generation, the grid becomes weaker and the oscillation events are frequently observed in weak-grid-tied large-scale grid-connected PMSG wind farms. Although the impedance-based method is effective to analyze the stability of grid-connected systems, the mathematical relationship between external impedance characteristics and the internal controllers has not been quantitatively analyzed in depth, which is beneficial to the controller design. This paper studies the influence of phase-locked loop (PLL) on the impedance characteristics based on the analytical sequence impedance model of PMSG with typical topology and control structure. The shaping effect of PLL on the impedance characteristics is described so as to clearly describe the relationship between the external impedance characteristics of the wind turbines and the internal controller. Finally, the stability analysis of the grid-connected PMSG wind turbine system is provided in Matlab and simulation results are given to verify the oscillating mechanism caused by PLL.
Aiming at the problem that the process of gesture recognition based on color image is greatly affected by environmental factors such as lighting, a gesture intent understanding method based on the fusion of Red-Green-...
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Aiming at the problem that the process of gesture recognition based on color image is greatly affected by environmental factors such as lighting, a gesture intent understanding method based on the fusion of Red-Green-Blue (RGB) data and depth data is proposed. Firstly, the gesture feature extraction based on the Speeded Up Robust Feature (SURF) method after foreground segmentation are used to get gesture information. Then, we apply Backpropagation (BP) neural network to classify and recognize gestures. The final recognition results are obtained through data fusion from recognition results based on both RGB images and depth images. We evaluated the effectiveness of the proposed method through ChaLearn Gesture Database.
To meet the needs of high speed and good environmental adaptability for data transmission in industrial robot servo systems, this paper presents a wireless transmission technology on a data acquisition control termina...
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To meet the needs of high speed and good environmental adaptability for data transmission in industrial robot servo systems, this paper presents a wireless transmission technology on a data acquisition control terminal. The system is based on STM32F103RET6 processor and reads cache data from the SRAM of FPGA in DMA method, and communicates with a WIFI chip, Marvell 88w8686, through the SDIO interface. A host computer segments and filters the data received by the WIFI chip and sends control commands back to STM32. The functions of the hardware and software of the system contains data compression and storage, wireless data transmission, data display, and control-command transmission. An experimental platform has been built. It carries out real-time transmission of 8-16 digits based on the TCP/IP protocol with expected performance.
A new measuring system for magnetic properties of the ferromagnetic thin film has developed based on magneto-optical Kerr effect (MOKE). This system can realize both polar MOKE and longitudinal MOKE measurements throu...
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A new measuring system for magnetic properties of the ferromagnetic thin film has developed based on magneto-optical Kerr effect (MOKE). This system can realize both polar MOKE and longitudinal MOKE measurements through the optimization of optical path and electromagnet's poles. The signal processing software on Lab View has been also designed to acquire the Kerr signal and plot the hysteresis loop. The MOKE measurements have been performed to investigate the magnetic properties of ferromagnetic films such as CoFeSiB, permalloy and NiFe/Ag/NiFe multilayer. The experimental results proved that the system has a high angular accuracy of 0.0008°.
Protein complexes are the key molecular entities which plays an indispensable role in our life activities. Systematic identification of protein complexes is an important application of data mining in bioscience. The e...
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Protein complexes are the key molecular entities which plays an indispensable role in our life activities. Systematic identification of protein complexes is an important application of data mining in bioscience. The existing computation methods of detecting protein complexes are usually based on the topological properties of protein-protein interaction(PPI) network ***, limited by the inherent single structure of the PPI network, the mining of protein complexes may not be fully *** this paper, we propose an original multi-objective optimization strategy based protein complex detection method, which is used Adaptive Multi-Objective Black Hole algorithm, called AMOBH. In the selection of objective function strategy, we integrate the topological structure of PPI network data with semantic similarity based on GO(Gene Ontology) annotation data. Experiments demonstrate that the method we adopt provide more convinced results and higher computational efficiency compared with the existing prediction measures.
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