The problem of door opening is very fundamental for mobile manipulators operating in domestic environments. In order to successfully achieve the door opening task with wheeled mobile redundant manipulators, a manipula...
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ISBN:
(纸本)9781479973989
The problem of door opening is very fundamental for mobile manipulators operating in domestic environments. In order to successfully achieve the door opening task with wheeled mobile redundant manipulators, a manipulability improving scheme is proposed and investigated in this paper. The scheme treats the wheelchair and the manipulator as a whole system and can improve the manipulator's manipulability when opening the door. And thus remedy the manipulator's manipulability decreasing and/or joint variable' abrupt change as well as the workspace limitations during opening the doors. What's more, the control scheme can drive the wheelchair to move according to the end-effector so as not to collide with the door, and can open door smoothly. Firstly, the velocity of the end-effector is generated with the hybrid position/force control for opening doors, and then the coordinated motion control of mobile platform and the manipulator is adopted to drive the whole system moving to a suitable position to open doors successfully. The control scheme can be used by any mobile manipulator that can be velocity controlled. For verifying the performance of the proposed scheme during opening doors, simulations performed on a wheelchair mounted with a 6-DOF robot arm.
作者：
Y L ZhangJ H QiL QinF WangM X PangCollege of Food Science and Engineering
Beijing Key Laboratory of Detection and Control of Spoilage Organisms and Pesticide Residue in Agricultural Products Beijing Laboratory of Food Quality and Safety Beijing University of Agriculture Beijing 102206 China Pig processing team
Modern agricultural industry technology system Beijing innovation team Beijing 100102 China College of Plant Science
Beijing University of Agriculture Beijing 102206 China
Anthraquinones (AQS) represent a group of secondary metallic products in plants. AQS are often naturally occurring in plants and microorganisms. In a previous study, we found that AQS were produced by enzymatic browni...
Anthraquinones (AQS) represent a group of secondary metallic products in plants. AQS are often naturally occurring in plants and microorganisms. In a previous study, we found that AQS were produced by enzymatic browning reaction in Chinese chestnut kernels. To find out whether non-enzymatic browning reaction in the kernels could produce AQS too, AQS were extracted from three groups of chestnut kernels: fresh kernels, non-enzymatic browned kernels, and browned kernels, and the contents of AQS were determined. High performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) methods were used to identify two compounds of AQS, rehein(1) and emodin(2). AQS were barely exists in the fresh kernels, while both browned kernel groups sample contained a high amount of AQS. Thus, we comfirmed that AQS could be produced during both enzymatic and non-enzymatic browning process. Rhein and emodin were the main components of AQS in the browned kernels.
With the rapid development of e-commerce, the application of web service composition is becoming increasingly important in many areas. If we apply unchecked web service composition, then we can only discover problems ...
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Because the new approach cannot be applied directly in the hot-rolled strip laminar cooling process, a simulation is necessary to verify the new approach effectively which can improve the strip quality and production ...
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作者：
Guiyuan FuDepartment of Automation
Shanghai Jiaotong University and Key Laboratory of System Control and Information Processing Ministry of Education of China Shanghai 200240 China
A watermarking scheme designed for remote sensing images needs to meet the same demand of both invisibility as for ordinary digital images. Due to specific perceptual characteristics of Synthetic Aperture Radar(SAR) i...
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A watermarking scheme designed for remote sensing images needs to meet the same demand of both invisibility as for ordinary digital images. Due to specific perceptual characteristics of Synthetic Aperture Radar(SAR) images, the watermarking algorithms with consideration of Human Vision system(HVS) modeling from optical images give poor performance when applied on SAR images. This paper examines a variety of factors affecting the noise sensitivity, and further proposes a refined pixel-wise masking approach for watermarking on SAR images. The proposed approach is applied on logarithmic transformed SAR images, and has increased the acceptable watermark embedding strength by about 6 dB to 10 dB while achieving the same levels of watermarked image visual quality. Experimental results show that this approach enhanced the perceptual invisibility of watermarking based on wavelet decomposition.
This paper studies the problem of designing insensitive H∞ output-feedback controllers for linear discrete-time systems. The designed controllers are insensitive to additive/multiplicative controller coefficient vari...
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This paper considers a multi-antenna transmission strategy for high speed railway communications. In order to achieve better performance than conventional space-frequency block coding schemes, we propose a directional...
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This paper considers a multi-antenna transmission strategy for high speed railway communications. In order to achieve better performance than conventional space-frequency block coding schemes, we propose a directional beamforming strategy for the High-speed railway(HSR) communication by exploiting some characteristic of the railway system including predetermined moving tracks and real-time positioning information. Moreover,for alleviating the effect of Doppler shift due to the moving train, a frequency offset precorrection method is also incorporated with direction beamforming. Theoretical Signalto-noise ratio(SNR) gain of the proposed beamforming scheme over traditional HSR communication schemes is also derived for illustrating the performance *** results verify the effectiveness of our proposed scheme even with some kind of imperfect position information available at the transmitter.
In this paper, indirect adaptive sliding mode control schemes are developed to solve the robust fault tolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant sy...
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ISBN:
(纸本)9781479987313
In this paper, indirect adaptive sliding mode control schemes are developed to solve the robust fault tolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant systems. While both eventual faults on actuators and perturbations are unknown, the adaptive schemes are addressed to estimate the upper bounds of perturbations online, as well as to estimate control effectiveness on actuators. Thus, on the basis of the information from adaptive schemes, an adaptive sliding mode controller is designed to compensate the effects of faults and perturbations automatically. According to Lyapunov stability theory, it is shown that both the reachability of sliding surfaces and the stability of sliding mode dynamics can be ensured even in the presence of actuator faults and disturbances. Moreover, the adaptive sliding mode control can reduce the phenomenon of chattering. An example is provided to further illustrate the fault compensation effectiveness.
La2O3 films are grown on Si （100） substrates by the radio-frequency magnetron sputtering technique. The band alignment of the La203/Si heterojunction is analyzed by the x-ray photoelectron spectroscopy. The valence-...
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La2O3 films are grown on Si （100） substrates by the radio-frequency magnetron sputtering technique. The band alignment of the La203/Si heterojunction is analyzed by the x-ray photoelectron spectroscopy. The valence- band and the conduction-band offsets of La2 Oa films to Si substrates are found to be 2.40±0.1 and 1.66±0.3 eV, respectively. Based on 0 ls energy loss spectrum analysis, it can be noted that the energy gap of La203 films is 5.18±0.2eV, which is confirmed by the ultra-violet visible spectrum. According to the suitable band offset and large band gap, it can be concluded that La2O3 could be a promising candidate to act as high-k gate dielectrics.
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