An Adaptive Dynamic Surface Controller for Ultralow Altitude Airdrop Flight Path Angle with Actuator Input Nonlinearity

In the process of ultralow altitude airdrop, many factors such as actuator input dead-zone, backlash, uncertain external atmospheric disturbance, and model unknown nonlinearity affect the precision of trajectory tracking. In response, a robust adaptive neural network dynamic surface controller is developed. As a result, the aircraft longitudinal dynamics with actuator input nonlinearity is derived; the unknown nonlinear model functions are approximated by means of the RBF neural network. Also, an adaption strategy is used to achieve robustness against model uncertainties. Finally, it has been proved that all the signals in the closed-loop system are bounded and the tracking error converges to a small residual set asymptotically. Simulation results demonstrate the perfect tracking performance and strong robustness of the proposed method, which is not only applicable to the actuator with input dead-zone but also suitable for the backlash nonlinearity. At the same time, it can effectively overcome the effects of dead-zone and the atmospheric disturbance on the system and ensure the fast track of the desired flight path angle instruction, which overthrows the assumption that system functions must be known

Research on Wavelet Based Autofocus Evaluation in Micro-vision

AbstractThis paper presents the construction of two kinds of focusing measure operators defined in wavelet domain. One mechanism is that the Discrete Wavelet Transform (DWT) coefficients in high frequency subbands of in-focused image are higher than those of defocused one. The other mechanism is that the autocorrelation of an in-focused image filtered through Continuous Wavelet Transform (CWT) gives a sharper profile than blurred one does. Wavelet base, scaling factor and form to get the sum of high frequency energy are the key factors in constructing the operator. Two new focus measure operators are defined through the autofocusing experiments on the micro-vision system of the workcell for micro-alignment. The performances of two operators can be quantificationally evaluated through the comparison with two spatial domain operators Brenner Function (BF) and Squared Gradient Function (SGF). The focus resolution of the optimized DWT-based operators is 14% higher than that of BF and its computational cost is 52% approximately lower than BF's. The focus resolution of the optimized CWT-based operators is 41% lower than that of SGF whereas its computational cost is approximately 36% lower than SGF's. It shows that the wavelet based autofocus measure functions can be practically used in micro-vision applications

Effect of Alisma plantago-aquatica Linn extract on chronic prostatitis in rats

Purpose: To study the effect of Alisma plantago-aquatica Linn. extract (APLE) on chronic prostatitis in rats.Methods: Experimental chronic non-bacterial prostatitis (CNP) was induced in rats by injecting carrageenan into prostate. Rats in drug-treated groups were administered APLE or cernilton (positive control, i.e., reference standard) for 3 weeks while rats in normal and negative control groups were treated with saline at the same time. After treatment, prostate index (PI) and prostate-specific antigen (PSA) of all the rats were examined by enzyme-linked immunosorbent assay (ELISA). In addition, the relative inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), cyclooxygenase-2 (COX-2), prostaglandin E2 (PEG2), transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) of the prostate tissues were measured by ELISA.Results: A high dose of APLE (480 mg/kg) significantly decreased PI (0.7 ± 0.2 mg/g) relative to reference group (2.8 ± 0.3 mg/g, p < 0.01), and significantly decreased PSA level (128.6 ± 12.3 pg/mL) relative to reference group (321.3 ± 16.4 pg/mL, p < 0.01). Compared with reference group, TNF-α level (109.7 ± 9.3 pg/mL, p < 0.01), IL-1β level (98.3 ± 12.5 pg/mL, p < 0.01), PEG2 level (81.5 ± 4.2 pg/mL, p < 0.01), COX-2 level (10.5 ± 2.6 pg/mL, p < 0.01), TGF-β1 level (86.8 ± 7.3 pg/mL, p < 0.01) and CTGF level (70.3 ± 4.3 pg/mL, p < 0.01) of prostate tissues of high-dose APLE group rats decreased significantly.Conclusion: APLE shows significant anti-chronic prostatitis activity in rats. Further studies are, however, required to ascertain its therapeutic potentials in humansKeywords: Alisma plantago-aquatica, Chronic prostatitis, Inflammation, Prostate index, Morphometric analysis, Interstitial fibrosi