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Dynamical analysis and performance evaluation of a biped robot under multi-source random disturbances

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Acta Mechanica Sinica 2014年第6期30卷 983-994页

作者： Chun-Biao Gan chang-tao Ding Shi-Xi Yang The State Key Laboratory of Fluid Power Transmission and Control Department of Mechanical EngineeringZhejiang University

During bipedal walking,it is critical to detect and adjust the robot postures by feedback control to maintain its normal state amidst multi-source random disturbances arising from some unavoidable uncertain *** radical basis function（RBF）neural network model of a five-link biped robot is established,and two certain disturbances and a randomly uncertain disturbance are then mixed with the optimal torques in the network model to study the performance of the biped robot by several evaluation indices and a specific Poincar′e *** contrast with the simulations,the response varies as desired under optimal inputting while the output is fluctuating in the situation of disturbance *** results from noise inputting also show that the dynamics of the robot is less sensitive to the disturbance of knee joint input of the swing leg than those of the other three joints,the response errors of the biped will be increasing with higher disturbance levels,and especially there are larger output fluctuations in the knee and hip joints of the swing leg.

关键词： Biped robot Multi-source random disturbances Sensitive parameters RBF neural network Taguchi method Performance evaluation

Input torque sensitivity to uncertain parameters in biped robot

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Acta Mechanica Sinica 2013年第3期29卷 452-461页

作者： chang-tao Ding Shi-Xi Yang Chun-Biao Gan Department of Mechanical Engineering Zhejiang University

Input torque is the main power to maintain bipedal walking of robot, and can be calculated from trajectory planning and dynamic modeling on biped robot. During bipedal walking, the input torque is usually required to be adjusted due to some uncertain parameters arising from objective or subjective factors in the dynamical model to maintain the pre-planned stable trajectory. Here, a planar 5-link biped robot is used as an illustrating example to investigate the effects of uncertain parameters on the input torques. Kine-matic equations of the biped robot are firstly established by the third-order spline curves based on the trajectory planning method, and the dynamic modeling is accomplished by taking both the certain and uncertain parameters into account. Next, several evaluation indices on input torques are intro-duced to perform sensitivity analysis of the input torque with respect to the uncertain parameters. Finally, based on the Monte Carlo simulation, the values of evaluation indices on input torques are presented, from which all the robot param-eters are classified into three categories, i.e., strongly sensi-tive, sensitive and almost insensitive parameters.

关键词： Biped robot · Uncertain parameter · Trajectory planning · Input torque · Sensitivity

Optimized shearing strategy for heavy plate based on contour recognition

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Journal of Iron and Steel Research International 2023年第9期30卷 1821-1833页

作者： Jian-zhao Cao Yu-xia Wang Shao-wen Huang chang-tao Wang School of Computer Science and Engineering Shenyang Jianzhu UniversityShenyang 110168LiaoningChina Shandong Iron and Steel Co. Ltd.Jinan 271105ShandongChina School of Electrical and Control Engineering Shenyang Jianzhu UniversityShenyang 110168LiaoningChina

The shearing line is the key to improve the quality and efficiency of heavy plates.A model of contour recognition and intelligent shearing strategy for the heavy plate was ***,multi-array binocular vision linear cameras were used to complete the image ***,the total length of the steel plate after cooling was predicted by back propagation neural network algorithm according to the contour ***,using the scanning line and a new camber description method,the shearing strategy including head/tail irregular shape length and rough dividing strategy was *** practical application shows that the model and strategy can effectively solve the problems existing in the shearing process and can effectively improve the yield of steel *** maximum error of detection width,length,camber,and the length of the irregular deformation area at the head/tail of the plate are all less than 5 *** correlation coefficient of the length prediction model based on the back propagation neural network is very *** reverse ratio result of edge cutting failure using the proposed rough dividing strategy is 1/401=0.2%,which is 2%higher than that by human.

关键词： Heavy plate Contour detection Intelligent shearing strategy Length prediction Neural network model

Photocatalytic degradation of Acid Blue 62 over CuO-SnO_2 nanocomposite photocatalyst under simulated sunlight

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Journal of Environmental Sciences 2007年第9期19卷 1141-1145页

作者： XIA Hui-li ZHUANG Hui-sheng ZHANG tao XIAO Dong-chang College of Environmental Science and Engineering Donghua University Shanghai 201620 China.

The novel CuO-SnO2 nanocomposite oxide photocatalysts were prepared by simple co-precipitation method, and characterized by X- ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurement and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of CuO-SnO2, evaluated using the photodegradation of Acid Blue 62 as a probe reaction under the irradiation of Xenon light, were also found to be related to the calcination temperature and the molar ratio of Cu to Sn. The maximum photocatalytic activity of the CuO-SnO2 photocatalyst was observed to be calcined at 500~C for 3 h （the molar ratio of Cu to Sn was 1：1） due to the sample with good crystallization and high surface area. It also showed much higher photocatalytic activity in treatment dye wastewater under simulated sunlight irradiation compared to Degussa P25 TiO2.

关键词： photocatalysis copper oxide tin dioxide Acid Blue 62 (AB62) simulated sunlight

Mosaic isodicentric Y chromosome harboring intact AZF region in a cryptozoospermic male with normal hormone levels

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Asian Journal of Andrology 2021年第4期23卷 437-438页

作者： Sheng-Yu Xie Da-chang tao Yuan Yang Department of Medical Genetics State Key Laboratory of BiotherapyWest China HospitalWest China Medical SchoolSichuan UniversityChengdu 610041China

Dear Editor,Structural aberrations of the Y chromosome,including deletions,ring chromosomes,Y-autosomal or Y-X translocations,isochromosomes,and dicentrics,occur in approximately 0.2%of live births;1 among these,partial deletion in the azoospermia factor(AZF)region of the Y chromosome is a well-characterized cause of nonobstructive severe oligozoospermia and azoospermia.2 Meanwhile,a dicentric Y chromosome,abbreviated as dic(Y),was observed to be exclusively present in males with azoospermia,suggesting more severe negative consequences of the AZF deletion for spermatogenesis.

关键词： Mosaic harbor AZF

Topology Optimization with Aperiodic Load Fatigue Constraints Based on Bidirectional Evolutionary Structural Optimization

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Computer Modeling in Engineering & Sciences 2022年第1期130卷 499-511页

作者： Yongxin Li Guoyun Zhou tao chang Liming Yang Fenghe Wu Heavy-Duty Intelligent Manufacturing Equipment Innovation Center of Hebei Province School of Mechanical EngineeringYanshan UniversityQinhuangdaoChina Space Star Technology Co. Ltd.BeijingChina

Because of descriptive nonlinearity and computational inefficiency,topology optimization with fatigue life under aperiodic loads has developed slowly.A fatigue constraint topology optimization method based on bidirectional evolutionary structural optimization(BESO)under an aperiodic load is proposed in this *** viewof the severe nonlinearity of fatigue damagewith respect to design variables,effective stress cycles are extracted through transient dynamic *** on the Miner cumulative damage theory and life requirements,a fatigue constraint is first quantified and then transformed into a stress ***,a normalized termination criterion is proposed by approximatemaximum stress measured by global stress using a P-normaggregation ***,optimization examples show that the proposed algorithm can not only meet the requirements of fatigue life but also obtain a reasonable configuration.

关键词： Topology optimization bidirectional evolutionary structural optimization aperiodic load fatigue life stress constraint

Experimental and first-principles calculation of TiN growth mechanism on CeAlO_(3) surface in steel

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Journal of Iron and Steel Research International 2024年第2期31卷 452-463页

作者： Fei-hu He Jun Peng Fang Zhang Yong-bin Wang Hong-tao chang School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou014010Inner MongoliaChina

Regular TiN is harmful to the toughness of steel,and its shape and size need to be *** the behavior of TiN precipitation on CeAlO_(3) surfaces is critical for controlling the morphology and formation process of CeAlO_(3)–TiN composite inclusions in the *** results showed that TiN had a square morphology on the CeAlO3 surface,and electron backscatter diffraction phase identification results revealed the orientation relationship between CeAlO_(3) and TiN as follows:(001)_(CeAlO_(3))//(110)_(TiN),(100)_(CeAlO_(3))/(001)_(TiN),and[010]_(CeAlO_(3))/[110]_(TiN).The CeAlO3 crystal structure was studied using the first-principles calculation method,and the adsorption and growth process of TiN on the CeAlO_(3) surface were investigated from the atomic *** calculation results indicate that there is no metallic bonding present in the CeAlO_(3) *** the low-index crystal planes of CeAlO_(3),the(110)planes terminated with O and CeAlO have the highest and lowest surface energies,respectively,with values of 0.373 and 0.051 eV/Å^(2).On the high surface energy plane of CeAlO_(3),the TiN atomic permutation structure is consistent with the arrangement of Ti and N atoms in TiN(100)or(110).For the low surface energy plane of CeAlO_(3),the Ti and N atoms are arranged in a ring-like structure.

关键词： CeAlO_(3)-TiN inclusion Orientation relationship Crystal structure First principle Surface energy

Cerebral venous sinus thrombosis following transsphenoidal surgery for craniopharyngioma:A case report

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World Journal of Clinical Cases 2020年第6期8卷 1158-1163页

作者： tao chang Yan-Long Yang Li Gao Li-Hong Li Department of Emergency Medicine Second Affiliated Hospital of Air Force Medical UniversityXi’an 710038Shaanxi ProvinceChina Department of Neurosurgery Second Affiliated Hospital of Air Force Medical UniversityXi’an 710038Shaanxi ProvinceChina

BACKGROUND Cerebral venous sinus thrombosis(CVST)is a rare condition in patients with craniopharyngioma following transsphenoidal *** SUMMARY A 56-year-old man who underwent transsphenoidal surgery for craniopharyngioma 26 d ago presented gradual headache and cerebrospinal fluid leakage while vomiting 5 d post-discharge and required readmission to our department of *** admission,head imaging examination showed a hyperdense shadow in the superior sagittal sinus and right transverse sinus,edema at the bilateral parietal lobe,and hemorrhage at the left parietal lobe and right occipital lobe;the venous phase of cerebral angiography revealed *** patient was treated immediately by intravenous thrombolysis,endovascular thrombolysis,and mechanical thrombectomy after the definite ***,the neurological status of the patient continued to deteriorate and he died on the fourth day after *** For craniopharyngioma undergoing transsphenoidal surgery,it is vital to take an effective strategy to manage the postoperative complications,such as diabetes insipidus,severe electrolyte imbalance,and cerebrospinal fluid ***,the early differential diagnosis of CVST is essential when it develops clinical symptoms,especially in patients following transsphenoidal surgery with a high risk of ***,the timely and effective treatment of the CVST is critical for preventing neurological deterioration.

关键词： Craniopharyngioma Transsphenoidal surgery Cerebral venous sinus thrombosis Case report

Detection technology of micro residual core in small inner cavity of complex castings

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China Foundry 2018年第4期15卷 307-313页

作者： jun-hao zhao shi-ping wu yin dong tao-qi chang school of material science and engineering harbin institute of technologyHarbin 150001China avic xi'an aero-engine precision casting co. ltd.Xi'an 710021China

A new technology for detecting a tiny residual core in the small inner cavity of complex castings is proposed. The residual core is identified by using image recognition technology. Tracer processing and image signal processing are combined to enhance the image contrast. The relationships between the concentration of tracer, the size of the residual core, the wall thickness of the castings and the contrast were obtained. Based on the experimental data, the minimum detectable amount of residual core under different conditions was obtained. The results show that the minimum detectable amount decreases from 4.398 mg to 0.438 mg for the 1.0 mm wall thickness casting when the concentration of tracer increases from 0% to 20%. The signal-to-noise ratio(SNR) of the detection results increases by 27.010 by means of average filtering and linear point operation. The subtraction of image and image background was performed, and then the boundary extraction was carried out to obtain a clear and reliable result. The experimental results show that the non-traced residual core cannot be detected for a blade with a thickness less than 5 mm. The residual core of 1 mm thickness can be barely identified by artificial recognition after tracer processing and image processing, while the residual core of 0.6 mm thickness can be detected clearly using image recognition technology.

关键词： hollow blades X-ray detection residual ceramic core tracer image processing