The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to t...The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to the linearity in the segment for the plan view pattern control function. The compensation volume can be dispersed for easy calculation. By comparing the model calculation result with the actual result, it was concluded that the simplified model can be used for the online control process.展开更多
Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation f...Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.展开更多
The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper...The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper thickness can be obtained. The numerical solution for this formula was used on site. According to the simulation result, the roll gap value should be changed linearly with rolling time.展开更多
High vocal center (HVC) can produce single sound with one or two syllables by the sin-gle-type vocal control pattern in songbirds ruddy bunting (Emberiza rutila). It obviously shows left-side dominance in controlling ...High vocal center (HVC) can produce single sound with one or two syllables by the sin-gle-type vocal control pattern in songbirds ruddy bunting (Emberiza rutila). It obviously shows left-side dominance in controlling double syllables, principal frequency (PF) and increasing sound intensity of the evoked calls. Meanwhile, the complex-type control pattern can produce complex calls with multisyllable, and also shows significant left-side dominance in controlling the number of syllables, tone changing and sound intensity. These indicate that left-side HVC controls higher frequency and complicated sentence structure. The basic vocal center, dorsomedial nucleus of the intercollicular complex (DM), controls the monosyllable sound in songbirds, and shows left-side dominance in controlling both the number of syllable and sound intensity. These results not only provide some direct evidence for left-side dominance in high vocal center, but also indicate that there is some internal connection between the high and basic vocal centers in songbirds.展开更多
The identification of control chart patterns is very important in statistical process control. Control chart patterns are categorized as natural and unnatural. The presence of unnatural patterns means that a process i...The identification of control chart patterns is very important in statistical process control. Control chart patterns are categorized as natural and unnatural. The presence of unnatural patterns means that a process is out of statistical control and there are assignable causes for process variation that should be investigated. This paper proposes an artificial neural network algorithm to identify the three basic control chart patterns;natural, shift, and trend. This identification is in addition to the traditional statistical detection of runs in data, since runs are one of the out of control situations. It is assumed that a process starts as a natural pattern and then may undergo only one out of control pattern at a time. The performance of the proposed algorithm was evaluated by measuring the probability of success in identifying the three basic patterns accurately, and comparing these results with previous research work. The comparison showed that the proposed algorithm realized better identification than others.展开更多
As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by g...As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.展开更多
The trajectory of the controlled system in phase space has been investigated, and different learning methods are applied to the single adaptive neuron controller according to the pattem of the control system. The adva...The trajectory of the controlled system in phase space has been investigated, and different learning methods are applied to the single adaptive neuron controller according to the pattem of the control system. The advantage of the controller presented has been shown by simulation of a satellite attitude stability control system.展开更多
AIM：To assess the relation between nutrient patterns and cataract risk.METHODS：This is a hospital-based case-control study with 97 cataract patients and 198 matched controls.Dietary consumption was collected through...AIM：To assess the relation between nutrient patterns and cataract risk.METHODS：This is a hospital-based case-control study with 97 cataract patients and 198 matched controls.Dietary consumption was collected through a valid food frequency questionnaire（FFQ）.Nutrient patterns were detected by applying factor analysis.Unconditional logistic regression models were used to estimate odds ratio（ORs） and 95%CIs.RESULTS：We extracted 5 main nutrient patterns.Factor 1 included niacin,thiamin,carbohydrates,protein,zinc,vitamin B6 and sodium（sodium pattern）.Factor 2 was characterized by oleic acid,monounsaturated fats,polyunsaturated fats,linoleic acid,trans fatty acid,linolenic acid,vitamin E and saturated fats（fatty acid pattern）.The third factor represented high intake of vitamin B12,vitamin D,cholesterol and calcium（mixed pattern）.The 4^（th） pattern was high in intake of beta and alpha carotene,vitamin A and vitamin C（antioxidant pattern）.Finally,the 5^（th） pattern loaded heavily on docosahexaenoic acid（DHA） and eicosapentaenoic acid（EPA）（omega-3 pattern）.In crude and multivariate analysis,the sodium pattern was associated with increased risk of cataract（OR=1.97,95%CI：1.09-3.96）.The fatty acid pattern elevated the risk of cataract（OR=1.94,95%CI：1.1-3.86）.Antioxidant pattern was associated with a significant 79% reduced risk（2^（nd） category compared with the 1st）.Omega-3 pattern was significantly negatively associated with risk of cataract（P=0.04）.CONCLUSION：These findings imply that nutrient patterns reflecting a combined consumption of nutrients might be important in the etiology of cataract.Additional studies with more efficient designs are warranted to confirm our findings.展开更多
1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et ...1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et al.,2008;Zhang et展开更多
The paper covers analysis and investigation of lighting automation system in low-traffic long-roads. The main objective is to provide optimal solution between expensive safe design that utilizes continuous street ligh...The paper covers analysis and investigation of lighting automation system in low-traffic long-roads. The main objective is to provide optimal solution between expensive safe design that utilizes continuous street lighting system at night for the entire road, or inexpensive design that sacrifices the safety, relying on using vehicles lighting, to eliminate the problem of high cost energy consumption during the night operation of the road. By taking into account both of these factors, smart lighting automation system is proposed using Pattern Recognition Technique applied on vehicle number-plates. In this proposal, the road is sectionalized into zones, and based on smart Pattern Recognition Technique, the control system of the road lighting illuminates only the zone that the vehicles pass through. Economic analysis is provided in this paper to support the value of using this design of lighting control system.展开更多
The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built ...The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.展开更多
The wind tunnel experiments is conducted to get inspiration for understanding the mechanism of the asymmetric flow pattern and developing an innovative flow control technique for a slender body at high angle of attack...The wind tunnel experiments is conducted to get inspiration for understanding the mechanism of the asymmetric flow pattern and developing an innovative flow control technique for a slender body at high angle of attack. The bi-stable situation of the side forces is observed, which could be easily switched by a tiny disturbances either from coming flow or from artificial disturbances at nose tip （including manufacturing defect）. In turbulent flows the side forces switched randomly between positive and negative. There exists a hysteresis loop of side force with the rolling angle. A rod in front of the slender body is used to change the vortex pattern, which could be kept even the rod is moved out from the stream. A miniature strake attached to the nose tip of the model can be moved to different circumferential position. When the strake is stationary, the hysteresis loop disappears and the side force does not change with the turbulent fluctuation of coming flow. The results from dynamic measurements of section side force indicates that when the strake swung at lower frequency the side force can follow the cadence of the swinging strake. With increasing frequency, the magnitude of the side force decreases. At still high frequency, the side force diminishes to zero. If the strake is swinging, while the middle position can be changed to different circumferential angle Фs on either left or right side, the side forces can be changed proportionally with the angle Фs. On the basis of the experimental results, the mechanism of the asymmetry is discussed.展开更多
An adaptive actuator failure compensation control scheme is developed using an indirect adaptive control method,by calculating the controller parameters from adaptive estimates of system parameters and actuator failur...An adaptive actuator failure compensation control scheme is developed using an indirect adaptive control method,by calculating the controller parameters from adaptive estimates of system parameters and actuator failure parameters.A key technical issue is how to deal with the actuator failure uncertainties such as failure pattern,time and values.A complete parametrization covering all possible failures is used to solve this issue for adaptive parameter estimation.A simultaneous mapping from the estimated system/failure parameters to the controller parameters is employed to make the control system capable of ensuring the desired system performance under failures,which is verified by simulation results.展开更多
To realize the coordinated and stable rhythmic motion of quadruped robots （QRs）, the locomotion control method of QRs based on central pattern generator （CPG） was explored. In tradi- tional control strategies base...To realize the coordinated and stable rhythmic motion of quadruped robots （QRs）, the locomotion control method of QRs based on central pattern generator （CPG） was explored. In tradi- tional control strategies based on CPG, few CPG models care about the intra-limb coordination of QRs, and the durations of stance phase and swing phase are always equal. In view of these deficien- cies, a new and simpler multi-joint coordinated control method for both inter-limb and intra-limb was proposed in this paper. A layered CPG control network to realize the locomotion control of QRs was constructed by using modified Hopf oscillators. The coupled relationships among hip joints of all limbs and between hip joint and knee joint within a limb were established. Using the co-simulation method of ADAMS and MATLAB/Simulink, various gait simulation experiments were carried out and the effectiveness of the designed control network was tested. Simulation results show that the pro- posed control method is effective for QRs and can meet the control requirements of QRs＇ gaits with different duty factors.展开更多
Some typical structural schemes of learning control have been investigated.The schemes involve the pattern recognitionbased learning control,iterative learning control,repetitive learning control,and connectionist lea...Some typical structural schemes of learning control have been investigated.The schemes involve the pattern recognitionbased learning control,iterative learning control,repetitive learning control,and connectionist learning control,etc.This study focuses on the control mechanism and provides a basis for potential applications.Most of the structural schemes have been applied to various control fields.展开更多
A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,＂test pattern＂ caused by test signal...A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,＂test pattern＂ caused by test signal or radar hardware failures in CINRAD （China New Generation Weather Radar） SA and SB radar operational observations are investigated.In order to distinguish the test pattern from other types of radar echoes,such as precipitation,clear air and other non-meteorological echoes,five feature parameters including the effective reflectivity data percentage （Rz）,velocity RF （range folding） data percentage （RRF）,missing velocity data percentage （RM）,averaged along-azimuth reflectivity fluctuation （RNr,z） and averaged along-beam reflectivity fluctuation （RNa,z） are proposed.Based on the fuzzy logic method,a test pattern identification algorithm is developed,and the statistical results from all the different kinds of radar echoes indicate the performance of the algorithm.Analysis of two typical cases with heavy precipitation echoes located inside the test pattern are performed.The statistical results show that the test pattern identification algorithm performs well,since the test pattern is recognized in most cases.Besides,the algorithm can effectively remove the test pattern signal and retain strong precipitation echoes in heavy rainfall events.展开更多
The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the hole...The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the holes. The effects of the perforated conic shroud on the vortex shedding pattern in the near wake was mainly investigated, as well as the time history of the drag and lift forces. In the investigated parameter space, three flow regimes were generally identified, corresponding to weak, moderate, and strong disturbance effects.In regime I, the wake can mainly be described by alternately shedding Kármán or Kármán-like vortices. In regime II, the spanwise vortices are obviously disturbed along the span due to the appearance of additional vorticity components and their interactions with the spanwise vortices, but still shed in synchronization along the spanwise direction. In regime III,the typical Kármán vortices partially or totally disappear,and some new vortex shedding patterns appear, such as-type, obliquely shedding, and crossed spanwise vortices with opposite sign. Corresponding to these complex vortex shedding patterns in the near wake, the fluid forces no longer oscillate regularly at a single vortex shedding frequency, but rather with a lower modulation frequency and multiple amplitudes. An overview of these flow regimes is presented.展开更多
基金Item Sponsored by National Economy Trade Committee Foundation(ZZ0113A040201)
文摘The plan view pattern control theoretical models were simplified. Under the condition of constant volume for the plan view pattern compensation, the relation between the thickness and the length can be simplified to the linearity in the segment for the plan view pattern control function. The compensation volume can be dispersed for easy calculation. By comparing the model calculation result with the actual result, it was concluded that the simplified model can be used for the online control process.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.N120407007)
文摘Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.
基金Item Sponsored by National Economy Trade Committee Foundation (ZZ0113A040201)
文摘The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper thickness can be obtained. The numerical solution for this formula was used on site. According to the simulation result, the roll gap value should be changed linearly with rolling time.
基金supported by the National Natural Science Foundation of China(Grant No.39570195)Outstanding Youth Foundation of Ministry of Education of China,Science and Technology Research Project of Ministry of Education of China(Grant No.01062)Laboratory of Visual Information Processing Foundation of the Chinese Academy of Sciences.
文摘High vocal center (HVC) can produce single sound with one or two syllables by the sin-gle-type vocal control pattern in songbirds ruddy bunting (Emberiza rutila). It obviously shows left-side dominance in controlling double syllables, principal frequency (PF) and increasing sound intensity of the evoked calls. Meanwhile, the complex-type control pattern can produce complex calls with multisyllable, and also shows significant left-side dominance in controlling the number of syllables, tone changing and sound intensity. These indicate that left-side HVC controls higher frequency and complicated sentence structure. The basic vocal center, dorsomedial nucleus of the intercollicular complex (DM), controls the monosyllable sound in songbirds, and shows left-side dominance in controlling both the number of syllable and sound intensity. These results not only provide some direct evidence for left-side dominance in high vocal center, but also indicate that there is some internal connection between the high and basic vocal centers in songbirds.
文摘The identification of control chart patterns is very important in statistical process control. Control chart patterns are categorized as natural and unnatural. The presence of unnatural patterns means that a process is out of statistical control and there are assignable causes for process variation that should be investigated. This paper proposes an artificial neural network algorithm to identify the three basic control chart patterns;natural, shift, and trend. This identification is in addition to the traditional statistical detection of runs in data, since runs are one of the out of control situations. It is assumed that a process starts as a natural pattern and then may undergo only one out of control pattern at a time. The performance of the proposed algorithm was evaluated by measuring the probability of success in identifying the three basic patterns accurately, and comparing these results with previous research work. The comparison showed that the proposed algorithm realized better identification than others.
基金supported by the National Natural Science Foundation of China(Nos.11232005 and11472104)the Doctoral Fund of Ministry of Education of China(No.20120074110020)
文摘As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.
文摘The trajectory of the controlled system in phase space has been investigated, and different learning methods are applied to the single adaptive neuron controller according to the pattem of the control system. The advantage of the controller presented has been shown by simulation of a satellite attitude stability control system.
基金Supported by the National Nutrition and Food Technology Research Institute(NNFTRI)of Shahid Beheshti University of Medical Sciences,Tehran,Iran
文摘AIM：To assess the relation between nutrient patterns and cataract risk.METHODS：This is a hospital-based case-control study with 97 cataract patients and 198 matched controls.Dietary consumption was collected through a valid food frequency questionnaire（FFQ）.Nutrient patterns were detected by applying factor analysis.Unconditional logistic regression models were used to estimate odds ratio（ORs） and 95%CIs.RESULTS：We extracted 5 main nutrient patterns.Factor 1 included niacin,thiamin,carbohydrates,protein,zinc,vitamin B6 and sodium（sodium pattern）.Factor 2 was characterized by oleic acid,monounsaturated fats,polyunsaturated fats,linoleic acid,trans fatty acid,linolenic acid,vitamin E and saturated fats（fatty acid pattern）.The third factor represented high intake of vitamin B12,vitamin D,cholesterol and calcium（mixed pattern）.The 4^（th） pattern was high in intake of beta and alpha carotene,vitamin A and vitamin C（antioxidant pattern）.Finally,the 5^（th） pattern loaded heavily on docosahexaenoic acid（DHA） and eicosapentaenoic acid（EPA）（omega-3 pattern）.In crude and multivariate analysis,the sodium pattern was associated with increased risk of cataract（OR=1.97,95%CI：1.09-3.96）.The fatty acid pattern elevated the risk of cataract（OR=1.94,95%CI：1.1-3.86）.Antioxidant pattern was associated with a significant 79% reduced risk（2^（nd） category compared with the 1st）.Omega-3 pattern was significantly negatively associated with risk of cataract（P=0.04）.CONCLUSION：These findings imply that nutrient patterns reflecting a combined consumption of nutrients might be important in the etiology of cataract.Additional studies with more efficient designs are warranted to confirm our findings.
基金funding support of this project from National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2011ZX05010-002-005)
文摘1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et al.,2008;Zhang et
文摘The paper covers analysis and investigation of lighting automation system in low-traffic long-roads. The main objective is to provide optimal solution between expensive safe design that utilizes continuous street lighting system at night for the entire road, or inexpensive design that sacrifices the safety, relying on using vehicles lighting, to eliminate the problem of high cost energy consumption during the night operation of the road. By taking into account both of these factors, smart lighting automation system is proposed using Pattern Recognition Technique applied on vehicle number-plates. In this proposal, the road is sectionalized into zones, and based on smart Pattern Recognition Technique, the control system of the road lighting illuminates only the zone that the vehicles pass through. Economic analysis is provided in this paper to support the value of using this design of lighting control system.
基金Supported by the National Program on Key Basic Research Program(″973″Program)(2012CB026000)the Ph.D.Programs Foundation of Ministry of Education of China(20110010110009)
文摘The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.
文摘The wind tunnel experiments is conducted to get inspiration for understanding the mechanism of the asymmetric flow pattern and developing an innovative flow control technique for a slender body at high angle of attack. The bi-stable situation of the side forces is observed, which could be easily switched by a tiny disturbances either from coming flow or from artificial disturbances at nose tip （including manufacturing defect）. In turbulent flows the side forces switched randomly between positive and negative. There exists a hysteresis loop of side force with the rolling angle. A rod in front of the slender body is used to change the vortex pattern, which could be kept even the rod is moved out from the stream. A miniature strake attached to the nose tip of the model can be moved to different circumferential position. When the strake is stationary, the hysteresis loop disappears and the side force does not change with the turbulent fluctuation of coming flow. The results from dynamic measurements of section side force indicates that when the strake swung at lower frequency the side force can follow the cadence of the swinging strake. With increasing frequency, the magnitude of the side force decreases. At still high frequency, the side force diminishes to zero. If the strake is swinging, while the middle position can be changed to different circumferential angle Фs on either left or right side, the side forces can be changed proportionally with the angle Фs. On the basis of the experimental results, the mechanism of the asymmetry is discussed.
基金supported by the US National Science Foundation (ECS0601475)the National Natural Science Foundation of China (60904042)
文摘An adaptive actuator failure compensation control scheme is developed using an indirect adaptive control method,by calculating the controller parameters from adaptive estimates of system parameters and actuator failure parameters.A key technical issue is how to deal with the actuator failure uncertainties such as failure pattern,time and values.A complete parametrization covering all possible failures is used to solve this issue for adaptive parameter estimation.A simultaneous mapping from the estimated system/failure parameters to the controller parameters is employed to make the control system capable of ensuring the desired system performance under failures,which is verified by simulation results.
基金Supported by the Ministerial Level Advanced Research Foundation(40401060305)
文摘To realize the coordinated and stable rhythmic motion of quadruped robots （QRs）, the locomotion control method of QRs based on central pattern generator （CPG） was explored. In tradi- tional control strategies based on CPG, few CPG models care about the intra-limb coordination of QRs, and the durations of stance phase and swing phase are always equal. In view of these deficien- cies, a new and simpler multi-joint coordinated control method for both inter-limb and intra-limb was proposed in this paper. A layered CPG control network to realize the locomotion control of QRs was constructed by using modified Hopf oscillators. The coupled relationships among hip joints of all limbs and between hip joint and knee joint within a limb were established. Using the co-simulation method of ADAMS and MATLAB/Simulink, various gait simulation experiments were carried out and the effectiveness of the designed control network was tested. Simulation results show that the pro- posed control method is effective for QRs and can meet the control requirements of QRs＇ gaits with different duty factors.
文摘Some typical structural schemes of learning control have been investigated.The schemes involve the pattern recognitionbased learning control,iterative learning control,repetitive learning control,and connectionist learning control,etc.This study focuses on the control mechanism and provides a basis for potential applications.Most of the structural schemes have been applied to various control fields.
基金supported by the National Key Program for Developing Basic Sciences under Grant 2012CB417202the National Natural Science Foundation of China under Grant No. 41175038, No. 41305088 and No. 41075023+4 种基金the Meteorological Special Project "Radar network observation technology and QC"the CMA Key project "Radar Operational Software Engineering"the Chinese Academy of Meteorological Sciences Basic ScientificOperational Projects "Observation and retrieval methods of micro-physics and dynamic parameters of cloud and precipitation with multi-wavelength Remote Sensing"Project of the State Key Laboratory of Severe Weather grant 2012LASW-B04
文摘A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,＂test pattern＂ caused by test signal or radar hardware failures in CINRAD （China New Generation Weather Radar） SA and SB radar operational observations are investigated.In order to distinguish the test pattern from other types of radar echoes,such as precipitation,clear air and other non-meteorological echoes,five feature parameters including the effective reflectivity data percentage （Rz）,velocity RF （range folding） data percentage （RRF）,missing velocity data percentage （RM）,averaged along-azimuth reflectivity fluctuation （RNr,z） and averaged along-beam reflectivity fluctuation （RNa,z） are proposed.Based on the fuzzy logic method,a test pattern identification algorithm is developed,and the statistical results from all the different kinds of radar echoes indicate the performance of the algorithm.Analysis of two typical cases with heavy precipitation echoes located inside the test pattern are performed.The statistical results show that the test pattern identification algorithm performs well,since the test pattern is recognized in most cases.Besides,the algorithm can effectively remove the test pattern signal and retain strong precipitation echoes in heavy rainfall events.
基金supported by the National Key Scientific Instrument and Equipment Development Program of China (Grant 2011YQ120048)
文摘The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the holes. The effects of the perforated conic shroud on the vortex shedding pattern in the near wake was mainly investigated, as well as the time history of the drag and lift forces. In the investigated parameter space, three flow regimes were generally identified, corresponding to weak, moderate, and strong disturbance effects.In regime I, the wake can mainly be described by alternately shedding Kármán or Kármán-like vortices. In regime II, the spanwise vortices are obviously disturbed along the span due to the appearance of additional vorticity components and their interactions with the spanwise vortices, but still shed in synchronization along the spanwise direction. In regime III,the typical Kármán vortices partially or totally disappear,and some new vortex shedding patterns appear, such as-type, obliquely shedding, and crossed spanwise vortices with opposite sign. Corresponding to these complex vortex shedding patterns in the near wake, the fluid forces no longer oscillate regularly at a single vortex shedding frequency, but rather with a lower modulation frequency and multiple amplitudes. An overview of these flow regimes is presented.
