The influence of plate thickness on the penetration in GTAW has been investigated and a front pool width penetration control approach has been studied, which controls the penetration under the variation of plate thick...The influence of plate thickness on the penetration in GTAW has been investigated and a front pool width penetration control approach has been studied, which controls the penetration under the variation of plate thickness. A theoretical heat flow model for a plate of a finite thickness has been utilized to investigate the relationship of the pool widths on both sides. A penetration control system for autogenous GTA welding has been utilized which uses a coaxial weld pool imaging system and computer vision processing to sense the width of the GTA weld pool. Empirical results show the good performance of this penetration control approach in the presence of variations in a joint root thickness of 1 mm (0.04 inch) to 3 mm (0.125 inch).展开更多
Colormetric method of images by using two different wavelength images is a new measuring method for welding temperature field on the basis of ordinary colorimetric method, which depends little on the measuring distanc...Colormetric method of images by using two different wavelength images is a new measuring method for welding temperature field on the basis of ordinary colorimetric method, which depends little on the measuring distance, emissivity of body etc. In this paper the real time measuring system and measuring principle of welding temperature field are described, the whole welding temperature field is real time measured, so the temperature distribution at the welding direction and its cross section is obtained, then parameters of thermal cycle. With data from the temperature closed loop control system of the parameters of temperature field is developed and tested. Experimental results prove that it has high measurement speed (time of a field within 0.5 s ) and good dynamic response quality. Weld penetration can be controlled satisfactorily under the variation of welding condition such as welding thickness, welding speed and weldment gap etc.展开更多
Realizing of weld penetration control in gas tungsten arc welding requires establishment of a model describing the relationship between the front-side geometrical parameters of weld pool and the back-side weld width w...Realizing of weld penetration control in gas tungsten arc welding requires establishment of a model describing the relationship between the front-side geometrical parameters of weld pool and the back-side weld width with sufficient accuracy. A neural network model is developed to attain this aim. Welding experiments are conducted to obtain the training data set （including 973 groups of geometrical parameters of the weld pool and back-side weld width） and the verifying data set （108 groups）. Two data sets are used for training and verifying the neural network, respectively. The testing results show that the model has sufficient accuracy and can meet the requirements of weld penetration control.展开更多
To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed loop control system was established. In the system, welding current and plasma gas flow rate were se...To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed loop control system was established. In the system, welding current and plasma gas flow rate were selected as adjusting variables. The wavelet method was used to detect penetration status from welding arc voltage in real time. The control strategy of one keyhole per pulse was adapted to fulfill stable and high quality welding process. Experimental results show that the developed system can apparently increase the penetrating force of plasma arc and keyhole plasma arc welding is realized successfully in stainless steel with 10 mm in thickness. Moreover, the disturbances of gradual change and break change from 3 mm to 6 mm in thickness are come over due to the good response property of the developed system.展开更多
This paper presents a technique for controlling the pressure of a molten metal when using a new type of iron casting method called sand mold press casting to realize high productivity and obtain high-quality products....This paper presents a technique for controlling the pressure of a molten metal when using a new type of iron casting method called sand mold press casting to realize high productivity and obtain high-quality products.The past test results using this method showed a casting yield of 90% to 95%,while conventional methods only show a casting yield of 60% to 70%.Although the press casting method does not require a sprue cup or runner channel casting defects such as metal penetration are often caused by the high pressure in the high-velocity pressing part of this casting process.Therefore,we proposed a pressure control method with a mathematical model of molten metal pressure,and with it we achieved experimental confirmation of the successful production of brake drums at different pressing temperatures.Results show that the proposed pressing control method can realize sound,penetration-free casting production.However,the theoretical analysis and design of this pressing process had not previously been studied sufficiently,and therefore this paper presents the theoretical design algorithm for the process as well as its experimental confirmation.展开更多
An intelligent system including both a neural network(NN) and a self adjusting fuzzy controller(FC) for modeling and control of the penetration depth during gas tungsten arc welding(GTAW) process is presented in this...An intelligent system including both a neural network(NN) and a self adjusting fuzzy controller(FC) for modeling and control of the penetration depth during gas tungsten arc welding(GTAW) process is presented in this paper. The discussion is mainly focused on two parts. One is the modeling of the penetration depth with NN. A visual sensor CCD is used to obtain the image of the molten pool. A neural network model is established to estimate the penetration depth from the welding current, pool width and seam gap. It is demonstrated that the proposed neural network can produce highly complex nonlinear multi variable model of the GTAW process that offer the accurate prediction of welding penetration depth. Another is the control for the penetration depth with FC.A self adjusting fuzzy controller is proposed,which used for controlling the penetration depth.The control parameters are adjusted on line automatically according to the controlling errors of penetration and the errors can be decreased sharply. The effectiveness of the proposed intelligent methods is demonstrated by the real experiments and the improved performance results are obtained.展开更多
The influence of plate thickness on the penetration in GTAW was investigated and a theoretical heat flow model for a plate of finite thickness has been utilized to investigate the relationship between front and back p...The influence of plate thickness on the penetration in GTAW was investigated and a theoretical heat flow model for a plate of finite thickness has been utilized to investigate the relationship between front and back pool widths.Then,front pool width penetration control approach approach has been studied, which controls penetration under the variation of plate thickness.A penetration control system for autogenous GTA welding has been utilized which includes a coaxial weld pool imaging system and computer vision processing system to sense the front width of the GTA weld pool.Empirical results show the good performance of this penetration control approach in the presence of variations in joint plant thickness of 1 mm 0.04 inch) to 3 mm(0.125 inch)展开更多
Presents penetration control by weld pool resonance which occurs when the natural frequency of weld pool is equal to the frequency of sine wave current while the weld pool is excited into oscillation by superimposing ...Presents penetration control by weld pool resonance which occurs when the natural frequency of weld pool is equal to the frequency of sine wave current while the weld pool is excited into oscillation by superimposing sine wave current with definite frequency or regular frequency on DC current, and experiments carried out on detecting resonance signals during both stationary and travelling arc welding with variant frequency pulse current, and concludes with experimental results that penetration control can be realized by weld pool resonance when welding speed is lower than 80mm/min, and this control method is applicable to welding thin (0.5～3.0 mm) plates of carbon steel, low alloy steel, high strength steel and superhigh strength steel, and suitable for alternating polarity welding of stainless steel, titanium alloy steel and aluminum alloy.展开更多
A integrated intelligent system for seam tracking and penetration control is given. The system received information of welding seam error and penetration depth from only one sensor, then, it realized seam tracking and...A integrated intelligent system for seam tracking and penetration control is given. The system received information of welding seam error and penetration depth from only one sensor, then, it realized seam tracking and penetration control simultaneously. This paper introduces constitution of the system, methods of information recognition, design of the neural fuzzy controller and results practically.展开更多
A three dimensional analytical model for heat conduction in a plate of finite size with a Gaussian distributed moving heat source, is obtained using the Heat Cumulating Principle and the Method of Image in arc we...A three dimensional analytical model for heat conduction in a plate of finite size with a Gaussian distributed moving heat source, is obtained using the Heat Cumulating Principle and the Method of Image in arc welding, and an estimated method of back width of seam is introduced by making use of the model and the measured top face information of temperature field . To prove the validity of the model, a series of GTA bead on plate welding were performed on a medium carbon steel under various welding conditions, the experimental results show that the theoretical prediction can provide acceptable accuracy, so the next penetration control will be based on the model.展开更多
The rapid development of the anti-missile weapon technology brings new challenges to the cooperative penetration strategy solution and the guidance law design for Hypersonic Vehicles(HVs).This paper studies the coordi...The rapid development of the anti-missile weapon technology brings new challenges to the cooperative penetration strategy solution and the guidance law design for Hypersonic Vehicles(HVs).This paper studies the coordinated game penetration guidance problem for multiple hypersonic vehicles faced with space threat areas.A scheme for seeking cooperative game penetration guidance strategy under safety critical control framework is presented.In this scheme,a multiHV cooperative game model is proposed in a minimum optimization form which can simplify the solving process and accelerate the computing speed.Then,a second-order control barrier function is developed to transform the implicit nonlinear constraints of the proposed model into linear ones.In order to obtain better performance of guidance strategy,a composite guidance law under the safety critical control framework is presented to allocate guidance strategies appropriately in the whole process.It is shown that the proposed scheme can guarantee successful penetration while avoiding threat areas.Finally,a comparative simulation with a two-on-three game is conducted to verify the effectiveness of the proposed method.展开更多
某些垃圾填埋场由于相关资料严重缺失,给污染物的治理工作带来了困难。为了解决老垃圾填埋场的污染物治理问题,将高密度电法和探地雷达法相结合,对某村老垃圾填埋场进行了全方位探查,取得了以下成果:1)成功识别出垃圾与原位土层的界线,...某些垃圾填埋场由于相关资料严重缺失,给污染物的治理工作带来了困难。为了解决老垃圾填埋场的污染物治理问题,将高密度电法和探地雷达法相结合,对某村老垃圾填埋场进行了全方位探查,取得了以下成果:1)成功识别出垃圾与原位土层的界线,得到了垃圾层的范围和厚度,并以此为基础计算出回填方量为132454 m ^(3),为污染物的清除和治理提供了重要的参考;2)依据电阻率的分布,划分出填埋物的种类主要为建筑垃圾、生活垃圾或者粪便;3)识别出垃圾渗液的污染范围,圈定需要隔绝污染和回收清洁土壤的位置。本次研究结果为今后的垃圾治理工作提供了重要的参考。展开更多
文摘The influence of plate thickness on the penetration in GTAW has been investigated and a front pool width penetration control approach has been studied, which controls the penetration under the variation of plate thickness. A theoretical heat flow model for a plate of a finite thickness has been utilized to investigate the relationship of the pool widths on both sides. A penetration control system for autogenous GTA welding has been utilized which uses a coaxial weld pool imaging system and computer vision processing to sense the width of the GTA weld pool. Empirical results show the good performance of this penetration control approach in the presence of variations in a joint root thickness of 1 mm (0.04 inch) to 3 mm (0.125 inch).
文摘Colormetric method of images by using two different wavelength images is a new measuring method for welding temperature field on the basis of ordinary colorimetric method, which depends little on the measuring distance, emissivity of body etc. In this paper the real time measuring system and measuring principle of welding temperature field are described, the whole welding temperature field is real time measured, so the temperature distribution at the welding direction and its cross section is obtained, then parameters of thermal cycle. With data from the temperature closed loop control system of the parameters of temperature field is developed and tested. Experimental results prove that it has high measurement speed (time of a field within 0.5 s ) and good dynamic response quality. Weld penetration can be controlled satisfactorily under the variation of welding condition such as welding thickness, welding speed and weldment gap etc.
基金the Shandong Provincial Natural Science Foundation of China （No. Z2003F05 ）.
文摘Realizing of weld penetration control in gas tungsten arc welding requires establishment of a model describing the relationship between the front-side geometrical parameters of weld pool and the back-side weld width with sufficient accuracy. A neural network model is developed to attain this aim. Welding experiments are conducted to obtain the training data set （including 973 groups of geometrical parameters of the weld pool and back-side weld width） and the verifying data set （108 groups）. Two data sets are used for training and verifying the neural network, respectively. The testing results show that the model has sufficient accuracy and can meet the requirements of weld penetration control.
文摘To improve the penetrating ability and the welding quality of keyhole plasma arc welding, a novel penetration closed loop control system was established. In the system, welding current and plasma gas flow rate were selected as adjusting variables. The wavelet method was used to detect penetration status from welding arc voltage in real time. The control strategy of one keyhole per pulse was adapted to fulfill stable and high quality welding process. Experimental results show that the developed system can apparently increase the penetrating force of plasma arc and keyhole plasma arc welding is realized successfully in stainless steel with 10 mm in thickness. Moreover, the disturbances of gradual change and break change from 3 mm to 6 mm in thickness are come over due to the good response property of the developed system.
文摘This paper presents a technique for controlling the pressure of a molten metal when using a new type of iron casting method called sand mold press casting to realize high productivity and obtain high-quality products.The past test results using this method showed a casting yield of 90% to 95%,while conventional methods only show a casting yield of 60% to 70%.Although the press casting method does not require a sprue cup or runner channel casting defects such as metal penetration are often caused by the high pressure in the high-velocity pressing part of this casting process.Therefore,we proposed a pressure control method with a mathematical model of molten metal pressure,and with it we achieved experimental confirmation of the successful production of brake drums at different pressing temperatures.Results show that the proposed pressing control method can realize sound,penetration-free casting production.However,the theoretical analysis and design of this pressing process had not previously been studied sufficiently,and therefore this paper presents the theoretical design algorithm for the process as well as its experimental confirmation.
文摘An intelligent system including both a neural network(NN) and a self adjusting fuzzy controller(FC) for modeling and control of the penetration depth during gas tungsten arc welding(GTAW) process is presented in this paper. The discussion is mainly focused on two parts. One is the modeling of the penetration depth with NN. A visual sensor CCD is used to obtain the image of the molten pool. A neural network model is established to estimate the penetration depth from the welding current, pool width and seam gap. It is demonstrated that the proposed neural network can produce highly complex nonlinear multi variable model of the GTAW process that offer the accurate prediction of welding penetration depth. Another is the control for the penetration depth with FC.A self adjusting fuzzy controller is proposed,which used for controlling the penetration depth.The control parameters are adjusted on line automatically according to the controlling errors of penetration and the errors can be decreased sharply. The effectiveness of the proposed intelligent methods is demonstrated by the real experiments and the improved performance results are obtained.
文摘The influence of plate thickness on the penetration in GTAW was investigated and a theoretical heat flow model for a plate of finite thickness has been utilized to investigate the relationship between front and back pool widths.Then,front pool width penetration control approach approach has been studied, which controls penetration under the variation of plate thickness.A penetration control system for autogenous GTA welding has been utilized which includes a coaxial weld pool imaging system and computer vision processing system to sense the front width of the GTA weld pool.Empirical results show the good performance of this penetration control approach in the presence of variations in joint plant thickness of 1 mm 0.04 inch) to 3 mm(0.125 inch)
文摘Presents penetration control by weld pool resonance which occurs when the natural frequency of weld pool is equal to the frequency of sine wave current while the weld pool is excited into oscillation by superimposing sine wave current with definite frequency or regular frequency on DC current, and experiments carried out on detecting resonance signals during both stationary and travelling arc welding with variant frequency pulse current, and concludes with experimental results that penetration control can be realized by weld pool resonance when welding speed is lower than 80mm/min, and this control method is applicable to welding thin (0.5～3.0 mm) plates of carbon steel, low alloy steel, high strength steel and superhigh strength steel, and suitable for alternating polarity welding of stainless steel, titanium alloy steel and aluminum alloy.
文摘A integrated intelligent system for seam tracking and penetration control is given. The system received information of welding seam error and penetration depth from only one sensor, then, it realized seam tracking and penetration control simultaneously. This paper introduces constitution of the system, methods of information recognition, design of the neural fuzzy controller and results practically.
文摘A three dimensional analytical model for heat conduction in a plate of finite size with a Gaussian distributed moving heat source, is obtained using the Heat Cumulating Principle and the Method of Image in arc welding, and an estimated method of back width of seam is introduced by making use of the model and the measured top face information of temperature field . To prove the validity of the model, a series of GTA bead on plate welding were performed on a medium carbon steel under various welding conditions, the experimental results show that the theoretical prediction can provide acceptable accuracy, so the next penetration control will be based on the model.
基金supported by the Natural Science Foundation of Jiangsu Province,China(No.BK20220945)。
文摘The rapid development of the anti-missile weapon technology brings new challenges to the cooperative penetration strategy solution and the guidance law design for Hypersonic Vehicles(HVs).This paper studies the coordinated game penetration guidance problem for multiple hypersonic vehicles faced with space threat areas.A scheme for seeking cooperative game penetration guidance strategy under safety critical control framework is presented.In this scheme,a multiHV cooperative game model is proposed in a minimum optimization form which can simplify the solving process and accelerate the computing speed.Then,a second-order control barrier function is developed to transform the implicit nonlinear constraints of the proposed model into linear ones.In order to obtain better performance of guidance strategy,a composite guidance law under the safety critical control framework is presented to allocate guidance strategies appropriately in the whole process.It is shown that the proposed scheme can guarantee successful penetration while avoiding threat areas.Finally,a comparative simulation with a two-on-three game is conducted to verify the effectiveness of the proposed method.
文摘某些垃圾填埋场由于相关资料严重缺失,给污染物的治理工作带来了困难。为了解决老垃圾填埋场的污染物治理问题,将高密度电法和探地雷达法相结合,对某村老垃圾填埋场进行了全方位探查,取得了以下成果:1)成功识别出垃圾与原位土层的界线,得到了垃圾层的范围和厚度,并以此为基础计算出回填方量为132454 m ^(3),为污染物的清除和治理提供了重要的参考;2)依据电阻率的分布,划分出填埋物的种类主要为建筑垃圾、生活垃圾或者粪便;3)识别出垃圾渗液的污染范围,圈定需要隔绝污染和回收清洁土壤的位置。本次研究结果为今后的垃圾治理工作提供了重要的参考。
