Predicting weld responses is a very important but difficult area in the field of welding which can greatly reduce the overall cost of try and error method for any fabrication industry. Fuzzy logic expert tool was used...Predicting weld responses is a very important but difficult area in the field of welding which can greatly reduce the overall cost of try and error method for any fabrication industry. Fuzzy logic expert tool was used to predict the weld penetration size factor of a weld. The aim of this study is to predict the weld penetration size factor (WPSF) of TIG mild steel welds using fuzzy logic. In this study, the weld specimens were produced using the TIG welding process guided by the central composite experimental design, and thereafter the weld penetration size factor (WPSF) was measured. The process parameters include the voltage, current, gas flow rate and welding speed. The model’s significance, strength and adequacy were checked;for fuzzy logic, fuzzification was done using fuzzy linguistic variable, fuzzy linguistic terms and membership function after which an inference was made based on a set of rules and the output result was defuzzified to a crisp output. Fuzzy logic predicted beyond the boundaries of the given range of parameters. The model developed has proven to be very effective in predicting responses even before actual weld is initiated.展开更多
In the recent decade,different researchers have performed hardware implementation for different applications covering various areas of experts.In this research paper,a novel analog design and implementation of differe...In the recent decade,different researchers have performed hardware implementation for different applications covering various areas of experts.In this research paper,a novel analog design and implementation of different steps of fuzzy systems with current differencing buffered amplifier(CDBA)are proposed with a compact structure that can be used in many signal processing applications.The proposed circuits are capable of wide input current range,simple structure,and are highly linear.Different electrical parameters were compared for the proposed fuzzy system when using different membership functions.The novelty of this paper lies in the electronic implementation of different steps for realizing a fuzzy system using current amplifiers.When the power supply voltage of CDBA is 2V,it results in 155mW,power dissipation;4.615KΩ,input resistance;366KΩ,output resistances;and 189.09 dB,common-mode rejection ratio.A 155.519 dB,voltage gain,and 0.76V/μs,the slew rate is analyzed when the power supply voltage of CDBAis 3V.The fuzzy system is realized in 20nm CMOS technology and investigated with an output signal of high precision and high speed,illustrating that it is suitable for realtime applications.In this research paper,a consequence of feedback resistance on the adder circuit and the defuzzified circuit is also analyzed and the best results are obtained using 100K resistance.The structure has a low hardware complexity leading to a low delay and a rather high quality.展开更多
模糊系统通过测量数据或数字传感器来获取反应输入和输出之间的映射关系,虽然它不依赖于精确的数学模型,但却具有逻辑推理、数值计算和对非线性函数的逼近能力。双输入单输出(Double input and single output,DISO)模糊系统的构造与逼...模糊系统通过测量数据或数字传感器来获取反应输入和输出之间的映射关系,虽然它不依赖于精确的数学模型,但却具有逻辑推理、数值计算和对非线性函数的逼近能力。双输入单输出(Double input and single output,DISO)模糊系统的构造与逼近是进一步研究多输入单(多)输出模糊系统的关键所在,本文将常规模糊推理机推广为一类正则蕴涵算子,并基于该蕴涵算子、参数单点模糊化和重心解模糊器等步骤构造三种DISO模糊系统,进而导出该模糊系统输入输出的解析表达式。展开更多
This paper presents a new Center of Gravity （COG） trajectory planning algorithm for a quadruped robot with redundant Degrees of Freedom （DOFs）. Each leg has 7 DOFs, which allow the robot to exploit its kinematic r...This paper presents a new Center of Gravity （COG） trajectory planning algorithm for a quadruped robot with redundant Degrees of Freedom （DOFs）. Each leg has 7 DOFs, which allow the robot to exploit its kinematic redundancy for various locomotion and manipu- lation tasks. Also, the robot can suitably adapt to different environment （e.g., passing through a narrow gap） by simply changing the body posture. However, the robot has significant COG movement during the leg swinging phase due to the heavy leg weights; the weight of all the four legs takes up 80% of the robot＇s total weight. To achieve stable walking in the presence of undesired COG movements, a new COG trajectory planning algorithm was proposed by using a combined Jacobian of COG and centroid of a support polygon including a foot contact constraint. Additionally, the inverse kinematics of each leg was solved by modified improved Jacobian pseudoinverse （mIJP） algorithm. The mIJP algorithm could generate desired trajectories for the joints even when the robot＇s leg is in a singular posture. Owing to these proposed methods, the robot was able to perform various modes of locomotion both in simulations and experiments with improved stability.展开更多
文摘Predicting weld responses is a very important but difficult area in the field of welding which can greatly reduce the overall cost of try and error method for any fabrication industry. Fuzzy logic expert tool was used to predict the weld penetration size factor of a weld. The aim of this study is to predict the weld penetration size factor (WPSF) of TIG mild steel welds using fuzzy logic. In this study, the weld specimens were produced using the TIG welding process guided by the central composite experimental design, and thereafter the weld penetration size factor (WPSF) was measured. The process parameters include the voltage, current, gas flow rate and welding speed. The model’s significance, strength and adequacy were checked;for fuzzy logic, fuzzification was done using fuzzy linguistic variable, fuzzy linguistic terms and membership function after which an inference was made based on a set of rules and the output result was defuzzified to a crisp output. Fuzzy logic predicted beyond the boundaries of the given range of parameters. The model developed has proven to be very effective in predicting responses even before actual weld is initiated.
文摘In the recent decade,different researchers have performed hardware implementation for different applications covering various areas of experts.In this research paper,a novel analog design and implementation of different steps of fuzzy systems with current differencing buffered amplifier(CDBA)are proposed with a compact structure that can be used in many signal processing applications.The proposed circuits are capable of wide input current range,simple structure,and are highly linear.Different electrical parameters were compared for the proposed fuzzy system when using different membership functions.The novelty of this paper lies in the electronic implementation of different steps for realizing a fuzzy system using current amplifiers.When the power supply voltage of CDBA is 2V,it results in 155mW,power dissipation;4.615KΩ,input resistance;366KΩ,output resistances;and 189.09 dB,common-mode rejection ratio.A 155.519 dB,voltage gain,and 0.76V/μs,the slew rate is analyzed when the power supply voltage of CDBAis 3V.The fuzzy system is realized in 20nm CMOS technology and investigated with an output signal of high precision and high speed,illustrating that it is suitable for realtime applications.In this research paper,a consequence of feedback resistance on the adder circuit and the defuzzified circuit is also analyzed and the best results are obtained using 100K resistance.The structure has a low hardware complexity leading to a low delay and a rather high quality.
文摘模糊系统通过测量数据或数字传感器来获取反应输入和输出之间的映射关系,虽然它不依赖于精确的数学模型,但却具有逻辑推理、数值计算和对非线性函数的逼近能力。双输入单输出(Double input and single output,DISO)模糊系统的构造与逼近是进一步研究多输入单(多)输出模糊系统的关键所在,本文将常规模糊推理机推广为一类正则蕴涵算子,并基于该蕴涵算子、参数单点模糊化和重心解模糊器等步骤构造三种DISO模糊系统,进而导出该模糊系统输入输出的解析表达式。
文摘This paper presents a new Center of Gravity （COG） trajectory planning algorithm for a quadruped robot with redundant Degrees of Freedom （DOFs）. Each leg has 7 DOFs, which allow the robot to exploit its kinematic redundancy for various locomotion and manipu- lation tasks. Also, the robot can suitably adapt to different environment （e.g., passing through a narrow gap） by simply changing the body posture. However, the robot has significant COG movement during the leg swinging phase due to the heavy leg weights; the weight of all the four legs takes up 80% of the robot＇s total weight. To achieve stable walking in the presence of undesired COG movements, a new COG trajectory planning algorithm was proposed by using a combined Jacobian of COG and centroid of a support polygon including a foot contact constraint. Additionally, the inverse kinematics of each leg was solved by modified improved Jacobian pseudoinverse （mIJP） algorithm. The mIJP algorithm could generate desired trajectories for the joints even when the robot＇s leg is in a singular posture. Owing to these proposed methods, the robot was able to perform various modes of locomotion both in simulations and experiments with improved stability.
