Tungsten Inert Gas (TIG) arc is the most widely employed type of a plasma torch and enables to produce arc plasma with high energy density. Therefore it is suitable as a heat source especially for processes to require...
详细信息
ISBN:
(纸本)9783540733737
Tungsten Inert Gas (TIG) arc is the most widely employed type of a plasma torch and enables to produce arc plasma with high energy density. Therefore it is suitable as a heat source especially for processes to require concentrating the heat input at a point. On the other hand, Tube Cathode Arc (TCA) to be a kind of TIG produces the arc plasma by introducing inner shielding gas through the central hole of the tube cathode. In this paper, as the basic heat source property of argon (Ar) TCA, the property of the arc plasma and the heat input intensity onto a water-cooled copper anode for various inner shielding gas flow rates were numerically analyzed. Furthermore, by employing stainless steel SUS304 anode, the geometry of it's weld penetration was also predicted. The results were compared with those for the conventional TIG. As a result, it was found that since TCA enables to heat the target material uniformly by controlling the inner shielding gas flow rate and preserve it from damage due to excessive heat input during the process, it is suitable for processes such as brazing, buildup or thermal spraying.
Currently, widespread clinical application of medical robots is hindered by not only low security and operation efficiency but also the high cost for robot control system. In response, a framework of medical robot con...
详细信息
ISBN:
(纸本)9783540733737
Currently, widespread clinical application of medical robots is hindered by not only low security and operation efficiency but also the high cost for robot control system. In response, a framework of medical robot control system based on PLC was presented according to the clinical requirement of medical robot. In terms of the design process of function analysis, the hardware and software structures were confirmed. Based upon the concern of safety problems that the operation system of medical robot was confronted with, the safety strategy performed in the system and orientation precisions of the system were discussed in detail. The specific safety schemes responding to the above problems were put forward. Clinical experimentations were accomplished in the Neurosurgery Institute of General Navy Hospital. The stable performance was verified.
The stabilization problem of nonholonomic mobile robots that move on uneven surface is investigated. Smooth control laws ensuring practical stabilization are proposed based on the transverse function approach and the ...
详细信息
ISBN:
(纸本)9783540733737
The stabilization problem of nonholonomic mobile robots that move on uneven surface is investigated. Smooth control laws ensuring practical stabilization are proposed based on the transverse function approach and the integrator backstepping technique. Firstly, a transverse function which defines a smooth embedded submanifold is constructed, and an augmentation procedure is applied to the kinematic model of the robots. Then, the left-invariance property of the kinematic model is explored, and after the defining of the error variables via group operation, smooth exponential stabilizing control laws are derived for the error dynamic system, thus the kinematic model is rendered practically stable. Finally, the obtained control laws are utilized in the integrator backstepping process to stabilize the dynamic model. Simulations are provided to demonstrate the effectiveness of the algorithm.
A fuzzy controller (FC) was developed to improve deposit dimension accuracy in spray forming process, fuzzy rules of FC were extracted from experimental sample data by dynamic clustering method. Simulation results sho...
详细信息
ISBN:
(纸本)9783540733737
A fuzzy controller (FC) was developed to improve deposit dimension accuracy in spray forming process, fuzzy rules of FC were extracted from experimental sample data by dynamic clustering method. Simulation results show that fuzzy controller is available to regulate deposit dimension, main advantage of FC is it has a stronger adaptability for nonlinear process control than PID controller, and FC of identical structure has satisfying control performance for different predetermined target values. FC closed-loop control experimental results show that average deposit thickness is 5.22m in steady growth period, average error between actual size and 5.5mm target value is 0.28mm, and RMS (mean square root) is 0.31mm.
A class of two-parameter Poisson-Dirichlet distributions have non-vanishing coefficient of variation. This phenomenon is also known as non-self averaging stochastic multi-sector endogenous growth model. This model is ...
详细信息
ISBN:
(纸本)9783540735694
A class of two-parameter Poisson-Dirichlet distributions have non-vanishing coefficient of variation. This phenomenon is also known as non-self averaging stochastic multi-sector endogenous growth model. This model is used to raise questions on the use of means in assessing effectiveness of macroeconomic or other macro-policy effects. The coefficients of variations of the number of total sectors, and of sectors of a given size all remain positive as the model size grows unboundedly.
An open problem, set by *** in his contribution to the volume "Open Problems in Mathematical Systems and control Theory", ***, *** Eds., 2004, regards regularization of optimal control-affine problems with c...
详细信息
ISBN:
(纸本)9783540738893
An open problem, set by *** in his contribution to the volume "Open Problems in Mathematical Systems and control Theory", ***, *** Eds., 2004, regards regularization of optimal control-affine problems with control-independent state-quadratic cost. It is asked whether the infima of the regularized (by adding squared L-2-norm of controls) functionals converge to the infimum of the original functional? We show that this question can be resolved by an elementary argument. We claim that one should study minimizing sequences of the original functional, rather than its infimum. We advocate the relevance of this question, formulating it via notion of order of singularity of an optimal problem. We study this question and provide computations of the order of singularity for arbitrary singular linear-quadratic problem and also for some classes of nonlinear control-affine problems. Some open problems are,set.
A real-time automatic inspection algorithm of weld defects in X-ray images was developed in this paper. Using optimized image smoothing and image information fusion based heuristic best-first search techniques, the al...
详细信息
ISBN:
(纸本)9783540733737
A real-time automatic inspection algorithm of weld defects in X-ray images was developed in this paper. Using optimized image smoothing and image information fusion based heuristic best-first search techniques, the algorithm can detect different kinds of defects in weld, such as slag inclusion, blow hole, incomplete penetration, lack of fusion and undercut etc. Experiments show that the algorithm is efficient, reliable and can be used for industrial purpose.
An intelligent waveform control system with micro-controller is developed for robotic high-speed CO2 arc welding. In order to resolve the problems of bad weld formation and heavy spatter in high-speed CO2 arc welding,...
详细信息
ISBN:
(纸本)9783540733737
An intelligent waveform control system with micro-controller is developed for robotic high-speed CO2 arc welding. In order to resolve the problems of bad weld formation and heavy spatter in high-speed CO2 arc welding, A new method of welding current waveform control is investigated, which controls the short-circuit current and its rising rate in short-circuit period, and adopts the two-step constant current control to adjust the arc energy in arc period. The control principle of the method is discussed, the system structure and the control software are introduced, and the optimized waveform control parameters are provided by experiments. The results show that this system can precisely control the arc energy by the two-step constant current method and improves the performance of high-speed welding process obviously.
In vision-based robotic arc welding had some degree of autonomy functions, sensors must be used to detect the position and orientation of a weld seam and determine its path in order to carry out the autonomy of weldin...
详细信息
ISBN:
(纸本)9783540733737
In vision-based robotic arc welding had some degree of autonomy functions, sensors must be used to detect the position and orientation of a weld seam and determine its path in order to carry out the autonomy of welding process. This paper represented a method to recognize whole seam in complex robotic welding environment. According to the parameter we defined to judge the degree of image noise, then different size of filter windows were selected to preprocess the image. Algorithm to eliminate effect of complex changing background is proposed. Parameters are defined to judge if it is necessary to use this algorithm. The threshold and edge detect algorithms that adapt to the recognition for robotic welding environment is also addressed in this paper. The experiments give the recognition results of two different shapes and material of seams. The results showed that the recognized method was robust to the recognition of macroscopic seam for complex robotic welding environment.
The unfitness of weld and gap variation are salient using traditional TIG procedure for the five-port connector flange. Insufficient reliability and the instability of the weld are catastrophe, which cannot accommodat...
详细信息
ISBN:
(纸本)9783540733737
The unfitness of weld and gap variation are salient using traditional TIG procedure for the five-port connector flange. Insufficient reliability and the instability of the weld are catastrophe, which cannot accommodate to new generation type production's requirement. In this study, a finite element model of the five-port connector was built and the distribution of temperature field and deformation were studied. The result shows that welding thermal cycle is greatly different from the ordinary butt weld during welding of the flange and spherical shell. The welding deformation is complex from the direction of UX and UZ. Especially maximum deformation from the direction of UZ is about 4.96mm. According to the result, the optimum welding fixture is designed on the view of the smallest deformation, to critically control the deformation of the both sides of the welding line, finally to accomplish the robotic flexible welding.
暂无评论