Abstract: GMAW is a complete arc welding process of creating all types of metal joints of desirable qualityinvolving virtually all metals of any thickness in any position. However, in doing so, there is continuous shift inoperating point of arc and/or in arc characteristics leading to wide range parametric variations anddisturbances injected into the system. Moreover, the process involves multiple dynamical events such as in arccharacteristics, melting rate, dynamics of arc length and droplet transfer mechanism etc. for creating eventualwelding joints where each event suffers from non-linearity as well as parametric variations. Control of suchprocess optimally, though complex, but is essentially required as welding joints are made through indirectcontrol of operating point of arc where for certain events feedback signals are difficult to get. Sliding modecontrol (SMC) concepts are considered as robust and have the ability to reject external disturbances andgenerate parametric insensitive response characteristics. This article, using already established control laws,explores the ability of SOSM in GMAW with robust performance characteristics. Implementation along withresults of popular short-circuit mode of transfer is presented here.
Abstract: Welders in large numbers are engaged in manual shielded metal arc welding (SMAW) process to make mechanical joints in metals.Inputs to the process have multiple origin and specified joint characteristics are wide. Welder and controller are two active elements involvedin the process. Modern welding controllers have greatly simplified the role of welders in making good quality joints. However, in that processof technological evolution, essential aspects such as health hazards and welder friendliness have not been paid due attention. Processefficiency is also poor. The present article details, with detailed practical implementations, the extended role of power electronics controllerwith the help of selective use of sliding mode control (SMC) ideas for achieving conflict free multi-objective optimization program of theprocess. Traditional structure switching has been completely avoided for implementation of SMC.
Abstract: GMAW is a complete arc welding process. It is equipped to createall types of joints of desirable quality involving virtually all metals of anythickness in any position. However, in doing so there are parametric shifts inarc gap or load characteristics. Change in materials such as shielding gas, weldmetal and work piece etc. influence the operating point of the process.Moreover, the controller needs to ensure smooth starting, normal operation andalso its stopping where multiple dynamic activities such as melting rate, droplettransfer, re-ignition post short circuit and spatter rate are optimized. It is idealfor end users if one controller or equipment can have grip of control overactivities of entire process. This article explores practicability criteria ofpopular PI and SMC control ideas to inclusively achieve control over completeprocess requirement of GMAW to cater its application prospects
Abstract: Many processapplications of induction heating do nothave access to proper feedback for control ofoutput parameters. Itbecomes more complex in cap sealing whereusing non-uniformlydistributed heat input on aluminium foilsmultiple actions aresimultaneously executed to complete sealingoperations. Here morethan one parasitic output is present. It is anunder actuated process.Large variant in cap size at uncompromisedspeed of sealingrequirement causes serious problems forconsistent quality sealing.Under actuation is more noticeable whilesealing bottles of larger foilsize. This article analyzes the constraintsexisting in inductionsealing of bottles with wide range cap sizeand details the journey toresolve under actuation and achieve Paretooptimal solution of theprocessof high speed quality sealing using thin aluminium foils.
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