Modular control of a reconfigurable conveyor system

Kotze, Marcus J. (2016-12)

Thesis (MEng)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: This thesis documents research into the control of a reconfigurable conveyer system. The conveyer forms part of a reconfigurable assembly system. The main reason for research into reconfigurable systems is the need in the modern manufacturing industry for systems to be adaptable to changing product designs. Modern manufacturing requires many short production runs of different products, instead of the traditional long term production run of a standard product. The objective of this thesis was to design and implement a controller for a reconfigurable conveyer system. The conveyer hardware was fixed, but the control system had to be developed. A distributed control architecture was chosen. The conveyer was sectioned into different modules, and each module was controlled by a separate controller. This modularity enhanced the conveyer’s reconfigurability properties. The control was split into two sections, low level control (LLC) and high level control (HLC). LLC was responsible for the actuation of the conveyer’s hardware, using programmable logic controllers (PLCs). The HLC did more advanced tasks such as communication, task management and path planning. The software design was based on a modified ADACOR holonic architecture. The holonic architecture was used because it promotes reconfigurability. Path planning was done using Dijkstra’s algorithm. Experimental results show that the conveyer was able to successfully handle multiple pallets. A reconfiguration test was done, which showed improved results from previous work. The design mostly exhibits the characteristics of reconfigurability, which are modularity, customizability, scalability, integratibilty and diagnosability.

AFRIKAANSE OPSOMMING: Hierdie tesis dokumenteer navorsing oor die beheer van ‘n herkonfigureerbare vervoerbandstelsel. Die vervoerband vorm deel van ‘n herkonfigureerbare vervaardiging stelsel. Die hoofrede vir die navorsing in herkonfigureerbare stelsels is die behoefte in die moderne vervaardigingsbedryf aan stelsels wat aanpasbaar kan wees vir veranderinge in produk-ontwerpe. Moderne vervaardiging vereis kort produksie lopies van verskillende produkte, in plaas van ‘n tradisionele langtermyn produksie lopie van ‘n standaard produk. Die doel van hierdie tesis was om ‘n beheerder vir ‘n herkonfigureerbare vervoerbandstelsel te ontwerp en implementeer. Die vervoerband hardeware was vooraf bepaal, maar die beheerstel moes ontwikkel word. ‘n Verspreide beheerargitektuur is gekies. Die vervoerband is verdeel in verskillende modules, en elke module is deur ‘n afsonderlike beheerder beheer. Die modulariteit van die ontwerp het die herkonfigureerbaarheid van die stelsel versterk. Die beheer was verdeel in twee gedeeltes, lae-vlak-beheer (LVB) en hoë-vlakbeheer (HVB). LVB was verantwoordelik vir aktueer van die vervoerband se hardeware, deur middel van programmeerbare-logika-beheerders (PLBs). Die HVB het meer gevorderde take hanteer, soos kommunikasie, taakbestuur en roetebeplanning. Die sagteware-ontwerp was gebaseer op ‘n aangepaste ADACOR holoniese argitektuur. Die holoniese argitektuur was gebruik omdat dit herkonfigureerbaarheid bevorder. Roete-beplanning was gedoen deur die gebruik van Dijkstra se algoritme. Eksperimentele resultate dui daarop dat die vervoerband veelvuldige pallette suksesvol kon hanteer. ‘n Herkonfigurasie toets is gedoen, wat verbeterde resultate getoon het in vergelyking met vorige navorsing. Die ontwerp vertoon in die meeste opsigte die eienskappe van herkonfigureerbaarheid, naamlik modulariteit, aanpasbaarheid (flexibility), skaleerbaarheid, integreerbaarheid en diagnoseerbaarheid.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/100171
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