Generative design using Lindenmayer-systems and numerical optimization

Joubert, Izak Johannes (2020-03)

Thesis (MEng)--Stellenbosch University, 2020.

Thesis

ENGLISH ABSTRACT: Traditional methods of generative design for structural design applications typically utilise finite element analysis or other resource intensive methods. A more efficient method of design generation is needed in order for generative design to be utilised for these applications. A generative design method is presented, utilising reduced-order modelling, Lindenmayer-systems and numerical optimisation. Through the use of recursive design techniques, this method reduces the computational cost of generating structural designs and through numerical optimisation is capable of developing targeted designs, using a genetic algorithm. This method was applied to generate soft robotic bending actuator designs. The actuator is assembled from 15 modular cells and targeted for maximum bending, vertical and horizontal extension. An idealised reduced-order model is developed for the modular cells and reduced the evaluation runtime of the designs by a factor of approximately 6600. In all target objectives, the generated designs produced comparable results to a full 3D nite element model. Soft robotic bending actuator designs for grasping various different objects were also developed. Grasping was prescribed through curve ftting of the actuator to the object. All designs generated exhibited successful grasping of the objects of different sizes and positioned at different locations.

AFRIKAANSE OPSOMMING: Tradisionele generatiewe ontwerp metodes vir strukturele ontwerpe maak tradisioneel gebruik van eindige elementanalise of ander hulpbron intensiewe metodes. 'n Meer effektiewe metode van ontwerp generering is nodig om generatiewe ontwerp vir hierdie toepassings te gebruik. 'n Generatiewe ontwerp metode word ontwikkel met behulp van verminderdeorde modellering, Lindenmayer-stelsels en numeriese optimering. Deur gebruik te maak van rekursiewe ontwerp tegnieke verminder hierdie metode die berekenings koste van die generering van strukturele ontwerpe en deur numeriese optimering is dit in staat om doelgerigte ontwerpe te ontwikkel met behulp van 'n genetiese algoritme. Hierdie metode is toegepas om sagte robot buig toestel ontwerpe te genereer. Die buig toestel is saamgestel uit 15 modulêre eenhede en is gemik op maksimum buig-, vertikale en horisontale verlenging te bekom. 'n Geïdealiseerde beperkte orde model word vir die modulêre eenhede ontwikkel wat die evalueringstyd van die ontwerpe verminder met 'n faktor van ongeveer 6600. In al die gevalle het die gegenereerde ontwerpe vergelykbare resultate gelewer met 'n volledige 3D-eindige elementmodel. Sagte robot buig toestel ontwerpe vir die gryp van verskillende voorwerpe is ook ontwikkel. Gryping is voorgeskryf deur die liggaam van die buig toestel op die voorwerp te pas met behulp van krommepassing. Al die ontwerpe wat gegenereer is, het die voorwerpe, van verskillende groottes en op verskillende plekke geposisioneer, suksesvol aangegryp.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/108235
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