An evolutionary approach to the extraction of object construction trees from 3D point clouds

In order to extract a construction tree from a finite set of points sampled on the surface of an object, we present an evolutionary algorithm that evolves set-theoretic expressions made of primitives fitted to the input point-set and modeling operations. To keep relatively simple trees, we use a penalty term in the objective function optimized by the evolutionary algorithm. We show with experiments successes but also limitations of this approach

A new CNC programming method using STEP-NC

Novi metod programiranja numerički upravljanih mašina alatki, koji se javlja kao alternativa G kôdu (po standardu ISO6983), je protokol AP238, ili STEP-NC, po standardu ISO 10303. U radu je dato poređenje klasičnog (G kôd) i novog načina programiranja (STEP-NC), struktura opreme potrebne za novi metod programiranja, struktura programa i aktuelni scenariji za primenu protokola STEP-NC.A new programmnig method of CNC Machine tools, which is developing as an alternative to G code, is AP238 protocol or STEP-NC, according to ISO 10303 standard. In this paper, a comparation between classical (G code) and new way of programming (STEP-NC ) is given. A structure of ecquipment needed for new programming metod, program structure and current scenario for imlementation of STEP-NC are shown

A new CNC programming method using STEP-NC

Novi metod programiranja numerički upravljanih mašina alatki, koji se javlja kao alternativa G kôdu (po standardu ISO6983), je protokol AP238, ili STEP-NC, po standardu ISO 10303. U radu je dato poređenje klasičnog (G kôd) i novog načina programiranja (STEP-NC), struktura opreme potrebne za novi metod programiranja, struktura programa i aktuelni scenariji za primenu protokola STEP-NC.A new programmnig method of CNC Machine tools, which is developing as an alternative to G code, is AP238 protocol or STEP-NC, according to ISO 10303 standard. In this paper, a comparation between classical (G code) and new way of programming (STEP-NC ) is given. A structure of ecquipment needed for new programming metod, program structure and current scenario for imlementation of STEP-NC are shown

Prilagodljivi neuro-fazi model za predviđanje tehnoloških parametara

The main goal of each technologist is the prediction of technological parameters by fulfilling the set design and technological demands. The work of the technologist is made easier by acquired knowledge and previous experience. A plan of input-output data was made by using the hybrid system of modelling ANFIS (Adaptive Neuro-Fuzzy Inference System) based on the results of seam tube production. This plan is the prerequisite for generating the system of fuzzy logic. The generated system can be used to estimate the output (speed of polishing) based on the given input (external tube diameter, oval shaping of the tube after the first phase of production, gradation of belts for grinding or polishing, condition of belts - time of usage, pressure of belts).The more precise predictions of technological time provided by the model supplement the previously defined manufacturing operations, replace the predictions based on the technologists\u27 experience and form the basis on which to plan production and control delivery times. The work of technologists is thus made easier and the production preparation technological time shorter.Procijeniti tehnološke parametre na način da se ispune postavljeni konstrukcijski i tehnološki zahtjevi cilj je i želja svakog tehnologa. Procjenu tehnologu mogu olakšati prikupljena znanja i ranije stečena iskustva. Na temelju sustavno prikupljenih podataka iz proizvodnje šavnih cijevi u radu je primjenom hibridnog sustava za modeliranje ANFIS (Adaptive Neuro-Fuzzy Inference System) oblikovan plan ulazno/izlaznih podataka. Taj je plan pretpostavka za generiranje sustava neizrazitog zaključivanja. Generirani sustav ima mogućnost procjene izlaza (brzine poliranja) na temelju danih ulaza (vanjski promjer cijevi, ovalnost cijevi nakon prve faze proizvodnje, gradacija remenja za brušenje ili poliranje, stanje remenja - vrijeme uporabe remenja, pritisak remenja). Točnije procjene tehnološkog vremena koje daje model upotpunjavaju prethodno definirane tehnološke operacije, zamjenjuje iskustvene procjene tehnologa i predstavljaju osnovu za planiranje proizvodnje i kontrolu rokova isporuke. Na ovaj se način olakšava rad tehnologa i skraćuje vrijeme tehnološke pripreme proizvodnje

Doctor of Philosophy

dissertationThree-dimensional (3D) rapid prototyping holds significant promise for future antenna designs. Many complex designs that would be unmanufacturable or costly are realizable on a 3D printing machine. The ability to create 3D designs of virtually any configuration makes it possible to build compact antennas that can form fit to any space. These antennas build on the concept that small antennas can best reach the ideal operating limit when utilizing the entire 3D space in a sphere surrounding the antenna. Antennas require a combination of dielectric and conductive materials. 3D rapid prototyping is already well advanced for plastics and dielectric materials (with more options coming online). Prototyping with conductive materials has lagged behind; due mainly to their higher melting points, but this is advancing as well. This dissertation focuses on 3D rapid prototyping for antenna design. A 3D antenna made from small cubical cells is optimized for 2.4-3GHz using a genetic algorithm (GA). The antennas are built using 3D printing of plastic covered by conductive paint. The effects of the conductivity of the paint and number of layers on the resonance and gain of the antenna are evaluated. These results demonstrate the feasibility of using 3D rapid prototyping for antenna design

Mobile collaborative working environment of product design

In response to the arrival of new Web/Internet environments, one of the most attractive challenges in current research is to exploit wireless computing technologies in collaborative product design, and hence to build a ubiquitous mobile information system to enable the collaborative product design within a mobile environment. However, the literature review reveals that although the progress of mobile technologies on wireless networks has largely changed the way people access the Internet; little has been achieved in mobile computing for collaborative product design. The reason is that, due to the distinct features of mobile devices and wireless networks (such as small display screen, limited bandwidth, unreliability of wireless networks, etc.), the methodologies and technologies used in stationary networks are not always applicable to mobile systems. The aim of this research is to establish a Wireless Internet-based Collaborative Working Environment for product design through the combination of multiple technologies, by including: Web services, Parametric Design, the Semantic Web, Agent and Flex Technologies. In order to create, deploy, and manage the distributed resources, Web service is used to implement design resource integration in a platform-independent manner. In addition, Semantic Web Technology is used to create a general knowledge base. This approach includes two components: (1) ontology is used to represent abstract views of product data and (2) added semantic rules are also used to represent relationships among product data. Therefore, an ontology-based description model is thus proposed to facilitate expression and organisation of product information in order to manage and deploy the distributed design resources

Internet-enabled fixture design system using case-based reasoning technology

Master'sMASTER OF ENGINEERIN

A new three phase method (SDP method) for the multi-objective vehicle routing problem with simultaneous delivery and pickup (VRPSDP)

Transportation service operators are witnessing a growing demand for bi-directional movement of goods. Given this, the following thesis considers an extension to the vehicle routing problem (VRP) known as the delivery and pickup transportation problem (DPP), where delivery and pickup demands may occupy the same route. The problem is formulated here as the vehicle routing problem with simultaneous delivery and pickup (VRPSDP), which requires the concurrent service of the demands at the customer location. This formulation provides the greatest opportunity for cost savings for both the service provider and recipient. The aims of this research are to propose a new theoretical design to solve the multi-objective VRPSDP, provide software support for the suggested design and validate the method through a set of experiments. A new real-life based multi-objective VRPSDP is studied here, which requires the minimisation of the often conflicting objectives: operated vehicle fleet size, total routing distance and the maximum variation between route distances (workload variation). The former two objectives are commonly encountered in the domain and the latter is introduced here because it is essential for real-life routing problems. The VRPSDP is defined as a hard combinatorial optimisation problem, therefore an approximation method, Simultaneous Delivery and Pickup method (SDPmethod) is proposed to solve it. The SDPmethod consists of three phases. The first phase constructs a set of diverse partial solutions, where one is expected to form part of the near-optimal solution. The second phase determines assignment possibilities for each sub-problem. The third phase solves the sub-problems using a parallel genetic algorithm. The suggested genetic algorithm is improved by the introduction of a set of tools: genetic operator switching mechanism via diversity thresholds, accuracy analysis tool and a new fitness evaluation mechanism. This three phase method is proposed to address the shortcoming that exists in the domain, where an initial solution is built only then to be completely dismantled and redesigned in the optimisation phase. In addition, a new routing heuristic, RouteAlg, is proposed to solve the VRPSDP sub-problem, the travelling salesman problem with simultaneous delivery and pickup (TSPSDP). The experimental studies are conducted using the well known benchmark Salhi and Nagy (1999) test problems, where the SDPmethod and RouteAlg solutions are compared with the prominent works in the VRPSDP domain. The SDPmethod has demonstrated to be an effective method for solving the multi-objective VRPSDP and the RouteAlg for the TSPSDP

Engine modelling for virtual mapping. Development of a physics based cycle-by-cycle virtual engine that can be used for cyclic engine mapping applications, engine flow modelling, ECU calibration, real-time engine control or vehicle simulation studies.

After undergoing a study about current engine modelling and mapping approaches as well as the engine modelling requirements for different applications, a major problem found to be present is the extensive and time consuming mapping procedure that every engine has to go through so that all control parameters can be derived from experimental data. To improve this, a cycle-by-cycle modelling approach has been chosen to mathematically represent reciprocating engines starting by a complete dynamics crankshaft mechanism model which forms the base of the complete engine model. This system is modelled taking into account the possibility of a piston pin offset on the mechanism. The derived Valvetrain model is capable of representing a variable valve lift and phasing Valvetrain which can be used while modelling most modern engines. A butterfly type throttle area model is derived as well as its rate of change which is believed to be a key variable for transient engine control. In addition, an approximation throttle model is formulated aiming at real-time applications. Furthermore, the engine inertia is presented as a mathematical model able to be used for any engine. A spark ignition engine simulation (SIES) framework was developed in MATLAB SIMULINK to form the base of a complete high fidelity cycle-by-cycle simulation model with its major target to provide an environment for virtual engine mapping procedures. Some experimental measurements from an actual engine are still required to parameterise the model, which is the reason an engine mapping (EngMap) framework has been developed in LabVIEW, It is shown that all the moving engine components can be represented by a single cyclic variable which can be used for flow model development

Empirical Control for Intelligent Robotic Systems – State-of-the-Art

Емпиријско управљање представља нов приступ у концепцијском пројектовању управљачких система мобилних робота и робота вертикалне зглобне конфигурације. У односу на конвенционалне приступе, емпиријски системи имају способност машинског учења на основу прикупљених информација из технолошког окружења, перманентно унапређујући своје понашање сходно постављеном задатку. У раду је дат детаљан преглед истраживања у овој области са посебним освртом на развој и имплеметацију емпиријских управљачких система на бази машинског Q-учења ојачавањем и soft computing техника вештачке интелигенције. Извршена је анализа актуелних праваца истраживања са становишта карактеристичних проблема управљања роботских система (проблем навигације, избегавања препрека, праћења зида технолошког окружења, и/или визуелног навођења). Сваки од презентованих истраживачких резултата је укратко описан, са јасно наглашеном предношћу примене теорије емпиријског управљања у процесу концепцијског пројектовања управљачких система.Empirical control presents a new approach in the domain of the conceptual design of the control systems for mobile robots and robot manipulators. Compared to the conventional design methods, empirical control systems have the ability to learn based on the information obtained from the environment, continuously improving robot’s behaviour. This paper presents a review on current research results, with emphasis on control systems based on the Q-learning algorithm and soft computing techniques. Comparative analysis has been conducted in terms of common robot-based and vision-based tasks. Described algorithms and experimental evaluations in real world clearly points out the advantages of implementation of the empirical theory in the conceptual design process of the control systems