Advanced Knowledge Application in Practice

The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research

Time Localization of Abrupt Changes in Cutting Process using Hilbert Huang Transform

Cutting process is extremely dynamical process influenced by different phenomena such as chip formation, dynamical responses and condition of machining system elements. Different phenomena in cutting zone have signatures in different frequency bands in signal acquired during process monitoring. The time localization of signal’s frequency content is very important. An emerging technique for simultaneous analysis of the signal in time and frequency domain that can be used for time localization of frequency is Hilbert Huang Transform (HHT). It is based on empirical mode decomposition (EMD) of the signal into intrinsic mode functions (IMFs) as simple oscillatory modes. IMFs obtained using EMD can be processed using Hilbert Transform and instantaneous frequency of the signal can be computed. This paper gives a methodology for time localization of cutting process stop during intermittent turning. Cutting process stop leads to abrupt changes in acquired signal correlated to certain frequency band. The frequency band related to abrupt changes is localized in time using HHT. The potentials and limitations of HHT application in machining process monitoring are shown

Austenitization of Ultra High Strength Steel by Direct Contact Heating for Hot Forming Die Quenching

Hot forming die quenching (HFDQ) is a heat treatment process used in automotive manufacturing to produce ultra-high strength steels. It involves heating steel sheets to a temperature above 1153 K and holding them for a period of time to ensure that the microstructure has fully transformed to austenite. Rapid quenching is subsequently performed to insure the austenite-martensite transformation of the steel crystallographic structure. The improved strength of these steels allows automotive manufacturers to use thinner sheets for structural members, resulting in reduced net vehicle weight and improved fuel efficiency without compromising safety performance. Austentization is mainly done using roller hearth furnaces, but the high energy requirements, slow heating time, and large production space has motivated investigation of direct contact heating as an alternative strategy. Previous work using a small scale prototype produced austenitized steel coupons in less than 25 seconds, and accomplished tailored microstructures within a coupon by use of different thermal effusivities in the die striking surface. Even though the striking surface is isothermal, the differing thermal properties of the steel and ceramic provide nonuniform heating over the blank and incomplete austenitization, leading to bainitic regions in the formed part. This method may be easier to control compared to other tailoring procedures, which focus on slower and nonuniform cooling during the quenching stage. This thesis builds upon the previous work and describes the design and fabrication of an electrically-fired, half scale industrial sized direct contact heating die with tailoring capabilities. The die was installed alongside a flat quenching die, with a transfer system between them, all encompassed within a 900 ton press. An FEM simulation was used to design the direct contact heating die. The model also included a constitutive metallurgical submodel, derived from Gleeble dilatometry measurements, that was used to predict heating and austenitization kinetics of the blank. Model predictions were confirmed using thermocouple measurements recorded during HFDQ, and metallurgical and microstructural analysis of formed blanks. The austenitization model allows for future optimization in the striking surface design as well as the performance of heat treated ultrahigh strength steels

Optimization of Operation Sequencing in CAPP Using Hybrid Genetic Algorithm and Simulated Annealing Approach

In any CAPP system, one of the most important process planning functions is selection of the operations and corresponding machines in order to generate the optimal operation sequence. In this paper, the hybrid GA-SA algorithm is used to solve this combinatorial optimization NP (Non-deterministic Polynomial) problem. The network representation is adopted to describe operation and sequencing flexibility in process planning and the mathematical model for process planning is described with the objective of minimizing the production time. Experimental results show effectiveness of the hybrid algorithm that, in comparison with the GA and SA standalone algorithms, gives optimal operation sequence with lesser computational time and lesser number of iterations

Optimization of Operation Sequencing in CAPP Using Hybrid Genetic Algorithm and Simulated Annealing Approach

In any CAPP system, one of the most important process planning functions is selection of the operations and corresponding machines in order to generate the optimal operation sequence. In this paper, the hybrid GA-SA algorithm is used to solve this combinatorial optimization NP (Non-deterministic Polynomial) problem. The network representation is adopted to describe operation and sequencing flexibility in process planning and the mathematical model for process planning is described with the objective of minimizing the production time. Experimental results show effectiveness of the hybrid algorithm that, in comparison with the GA and SA standalone algorithms, gives optimal operation sequence with lesser computational time and lesser number of iterations

Autonomous Navigation of Automated Guided Vehicle Using Monocular Camera

This paper presents a hybrid control algorithm for Automated Guided Vehicle (AGV) consisting of two independent control loops: Position Based Control (PBC) for global navigation within manufacturing environment and Image Based Visual Servoing (IBVS) for fine motions needed for accurate steering towards loading/unloading point. The proposed hybrid control separates the initial transportation task into global navigation towards the goal point, and fine motion from the goal point to the loading/unloading point. In this manner, the need for artificial landmarks or accurate map of the environment is bypassed. Initial experimental results show the usefulness of the proposed approach.COBISS.SR-ID 27383808

Autonomous Navigation of Automated Guided Vehicle Using Monocular Camera

This paper presents a hybrid control algorithm for Automated Guided Vehicle (AGV) consisting of two independent control loops: Position Based Control (PBC) for global navigation within manufacturing environment and Image Based Visual Servoing (IBVS) for fine motions needed for accurate steering towards loading/unloading point. The proposed hybrid control separates the initial transportation task into global navigation towards the goal point, and fine motion from the goal point to the loading/unloading point. In this manner, the need for artificial landmarks or accurate map of the environment is bypassed. Initial experimental results show the usefulness of the proposed approach.COBISS.SR-ID 27383808