Simulation of multi-axis machining processes using z-mapping technique

Parameter selection in machining operations is curial for product quality and high productivity. Process parameters such as feed, spindle speed and depth of cuts are often chosen by trial-error methods. Mathematical models can be employed to predict the mechanics and the dynamics of the process. In this study, Z-mapping technique is utilized to simulate the process step by step by updating the workpiece according the given tool path where the cutter engagement areas are also determined. Using the numerical generalized process model, whole process is simulated for any milling tool geometry including intricate profiling tools, serrated cutters and tools with variable edge geometries

Automatic triangulation positioning system for wide area coverage from a fixed sensors network

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonIn a wide area that many Transmitters (TRs) operate, systems of Fixed Sensors (FS) might be used in order to detect them and find TRs position. The detection and the accurate location of a new TR entering in the area frequently can be missed if the system fails to triangulate accurately the relative readings and analyze the changes in the received data. Additionally, there are cases that a Triangulation Station Network (TSN) can detect the heading as well as the transmitter’s position wrong. This thesis presents the design of a Sensors Network (FSN) system which is able to interact with a user, and exploit the relative data of the Sensors (SRs) in real time. The system performs localization with triangulation and the SRs are detect only TRs bearing data (range free). System design and algorithms are also explained. Efficient algorithms were elaborated and the outcomes of their implementation were calculated. The system design targets to reduce system errors and increase the accuracy and the speed of detection. Synchronously and through interaction with the user and changes of relative settings and parameters will be able to offer the user accurate results on localization of TRs in the area minimizing false readings and False Triangulations (FTRNs). The system also enables the user to apply optimization techniques in order to increase the system detection rate and performance and keep the surveillance in the Field of Interest (FoI) on a high level. The optimization methodology applied for the system proves that the FSN system is able to operate with a high performance even when saturation phenomena appear. The unique outcome of the research conducted, is that this thesis paves the way to enhance the localization via Triangulation for a network of Fixed Sensors with known position. The value of this thesis is that the FSN system performs bearing only detection (Range free) with a certain accuracy and the Area of Interest (AOI) is covered efficiently

The Computational Complexity of Knot and Link Problems

We consider the problem of deciding whether a polygonal knot in 3-dimensional Euclidean space is unknotted, capable of being continuously deformed without self-intersection so that it lies in a plane. We show that this problem, {\sc unknotting problem} is in {\bf NP}. We also consider the problem, {\sc unknotting problem} of determining whether two or more such polygons can be split, or continuously deformed without self-intersection so that they occupy both sides of a plane without intersecting it. We show that it also is in NP. Finally, we show that the problem of determining the genus of a polygonal knot (a generalization of the problem of determining whether it is unknotted) is in {\bf PSPACE}. We also give exponential worst-case running time bounds for deterministic algorithms to solve each of these problems. These algorithms are based on the use of normal surfaces and decision procedures due to W. Haken, with recent extensions by W. Jaco and J. L. Tollefson.Comment: 32 pages, 1 figur

Complete coverage path planning in an agricultural environment

The problem of finding a collision-free path through a region has garnered a lot of research over the years. One branch of this is the problem of finding a path that completely covers a region. Solutions to the complete coverage path planning problem have applications in many different areas, such as search and rescue, automotive painting, and agriculture. In many cases, it is not sufficient to find any route that completely covers the field. It is desired that the path also be optimal so as to minimize certain costs. This is especially true in the agricultural environment. In the area of precision farming alone, the complete coverage path planning problem exists while performing many different operations, such as harvesting, seeding, spraying, applying fertilizer, and tillage. The fundamental concern of farmers is reducing the costs of running the farm. Since most farming costs ultimately depend on time in the field and area covered, the more efficient an operation can be completed, the lower the costs. Optimality is thus typically in terms of finding the shortest complete coverage path through the field. In this paper, we present an O(n2) algorithm for solving the optimal complete coverage problem on a field boundary with n sides. This multi-phase algorithm makes use of a plane-sweep algorithm to subdivide the field into smaller, trapezoidal regions. The optimal paths through the subregions are then calculated. Finally there is a merge phase where it is determined whether neighboring regions can be more efficiently covered if they were merged together than if they were left separate

ZCAP Research And Development: Final Report

ZCAP is a suite of terrain database correlation tools created by IST. This document is a report on the steps taken to meet the goals of handling a larger set of database formats, accessing the quality of terrain data contained in larger databases, and investigating approaches to improve the usability of the ZCAP correlation. The report details the results of the research and suggestions for future directions in terrain database research

Terrain Representation And Reasoning In Computer Generated Forces : A Survey Of Computer Generated Forces Systems And How They Represent And Reason About Terrain

Report on a survey of computer systems used to produce realistic or intelligent behavior by autonomous entities in simulation systems. In particular, it is concerned with the data structures used by computer generated forces systems to represent terrain and the algorithmic approaches used by those systems to reason about terrain