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The objective of this dissertation is to design a concept that would allow to increase the flexibility of currently available Time Triggered Ethernet based (TTEB) systems, however, without affecting their performance and robustness. The main challenges are related to scheduling of time triggered communication that may take significant amount of time and has to be performed on a powerful platform. Additionally, the reliability has to be considered and kept on the required high level. Finally, the reconfiguration has to be optimally done without affecting the currently running system.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
The current technical processes in the industry are controlled by the Programmable Logic Controllers (PLCs), which connected together with Sensors and Actuators via network system form a Networked Control System (NCS)[1]. Depending on the type of technical process, requirements in terms of sampling rates of controlled processes and corresponding reaction times may differ [2]. They may require reaction times in the range of few milliseconds, in case of motion control applications, up to hundreds of milliseconds or more in case of process automation applications, such as control of biochemical processes.
Lukasz Wisniewski

Chapter 2. Fundamentals

Abstract
This chapter provides a general state of the art analysis that is relevant for this work. Section 2.1 gives an overview about the production systems and provides deep insights into NCSs build upon TTEB systems. Furthermore, in section 2.2 requirements in terms of real-time and reliability that have to be fulfilled by INS are discussed and summarised. Afterwards, in section 2.3, existing concepts to achieve deterministic and reliable realtime communication are described. Section 2.4 elaborates on the engineering process and all steps that have to be performed in order to bring an INS into work.
Lukasz Wisniewski

Chapter 3. Timeliness in Ethernet Based Network Control Systems

Abstract
This chapter provides a state of the art analysis for one of the three main contributions of this work that is an efficient and simple scheduling approach. Section 3.1 gives an overview about relevant industrial network topologies. Since in this work only Ethernet based communication technologies are considered in section 3.2 the Ethernet standard is briefly descried and in 3.3 its real-time capabilities are discussed.
Lukasz Wisniewski

Chapter 4. Communication Reliability

Abstract
The following chapter deals with the communication reliability methods in TTEB systems. In section 4 a general overview about redundancy methods is provided and two main redundancy namely dynamic and static are distinguished. Section 4.2 provides deep insights into dynamic redundancy methods and highlights their limitations.
Lukasz Wisniewski

Chapter 5. Seamless Reconfiguration of the Industrial Network System

Abstract
This chapter deals with the last step of the TTEB reconfiguration process that is an integration and activation of the newly calculated schedule into a system. A special focus is put on the fact that this process should not influence the currently running system in any case. In order to highlight all challenges and also to distinguish all necessary actions to be performed, section 5.1 is provided.
Lukasz Wisniewski

Chapter 6. Proposed Approach Evaluation

Abstract
In this chapter the proposed concept to increase flexibility of static TTEB INSs is evaluated. Since the proposed approach consists of three main contributions described in chapters 3 - 5, the evaluation will be also divided into three main parts. However, without loosing the validity of the whole approach.
Lukasz Wisniewski

Chapter 7. Conclusions and Outlook

Abstract
The aim of this dissertation is to increase flexibility of TTEB INSs by partly shifting the engineering process, including disjoint path search and communication scheduling to the field level. Since devices at this level have a limited processing power, the challenge is to develop algorithms and methods, which on one hand, have low time complexity, and on the other hand, allow to deliver a good and valid solution at the same time. Another challenge, is to deliver information required for the reconfiguration at the field level, without involvement of an engineering tool or necessity of performing manual operations.
Lukasz Wisniewski

Backmatter

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