Achieving resilience for cyber-physical systems with 4DIAC IEC 61499 through parametric contracts

• Main Author: Ng, Daniel Jun Xian
• Other Authors: Arvind Easwaran
• Format: Thesis-Master by Research
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Computer science and engineering::Computer applications::Computers in other systems
• Online Access: https://hdl.handle.net/10356/137595
• Institution: Nanyang Technological University

Industry 4.0 has garnered much interest in traditional manufacturing setups to play catch up with the state-of-the-art. This fourth industrial revolution has caused a proliferation of computing devices and sensors onto the factory floor. This proliferation has also caused a paradigm shift in the designing of the plant supervisory management control systems such as Supervisory Control and Data Acquisition, which traditionally controls the automation systems for manufacturing plants and manages the fault recovery mechanisms. With this said, the fourth industrial revolution requires a new framework to improve resiliency in these systems to account for a large number of interconnected devices in a Cyber-Physical System (CPS). Software-based resilience solutions can provide the necessary flexibility in dealing with failures to reduce downtime and the need for human intervention. We present a contract-based resilience framework for CPS that incorporates Assume-Guarantee contracts to define the user requirements of the CPS. These contracts describe the non-functional requirements which the system is expected to meet and provides a threshold for triggering an alarm (i.e., a fault occurrence). The top-level contract (i.e., root contract) represents the overall requirement of the system, and this necessitates decomposition, which is the process of decomposing the root contract into smaller sub-contracts. The decomposed sub-contracts represent the requirements asked of the different interconnected components in the system. The framework also has observers which serve to check for violations of the sub-contracts and Resilience Managers (RMs) who manage the set of sub-contracts. Together, RMs and observers form a logical hierarchy for decentralized fault monitoring of the entire CPS. A Fischertechnik Sorting Line with Color Detection training model, which represents a factory's assembly line, as well as an industrial Festo Didactic Cyber-Physical Factory, are used to demonstrate the capabilities of the resilience framework. Both the control logic and resilience framework of the assembly line use an open-source platform, 4DIAC, which is a Programmable Logic Controller framework for distributed industrial control based on the International Electrotechnical Commission 61499 standard. The process described above would require a great deal of manual work if it were to be done for a large-scale CPS. As part of our contribution, we present an automated way of generating the contract hierarchy and deploying it on 4DIAC. This process starts from defining the user requirements, which is in the form of a root contract, and the hardware information of the CPS in an AutomationML (AML) file. Then, the information from the AML file is used to decompose the root contract into a hierarchy of sub-contracts. The entire process completes when we port the decomposed contracts onto the 4DIAC platform by generating the function blocks for resilience management (i.e., RM and observer blocks). The user can then download the function blocks onto its associated hardware for deployment. Finally, we demonstrate the framework on an industrial testbed to showcase the framework with better interoperability. This master's report presents the translation of a resilience framework into reality.