Increasing System Test Coverage in Production Automation Systems

An approach is introduced, which supports a testing technician in the identification of possibly untested behavior of control software of fully integrated automated production systems (aPS). Based on an approach for guided semi-automatic system testing, execution traces are recorded during testing, allowing a subsequent coverage assessment. As the behavior of an aPS is highly dependent on the software, omitted system behavior can be identified and assessed for criticality. Through close cooperation with industry, this approach represents the first coverage assessment approach for system testing in production automation to be applied on real industrial objects and evaluated by industrial experts

Industrially Applicable System Regression Test Prioritization in Production Automation

When changes are performed on an automated production system (aPS), new faults can be accidentally introduced in the system, which are called regressions. A common method for finding these faults is regression testing. In most cases, this regression testing process is performed under high time pressure and on-site in a very uncomfortable environment. Until now, there is no automated support for finding and prioritizing system test cases regarding the fully integrated aPS that are suitable for finding regressions. Thus, the testing technician has to rely on personal intuition and experience, possibly choosing an inappropriate order of test cases, finding regressions at a very late stage of the test run. Using a suitable prioritization, this iterative process of finding and fixing regressions can be streamlined and a lot of time can be saved by executing test cases likely to identify new regressions earlier. Thus, an approach is presented in this paper that uses previously acquired runtime data from past test executions and performs a change identification and impact analysis to prioritize test cases that have a high probability to unveil regressions caused by side effects of a system change. The approach was developed in cooperation with reputable industrial partners active in the field of aPS engineering, ensuring a development in line with industrial requirements. An industrial case study and an expert evaluation were performed, showing promising results.Comment: 13 pages, https://ieeexplore.ieee.org/abstract/document/8320514

Modularity and Architecture of PLC-based Software for Automated Production Systems: An analysis in industrial companies

Adaptive and flexible production systems require modular and reusable software especially considering their long term life cycle of up to 50 years. SWMAT4aPS, an approach to measure Software Maturity for automated Production Systems is introduced. The approach identifies weaknesses and strengths of various companie's solutions for modularity of software in the design of automated Production Systems (aPS). At first, a self assessed questionnaire is used to evaluate a large number of companies concerning their software maturity. Secondly, we analyze PLC code, architectural levels, workflows and abilities to configure code automatically out of engineering information in four selected companies. In this paper, the questionnaire results from 16 German world leading companies in machine and plant manufacturing and four case studies validating the results from the detailed analyses are introduced to prove the applicability of the approach and give a survey of the state of the art in industry

Experimental-numerical analysis of the fracture process in smooth and notched V specimens

This paper presents the outcomes of quality tests conducted on specimens, both smooth and V-notched, subjected to uniaxial tension, which were extracted from a gas transport pipeline. The introduction of the V-notch introduced variations in the stress and strain component fields near the plane of maximum constriction, consequently leading to their failure through different mechanisms. The process included the implementation of quality management practices such as numerical modeling and simulation of the loading of the specimens using ABAQUS. The material model employed in these calculations was defined and verified to ensure quality control. Subsequent to the numerical calculations, maps of the stress and strain component fields were generated, contributing to the quality assessment of the specimens. It was determined that the quality management process for the smooth specimen identifies the initiation of failure primarily due to the normal stress component in the central region of the plane with the largest constriction. In contrast, in the V-notched specimen, quality management efforts revealed that failure initiation occurs due to the tangential stress component, and failure proceeds through the shear mechanism. These results are valuable in developing a quality-driven methodology for monitoring the operational safety of gas network pipelines, primarily based on the analysis of acoustic emission signals