Industry 4.0 as a Cyber-Physical System study

Advances in computation and communication are taking shape in the form of the Internet of Things, Machine-to-Machine technology, Industry 4.0, and Cyber-Physical Systems (CPS). The impact on engineering such systems is a new technical systems paradigm based on ensembles of collaborating embedded software systems. To successfully facilitate this paradigm, multiple needs can be identified along three axes: (i) online configuring an ensemble of systems, (ii) achieving a concerted function of collaborating systems, and (iii) providing the enabling infrastructure. This work focuses on the collaborative function dimension and presents a set of concrete examples of CPS challenges. The examples are illustrated based on a pick and place machine that solves a distributed version of the Towers of Hanoi puzzle. The system includes a physical environment, a wireless network, concurrent computing resources, and computational functionality such as, service arbitration, various forms of control, and processing of streaming video. The pick and place machine is of medium-size complexity. It is representative of issues occurring in industrial systems that are coming online. The entire study is provided at a computational model level, with the intent to contribute to the model-based research agenda in terms of design methods and implementation technologies necessary to make the next generation systems a reality.     

Signal interpretation for monitoring and diagnosis, a coolingsystem testbed

This paper discusses a method for fault detection and isolation (FDI) in continuous dynamic systems. A key aspect of this approach is the coupling of a qualitative diagnosis engine and a monitoring system that computes symbolic feature values through a signal-to-symbol transformation on the continuously sampled measurement data. Signal analysis techniques with a sound statistical basis are employed to generate reliable symbolic data. The methodology is evaluated on the diagnosis of engineered faults in the cooling system of an automobile engine that has been instrumented with temperature and pressure sensors. Results show the interdependency between modeling for diagnosis and the feature extraction system     

Cyber-physical systems challenges: a needs analysis for collaborating embedded software systems

Embedding computing power in a physical environment has provided the functional flexibility and performance necessary in modern products such as automobiles, aircraft, smartphones, and more. As product features came to increasingly rely on software, a network infrastructure helped factor out common hardware and offered sharing functionality for further innovation. A logical consequence was the need for system integration. Even in the case of a single original end manufacturer who is responsible for the final product, system integration is quite a challenge. More recently, there have been systems coming online that must perform system integration even after deployment—that is, during operation. This has given rise to the cyber-physical systems (CPS) paradigm. In this paper, select key enablers for a new type of system integration are discussed. The needs and challenges for designing and operating CPS are identified along with corresponding technologies to address the challenges and their potential impact. The intent is to contribute to a model-based research agenda in terms of design methods, implementation technologies, and organization challenges necessary to bring the next-generation systems online.     

A computational model of time for stiff hybrid systems applied to control synthesis

Computation has quickly become of paramount importance in the design of engineered systems, both to support their features as well as their design. Tool support for high-level modeling formalisms has endowed design specifications with executable semantics. Such specifications typically include not only discrete-time and discrete-event behavior, but also continuous-time behavior that is stiff from a numerical integration perspective. The resulting stiff hybrid dynamic systems necessitate variable-step solvers to simulate the continuous-time behavior as well as solver algorithms for the simulation of discrete-time and discrete-event behavior. The combined solvers rely on complex computer code which makes it difficult to directly solve design tasks with the executable specifications. To further leverage the executable specifications in design, this work aims to formalize the semantics of stiff hybrid dynamic systems at a declarative level by removing implementation detail and only retaining ‘what’ the computer code does and not ‘how’ it does it. A stream-based approach is adopted to formalize variable-step solver semantics and to establish a computational model of time that supports discrete-time and discrete-event behavior. The corresponding declarative formalization is amenable to computational methods and it is shown how model checking can automatically generate, or synthesize, a feedforward control strategy for a stiff hybrid dynamic system. Specifically, a stamper in a surface mount device is controlled to maintain a low acceleration of the stamped component for a prescribed minimum duration of time.     

Virtual Engineering Laboratories: Design and Experiments

This paper describes the creation and testing of computer-simulated laboratories for use in undergraduate engineering education. The design and implementation of a ‘virtual laboratory’ that closely mimics the capabilities of a physical laboratory is explained. Experiments that compare time and learning gains of students using physical and virtual laboratories are discussed. Experimental results indicate that students who use the virtual laboratory prior to a physical laboratory are able to complete the physical laboratory in a much shorter time, require less assistance, and also report that they are very satisfied with their laboratory experience.     

Diagnosis of continuous valued systems in transient operatingregions

The complexity of present day embedded systems (continuous processes controlled by digital processors), and the increased demands on their reliability motivate the need for monitoring and fault isolation capabilities in the embedded processors. This paper develops monitoring, prediction, and fault isolation methods for abrupt faults in complex dynamic systems. The transient behavior in response to these faults is analyzed in a qualitative framework using parsimonious topological system models. Predicted transient effects of hypothesized faults are captured in the form of signatures that specify future faulty behavior as higher order time-derivatives. The dynamic effects of faults are analyzed by a progressive monitoring scheme till transient analysis mechanisms have to be suspended in favor of steady state analysis. This methodology has been successfully applied to monitoring of the secondary sodium cooling loop of a fast breeder reactor     

The Effectiveness of Learning Simulations for Electronic Laboratories

This work investigates the efficacy of software simulations of electronic circuits laboratories to support beginning electrical engineering students. Experiment 1 was a formative evaluation of an Electronic Laboratory Simulator (ELS), as an optional add‐on to physical labs for 120 subjects at four universities. All subjects received the same treatment: their normal classes and physical labs, with optional use of simulated labs. Subjects took written tests specific to the lab's content, before and after using each simulated lab. Only subjects who took both pre‐ and post‐tests were included. Pre‐ and post‐test comparisons indicated significant improvement in both theory and lab knowledge when scores for all labs were combined, but inconsistent performance on individual labs. As the treatment included other learning opportunities in addition to simulated labs, the results were not attributed to the simulations, but provided initial indications and qualitative data on subjects' experiences. These helped to improve the labs and the implementation strategies. Experiment 2 used 40 college sophomores in a beginning electronic circuits lab. Physical lab subjects received seven physical labs. Combined lab subjects received a combination of seven simulated labs and two physical labs. The latter repeated two of the simulated labs to provide physical lab practice. Both treatments used the same assignments. Learner outcome measures were: (a) time required to complete a new criterion physical lab; (b) score on written lab and theory tests over all the labs; and (c) comments on the lab experience. The group that used combined simulated and physical labs performed significantly better on the written tests than the group using entirely physical labs. Both groups were equivalent in time to complete the criterion physical lab. Comments about the simulated labs were generally positive, and also provided specific suggestions for changes.     

Design and implementation of an electronics laboratory simulator

This paper describes the design and implementation of a computer-simulated laboratory for use in undergraduate engineering education. The simulated laboratory is implemented in a Windows environment. Several forms of tutorials and other assistance are available to the user to complete the laboratory. Evaluations indicate that when the simulation is used with class lectures, there is a significant improvement in both theory and lab knowledge. Use of the simulation significantly cuts subsequent time and requests for assistance in the physical lab