One of the most significant advances in the development of computer science, information and communication technologies is represented by the cyber-physical systems (CPS). They are systems of collaborating computational entities which are in intensive connection with the surrounding physical world and its on-going processes, providing and using, at the same time, data-accessing and data-processing services available on the Internet. Cyber-physical production systems (CPPS), relying on the latest, and the foreseeable further developments of computer science, information and communication technologies on one hand, and of manufacturing science and technology, on the other, may lead to the 4th industrial revolution, frequently noted as Industrie 4.0. The paper underlines that there are significant roots in general – and in particular to the CIRP community – which point towards CPPS. Expectations towards research in and implementation of CPS and CPPS are outlined and some case studies are introduced. Related new R&D challenges are highlighted.

Cyber-physical systems in manufacturing

https://cyberleninka.org/article/n/991959.pdf

Cyber-physical production systems: Roots, expectations and R&D challenges

Cyberphysical systems (CPSs) are new class of engineered systems that offer close interaction between cyber and physical components. The field of CPS has been identified as a key area of research, and CPSs are expected to play a major role in the design and development of future systems. In this paper, we survey recent advancements made in the development and applications of CPSs. We classify the existing research work based on their characteristics and identify the future challenges. We also discuss the examples of prototypes of CPSs. The aim of this survey is to enable researchers and system designers to get insights into the working and applications of CPSs and motivate them to propose novel solutions for making wide-scale adoption of CPS a tangible reality.

Design Techniques and Applications of Cyberphysical Systems: A Survey

Currently autonomous or self-driving vehicles are at the heart of academia and industry research because of its multi-faceted advantages that includes improved safety, reduced congestion, lower emissions and greater mobility. Software is the key driving factor underpinning autonomy within which planning algorithms that are responsible for mission-critical decision making hold a significant position. While transporting passengers or goods from a given origin to a given destination, motion planning methods incorporate searching for a path to follow, avoiding obstacles and generating the best trajectory that ensures safety, comfort and efficiency. A range of different planning approaches have been proposed in the literature. The purpose of this paper is to review existing approaches and then compare and contrast different methods employed for the motion planning of autonomous on-road driving that consists of (1) finding a path, (2) searching for the safest manoeuvre and (3) determining the most feasible trajectory. Methods developed by researchers in each of these three levels exhibit varying levels of complexity and performance accuracy. This paper presents a critical evaluation of each of these methods, in terms of their advantages/disadvantages, inherent limitations, feasibility, optimality, handling of obstacles and testing operational environments. Based on a critical review of existing methods, research challenges to address current limitations are identified and future research directions are suggested so as to enhance the performance of planning algorithms at all three levels. Some promising areas of future focus have been identified as the use of vehicular communications (V2V and V2I) and the incorporation of transport engineering aspects in order to improve the look-ahead horizon of current sensing technologies that are essential for planning with the aim of reducing the total cost of driverless vehicles. This critical review on planning techniques presented in this paper, along with the associated discussions on their constraints and limitations, seek to assist researchers in accelerating development in the emerging field of autonomous vehicle research.

Real-time motion planning methods for autonomous on-road driving: State-of-the-art and future research directions

A worldwide movement in advanced manufacturing countries is seeking to reinvigorate (and revolutionize) the industrial and manufacturing core competencies with the use of the latest advances in information and communications technology. Visual computing plays an important role as the "glue factor" in complete solutions. This article positions visual computing in its intrinsic crucial role for Industrie 4.0 and provides a general, broad overview and points out specific directions and scenarios for future research.

Visual Computing as a Key Enabling Technology for Industrie 4.0 and Industrial Internet

Cyber-physical systems (CPSs) are the next generation of engineered systems in which computing, communication, and control technologies are tightly integrated. Research on CPSs is fundamentally important for engineered systems in many important application domains such as transportation, energy, and medical systems. We overview CPS research from both a historical point of view in terms of technologies developed for early generations of control systems, as well as recent results on CPSs in many relevant research domains such as networked control, hybrid systems, real-time computing, real-time networking, wireless sensor networks, security, and model-driven development. We outline the potential for CPSs in many societally important application domains.

http://cesg.tamu.edu/wp-content/uploads/2012/03/ps_files/12-02-10-CPS-Centennial.pdf

Cyber–Physical Systems: A Perspective at the Centennial

Even with recent advances in electronics, sensors, and communication technologies, it is still a grand challenge to develop an autonomous transportation system in which each vehicle can autonomously coordinate with other vehicles and drive itself on a road with a safety guarantee. We propose an approach to address this challenge. We formulate a Model Predictive Control (MPC) problem to generate a feasible trajectory for a vehicle. Constraints are particularly designed to ensure inter-vehicle safety. To further achieve system-wide safety and liveness, we additionally propose several simple yet effective rules for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) coordination. We establish system-wide safety and also liveness of the resulting autonomous traffic in various traffic situations such as single lane traffic, multi-lane traffic, and intersection crossing traffic.

Collision free autonomous ground traffic: a model predictive control approach

A well-designed software framework is important for the rapid implementation of reliable and evolvable networked control applications and to facilitate the proliferation of networked control by enhancing its ease of deployment. In this brief, we address the problem of developing such a framework for networked control that is both real-time and extensible. We enhance Etherware, a middleware developed at the University of Illinois, so that it is suitable for time-critical networked control applications. We introduce a notion of quality of service (QoS) for the execution of a component. We also propose a real-time scheduling mechanism so that the execution of components can not only be concurrent but also be prioritized based on the specified QoS of each execution. We have implemented this framework in Etherware. We illustrate the applicability of this software framework by deploying it for the control of an unstable system, namely, a networked version of an inverted pendulum control system, and verify the performance of the enhanced Etherware. We also exhibit sophisticated runtime functionalities, such as runtime controller upgrade and migration, to demonstrate the flexible and temporally predictable capabilities of the enhanced Etherware. Overall, Etherware thus facilitates rapid development of control system applications with temporally predictable behavior so that physical properties such as stability are maintained.

http://cesg.tamu.edu/wp-content/uploads/2012/02/11-CST2011_Pendulum1.pdf

Real-Time Middleware for Networked Control Systems and Application to an Unstable System

Today, societies across the globe, and the planet itself, are faced with several challenges in many domains such as water, energy, environment, transportation, and healthcare. Overcoming these challenges requires another step forward in the technological revolution involving the conjoint deployment of advanced computation, communication, and control. Cars along highways will need to be networked with each other and the infrastructure for greater safety and reduced delays. Renewable but unreliable energy from wind and solar will need to be integrated into the power grid, homes which have traditionally been the only consumers of energy can occasionally become producers, and batteries of hybrid cars can be used as reservoirs of energy to store energy and smooth fluctuations. Telesurgery can make surgery more reliable by reducing tremor while also enhancing access for patients. Large networks of sensors can monitor the environment and reveal important information about ecological and environmental processes. All these are next-generation engineered systems in which computing, communications, and control technologies are tightly integrated to achieve high level performance, reliability, flexibility, robustness, and efficiency in dealing with physical systems in many application domains. Dubbed cyber–physical systems (CPSs), they involve the interaction of computers, networks, sensors, and actuators, and are attracting much attention from academia, industry, and governments. These developments constitute an acceleration of a trend that has been happening over the past few decades. Looking back at the history of the technological evolution, one sees that there has been synergetic interaction among computing, communication, and control technologies that has accelerated further advancements in each area. As an example, computers were originally developed and used for calculations. However, when they started to be used in control loops, the necessity to deal with timing constraints of physical systems stimulated the development of realtime computing technology. Indeed this is a good example of what is meant by a CPS, though this name is a recent invention. Conversely, the evolution of computing technology has played a significant role in the development of control theory. When the platform began shifting from analog computers to digital computers, attention started shifting from the development of frequency-domain theory to state–space theory. There are several research challenges to the deployment of next-generation CPSs. Their dynamics are quite challenging to deal with since there is a tight interaction between the typically continuous dynamics of physical systems and the discrete dynamics of computing systems. Moreover, there is an interposed communication network mediating interactions, which can cause delays or packet losses between the computing and physical systems. One important focus within CPSs is networked control systems, where it is critically important to address the stability and performance of the control loop, focusing on the interaction between the physical system and the controllers over a communication network. Another important focus is the study of the dynamics of hybrid systems which involve both continuous and discrete dynamics, since it is valuable to provide formal verification of properties such as safety. Yet another focus is on real-time computing and networking, where it is important to deal with the timing constraints of physical systems and ensure temporal correctness of the interactions with both computing systems and the communication network. Wireless sensor networks are an important class of CPSs that can consist of a large number of computing nodes equipped with wireless communication and sensing capabilities. Some of the important issues are ensuring extremely energy-efficient networking, synchronization of their clocks, and performing in-network computation to extract relevant information from large-scale sensor data. One of the biggest challenges to the implementation of cyber technology systems is their complexity which makes it more difficult to design and develop software systems.

Prolog to the Section on Cyber–Physical Systems

Controller failures can result in unsafe physical plant operations and deteriorated performance in industrial cyber–physical systems. In this paper, we present a controller switching mechanism over wireless sensor–actuator networks to enhance the resiliency of control systems against problems and potential physical failures. The proposed mechanism detects controller failures and quickly switches to the backup controller to ensure the stability of the control system in case the primary controller fails. To show the efficacy of our proposed method, we conduct a performance evaluation using a hardware-in-the-loop testbed that considers both the actual wireless network protocol and the simulated physical system. Results demonstrate that the proposed scheme recovers quickly by switching to a backup controller in the case of controller failure.

https://www.mdpi.com/2076-3417/12/4/1841/pdf?version=1644818038

Kyoung-Dae Kim

Papers

Cyber–Physical Systems: A Perspective at the Centennial

Collision free autonomous ground traffic: a model predictive control approach

Real-Time Middleware for Networked Control Systems and Application to an Unstable System

Prolog to the Section on Cyber–Physical Systems

A Controller Switching Mechanism for Resilient Wireless Sensor–Actuator Networks