Fieldbus technology based, distributed control in process industries: a case study with LonWorks Technology

The manufacturing industry is becoming more dynamic than ever. The limitations of non-deterministic network delays and real-time requirements call for decentralized control. For such dynamic and complex systems, learning methods stand out as a transformational technology to have a more flexible control solution. Using simulation for learning enables the description of highly dynamic systems and provides samples without occupying a real facility. However, it requires prohibitively expensive computation. In this paper, we argue that simulation optimization is a powerful tool that can be applied to various simulation-based learning processes for tremendous effects. We proposed an efficient policy learning framework, ROSA (Reinforcement-learning enhanced by Optimal Simulation Allocation), with unprecedented integration of learning, control, and simulation optimization techniques, which can drastically improve the efficiency of policy learning in a cyber-physical system. A proof-of-concept is implemented on a conveyer-switch network, demonstrating how ROSA can be applied for efficient policy learning, with an emphasis on the industrial distributed control system.

Industry 4.0 is the German vision for the future of manufacturing, where smart factories use information and communication technologies to digitise their processes to achieve improved quality, lower costs, and increased efficiency. It is likely to bring a massive change to the way control systems function today. Future distributed control systems are expected to have an increased connectivity to the Internet, in order to capitalize on new offers and research findings related to digitalization, such as cloud, big data, and machine learning. A key technology in the realization of distributed control systems is middleware, which is usually described as a reusable software layer between operating system and distributed applications. Various middleware technologies have been proposed to facilitate communication in industrial control systems and hide the heterogeneity amongst the subsystems, such as OPC UA, DDS, and RT-CORBA. These technologies can significantly simplify the system design and integration of devices despite their heterogeneity. However, each of these technologies has its own characteristics that may work better for particular applications. Selection of the best middleware for a specific application is a critical issue for system designers. In this paper, we conduct a survey on available standard middleware technologies, including OPC UA, DDS, and RT-CORBA, and show new trends for different industrial domains.

Industrial distributed control systems would greatly benefit from the adoption of wireless communication technologies, if only guarantees could be provided on timing of time-critical data delivery over the ether. This paper presents solutions to handle single-hop deadline-constrained periodic traffic, which combine centralized transmission scheduling according to earliest deadline first (EDF) and automatic repeat request (ARQ). For each solution, an admission control test is provided, which guarantees a configurable number of retries to each data instance within its deadline, statically addressing both timeliness and reliability on a per-instance basis. Dynamic bandwidth management strategies are also introduced that use runtime information about unperformed guaranteed retries and reassign them, as extra retries, to failed instances whose deadline has not yet expired. Simulation results show that significant benefits can be obtained, in terms of both determinism and improved performance, by a careful static/dynamic management of the available communication resources.

State Feedback for Distributed Control Systems

In industrial distributed control systems, a sensor periodically collects a physical value from the environment and transmits it to an actuator, which performs a control action based on the value received from the sensor. For stable control operation, those messages from sensors to actuators have to be transmitted reliably end-to-end. This paper proposes a reliable message routing protocol for periodic messages on a wireless sensor network which guarantees a specified end-to-end target packet reception rate. For reliable message transmission for periodic traffic, the proposed protocol first finds paths with end-to-end packet reception rate higher than the target packet reception rate and chooses a path with the highest end-to-end packet reception rate among them, and transmits data packets periodically through the path after setting up a path. To maintain the target packet reception rate in the proposed protocol, the destination node monitors periodically its actual packet reception rate and transmits a feedback control message to the source if its reception rate drops below the target value. If the source node receives the feedback message, it sets up a new reliable path with end-to-end packet reception rate higher than the target packet reception rate. The performance of the proposed protocol has been analyzed by simulation using QualNet simulator. The simulation result has shown that the proposed protocol has a better packet reception rate than the previous routing protocols and maintains a target packet reception rate in a network where the amount of traffic changes dynamically.

The SCADA system applications in management of Yuvacik Dam and Reservoir

Automatic control has become one of the standard engineering fields and is inherently part of electrical engineering. Industrial controllers in any form are only a part of the hardware necessary for the control of industrial processes in, e.g., the process industry or manufacturing. The design of an industrial control system is greatly facilitated by an auto-tuning system, if it is available as part of the controller. Since the majority of control hardware for industry is of the proportional-integral-derivative (PID) type, most of the patents relating to auto-tuning are also about this type of control, though other patented methods and systems for control are available. In this paper, a survey of patents for autotuning methods and systems for industrial control is given. The patents are grouped into methods and systems based on model-based tuning with non-parametric and parametric models, relay tuning, multiple controllers for nonlinear processes, and other approaches. More stress is put on recent patents, but a wider survey of auto-tuning patents published in the past two decades is also given in the paper. The methods being patented are becoming more sophisticated and more universal and consequently they provide better assistance to the work of control-design engineers. Keywords: Auto-tuning system, industrial controllers, process control, PID control, controller tuning

The Local Operating Network is a technology that allows intelligent devices (or nodes) such as actuators and sensors, to communicate with one another through an assortment of communication media using a standard protocol. Both distributed and peer-to-peer communications are supported between the nodes in the network and a central control system or a file server is not required. In addition, the relatively high data rate and the availability of routers permit large amount of nodes to be tapped onto a network domain while at the same time maintain high communication efficiency. Consequently, it is suitable for developing low-cost consumers and professional communication products that can be widely applied in automating buildings, factories, vehicles, home and domestic appliances. In this paper we have reported on the development of a distributive control lighting system using the LON technology. The nodes in the system (i.e. lamps, switches and the central control units) are tapped onto the network bus and are linked by logical bindings instead of complicated hardwire connections. The system we have designed is economical to build, easy to service, modify, and provides reliable communication between the lamps and the switches. These attractive features demonstrate the feasibility of using LON in building distributive control networks, as well as the potential of our lighting system in practical applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An architecture for metamorphic control of holonic manufacturing systems

Use of multi-agent system for industrial production control

Distributed control and optimization form the backbone of many critical control systems, with typical examples including sensor networks, power grids, and intelligent transportation systems. As these systems grow in scale and complexity, ensuring the privacy of individual agents becomes increasingly essential. Privacy protection is no longer an optional add-on; it is a crucial element in the design of these systems. Sensitive data, such as states, measurements, and decisions, must be shielded from unauthorized access or malicious attacks, while still allowing the system to function effectively. This special issue aims to explore novel techniques and strategies that protect privacy in distributed control and optimization, showcasing how these approaches can be seamlessly integrated into real-world applications. The diverse contributions in this issue demonstrate the growing importance of privacy in the evolving field of distributed control systems. RNC7747 introduces a privacy-preserving method for coverage control in multi-agent systems with limited communication ranges, ensuring efficient operation without compromising agents' privacy. RNC7798 proposes a privacy-preserving consensus mechanism based on pulse-coupled oscillators, helping maintain privacy while agents coordinate in distributed networks. RNC7778 presents privacy preservation techniques for cloud-based cooperative LQG control systems, enabling privacy protection even when leveraging cloud resources. RNC8051 discusses achieving privacy-preserving average consensus in unreliable network environments, ensuring privacy despite communication challenges. RNC7929 introduces a novel approach to open privacy-preserving consensus via state decomposition, allowing agents to reach consensus while maintaining privacy. RNC7966 investigates leader-follower consensus in multi-agent systems with distributed event-triggered observations, ensuring privacy during agent coordination in real-time systems. RNC7789 discusses the tradeoff between privacy protection strength and control performance in control systems. RNC8029 proposes a new privacy mechanism for distributed average consensus on time-varying directed graphs. RNC7776 investigates event-triggered distributed optimization with differential privacy, reducing communication costs while safeguarding sensitive data. RNC7885 develops an event-triggered privacy-preserving optimization method for directed communication networks, emphasizing privacy during optimization tasks. RNC7791 focuses on robust optimization for virtual power plant scheduling under uncertainty, incorporating privacy preservation into the optimization process. RNC7730 explores prescribed-time distributed optimization with set constraints, offering time guarantees while maintaining privacy in dynamic optimization scenarios. RNC7926 provides a privacy-preserving algorithm for constrained resource allocation with communication delays, crucial for real-time decision-making in distributed systems. RNC7848 presents an adaptive event-triggered control strategy for cyber-physical systems under DoS and deception attacks, ensuring privacy and system security. RNC8068 addresses initial state privacy in nonlinear systems on Riemannian manifolds, offering methods to protect privacy in complex, high-dimensional control systems. RNC7906 focuses on dynamic consensus-based formation control for multi-robot systems, preserving privacy through output masking techniques while achieving coordination. RNC7688 introduces a periodic dynamic encoding mechanism for stealthy attack detection in distributed state estimation, focusing on security and privacy under attack scenarios. RNC70033 tackles robust consensus Kalman filtering for distributed state-saturated systems, incorporating dynamic-disturbed saturation levels and censored measurements to ensure privacy under uncertain conditions. The contributions in this special issue span a broad spectrum of topics related to privacy in distributed control and optimization. As distributed systems continue to evolve, these papers contribute to the ongoing conversation about balancing privacy protection with efficient system operation, highlighting the importance of privacy as a key consideration in the design and optimization of future distributed control systems. The authors declare no conflicts of interest.

State-of-the-Art industrial automation and control systems lack of universal communication technologies in order to handle their increasing engineering complexity. In opposition to the automation and control domain, where different field bus technologies are competing, the automotive domain has identified similar problems, founded a corporate consortium and introduced a new universal bus system. This new bus system is called FlexRay and is supposed to be the successor of CAN and analog bus systems for in-car applications. Similar to the introduction of CAN within the automation domain FlexRay may become the standard for distributed automation and control applications. This paper investigates the FlexRay communication system for its usage in the field of automation and control, by defining scenarios for the beneficial usage of FlexRay and by identifying the advantages and disadvantages compared to current available field bus systems.

Device Description that is described as C-based DDL(Device Description Language) should be provided for the control system to use the progressive function of field device in the distributed control system. DD expresses field device function itself and parameter. DD is used to set a necessary function far a control strategy in the central control system. DD technology which was adopted as international standard IEC 61804-Part 2 is being used in PROFIBUS, Foundation Fieldbus and HART. However, the DD is dependent to the fieldbus and it doesn't have a suitable form in the industrial Ethernet. This paper presents the possibility of a change from EDD(Electronic Device Description) and GSD(General Slave Data) used for integrating field devices to XDD(XML for Device Description) and verifies it's effectiveness. Also, this paper presents research assignment on the XML application in the distributional system from now on by examining the possibility of Ethernet`s development in the industrial area.

While networks of cooperating embedded devices are becoming more and more present in today's digital world, the development of software at process control and management levels must face the heterogeneity and dynamic of the components of these distributed systems. This paper presents a service oriented model that enhances interoperability between low-level devices and control level applications. This model has been applied to the development of a prototype application named FoxController that can be deployed on embedded systems and is compliant to the Devices Profile for Web Service (DPWS) specifications. FoxController simplifies the setting up of flexible and distributed data acquisition and control systems.

We have developed a novel railway signal control system that operates as a distributed system. It consists of a central control unit (called LC) and terminal devices (called FC) that are distributed at the railroad wayside and operate signal devices. The Internet technologies and optical LAN technologies have been used as communication methods between the LC and the FCs. While handling enormous amount of electric cables may cause human errors, the system is expected to reduce troubles of the current signal system at construction works thanks to the Internet technologies. The FC is a distributed terminal device that has its own processor and placed at the railroad wayside to control the field signal devices. The LC is a centralized computer device that has software arranged by the function of the fie ld devices. An optical network system and multiple communication paths between the LC and the FCs realize durable transmissions. Moreover, the assure performance of controls and transmissions have been investigated, and the autonomous distributed signal control system is also discussed as the next steps of the system.