Networked Control Systems with Intermittent Acknowledgement

具有间歇确认功能的网络控制系统

• 批准号: RGPIN-2021-02537
• 负责人: Shu, Zhan
• 金额: $ 2.4万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=752272
• 关键词: Networked; Control; Systems; Intermittent; Acknowledgement

Networked control systems (NCSs) utilize communication channels or networks to transmit signals among different components. A crucial issue in NCSs is that data transmission is no longer lossless, and data packets may be dropped due to various reasons. Two well-known transport protocols, Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), are usually used to treat this issue. NCSs with TCP and UDP deployed are called TCP-like and UDP-like NCSs, respectively. TCP-like NCSs feature the reliable data transmission by sending an acknowledgement (ACK) of receipt from destination to source but require extra resources to establish and maintain a connection between source and destination. Also, handshake, retransmission, and other mechanisms may cause a significant delay in the feedback loop. By contrast, UDP-like NCSs, at the cost of lower data delivery reliability, reduce resource consumption and cause lower latency. However, the performance deterioration resulting from data loss may be unacceptable for some control tasks. Despite the remarkable progress in TCP-like and UDP-like NCSs, emerging control-related applications such as wireless process automation, autonomous driving, and networked factory have posed new challenges. On the one hand, high data reliability and control performance are desired as many packets are related to the safety-critical message, whose loss and resulting performance deterioration can be harmful to people or equipment. On the other hand, low latency is essential to fulfiling stringent timeliness and agility requirements of control tasks. Besides, reduced resource consumption is desired as many devices are powered by batteries and have limited resources for computation, control, and communication. Neither TCP-like NCSs nor UDP-like NCSs is able to address all these issues, and this calls for new approaches and tools. To this end, a new type of NCSs with intermittent ACK (iACK-NCSs), and related control analysis and design framework covering modelling, estimation, control, and distributed deployment are to be developed in this research program. The novelty of iACK-NCSs is that a pair of source and destination generates ACK signals adaptively according to control targets, plant dynamics, and network conditions. Through deliberate integration of active and adaptive ACK, it has the potential to achieve fast responses, low latency, and high-performance estimation/control with minimum use of resources. The successful completion of the research program will not only deepen understanding of theory on control and communication in the context of networked and distributed systems but also provide novel algorithms and protocols which can be applied to practical networked control problems. Also, it will lead to the training of research students in a significant and rapidly growing area, enabling them to develop new approaches and skills which are very likely to impact both academic and industrial sectors.

网络控制系统(NCS)利用通信通道或网络在不同组件之间传输信号。网络控制系统中的一个关键问题是数据传输不再是无损的，数据分组可能会由于各种原因而被丢弃。通常使用两种著名的传输协议--传输控制协议(TCP)和用户数据报协议(UDP)来处理这一问题。部署了TCP和UDP的网络控制系统分别称为类TCP和类UDP网络控制系统。类似于TCP的NCS通过从目的地向源发送接收确认(ACK)来实现可靠的数据传输，但需要额外的资源来建立和维护源和目的地之间的连接。此外，握手、重传和其他机制可能导致反馈环路中的显著延迟。相比之下，类似UDP的NCS以较低的数据传输可靠性为代价，减少了资源消耗并导致了较低的延迟。然而，对于某些控制任务来说，数据丢失导致的性能下降可能是不可接受的。尽管类似TCP和UDP的网络控制系统取得了显著的进展，但与控制相关的新兴应用，如无线过程自动化、自动驾驶和网络化工厂，已经提出了新的挑战。一方面，由于许多分组与安全关键消息有关，因此需要高数据可靠性和控制性能，这些分组的丢失和由此导致的性能恶化可能对人或设备有害。另一方面，低延迟对于满足严格的控制任务的及时性和敏捷性要求是必不可少的。此外，由于许多设备由电池供电，用于计算、控制和通信的资源有限，因此需要减少资源消耗。无论是类似TCP的NCS还是类似UDP的NCS都不能解决所有这些问题，这就需要新的方法和工具。为此，本研究计划开发一种新型的间歇性确认网络控制系统(iACK-NCSs)，以及相关的控制分析和设计框架，涵盖建模、估计、控制和分布式部署。IACK-NCS的新颖之处在于，源和目的地对根据控制目标、对象动态和网络条件自适应地生成ACK信号。通过有意集成主动和自适应ACK，它有可能以最少的资源使用实现快速响应、低延迟和高性能估计/控制。该研究项目的成功完成不仅将加深对网络化和分布式系统背景下的控制和通信理论的理解，而且将为实际的网络控制问题提供新的算法和协议。此外，它还将导致在一个重要和快速增长的领域培训研究型学生，使他们能够开发新的方法和技能，这些方法和技能很可能对学术和工业部门产生影响。