Digital Metropolis Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte 59078-900, Brazil.
Department of Computer Engineering and Automation, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte 59078-900, Brazil.
Sensors (Basel). 2020 Sep 21;20(18):5417. doi: 10.3390/s20185417.
Wireless networked control systems (WNCSs) must ensure that control systems are stable, robust and capable of minimizing the effects of disturbances. Due to the need for a stable and secure WNCS, critical wireless network variables must be taken into account in the design. As wireless networks are composed of several links, factors that indicate the performances of these links can be used to evaluate the communication system in the WNCS. This work presents a wireless network control system composed of ISA 100.11a sensors, a network manager, a controller and a wired actuator. The system controls the liquid level in the tank of the coupled tank system. In order to assess the influence of the sensor link failure on the control loop, the controller calculates the link stability and chooses an alternative link in case of instability in the current link. Preliminary tests of WNCS performance were performed to determine the minimum stability value of the link that generates an error in the control loop. Finally, the tests of the control system based on link stability obtained excellent results. Even with disturbances in the network links, the control system error remained below the threshold.
无线网络控制系统 (WNCS) 必须确保控制系统稳定、鲁棒,并能够最小化干扰的影响。由于需要稳定和安全的 WNCS,因此在设计中必须考虑关键的无线网络变量。由于无线网络由多个链路组成,因此可以使用指示这些链路性能的因素来评估 WNCS 中的通信系统。本工作提出了一种由 ISA 100.11a 传感器、网络管理器、控制器和有线执行器组成的无线网络控制系统。该系统控制耦合罐系统中罐的液位。为了评估传感器链路故障对控制回路的影响,控制器计算链路稳定性,并在当前链路不稳定时选择备用链路。对 WNCS 性能进行了初步测试,以确定导致控制回路出现误差的链路的最小稳定性值。最后,基于链路稳定性的控制系统测试取得了优异的结果。即使在网络链路受到干扰的情况下,控制系统误差仍保持在阈值以下。