This paper deals with the control performance assessment of distributed networked control systems in the presence of communication delays. The best achievable steady-state performance of distributed networked control systems in the framework of distributed linear quadratic Gaussian (LQG) control is presented where communication delays serve as the most fundamental performance limitation. In the proposed distributed LQG control design, distributed controllers and distributed observers are designed simultaneously without using separation principle. And the non-applicability of separation principle is investigated and demonstrated in distributed networked control with communication delays. In order to handle time-varying communication delays, we propose to use lower and upper bounds to characterize the range of the best achievable control performance with respect to the range of the communication delays. The obtained results can be used to evaluate the potential performance improvement of an existing distributed networked control system. The proposed approach is illustrated through a numerical example.

本文涉及在存在通信延迟的情况下分布式网络控制系统的控制性能评估。分布式网络控制系统在分布式线性二次高斯 (LQG) 控制框架中可达到的最佳稳态性能，其中通信延迟是最基本的性能限制。在提出的分布式 LQG 控制设计中，分布式控制器和分布式观测器是同时设计的，不使用分离原理。研究并论证了分离原理在具有通信延迟的分布式网络控制中的不适用性。为了处理随时间变化的通信延迟，我们建议使用下限和上限来表征相对于通信延迟范围的最佳可实现控制性能的范围。获得的结果可用于评估现有分布式网络控制系统的潜在性能改进。通过一个数值例子说明了所提出的方法。