Heterogeneous wireless networked control systems based on modify Smith predictor and CMAC-PID control

Abstract

The cerebellar model articulation controller (CMAC) neural network is a practical tool for improving existing nonlinear control systems, and it can effectively reduce tracking error of control system. In order to effectively restrain the impact of network delays for wireless networked control systems (WNCS), a novel approach is proposed that modified Smith predictor combined with CMAC-PID control for the heterogeneous wireless networked control systems (HWNCS). The HWNCS adopts cascade control system structure, use P control and CMAC-PID control, and data communications adopt heterogeneous wireless networks in the inner and outer loops. Based on modified Smith predictor, achieve complete compensations for the delays of networks and controlled plants. Because modified Smith predictor does not include network delay models, it is no need for measuring, identifying or estimating network delays on line. Therefore it is applicable to some occasions that network delays are larger than one, even tens of sampling periods. Based on IEEE 802.15.4 (ZigBee) in the inner loop and IEEE 802.11b/g (WLAN) in the outer loop, and there are data packets loss in the loops. The results of simulation show validity of the control scheme, and can improve dynamic performance, enhance robustness, self-adaptability and anti-jamming ability.