A Filtered Predictive PI Controller for WirelessHART Networked Control System

Abstract

In recent years, increasing attention has been paid towards applying wireless technology for control. This is because of its advantages of flexibility, scalability, reduced cabling and overall reduced operational cost compared to its wired counterpart. But, the technology is often affected by stochastic delay and high frequency noise. PIDs proved inadequate to handle these challenges while model based controllers such as deadtime compensators (DTCs) such as Smith predictor and internal model controllers (IMCs) are complex and require exact plant model for implementation. Thus, Predictive PI (PPI) controller being a settlement between the PIDs and the model based controllers is a good candidate. The PPI retains the simplicity of the PID and has the ability to predict long time delay and can be used even with model mismatch. However, the PPI is severely affected by high frequency noise. Therefore, this paper proposes a Filtered PPI controller that can be used even in the presence of high frequency noise. Simulation and experimental results proved the viability of the proposed method.