An Enhanced process Identification Method for Automatic Tuning of PID Controller

摘要

An enhanced process identification method with biased-relay feedback is proposed for the design of PID controller. This paper suggested a new theorem to get the transfer function of a process from the definition of Laplace transformation without any approximation. Based on this theorem, the process is identified as the second-order plus time delay(SOPTD) model with a least-suares method in a viewpoint of amplitude ratio and phase angle between the process and the SOPTD model. Since the proposed identification method does not approximate the relay and process outputs as sinusoidal signals, then the obtained SOPTD model can represent the process dynamics more accurately. A simulation study demonstrates its effectiveness and robustness to the measurement noise.