Evaluating PID adaptive techniques for industrial implementation

This paper outlines several adaptive techniques considered for implementation in the PID controller. It presents frequency domain interpolators for tracking ultimate gain and ultimate period, model-free tuning based on balancing P and I terms, and the adaptation of controller switching and model switching with the interpolation of parameters. From the perspective of the authors, a model switching technique using the interpolation of parameters offers a clear advantage, particularly for feedforward/feedback loops and multivariable control.