A rule-based adaptive PID controller

The authors describe a functioning expert controller implemented with industrial programmable logic controller technology. In its present state the controller implements an adaptive PID (proportional, integral, and derivative) algorithm based on rule-based logical modules. The controller does not presume a model for the system. It detects several features of the current system response to a step input change and uses a pattern matching procedure to adjust the PID parameters to reshape the system output response.< >