PROCESS CONTROL SYSTEM WITH ASYMPTOTIC AUTO-TUNING

摘要

A process control system (100) controls a non-self regulating process through a control output signal (u(t)) based on a set point [err]and a measured process variable (y(t)). The process control system includes a control circuit (102, 104, 106, 108) having a set point input, aprocess variable input and a control output. The control circuit generates the control output signal (u(t)) on the control output as a functionof the set point [err] received on the set point input and the measured process variable (y(t)) received on the process variable input. Anauto-tuning circuit (106) excites the process, estimates a process model based on an intersection between rising and falling asymptotes ofthe measured process variable (y(t)), and then tunes the control function to the process (110) based on the process model. The auto-tuningcircuit obtains robust results, but is computationally simple such that the circuit can be implemented with hardware or software in low-powerand low-memory applications, such as in field-mounted controllers.