Self-tuning digital PID controller implemented on 8-bit Freescale microcontroller

Abstract

Příspěvek se zabývá implementací samočinně se nastavujícího digitálního PID regulátoru na 8 bitový mikropočítač MC68HC908GB60.

In this paper implementation of self-tuning digital PID controller on 8-bit Freescale MC68HC908GB60 microcontroller which is intended for general purpose applications is described. Controller firmware was created on development board M68EVB908GB60 by Axiom manufacturing providing number of useful peripherals for comfortable application development. Controlled process is identified using modified recursive least squares method with adaptive directional forgetting resulting in ?-model representation of controlled plant. This approach results in better numerical stability of identification process and allows lower sampling periods. Parameters of PSD controller are designed by pole placement method on the basis of estimated plant coefficients. Controller firmware was created in Freescale CodeWarrior integrated development environment in C and assembly language. Software works under real-time operating system RTMON for HCS08 which was created on our department. Controller was verified by temperature controlling of two different heat plant models.