Advanced PID architectures for tracking changing active constraints

TL;DR

This paper demonstrates that advanced PID architectures, known as ARC, can effectively control processes with changing constraints, challenging the notion that only model-based methods like MPC are suitable.

Contribution

It provides practical case studies showing ARC's effectiveness in managing conflicting constraints in real-world processes, with extended simulations.

Findings

ARC successfully manages bidirectional inventory control in a gas-liquid separation process.

ARC maintains acceptable air quality and temperature despite conflicting constraints.

Extended simulations support ARC's robustness in dynamic control scenarios.

Abstract

Advanced regulatory control (ARC), also known as advanced PID architectures, is a simple and robust way of controlling processes with changing and possibly conflicting constraints, where it previously was believed - at least in academia - that model-based solutions, such as MPC, were the only effective solution. To illustrate this, ARC is applied in two case studies. The first is a gas-liquid separation process, in which selectors and split-parallel control are combined to achieve bidirectional inventory control in which the throughput manipulator moves automatically to the most optimal position. The second case study is on keeping acceptable air quality (CO2-level) and temperature in a room (in this case, a barn for cows). The CO2 and temperature constraints can be conflicting, leading to a hierarchical switching network of PID controllers. Note: this is an extended version (with simulations) of paper at IFAC World Congress, August 2026, Korea.