Learning-Based Adaptive Optimal Control for Flotation Processes Subject to Input Constraints

• Published in: IEEE transactions on control systems technology Vol. 31; no. 1; pp. 252 - 264
• Main Authors: Li, Zhongmei, Huang, Mengzhe, Zhu, Jianyong, Gui, Weihua, Jiang, Zhong-Ping, Du, Wenli
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuator saturation; Actuators; Adaptation models; Adaptive control; adaptive dynamic programming (ADP); Algorithms; Antimony; Chemicals; Deep learning; deep learning (DL) model; Design parameters; Disturbances; Dynamic programming; Error detection; Feature extraction; Flotation; flotation processes; Indexes; Iterative methods; Linear quadratic regulator; Machine learning; Optimal control; Predictive models; Process control; Reagents; reagents’ control; Tracking errors
• ISSN: 1063-6536; 1558-0865
• DOI: 10.1109/TCST.2022.3171110

This article presents a learning-based adaptive optimal control approach for flotation processes subject to input constraints and disturbances using adaptive dynamic programming (ADP) along with double-loop iteration. First, the principle of the operational pattern is adopted to preset reagents' addition based on the feeding condition. Then, this article leverages a deep learning model, which is composed of multiple neural layers to detect flotation indexes directly from the raw froth images. After that, the tracking error between the detected flotation indexes and the reference values can be minimized by using ADP-based double-loop iteration. Particularly, a policy-iteration (PI) method is utilized for the proposed learning-based ADP algorithm. In the inner loop, the optimal control problem is formulated as a linear quadratic regulator (LQR) problem using the low-gain feedback design method. In the outer loop, the design parameters, i.e., weighting matrices, are tuned automatically to satisfy the input constraints. Finally, the analytical results demonstrate that the proposed scheme can guarantee asymptotic tracking in the presence of actuator saturation and disturbances.