Abstract
The object of the study is the process of copper-sulfide ore flotation in a mechanical flotation machine. The problem of increasing the stability of the process with changing power characteristics and the limited information content of standard measuring channels was addressed. A method of supervisory control of air and flotation-reagent flow rates is proposed, combining technological parameters and visual characteristics of the froth layer. A two-channel dynamic model, a froth-state index and an algorithm for limited correction of the setpoints of local PID controllers were developed, taking into account the dead zone and amplitude and rate limits. A distinctive feature of the method is the verification of the reliability of video data and the transition to control based on technological parameters in the event of loss of the visual channel. The study is a simulation-based demonstration on a generic model of a flotation cell; no industrial data were used. The efficiency was evaluated in 50 simulation runs with stepwise, random, and combined disturbances, measurement noise, transport delays, and a temporary loss of the video signal. Compared with PID control at constant setpoints, the multimodal supervisor reduced the integral absolute error of the froth state by 66.5%, the error of the conditional (simulated) concentrate quality indicator by 48.1%, the integral squared error by 84.6%, and the standard deviations of these indicators by 49.1% and 22.3%, respectively. The reductions are relative to fixed-setpoint PID in simulation; acceptance criteria for production must be defined on industrial data. The effect is explained by the combined use of visual and technological feedback. The results were obtained by simulation; the method is designed to be integrated into a PLC–SCADA structure without replacing local circuits, and its industrial validation is the next step.