Networked Multirate Output Feedback Control for Setpoints Compensation and Its Application to Rougher Flotation Process

Abstract

This paper investigates the setpoints compensation for a class of complex industrial processes. Plants at the device layer are controlled by the local regulation controllers, and a multirate output feedback control approach for setpoints compensation is proposed such that the local plants can reach the dynamically changed setpoints and the given economic objective can also be tracked via certain economic performance index (EPI). First, a sampled-data multivariable output feedback proportional integral (PI) controller is designed to regulate the performance of local plants. Second, the outputs and control inputs of the local plants at the device layer are sampled at operation layer sampling time to form the EPI. Thus, the multirate problem is solved by a lifting method. Third, the static setpoints are generated by real-time optimization and the dynamic setpoints are calculated by the compensator according to the error between the EPI and objective at each operation layer step. Then, a networked case is studied considering unreliable data transmission described by a stochastic packet dropout model. Finally, a rougher flotation process model is employed to demonstrate the effectiveness of the proposed method.