Study Of Model Predictive Control Aggregation Simplification Algorithm In Beer Fermentation Temperature

Because the temperature control system of beer fermentation process is a complex multivariable system with large-time delay, strong coupling, its control becomes an urgent and difficult research project. As a category of control algorithm adopting online receding horizon optimization,model predictive control (MPC) attracts much attention of industrial and theoretical researchers due to its good control performance.Due to the constraints of complex characteristics and running environment,MPC need a larger prediction horizon and control horizon.That increases the quantity of controller computation and control cycle time,and decreases the control quality.For a MPC controller, the issues such as stability or control performance are dependent on the online optimization strategy adopted. This paper presents a model predictive control, aggregation simplification algorithm, and applies it to the temperature of beer fermentation control. In order to guarantee the control performance of aggregation based MPC,the equivalent aggregation algorithm is put forward. The results demonstrate its effectiveness.The main contents of the research in this paper are asfollows(1) Under the premise of understanding the process and control requirements of beer fermentation, the difficulties in the process of beer fermentation represented by the temperature are analysed. The conventional PID control in dealing with large time-delay, strong coupling, multivariable, uncertainties objects are uneffective. This paper presents a new design method of multivariable decoupling and discuss its stability. The effectiveness and shortcoming of the proposed design method is confirmed by the experimental results.(2)The aggregation algorithm is introduced.Outline three typical aggregation algorithms;focus on the attenuation aggregation algorithms and analysis the relations between the dimensions of aggregation matrix,arrangement of elements,attenuation and control performance.The simulation analysis the results and obtain guidelines about aggregation matrix.(3) According to the characteristics of the beer fermentation temperature process object, the paper establishs the process object model of mutual coupling three input and three output through mechanism analyses on the model structure and through the test to identify the parameter values of model structure. Due to the model predictive control aggregation algorithm can deal with this model control well, it has better effects than decoupling control, and it has advantages in the respect of overcoming model uncertainty. But it does not guarantee its control performance in dealing with large time-delay object. So in order to guarantee the control performance of aggregation based MPC, according to the predictive control rolling optimization features, i.e. only the first control applied to the control object, the equivalent aggregation strategy is proposed,and the algorithm is applied to the temperature control of beer fermentation. Lastly, the paper has the simulation of algorithms, through simulation results, it shows the control method can be very good to overcome the difficulties of beer fermentation temperature control, and it has good control effects.