Fedotova M. Automation of the process of stabilizing the height of the boiling layer of seeds in grain dryers according to incomplete measurements

The object of the study is the process of controlling the height of the fluidized bed in a cascade type grain dryer. The aim of the study was to increase the efficiency of drying the seeds in a fluidized bed dryer as a result of maximizing the accuracy of stabilizing the height of the fluidized bed. As a result of the analysis of the design and operating conditions of the dryer, the general task of synthesizing an optimal multidimensional system for stabilizing the height of the fluidized bed of seeds was set and solved based on the signal on the change in the moisture content of the seeds at the dryer outlet, including the identification of the dynamics of a grain dryer with a fluidized bed, the determination of the transfer function matrix of the measuring system, compensation of delays in the grain dryer structure and determination of the optimal regulator model. The results of the simulation showed that with almost identical variances in the variation of the position signals of the gate and the temperature of the agent, the variance of the change in the height of the fluidized bed with respect to the change in height in the system without a regulator is significantly reduced. In this case, the change in the actual moisture content of the material at the outlet from the dryer approaches the theoretical curve of drying as much as possible, that is, by maximizing the accuracy of stabilizing the height of the seeds in the cascade, the drying efficiency is significantly improved.