Dynamic model and fuzzy adaptive control of a Chinese medicine sugar precipitation process

A model dedicated to Chinese medicine sugar precipitation was designed, without consideration of crystal size distribution. Fuzzy adaptive robust control algorithm was proposed for the uncertain nonlinear systems based on Lyapunov´s stability theory. The system was divided into nominal model and lumped disturbance term which embodies model mismatch, parameter uncertainties, and disturbances. Fuzzy adaptive control was adopted to approach uncertain parameters of the system in real time and the impact of unknown disturbances was eliminated by robust control. The on-line calculation amount of fuzzy logic system is relatively less, the convergence rate and accuracy are better, and the output of system tracks the setpoints well. The stability was proved and the algorithm was applied to the precipitation control of sucrose-glucose mixed solution. Simulation results supported the validity of the proposed algorithm.