Adaptive observer-based controller for biological clock in crassulacean acid metabolism

The nonlinear dynamical behavior of the crassu-lacean acid metabolism is discussed from the control theoretical viewpoint. The state-variables of the nonlinear dynamic equations are an internal CO₂ concentration, a malate concentration in the cytoplasm, a malate concentration in the vacuole, and an order of the tonoplast membrane. The input variables are an external CO₂ concentration, a light intensity and a temperature. The order of the tonoplast membrane cannot be measured. We have recently presented a dynamic estimator of the tonoplast order and a fuzzy identifier of the nonlinear function in the dynamics of the tonoplast order. In this paper, we propose two types of the feedback controllers of the CAM model using the estimate of the adaptive controller.