Recovery Methods of Unmeasured Variables for Biological Models

The paper presents modeling the SA-node operation. This research aims at comparing two different methods for constructing an observer according to some characteristics of numerical simulation for the pacemaker model: a nonlinear observer with linear error dynamics and a lower-order observer with nonlinear corrections. We compare two different observers using qualitative characteristics. The results show that the nonlinear observer with small tuning parameters converges more slowly than a lower-order observer. The nonlinear observer has the best accuracy with small tuning parameters. In the case of real-time monitoring, it is more optimal to use the nonlinear observer with linear error dynamics because it does not require a small integration step. The results can be appliyed to the further simulition of biological systems.