Survey of Modeling Failures, Dynamics, and Nonlinearities in Advanced Life Support Systems

System failures, dynamics, and nonlinearities can cause unacceptable performance and damaging instability in Advanced Life Support (ALS) systems. Much current ALS modeling assumes that ALS systems are linear, static, and failure-free. But in reality most ALS hardware is subject to failure, real ALS systems are dynamic, and many ALS processors are nonlinear beyond a limited operating range. Modeling and simulation are needed to study the stability and time behavior of nonlinear dynamic ALS systems with failures and to develop appropriate controls.

The nonlinear dynamics of ALS systems has many interesting potential consequences. Different equilibrium points may be reached for different initial conditions. The system stability can depend on the exact system inputs and initial conditions. The system may oscillate or even in rare cases behave chaotically. Temporary internal hardware failures or external perturbations can lead to dynamic instability and total ALS system failure. Appropriate control techniques can restore reliable operation and minimize the effects of dynamic instabilities due to anomalies or perturbations.