Continuous Drug Delivery System Design Using Nonlinear Decoupling: A Tutorial

The design of nonlinear, time varying, multivariable, coupled system is a complicated task which offers few intuitive guides. Such guides are by contrast abundant in the much simpler task of designing a linear decoupled control system. Decoupling also allows the independent control of the system outputs in the presence of input interactions. The implications of these ideas in the design of control systems for continuous drug infusion have never been explored. This tutorial demonstrates the usefulness of nonlinear decoupling in the context of drug delivery using simple examples. First, decoupling by differentiation of the output equation is demonstrated. Next, two special cases where decoupling is achievable by input redefinition ann by input and state redefinition are given. Finally, limitations of the approach are discussed together with ongoing research to overcome them. The presentation avoids complex mathematical derivations and demonstrates that nonlinear decoupling can be applied using basic calculus.