This work proposes a tracking error passivity-based multivariable control via
feedback passivation for a class of free-radical polymerization systems in a continuously
stirred tank reactor (CSTR). Firstly, this system dynamics with high nonlinearity is
passivized by input coordinate transformations, the resulting passive system is then rewritten into a canonical form strongly related to the so-called Port Control Hamiltonian
structure. Actually, this representation allows to show the physical meanings of system
dynamics such as dissipative, non-dissipative terms and supply rate. From this, a feedback
controller based on tracking error is designed for the globally exponential stabilization at
an arbitrarily chosen reference trajectory passing the desired equilibrium point. The
theoretical developments are then illustrated for polystyrene polymerization system in
the CSTR. The numerical simulations show that the trajectories of styrene polymerization
system considered as an illustrative example of FRP system converges globally
exponentially to the imposed trajectories.

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