Towards model‐guided feedback control of hydrogels bioprinting

Abstract This contribution addresses the problem of controlling the Degree of Crosslinking (DoC) in printed hydrogels through feedback control as a product quality indicator from a modeling approach. We set up a simulation that resembles co‐axial printing of calcium‐alginate (Ca‐Alg) hydrogel as a case study. A well‐known Ca‐Alg gelation model composed of a set of nonlinear coupled diffusion‐reactions equations is adopted as a high‐fidelity model (HFM). A traditional proportional‐integral (PI) controller is designed based on a reduced‐order state‐space linear model of the gelation process. The linear state‐space model is identified from input‐output data collected from the HFM. We formulate an optimization problem to find optimal PI controller parameters that minimize a closed‐loop performance index. The PI controller is directly applied to the nonlinear diffusion‐reaction model to guide the printing process towards a desired DoC. We show its efficacy via some numerical simulations.