Adaptive Robust Dynamic Surface Control of Nonlinear Continuous Bioreactor Systems with Actuator Dynamics Consideration

Advanced control of bioreactor systems is crucial for improving efficiency and reliability in industrial bioprocesses. This paper proposes an adaptive robust dynamic surface control (DSC) approach for continuous stirred bioreactors characterized by nonlinear microbial growth and significant model uncertainties. The novelty of the method lies in the explicit integration of actuator dynamics, which are often neglected in previous studies but play a critical role in practical implementations. The proposed DSC framework effectively compensates for both parametric and non-parametric uncertainties using adaptive estimation and robust control laws. Lyapunov-based stability analysis demonstrates that all tracking errors are uniformly ultimately bounded within a compact set. Numerical simulations performed in MATLAB validate that the substrate concentration rapidly and accurately tracks the desired trajectories despite considerable parameter uncertainties and actuator disturbances. Furthermore, the adaptive mechanism ensures that the estimated bounds on uncertainties remain stable throughout operation, confirming the robustness and practical applicability of the control scheme for industrial bioreactor systems.