System identification technique for control of hybrid bio-system

Effective and accurate system parameters in physical system are crucial for the analysis and prediction of dynamic performance and to conduct control. A hybrid bio-system combined using solid and flexible bio-elements is adopted as the target system in this study. Each individual system has its own nonlinearity in nature. A flexible muscle is represented using a Hill-type model. In addition, the hybrid dynamic system exhibiting nonlinearity is modeled using the Hammerstein-Wiener model. These nonlinearities are characterized through piecewise linear approaches. The dynamics and control performance of the systems using the proposed nonlinear system identification are compared with those of linear system identification. Simulation results show the feasibility of the proposed nonlinear system identification technique in extracting effective system parameters with a varying piecewise linearity. Moreover, the possibility of bio-system control is qualitatively revealed. A sequential PID control scheme also shows its successful performance for a hybrid bio-system.