Dynamic simulation research on a 2-DOF catheter robot

This study focused on the dynamic behavior of an active catheter actuated by 3 shape memory alloy (SMA) coil springs. The bending mechanics, the SMA's characteristic described by Iiang' s model, and a heat transfer model were combined to derive the dynamic model. A mixed fuzzy controller (MFC) was designed under the consideration that it is difficult to control 2 adjacent SMA actuators by decoupling since there exists strong coupling effect between two degrees of freedom (DOFs) of such a two-input two-output (TITO) system, and the SMA possesses high nonlinearity. In the controller two traditional fuzzy controllers control 2 DOFs respectively and two coupling fuzzy controllers compensate for the dynamic coupling between 2 DOFs. The simulation results indicate the derived dynamic model can accurately describe the characteristic of such a structure and the MFC possesses an effective performance.