Static modeling and analysis of continuum surgical robots

Continuum Robots have been investigated increasingly in recent years due to their potential applications in minimally invasive surgery (MIS). The constant curvature assumption is widely adopted in modeling the motion of continuum robots. However, due to their limited backbone rigidity, the backbone bending or end-effector position is significantly affected by both the internal driven force and external load. This paper focuses on the static analysis of the continuum robots. Statics model of the robot is established based on the Newton-Euler method. Gravity of the elastic tubes and the disks are both considered in the modeling. Based on the static model, the shape of the robot can be calculated with given external loads and internal driven force (i.e. cable tension). The model is validated using finite element method (FEM). The error is less than 0.02 percent. Simulation results reveal that, the shape of the robot is significantly affected by the external load. A S-type bending can be observed with certain loading conditions. Therefore, the commonly adopted constant curvature is invalid in loaded circumstances.