A Static Model for a Stiffness-Adjustable Snake-Like Robot

In minimally invasive surgery, miniaturisation and in situ adjustable stiffness of robotic manipulators are desired features. Previous research proposed a simple and effective tendon-driven curve-joint manipulator design using a variable neutral-line mechanism, which highly satisfies both criteria. A kinematic model was developed for such a manipulator based on the geometry of the structure. However, such a model assumes that joint angles are all equal between disks without a rigorous derivation, and fails if not all the shapes of the disks are identical. Moreover, the model does not involve an analysis of the tension of each tendon. This paper suggested a static model for predicting the articulation of such a manipulator given the applied tensions on driving tendons. It validates the assumption of equally distributed joint angles and works for manipulators with more general configurations of disks and tendons. It also sets a foundation for further development of tension based control and external force estimation. Simulations on Adams were conducted to prove the correctness of the proposed model. A video demonstrating the simulation results can be found via https://youtu.be/MXhL1LGwLtw

Authors

• Di Shun Huang
• Jian Hu
• Liuchunzi Guo
• Yi Sun 0008
• Liao Wu

Keywords

• Geometry
• Computational modeling
• Friction
• Simulation
• Estimation
• Kinematics
• Manipulators
• Static Model
• Snake-like Robot
• Minimally Invasive Surgery
• Joint Angles
• Rigorous Derivation
• Numerical Methods
• Reference Frame
• Static Conditions
• Rigid Body
• Rotation Axis
• External Load
• Central Axis
• Displacement Vector
• Force Vector
• Load Cases
• Numerical Errors
• Bending Angle
• Disc Center
• Proximal Joints
• Identical Orientation
• Coupler Force
• Static Stability
• Top Contact