A Robust Model-Based Radius Estimation Approach for Helical Climbing Motion of Snake Robots

In this article, a radius estimation approach for snake robot's helical climbing motion is proposed, which enables a snake robot successfully implementing compliant helical climbing along pipes/trees with varying radius. More specifically, a mathematical model is first set up to describe the relationship between the helical rolling gait and the radius information. Based on the model, a robust radius estimation approach, consisting of two important stages of multistep calculation and curve fitting, is then proposed, which utilizes the measurements of joint angles as feedback to generate an accurate estimation for the radius of pipes/trees. Utilizing the estimation result, a control algorithm is then employed to make the robot climb along pipes/trees successfully, even when the radius changes over time. Some experimental results are collected and then analyzed to show the superior performance of the proposed robust model-based radius estimation approach.