A Direct Discretization Method of Backbone Curve for Snake Robots With Multiple Roll Joints

A snake robot with multiple roll joints has good advantages in rotational grasping and movement. However, the existing motion methods have limitations in application range and low efficiency. In this article, we proposed a pitch-free motion model based on the backbone curve to represent the motion of snake robots with multiple roll joints. We summarized and classified the configurations of multiroll-joint snake robots and developed the motion equations using the existing indirect discretization method. To further enhance the discretization efficiency, the direct discretization method based on the posture difference of adjacent Frenet–Serret frames is proposed. Then, the number of operations of the proposed direct method compared with the benchmark indirect method shows that the proposed method has less computation burden. Finally, a numeric experiment and the robot manipulating an object experiment are carried out to verify the effectiveness of the proposed methods and the better efficiency of the direct discretization method over the existing indirect method while maintaining a low discretization error.