Modeling of novel circular gait motion through daisy sequence fitting algorithm in a vertical climbing snake robot

Abstract

Snake robots can be used in multiple tasks, like, climbing, surveillance, pipe inspection, welding, and so forth. Current gaits of snake robots do not support rotation on a single horizontal plane in a circular fashion of a pole or tree at a fixed height. This makes snake robot extremely difficult to take the end effector to the desired target position and orientation. In addition, torque requirement of individual actuators or links of snake robot proportionally increases based on the number of links to be lifted while performing any task. In this paper, we propose a new gait called circular gait using the Daisy Sequence Fitting algorithm to solve the problems of circular rotation on a horizontal plane at a certain height with low torque. A sliding mode (SM) controller is implemented to achieve the circular gait's required position dynamically. Simulation results show that using the proposed circular gait, the end effector can be moved to any point on the circumference of the fixed horizontal plane of the pole or tree with a lesser torque. For the 0.5 kg module, circular gait moved the end effector to the target point using only 4.5 N m torque. The SM controller outperforms the proportional, integral, and derivative controllers in terms of response characteristics.