Design and analysis of snake robot locomotion using artificial snake scale

Abstract

The amazing locomotion capability of natural snakes is the central essence of this research. Among the four-basic kind of locomotion, the serpentine locomotion gives the snake fastest and comfortable journey towards the destination. Snake robots are mainly designed and developed based on the assumption of frictional anisotropy of the ventral scales and sequential use of the muscles to move the body in a harmonic sinusoidal pattern. Very few works have been carried out on the effect of scales on the motion of the snake robots, specifically the effect of geometry of the scales. Thus this research tried to explore the effects of artificial snake scales and their geometry on the motion of snake robots. The research started with the study of the serpentine locomotion of a real snake. The subject of the investigation was a Python Reticulatus, a young python at an age of 10 months. A simple setup was designed and fabricated to study different locomotion parameters from the real snake. The study proved the previous literatures and thus showed a way to work on a robot. Afterward different types of snake scale were designed and a mechanism to extract the force data from the scale was developed. The scales along with the force sensing system were attached at the ventral side of a nine link snake robot. The motion and force data of the snake robot were then acquired while running in a test bed. The robot was operated on three different types of surfaces: floor mat, engine gasket, and artificial leather. Analyses of the data revealed that uniform friction in all directions gives some insignificant motion of the robot without any predicted path. Whereas higher frictional anisotropy gives the robot more definite direction of movement. It is also found that significant anisotropy, especially higher lateral friction, gives more stability in direction. On the other hand, reduction in forward friction gives faster forward movement to the robot. This finding conformed to the results of energy consumption. It was also found that small scales at the lateral edges of the robot body contribute to the effective forward motion of the robot while such scales covering small area on the central line do not give any motion along the direction of the robot except lateral oscillation. Thus, this research leads to further improvement in scale characteristics of the robot to reach an optimum point of speed, energy consumption and accuracy.