Tactile Sensing and Terrain-Based Gait Control for Small Legged Robots

Abstract

For small legged robots, ground contact interactions significantly affect the dynamics and locomotion performance. In this article, we designed thin, robust capacitive tactile sensors and applied them to the feet of a small hexapod with C-shaped rotating legs. The sensors measure contact forces as the robot traverses different types of terrain including hard surfaces with high or low friction, sand, and grass. Different gaits perform best on different types of terrain. Useful measured parameters include the magnitude and timing of the peak normal forces, in combination with the leg rotational velocity. The measured parameters were used in a support vector machine classifier to identify terrain types with 82.5% accuracy. Based on gait performance studies, we implemented a terrain-based gait control using real-time terrain classifications. A surface transitioning test shows 17.1% increase in body speed and 13.2% improvement in efficiency as the robot adjusts its gait.