Meeting Abstract
Limbless robots have the potential to assist with many applications, however their performance in heterogeneous environments does not match that of living systems. In particular, collisions with obstacles may lead to unwanted reorientations, impacting the ability of the robot to reach a goal. We hypothesize that sensing robot-obstacle contact forces and durations from collisions could be used to decrease the duration of the collision or reorient itself advantageously. To learn how important collisions – those with the head — affect locomotion, and how these interactions could be used to assist the snake, we studied a simple robophysical snake moving through vertical posts. The robot locomotes on hard ground by commanding the joint angle positions of 12 servo motors to vary sinusoidally with time and position along the body, and uses passive wheels attached to each segment to provide a frictional anisotropy. In an open-loop robot without sensing, the robot is “diffracted” by collisions. This rotation is dominated by head-obstacle collisions with larger rotations resulting from longer contact durations. We hypothesize that integrating sensing on the head of the robot will enable the robot to reduce collisional diffraction effects. Simulations show that there is a positive correlation between snake amplitude and scattering angle, so we expect that reducing the snake amplitude at the time of contact will reduce scattering behavior. We added capacitive sensors to the robot head and tested control schemes which temporarily and locally modify the shape of the snake to reduce the duration of the contact with the peg.
