Directional Compliance in Obstacle-Aided Navigation for Snake Robots
This addresses the problem of enabling snake robots to navigate tightly packed, unpredictable environments, which is incremental as it builds on biologically-inspired compliance strategies.
The paper tackled the challenge of coordinating snake robots' many degrees-of-freedom for motion in complex, unmodeled terrains by developing a closed-loop control strategy using proprioceptive force sensing, resulting in reliable traversal of a planar peg array and an outdoor 3D rock pile.
Snake robots have the potential to maneuver through tightly packed and complex environments. One challenge in enabling them to do so is the complexity in determining how to coordinate their many degrees-of-freedom to create purposeful motion. This is especially true in the types of terrains considered in this work: environments full of unmodeled features that even the best of maps would not capture, motivating us to develop closed-loop controls to react to those features. To accomplish this, this work uses proprioceptive sensing, mainly the force information measured by the snake robot's joints, to react to unmodeled terrain. We introduce a biologically-inspired strategy called directional compliance which modulates the effective stiffness of the robot so that it conforms to the terrain in some directions and resists in others. We present a dynamical system that switches between modes of locomotion to handle situations in which the robot gets wedged or stuck. This approach enables the snake robot to reliably traverse a planar peg array and an outdoor three-dimensional pile of rocks.