Dynamic Rolling for a Modular Loop Robot

Reconfigurable modular robots have the ability to use differ ent gaits and configurations to perform various tasks. A roll ing gait is the fastest currently implemented gait available for tra ve sal over level ground and shows dramatic improvements in efficiency. In this work, we analyze and implement a sensor-based feedba ck controller to achieve dynamic rolling for a loop robot. Th e robot senses its position relative to the ground and changes its shape as it rolls. This shape is such that its center of gra vity is maintained to be in front of its contact point with the ground , so in effect the robot is continuously falling and thus acce lerates forward. Using simulation and experimental results, we sho w w the desired shape can be varied to achieve higher termin al velocities. The highest velocity achieved in this work is 26 module lengths per second (1.6m/s) which is believed to be th e fastest gait yet implemented for an untethered modular robot. One of the major findings is that more elongated shapes achieve high er terminal velocities than rounder shapes. We demonstrate th t this trend holds going up as well as down inclines. We show t hat rounder shapes have lower specific resistance and are thus mo re energy efficient. The control scheme is scalable to an arbi tr y number of modules, shown here using 8 to 14 modules.