A passively sprawling miniature legged robot

The paper reports on the design and preliminary experimental testing of a novel 3D-printed miniature legged robot. It is called Passively Sprawling Robot (PSR), and it features a mechanism that achieves passive adjustment of the sprawl angle of the robot´s legs. Passive sprawling in this robot exhibits compliance by design, yet it can be controlled indirectly by regulating the yaw rate. Spring-loaded assemblies on the left and right side of the robot function independently, allowing the vehicle to overcome asymmetrical obstacles with improved lateral stability, and withstand falls from moderate heights without sustaining structural damage. The regulation of the sprawling angle by means of varying yaw rates, as well as the improved motion characteristics have been experimentally observed and verified, and open-loop motion accuracy along straight and constant curvature paths was tested on a number of repeated trials.