| Many applications, such as search and rescue missions, hazardous environment exploration, and surveillance, call for miniature robots capable of agile locomotion in a variety of unpredictable environments. Recent advances in meso-scale fabrication techniques and an understanding of biological insect locomotion have enabled the creation of multiple miniature legged robots to meet this demand. Nearly all insect-scale legged robots take inspiration from rigid-body hexapods; however, another unique body morphology found in nature is that of the centipede, characterized by its many legs and flexible body. These characteristics are expected to offer performance benefits in terms of agility, stability, robustness, and adaptability.;This thesis presents the design of a millirobot with many legs and a passively flexible backbone, both novel qualities for a robot at this scale. A modular hybrid-dynamic model of the horizontal plane motion effectively predicts locomotion trends on flat terrain and provides guidance in choosing design parameters for centipede-inspired millirobots. This millirobot demonstrates the use of body undulations similar to those of its biological counterpart, which are shown to enhance straight-line locomotion by increasing speed. These undulations arise passively, reducing the number of required actuators and simplifying control. A turning strategy is developed to enable an n-segment millirobot to perform a variety of maneuvers with only two independent drive signals. An experimental robustness study illustrates graceful degradation of locomotion performance, as opposed to immediate failure, in the presence of appendage damage, demonstrating an advantage to a many-legged design. Finally, the passively flexible body and many legs are shown to provide increased ground contact and stability when traversing obstacles, resulting in faster speeds over rough terrain compared to similar millirobots with rigid bodies and/or only six legs. These results suggest this millirobot design could result in improved performance for miniature legged robots as well as provide insight into biological locomotion at small scales. |
