UC Berkeley

Small-scale folded legged robots have demonstrated exceptional mobility in laboratory environments. However, in real-world applications, these robots require added robustness. This thesis introduces LoadRoACH, a 54.8 g palm-sized folded legged robot that carries a protective shell and an active tail (totaling 27.2 g). These added components enable LoadRoACH to survive high drops, rapidly self-right, and turn with enhanced maneuverability. First, a thermoforming manufacturing process is developed for integrated shells that protect folded legged robots from impacts and water/granular media. Next, design details are presented for LoadRoACH that enable dynamic running while carrying significantly larger payloads than previous folded legged robots. Then, dynamic self-righting with tail/terrain pushing is analyzed and tested using a modified VelociRoACH robot, which is a precursor to LoadRoACH. VelociRoACH can dynamically self-right on low-friction, high-friction, and granular terrain in as little time as 256 ms. In an autonomous self-righting experiment, VelociRoACH detects inversion and rapidly self-rights while walking over an obstacle with multiple step drops. Finally, two novel turning strategies that leverage tail/terrain contact during forward running are analyzed and implemented using LoadRoACH. The first strategy drags the tail against high-friction terrain to produce sustained turns with comparable maneuverability to differential drive turns. The second strategy impacts the tail against low-friction, high-friction, and granular terrain to produce rapid point turns with a heading change of up to 90 deg in 0.8 s. In an aggressive corner steering maneuver, a combination of tail drag and tail impact turning on a carpet surface enable the robot to advance further along the desired heading when compared to differential drive turning.