72.2 Saturday, Jan. 5 Using dynamic similarity scaling to inspire the design of a high-speed hexapedal millirobot. HALDANE, D. W.**; FEARING, R. S.; University of California, Berkeley; University of California, Berkeley firstname.lastname@example.org
The cockroach, Periplaneta americana, is a highly dynamic running insect, exhibiting a variety of robust and high speed gaits that we used as a model to study for the design of a highly dynamic robot. Using dynamic scaling from the cockroach, we determined the system parameters such as mass, leg stiffness and operating frequency for VELOCIRoACH, a 10cm long hexapedal millirobot, fabricated using our Smart Composite Micro Structure process. The robot weighs 30g, operates in a frequency range of 2 – 26Hz, and shows spring-mass like ground-reaction forces, like the insect. Noting that P. americana has very slender legs, we minimized the mass of the running appendages and all moving transmission components, to reduce the energy required for limb recycling. Surprisingly, the scaled legged robot was capable of locomotion at speeds up to 26 body lengths per second, making it, relative to size, the fastest running robot to date. This performance is comparable to the expected top speed of the scaled model system. In addition, using a novel application of an analysis based on the comparison of the three dimensional angular momentum of the robot and animal, we discovered significant similarities between the stable periodic angular rotations of the two systems during locomotion. All three components of rotation are comparable in magnitude, phase and frequency when mapped over a stride. The robotic model system successfully maintained the dynamic properties of the animal. These findings offer significant evidence for the power of using dynamic similarity as a design tool. Moreover, we demonstrated the degree to which -- even unaccounted for -- dynamic oscillations are preserved when a dynamically scaled system is implemented on a robotic platform.