Research over the past several decades has elucidated some of the mechanisms behind high speed, highly efficient, and robust locomotion in insects such as cockroaches. Roboticists have used this information to create biologically inspired machines capable of running, jumping, and climbing robustly over a variety of terrains. To date, little work has been done to develop an at-scale insect-inspired robot capable of similar feats due to challenges in fabrication, actuation, and electronics integration for a centimeter-scale device. This paper addresses these challenges through the design, fabrication, and control of a 1.27 g walking robot, the Harvard Ambulatory MicroRobot (HAMR). The current design is manufactured using a method inspired by pop-up books that enables fast and repeatable assembly of the miniature walking robot. Methods to drive HAMR at low and high speeds are presented, resulting in speeds up to 0.44 m/s (10.1 body lengths per second) and the ability to maneuver and control the robot along desired trajectories.

Abstract-Here we present the design, modeling, and fabrication of a 2g mobile robot. By applying principles from biology and existing meso-scale fabrication techniques, a 5.7cm hexapod robot with sprawled posture has been created, and is capable of locomotion up to 4 body-lengths per second using the alternating tripod gait at 20Hz actuation frequency. Furthermore, this work proves the viability of a new mechanical linkage design, fabricated using the smart composite microstructure process, to provide desirable leg trajectories for successful ambulation at the insect-scale.

Here we present the design and fabrication of a 90mg hexapedal microrobot with overall footprint dimensions of 17 mm long x 23 mm wide. Utilizing smart composite microstructure fabrication techniques, we combine composite materials and polymers to form articulated structures that assemble into an eight degree of freedom robot. Using thin foil shape memory alloy actuators and inspiration from biology we demonstrate the feasibility of manufacturing a robot with insect-like morphology and gait patterns. This work is a foundational step towards the creation of an insect-scale hexapod robot which will be robust both structurally and with respect to locomotion across a wide variety of terrains.

Abstract-Here we present an autonomous 1.7g hexapod robot as a platform for research on centimeter-scale walking robots. It features six spherical five-bar linkages driven by high energy density piezoelectric actuators and onboard power and control electronics. This robot has achieved autonomous ambulation using an alternating tripod gait at speeds up to 0.9 body lengths per second, making this the smallest and lightest hexapod robot capable of autonomous locomotion.

Abstract-Onboard power remains a major challenge for miniature robotic platforms. Locomotion at small scales demands high power densities from all system components, while limited payload capacities place severe restrictions on the size of the energy source, resulting in integration challenges and short operating times when using conventional batteries. Wireless power delivery has the potential to allow microrobotic platforms to operate autonomously for extended periods when near a transmitter. This paper describes the first demonstration of RF wireless power transfer in an insect-scale ambulatory robot. A wireless power transmission system based on magnetically coupled resonance is designed for the latest iteration of the Harvard Ambulatory MicroRobot (HAMR), a piezoelectrically driven quadruped that had previously received power through a tether. Custom power and control electronics are designed and implemented on lightweight printed circuit boards that form a part of the mechanical structure of the robot. The integration of the onboard receiver, power and control electronics, and mechanical structure yields a 4cm, 2.1g robot that can operate autonomously in two wireless power transmission scenarios.