Bio-inspired mechanisms for inclined locomotion in a legged insect-scale robot

Legged locomotion is an open problem in robotics, particularly for non-level surfaces. With decreasing robot size, different issues for climbing mechanisms and their attachment and detachment appear due to the physics of scaling. This paper describes micro-scale phenomena for different adhesion methods that can be employed in microrobots. These adhesion methods are applied to a sub-2 gram legged robot, the Harvard Ambulatory MicroRobot (HAMR), by leveraging recent advances in milli- and micrometer-scale manufacturing. The presented designs utilize different passively oriented adhesives on the legs of the robot to improve inclined locomotion performance. A 3DoF ankle joint is designed and implemented and the effects of a passive tail are studied. As a result, HAMR's climbing capability is increased from 3° inclines to 22° inclines and 45° declines. Finally, an analytical model of leg and foot force generation is presented and compared with experimental force data from the attachment mechanism on a single-leg experimental setup.