Origami-inspired, high energy-density, low-voltage voice coil actuators for autonomous micro-robotic applications

Sub-centimeter robotic systems have traditionally used piezoelectric bending actuators to actuate their various degrees of freedom due to their high-bandwidth and ease of control. However, they require high-voltage power electronics to operate, complex transmission mechanisms to amplify motion and thus, have a reduced force output limiting their ready implementation for actuating high-dimensional autonomous systems such as the limb of a legged robot to replicate animal-like dexterity. Voice-coil architecture based electromagnetic motors serve as attractive alternatives. Our origami-inspired, unidirectional, multi-scale fabrication technique leverages carbon fiber laminate and flexure based Sarrus linkage to function as both the housing and transmission unit, and when integrated into a single robot leg mechanism displays long-stroke high-force output and low-voltage operation. Preliminary modeling and experimental results show that our prototype (1.4cm in dimension), using a 3.175mm cubical N52 magnet produces about 50 times its body weight as static Lorenz force on a 41AWG, 46-turn, 4.75 mm diameter tightly wound coil with a constant input current of 0.1 A. Using impedance control, we propose to demonstrate various single-legged high-frequency hopping behaviors.