A paper-based electrostatic zipper actuator for printable robots

A paper-based electrostatic zipper actuator for printable robotics has been designed, fabricated and charac- terized. A simple fabrication process that utilizes paper with a carbon nanotube ink is used to create electrodes separated by either a mylar or parylene dielectric layer. A 5 cm x 1 cm actuator demonstrated a maximum static deflection of 1.8 cm and a bandwidth of approximately 12 Hz. Static power dissipation was under 1 µW. Two of these actuators are combined to demonstrate simple motion in a 6 cm x 1 cm x 1 cm robot using assymetric friction with the ground, achieving speeds up to 33 mm/min. I. INTRODUCTION Robots that can be printed on paper and folded into their final 3-dimensional shape offer the ability to easily, quickly, and inexpensively create robots with varying designs and functionality. Recent incarnations of these "printable" robots have demonstrated walking, crawling, rolling, and grasping (1), (2), (3), (4), (5). These robots are not far removed from previous demonstrations in robotic origami in which various shapes could be folded using compliant joints fabricated using the Smart Composite Microstructures (SCM) process (6), (7). In general, these robots have focused on printing and fold- ing to create robot mechanisms and linkages as opposed to active components like motors and sensors. Some actuators have been integrated to automatically fold printed robots - shape memory alloy (8) and shape memory polymer (3) are two examples. These materials can be integrated with fabrication processes like SCM, which make them compatible with printable robots. Once the robot is folded however (automatically or manually), locomotion is often driven by off-the-shelf electromagnetic actuators like DC motors or servos due to greater efficiency and speed (3), (4), but shape memory alloys are also used (2). Other work has demonstrated shape memory alloys integrated on printer paper (in contrast to the more expensive polymer materials used more commonly with SCM) to fold and actuate origami structures (9). Given the goal to quickly and inexpensively create print- able robots, it would be ideal if the actuation driving lo- comotion in these robots could also be printed. It is also advantageous to reduce the power requirements of these actuators (and therefore the requirement for a large battery) while maintaining high speeds for more dynamic robot