A 1.5g Ornithopter with Enhanced Maneuverability
S. Bergbreiter, S. K. Gupta, D. Vogtmann
This project is sponsored through an ISR seed grant.
Micro air vehicles, Meso-scale manufacturing, MEMS
Small, lightweight, highly maneuverable micro air vehicles (MAVs) have numerous applications in both military and civilian settings. Insect-inspired MAVs can fly through hallways and monitor an area undetected due to their small size and stealth. They will also be very helpful for search and rescue missions during natural disasters where terrain or rubble may be unstable. While insects such as moths and butterflies can accomplish similar tasks without difficulty, engineered versions of nature have yet to catch up with the real thing. To reach similar size scales, a number of challenges exist including a lightweight frame, motor, and control actuators. In addition, integration of the various robot parts is difficult based on the size, weight and inevitable packaging.
Given a target MAV mass of 1.5g, the following fundamental challenges need to be addressed:
1. High degrees of freedom (DOF) in small form factors. Replicating articulation found in nature using traditional assembly processes leads to high part counts and often impossible assembly steps. This also seriously limits the structure sizes due to the size constraints imposed by the currently available manufacturing processes. We will develop a new method of manufacturing highly articulated structures of small size – specifically a fully compliant wing flapping structure.
2. Small, high force, and energy efficient actuators. In nature, muscle provides small, relatively energy efficient, and compliant actuators that are not easily replicated and cannot be found off-the-shelf. Small actuators can be used to provide subtle changes in compliance to enhance maneuverability in MAVs or ground robots. Current actuation strategies are not energy efficient (thermal actuation – shape memory alloy or SMA), do not provide the high forces required (MEMS), or are not compliant. We will develop small, high force density, energy efficient, and compliant actuators to enhance maneuverability in MAVs, although focus in this first year will not be on energy efficiency.
3. Electronics integration with small form factors. The proposed MAV will require the use of sophisticated on-board electronics for remote control and will eventually require additional elements for control, communication, and sensing. In small systems such as MAVs, electronics can account for 30% of the overall weight, most of which is in component housings and circuit boards. In contrast to engineered systems, nature uses multi-functional packaging where structural members serve as the packaging material. We will need a fundamentally new approach to embed electronics components in small structural members.
Dr. Sarah Bergbreiter
Department of Mechanical Engineering and Institute for Systems Research
2170 Martin Hall
University of Maryland
College Park, MD-20742