Photo-patternable adhesives and silicones are introduced for use in centimeter-scale robotics. Traditional approaches to making robots at this size scale require the use of expensive start-up equipment and/or precise machining, and generally yield fragile and costly robots in small numbers. The multi-material milli-robot prototyping process that we have developed uses Loctite® polymer products and photolithography to rapidly fabricate robust, inexpensive, and compliant robots only centimeters in size. The process flow has been described and characterized with minimum feature sizes of 0.25mm in polymer layers 0.18mm thick. Both commercial and ink-jet printed masks are used for the photolithography steps. Finally, a functional inchworm robot and a small gripper have been designed and demonstrated with Nitinol shape memory alloy (SMA) used for actuation. The gripper is 1.2g and costs $3.31 in small numbers while the inchworm robot is 7.4g and costs $7.72 in small numbers. Building a functional robot from a computer design takes less than 1 hour.
Current and Future Research
Current small scale robots are expensive and require lengthy fabrication and assembly times. These robots also lack the compliance and robustness to perform well in unstructured environments. We have developed a new process to rapidly prototype inexpensive and robust centimeter-scale robots without the use of clean room facilities or expensive equipment. The use of Loctite® photo-patternable polymers can create several possibilities in the field of small robotics by eliminating the expense, fragility and complexity of traditional small-scale robots. We are currently pursuing prototyping more complex and efficient robots and demonstrate this process on a small scale with a robot that is fully autonomous and has embedded components. A future objective is a walking robot with an attached gripper for multi-robot assembly. Efforts will also be made to integrate more efficient actuators to improve robot efficiency. Finally, further testing of durability and long term use of the polymer structures are also extensions to this work.