American researchers at the Wyss Institute, Harvard University, and CSAIL, a laboratory at MIT, recently took a major step forward in the field of flexible robots by creating artificial muscles out of plastic inspired by origami, the Japanese art of folding paper.
These robotic, sturdy, affordable and lightweight "actuators" (muscles) have many strengths. They are able to lift one thousand times their own weight, and can also be dissolved in certain liquids. It is almost like giving super powers to the robots. Now that artificial muscles have similar properties to natural muscles, it is easy to imagine building a robot for any and every task!
The muscles comprise a compressible skeleton, actually a plastic sheet or metal spring folded into an accordion shape, covered with water or fluid and encapsulated in a plastic or paper membrane functioning as the "skin". A pipe pumps out the air or water to activate the muscle: the vacuum created causes the skin to shrink onto the skeleton and initiate the movement of the muscle. The shape and the type of fold will lead the muscle to "contract" or "relax". The results are impressive. Some of the muscles were able to contract to 10% of their initial size, deform into a spiral shape or pick a flower, all achieved by creating a vacuum under their skin.
Depending on the desired properties such as elasticity, transparency, solubility, etc., the skeleton may be made from silicon, polyester or steel, while the "skin" may be made from a TPU, PVC or PVA film.
A 2.6 g muscle can lift an object weighing 3 Kg. In addition to mobility and strength, the muscles are also quickly produced (in a dozen minutes) and affordable. The final advantage is that they behave almost identically regardless of whether they measure a few millimetres or a metre in size. This means that very varied applications will be possible, including surgery, portable robotic exoskeletons, architecture, exploring the depths of the ocean and space. These origami-shaped muscles could be the start of a revolution in robotics.