In an effort to make robots more effective and versatile teammates for soldiers in combat, researchers are looking to understand the value of the molecular living functionality of muscle and the fundamental mechanics that would need to be replicated in order to artificially achieve the capabilities arising from the proteins responsible for muscle contraction.

Bio-nanomotors, like myosins that move along actin networks, are responsible for most methods of motion in all life forms. Thus, the development of artificial nanomotors could be game-changing in the field of robotics research. Research is being conducted to identify a design that would allow the artificial nanomotor to take advantage of Brownian motion, the property of particles to agitatedly move simply because they are warm.

Developing these fundamental mechanics is a necessary foundational step toward making informed decisions on the viability of new directions in robotics involving the blending of synthetic biology, robotics, and dynamics and controls engineering. By controlling the stiffness of different geometrical features of a simple lever-arm design, for example, researchers used Brownian motion to make the nanomotor more capable of reaching the desired positions for creating linear motion. The nano-scale feature translates to more energetically efficient actuation at a macro scale, meaning robots that can do more for the warfighter over a longer amount of time.

The capacity for Brownian motion to kick a tethered particle from a disadvantageous elastic position to an advantageous one, in terms of energy production for a molecular motor, has been illustrated at a component level, a crucial step in the design of artificial nanomotors that offer the same performance capabilities as biological ones. These models will be integral to the design of distributed actuators that are silent, have a low thermal signature, and are efficient — features that will make the robots more impactful in the field.

The actuators are silent because the muscles don’t make a lot of noise when they actuate, especially compared to motors or servos. They are cold because the amount of heat generation in a muscle is far less than a comparable motor, and they are efficient because of the advantages of the distributed chemical energy model and potential escape via Brownian motion.

Applications for actuators inspired by the biomolecular machines in animal muscles include bio-inspired robotics, nanomachines, and energy harvesting.

For more information, contact the Army Research Laboratory Public Affairs Office at 301-394-3590.

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This article first appeared in the March, 2020 issue of Tech Briefs Magazine.

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