Robots gotta dance, too

September 25, 2023 Dennis D. McDonald

Despite a lifelong interest in movie robots I know nothing about real robotics. So, when I read the article Chemically fueling new microrobot abilities in the September 14, 2023 issue of SCIENCE at first I did not take it seriously.

This news report by Ryan Truby describes recently published research on the development of insect-sized chemically powered robots. Reading through the report one can see that serious work is being done to address the basic problem of weight: batteries are heavy. The larger electrically powered robots get, and the more complex their actions become, battery weight becomes an increasingly serious issue. We've seen the videos of the "dancing robots" developed by Boston Dynamics, but they rely on battery power. What if another power source could be developed, one with a more positive power-to-weight ratio? Could some of the issues with battery weight be overcome while still providing a reliable energy source to power necessary robotic mechanical actions?

According to the SCIENCE article, promising results are emerging from experiments with hydrocarbon fuels that possess high energy density compared with lithium-ion batteries. One such experiment involves construction of insect size microrobots that burn hydrocarbon fuels such as methane or butane. In one experiment, spark-based ignition of chemical fuel generates mechanical action via movement of a tiny 3D-printing-generated enclosing flexible combustion chamber. This movement is then captured and transferred to the microrobot’s "legs" and "feet." Jumping and movement result.

This is all necessarily "early stage" stuff. Challenges like fuel type selection, storage, and supply; electronic control; energy for spark ignition; and, exhaust venting of water vapor and carbon dioxide must still be addressed.

Still, it is interesting that chemical combustion-based energy production is being researched so seriously. Given the problems we face with declining energy supplies and global warming, shouldn't we also be researching alternative fuels without the baggage of environmentally unfriendly chemical fuels? I assume we are. After all, robots gotta dance, too!