Researchers keep looking at more efficient ways to distribute power, particularly in areas where the constraints are significant. Nature had billion of years in experimenting energy savvy solutions and through natural selection it has achieve impressive results. In most cases, particularly when we are looking at small sizes, Nature is a far better engineer. We have no ways, so far, to create a mosquito or a fly. These small insects (and there are plenty that are even smaller, I am just mentioning these since they are part of our everyday life) can move around, sense the environment and react really fast. The computation power of a fly brain is theoretically smaller than your laptop but in practice it is so much better in many ways, including power consumption.
Hence it is no surprise that researchers are seeking inspiration from Nature. In this news Cornell researchers show the creation of a circulatory system for a robotic fish that serves both as an actuator to move the fins (use of pneumatic fluid for propulsion) as a way to distribute energy. This latter is what makes the news so interesting. They have been inspired by the blood circulation in animals that is carrying oxygen an nutrients to cells. Similarly they have invented a fluid that can carry ions through the (plastic) body of the fish. These ions are gathered from batteries disseminated along the circulatory system. As the fluid flows through the cathode and anode of the batteries it harvest ions that can be used by micro actuators activating the fins. Yes, you might say, wouldn’t have been easier to use wires from the batteries to the actuators? Sure, but you need to have a fluid for moving the fins and at that point by providing the fluid with the capability to transport ions you can save the wiring. A little advantage for sure but this is what Nature does with evolution. A little advantage tends to stick and be inherited leading over time to better (more adapted and efficient) species.
This kind of advantages are particularly important as the size decreases since there is less “maneuvering” space. Even larger articrafts, like a human sized robot, have to deal with dimension constrains like a robotic hand has very little space to include all motors that would be required to provide it with all the kind of movements a human hands have (27 degrees of freedom, if you are asking how many, and for each of them you need a dedicated motor!).
As with all advanced research the robotic fish prototype is just that, a prototype that would require quite some engineering work to make the solution useful in practical application. However, as it always is the case, any long journey start with a litlle step.