Planet Arduino

Roboticists often look to nature for inspiration. That makes sense, because animals are very efficient machines, thanks to millions of years of evolution. Even our most sophisticated technology doesn’t come close to matching a common housefly. But we can get closer to mimicking nature at larger scales, as with this robot created by researchers at EPFL that does a great job of swimming like a lamprey.

Lampreys are long, jawless fish that often get mistaken for eels. They swim through the water with a motion similar to a snake slithering across loose sand. To replicate that movement, this robot’s body contains numerous segments joined by servo motors. Each segment also has a force plate on each side. That lets the robot sense the pressure of the water against its body as it swims. An Arduino Mini board monitors the plates through force cells and controls the motors.

This unique setup let the researchers study the ability of some vertebrates to move even with a damaged spinal cord. The “healthy” robot can coordinate the movement of all of its motors. But the robot with the simulated spinal cord injury cannot. The motors past the “injury” can only react to the force plates on their own segments. The team found that the robot was still able to swim efficiently, because the force plates provided enough information to control the motors as needed. This provides valuable information in the field of neuroscience and vertebrate nervous systems.

Images: Kamilo Melo, BIOROB-EPFL

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Biomimicry is often used to take the designs that nature has perfected over a period of millions of years and incorporate them into our own technology. One maker who goes by mcp on YouTube took this idea one step further and created a fish that can swim in the water like the actual creature. By carefully analyzing and studying the patterns a fish makes while it scurries through a lake, he was able to reduce these motions down to just a few joints. 

The body of this DIY robotic fish was constructed from a series of four joints that each contain a single mini servo motor to control their movements. Next, an Arduino Nano was selected as the microcontroller board due to its small size and ample amounts of GPIO pins. In order for the fish to sense if there is an obstacle in the way and avoid it, the device also features “eyes” that utilize IR emitter/receiver pairs.

Once the spine of servo motors was combined with the Arduino and a set of LiPo batteries, mcp slipped over a skin made from a waterproof latex-like material that aids in moving throughout the water. In his video below, the DIY robotic fish can be seen oscillating freely through a bathtub full of water, along with a pool. His device works very well as it generates plenty of forward force to swim wherever it wants while avoiding obstacles. 

The post This Arduino-powered robotic fish was inspired by the real thing appeared first on Arduino Blog.

Hydraulically-actuated robots are nothing new, but normally they come with a battery or external supply of some sort. This lifelike robotic lionfish developed by Cornell and the University of Pennsylvania researchers, however, has its own artificial circulatory that pumps synthetic ‘blood’ to help flap its fins and as the device’s power source itself. 

The trick is that the liquid is actually the cathode of a battery built into the fish, which powers its two hydraulic actuators, as well as the Arduino Uno control system. This integral battery—which would be analogous to blood in a real fish—gives it enough energy to operate untethered for 36 hours, though as it swims at 1.56 body lengths per minute, so it can use all the time it can get!

As James Pikul, a co-author on the study and researcher at Penn, told Gizmodo:

In our synthetic vascular system, the fluid stores chemical energy which we can use to power the fish robot. As the fluid is pumped through the fish robot, the moving fluid also causes the robot to move. The vascular system, therefore, is multifunctional. It is these multiple functions that allow the robot to maintain its dexterity while also having a long operational time.

You can also read more in IEEE Spectrum‘s article here.

This robotic fish is made from bent PVC pipe and moves its tail for locomotion.

If you’re going to build an underwater vehicle, propeller control is the conventional solution. Eric Dirgahayu, however, created his underwater creature in the form of a fish, complete with a tail that powers it through the water, and pectoral fins that could, in theory, steer it in the correct direction. There is also a ballast tank to adjust its buoyancy. Interestingly, control of this “fish” is accomplished via a TV remote, so the surrounding water would need to be relatively clear.

Now we already have a complete fish robot body, we need to provide it with life! We will use the Arduino Pro Mini because the shape is small and can fit into safety box. In addition, you also need Pro Mini Arduino Motor Driver for control of ballast tanks, UBEX for power protection and two cell LiPo battery 1000mAh for power.

Here’s Dirgahayu’s general project description. If you’re interested in making a fish like this yourself, the physical build is seen here, and the electronics are found on this page.