Cyberfish

CYBEREmpathy ISSUE 1/2012. Cyber Fields Forever Marcin Malec, Cyberfisch

MARCIN MALEC

CYBERFISH Mode of access: Internet via World Wide Web.

Cyberfish described by Marcin Malec The first version was built as a thesis project by me, Marcin Morawski and Dominik Wojtas. The first electronics was, of course, threading technology. There is a camera installed in it that allows point tracking, but it was homemade; for example, with a use of tree cutting machine etc. So the fish was not too lively, so to speak. But it was swimming. It was equipped with a swim bladder. It had all these basic essentials. The next version already emerged in SMT. It was the lightest (1.6 kg), the most agile fish with magnetic switching. All tests on the robot were run in a pool in Skawina, so that everyone could come - they like it. And that also allowed us to have a better access to the pool. As you can see, it swims pretty fast. A new design of swim bladder was used, in comparison to the first one. And starting with that second fish we work only in a team of two, me and Marcin Morawski.

The third version was built in cooperation with the Naval Academy. It was made with a use of Rapid Prototyping Technology, which is a simulator presenting the floating. An interesting thing is VN-100 sensor installed in it. This is a type of IMU sensors (Inertial measurement unit) www.CyberEmpathy.com

MARCIN MALEC

CYBEREmpathy ISSUE 1/2012. Cyber Fields Forever Marcin Malec, Cyberfisch and it measures all the parameters of motion: an angular position, accelerations, magnetic field in three axes; the system is additionally equipped with sensors for barriers’ detection. This approach, of course, works only in the laboratorial conditions - in pure water. But here, especially on this video, we see the advantages of the robot. It swims in the wall direction on the full speed. And here you see that right before the wall it avoids a collision. On this fragment the way the VN-100 sensor works can be seen. And here again it is shown how the robot moves in the water. It will now immerse by changing the angular setting of the side fins. It will dive, and then it will use only its swim bladder for emersion, changing its buoyancy like a real fish.

The fourth version is already much more advanced. Mathematics was used. A lot of things were taken from the literature, because similar constructions are created in the world. In Poland we are the only ones who deal with that. In Europe there are two or three centers where they do it as well.

This fish is also more advanced in terms of its operating - independent tail fins, a body is made of plastic P500. It has plugged one segment more than before; it weighs more than 6 kg. The interesting thing about this construction is PC104+ which is a much more advanced control system. It has static pressure sensors, dynamic pressure sensors, prepared slot for HD camera.

I am continuously improving the control system, so to speak. At this moment the control system in the fourth fish is finished, but we aim to make

it

an

autonomous

robot.

Marcin

Morawski’s

disease,

unfortunately, did not allow us to continue our work at the same level.

There is a total of five constructions.

The fifth design was constructed also in collaboration with the Naval Academy, as the third one was. Like in all other robots, we designed this one in Katja system, it is a part of that previous control system. Of course, we used also Maple simulator. A mechanical faculty graduate Adam Trzmiel helped us with this program, in this control application writing. This version of fish gives the ability to change any of the parameters: from a neutral point to frequency, to phase shift. So you can change any parameter of the fish floating. There is also a VN-100 sensor installed in the robot; modern engines enable the measurement of engine parameters: for example, moments on this engine, electric current flowing through the engine, voltage, angles’ position, angular www.CyberEmpathy.com

CYBEREmpathy ISSUE 1/2012. Cyber Fields Forever Marcin Malec, Cyberfisch velocity. Additionally, an application created by Adam Trzmiel has a visualization that allows receiving the signals from angular positions of servos, so we can see on the screen exactly how the fish is moving. For example, we choose some parameters, the fish moves in the pool with certain parameters, and we see how it is moving in the pool.

This is realized, of course, on basis of a feedback. So if we stop the tail, the visualization will show us that the tail was immobilized. If some servo is damaged, the visualization will show that some servo is damaged. This fragment shows how the fish swims using only the side fins. The particular setting of the side fins allows the fish to swim forward; the tail in this configuration is used only for changing the direction of floating. As we can see, the fish is very shunting. It can turn on the spot using only the side fins and the tail. And this part of the film shows how the fish moves using its waving tail, appropriately synchronized tail segments. This fish moves much faster, but the effect is even better if to watch an underwater video. Here we can see it.

These are not the optimal settings for this construction, of course. We aim to find the optimal settings for such construction and the optimal shape of the tail (both shape and stiffness), because this is very important. We already started the first studies that showed us that for this kind of constructions the best decision is a heart shape tail with a suitable stiffness. On this video you can see how the fish emerges by changing buoyancy only, so it does not move and emerges only by changing the parameters of it swim bladder. The same can be done for immersion. Well, these are the main advantages of this fish: high maneuverability, the ability to change the direction of floating on the spot, the ability to brake on the spot. That’s all because of its segments.

This robot is composed of interconnected segments. The swim bladder allows quiet immersion/emersion. And in this way the fish floats away.

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