This year in my engineering class we have been assigned individual projects that we got to choose. I picked working on an RC Blimp “Robot” (using the term loosely) that was modeled after the Oceanic Sunfish (Mola mola). However, this is my first robot and I’m not completely sure which parts will work together. I’m reading a lot but I need to have a part list ready by the end of the week. Can anyone tell me if these parts will work for my design? My basic idea is to have a Oceanic Sunfish body plan:
and shares many simular biological features such as the Sunfish’s neutral buoyancy (as apposed to dynamic lift) and its odd propulsion system. I also want this “Robot” to exhibit movement like that of the Sunfish, such as being able to swim horizontally or vertically:
Wow, can’t believe that’s basically all I need. You know what that mean? I’m under budget, yay! While the muscle wire will be propelling the balloon, it’s not going to make the body itself move, in fact, the body is stationary. The wires are going to be pulling on both sides of the fins on its back and underbelly. The fins handle the uplift, turning, forward movement, and stability. That’s a crucial part of the Oceanic Sunfish’s swimming locomotion and is very unique. It’s also very efficient which is why I want to implement it in my design. However, your idea has given me another idea using the same general technique. Instead of having the fins completely separated from the body (expect for the joint that holds them together) I’ll have them connected which will create a separate chamber for extra helium (which won’t be a lot but you never know). I’ll also use this idea for the small tail that will help with the turning. That might also help displace some of the weight from the back. I had thought about making my own controller with those components, I’ll look in to it more.
I did redraw my concept after you mentioned making the shape a rectangle. It’s not exactly a rectangle but it is more elongated. Here is an 4 way view of the body:
Don’t pay too much attention to the color differences, they’re just simple additions and won’t be implemented in the prototype, but might be included into the final design.
Ironic that you mentioned Festo’s AirJelly, that companies animal inspired balloons inspired this particular robot.
One thing that I’m a little worried about is how the muscle wires are going to move. I want them in a particular order. They will be two sets on the front of the fin (left and right) and one set on the back of the fin (left and right). For the movement of the Mola I want the front wires to activate first (on one side of course) and then the back wire just slightly after that. Would the micro controllers that I choose be able to do that or do I need to create an extra circuit?
I am planning on upload some videos and pictures, probably not the creation of the bot but maybe the prototype and final trials. Such keep an eye out.
You’re both right. I want to create a balloon robot sunfish (perhaps at a later date an aquatic version). During this first project I’ll be making it a simple RC Robot but later on when I have more experience I hope to created a “smart” version. The final idea (which will never be built unless some company buys the idea if I decide I want it to go commercial) is to create a more efficient active mode of air travel. Of course there are materials such as the Muslce Wires that will be replace in a blimp size version (I’m thinking Carbon Aerogels) but the blueprint holds the basic principles.
I do think the custom controller is the way I’m going to go with.
I’m not completely sure what size I want to use (I haven’t done the weight calculations yet) but I know it won’t be bigger than .01 in diameter and it’ll probably half that.
Um … where do I find pins for the mirco controller that rockclodbuster talked about? It’s a lot cheaper than what I was planning and it has more pins than the lilypad micro controller. Also can the Arduino be programmed with Python script?
Now on to the custom controller, do you know of any tutorials that could help me? Can I use buttons instead of a joystick (they’re cheaper). I thinking like one button for moving up, one for moving down, one for left turning, one for right turning, and one for propulsion. Will this antenna and connector work:
Okay so here is the RC thingy. I choose the same micro controller (link in previous post) that I’ll use for the body as well as the same power supply. They’ll also share an XBEE transmitter (link in last post). However I’m wondering if the transimitter is in the right spot? It can’t connect to the analog pins because the buttons and joystick take up all of those. Also does the motherboard have a regulator that’ll bring the 3.7 volt battery down to 3.3?
Okay so here we have the circuit that’ll be placed on the body. Should the muscle wires be placed on the analog pins or on digital pins? Right now I have them on analog.
Welcome to the RobotShop Forum. You are certainly on the right track with the Arduino Mini (lighter weight) or Lilypad (might be easier to incorporate into a round balloon) and muscle wire. If you will be trying to use the wire to propel the balloon, you may find it easier to divide the ballon into multiple sections rather than one whole - this will make it easier for the actuator wire to work (similar to “air bag” style packaging). Depending on the size of the balloon, you may need something a lot more lightweight than the Futaba receiver or the Fischertechnik IR receiver. Consider a custom setup using the Onshine modules.
Your main challenge will not be the electronics but rather the air flow and aerodynamics required to move the baloon forward. As an option, you may want to try a very basic shape (rectangle) filled with helium, where the rear section are separated as above and easily bent. You can actuate the sections using normal wire to see how the device will gain forward momentum.
In terms of electronics, you won’t need much more - a USB interface for the Arduino, a small battery and some wire. If you use thick muscle wire (probably not the case here), you’ll need a separate H-bridge to handleto current. You would most likely get a smooth, gentle motion such as that on the Festo AirJelly. See PDF here.
The choice of muscle wire gauge and length will greatly impact if you can drive it directly using the microcontroller. If the microcontroller cannot handle all the current requirements, you might need a small relay circuit. You will program rhe microcontroller to actuate the wire (by setting either the analog or digital pin high/low). Each wire is connected to its own pin.
A joystick with left/right, up/down and button will only set you back around $15. Buttons are fine too - so the choice is yours. The Arduino Mini can use straight pins, 90 degree pins or even regular wire. Consider conductuve thread to save you weight. The antenna and connector you choice work together, but for your prototype, consider an RF system that includes an antenna. The Onshine matched pairs work up to 100 feet without antenna.
In order to use a 3.7V battery, you would need a voltage regulator unless you choose a 3.3V Arduino (like the Arduino Pro Mini 3.3) for either. In that case, the Lithium ion batteries are lightweight and thin and would be a good choice. It would be sifficult to say how long the balloon would last though using muscle wire.
If you’re planning to use an XBee pair, you’ll need additional circuitry - the XBee is difficult to connect directly to an Arduino (we don’t discourage it because it can be done, but it’s not easy if you are just starting). If you are using the Pro Mini Microcontroller, it operates at 3.3V, so you might have to use a voltage regulator.
Although not indicated in your schematic, the buttons and joystick also need to be connected to a power supply (either the Arduino’s or external). The actuator wires will also need to be grounded. Try to get an idea of the current being used by the muscle (it depends on length as well as number of wires used and their diameter).
Very cool project charles, I hope you will send picture of your build.
Cbenson, I have supposed charles want to build a robot-sunfish, not a balloon. In this case, somting heavy may help the robot to go underwater because it harder to make a submarine sunk than to make it float.
Another thing, the output signal of a remote control receiver is refresh every 3 ms, made of a high and a low and is the difference between high and low state of the signal. You can program the arduino to understand this signal for every fonction of the robot. You have talk about a 4 channel, so 4 fonction like a plane: throttle, yaw, pitch and roll. this will use 4 pin on the arduino. or you can built a remote with the onshine combo and use only 1 pin.
Personnaly, I have choose the seconde option. I wille use an arduino pro-mini with an onshine, an mini joystick, a few button and a lcd 16x2 screen. by doing thas, i can upgrade the transmiter for a transceiver, the screen will display info on the sensor of the robot like batterie voltage and, in your case, deepness.
