This Instructable is going to show you how to build Hexabot, a large six-legged robot platform that is capable of carrying a human passenger! The robot can also be made fully autonomous with the addition of a few sensors and a little reprogramming.

I constructed this robot as a final project for Making Things Interactive, a course offered at Carnegie Mellon University.

Typically, most of the robotics projects I've done have been on the small scale, not exceeding a foot in their largest dimension. With the recent donation of an electric wheelchair to the CMU Robotics Club, I was intrigued by the thought of using the wheelchair motors in some sort of big project. When I brought up the idea about making a large-scale something with Mark Gross, the CMU professor who teaches Making Things Interactive, his eyes lit up like a kid on Christmas morning. His response was "Go for it!"

With his approval, I needed to actually come up with something to build with these motors. Since the wheelchair motors were very powerful, I definitely wanted to make something that I could ride on. The idea of a wheeled vehicle seemed kind of boring, so I began thinking about walking mechanisms. This was somewhat challenging since I only had two motors at my disposal and still wanted to create something capable of turning, not just moving forwards and backwards. After some frustrating prototyping attempts, I began looking at toys on the internet to get some ideas. I happened to find the Tamiya Insect. It was perfect! With this as my inspiration, I was able to create CAD models of the robot and begin construction.

During the creation of this project, I was stupid and didn't take any pictures during the actual construction process. So, to create this Instructable, I took the robot apart and took pictures of the assembly process step-by-step. So, you may notice that holes appear before I talk about drilling them, and other little discrepancies that wouldn't exist if I had done this right in the first place!

Edit 1/20/09: I discovered that, for some reason, Step 10 had the exact same text as Step 4. This discrepancy has been corrected. Step 10 now tells you how to attach the motors, rather than telling you how to machine the motor linkages again. Also, thanks to Instructables for saving a history of edits, I was simply able to find an early version with the right text and copy/paste it in!

Step 1: CAD Model

Using SolidWorks, I created a CAD model of the robot so I could position components easily and determine the location of holes for the bolts that connect the legs and linkages of the robot to the frame. I didn't model the bolts themselves to save time. The frame is made from 1" x 1" and 2" x 1" steel tubing.

A folder of part, assembly, and drawing files for the robot can be downloaded below. You'll need SolidWorks to open the various files. There are some .pdf drawings in the folder as well, and these are also available to download in subsequent steps of this report.

This is an absolutely exceptional project! Seriously well done on it. :) Do you know how much it cost you by the end?
<p>Thanks! Out of pocket expenses were under $200, but keep in mind I had a lot of parts donated (motors, batteries, steel tubing).</p>
Hi rpantaleo! Question: What did you end up doing with it in the end? I'm looking to exit my hexarideablepod gracefully, so I'm thinking of scrapping it for parts. Did you just end up hanging it from the ceiling or leaving it with your department or something?
I stripped the motors and batteries out and gave them back to the Robotics Club. The rest of the machine has been sitting in my garage for a couple years - I plan on turning it into a coffee table (welding the legs in place then putting a piece of plate glass on top).
thanks for the info! okay, I will probably take it apart for scrap steel and parts then.
This is AWESOME. If I can get a hold of the parts I'm totally doing this. I may want to invest in some shocks though...
How fast does it move with 24 V?
Never tried it. Probably about twice as fast?
you should put some tennis balls on tha feet so it doesn't scrape so much on tha floor. <br>
Just posted a video of a build derived from this instructable<br><br>http://www.youtube.com/watch?v=0jMmebn49EM
This is awesome! Great work!
@rpantaleo do you have dynamics calculations for finding minimum torque at the robot?
Unfortunately, I do not.
can this be made with just 2 batteries 2 motors and 2 seprate switches for the motors?
what a nice robot... i have a question about the motors. So those 2 motors are different type aren't it ? the one is for left side, and the other one for right side??<br><br>and those motors are for wheel chair motor? I'm from Indonesia , and I must think where can I find the motors.. please reply.. thank you very much
The motors are identical except for the gearbox. One has a gearbox that outputs to the left, the other to the right.<br><br>You may be able to find these motors on ebay.
Wow awesome! This wheel chair is amazing; if you would add treaded feet and shock absorbers to the chair then it will much better.<br><br>http://www.metal-supplies.com/12201/index.html
Yes, very cool project. <br><br>Rubber treaded feet with absorbers was the first thing that came to mind for me too while watching the video<br>
I think that if you put rubber pegs on the legs, you might be getting better results considering movement!
Wow awesome! This wheel chair is amazing; if you would add treaded feet and shock absorbers to the chair then it will much better.
sir please send microcontroler circuit <br>
I'm afraid the only circuit/schematic I have is the one in Step 16. Sorry.
sir i am using two 12v 4Amps batteries those are sufficient for run the motor
If you plan on riding on it, no. Otherwise, it may work with no load on the robot.
not for riding on it ,if riding on it what is the capacity of batteries means voltage and current
One or two batteries like this should be sufficient.<br> <br> <a href="http://www.amazon.com/UB12180-Sealed-Lead-Acid-Batteries/dp/B001DL7D1O">http://www.amazon.com/UB12180-Sealed-Lead-Acid-Batteries/dp/B001DL7D1O</a><br>
circuit for connecting two motors
which micro controler is used for this project and also mention the number of micro controler<br> circuit board for connections<br>
I used an older version of the&nbsp;<a href="http://arduino.cc/en/Main/ArduinoBoardUno">Arduino Uno</a>&nbsp;for this project. I used 4 digital input pins for the main control circuit.&nbsp;
how to analyse this model in ansys for static and dynamic analysis
I haven't used ANSYS much, so I'm really not sure. I used SolidWorks to make the model, and SolidWorks has a built-in analysis program, which is what I would use.
2 3&quot; 3/4-10 bolts what is this means<br>
2 bolts, 3 inches in length, 3/4 inch diameter, 10 threads per inch.
thanxs dude
This is brilliant. I wonder how much better it would be if you would add treaded feet and shock absorbers to the chair (kind of like what they use on public buses.) <br> <br>Build it bigger and with armor plating, you'd get the military's attention!!
where did you buy that mill and how much?
I believe the mill was a donation from the CMU Robotics Institute machine shop. We didn't buy it.
where did you guys buy the mill and how much?
can u upload a pdf file of microcontroler and relays because i am not good in electronics and it is confusing and i am new in robotics
I'm afraid the schematic on Step 13 is the best I'm going to be able to provide.<br> <br> In light of that, here is a forum thread on connecting relays to an Arduino: <a>http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1196698219</a><br> <br> Keep in mind that you really don't need to use a very complicated circuit to control the hexabot. I used a microcontroller and more complicated circuit because it was required for the class I was taking, but realistically all you need is a couple high-current rated switches to turn power on and off to each motor.
Great project, looks like loads of fun. <br><br>I do see some room for improvement in the legs. Why not hook up small shock dampeners in the legs, between the tubing and the feet? Something like the air shocks that hold open the rear hatches on SUVs should do the trick. I think one of those in each wheel, with of course a plastic foot on it, would even out the ride considerably, and make the whole process a bit more effective (not to mention easier on your spine!).<br><br>Even as it sits, it's an awesome project. When I get old, screw a wheelchair, I'm building one of these. XD
can we use other types of moter like 'a car starter or moter used in wiper in car'
A car starter motor would require some sort of gear reduction to reduce the speed and increase the torque. <br><br>A windshield wiper motor would work but the torque output would be too low for you to ride on it.
great robot, you guys are very talented, I was wondering if it would be possible not to use the middle legs? Maybe keep the top part to connect the front legs but cut out the bottom half???
The middle legs are actually what move the robot so they'd have to stay. It might still work if you remove either the front or back set of legs.
This is awesome! Unfortunately I have major budget constrainsts (as in I need to make this for $10 or less), so I'm going to make a pedal-powered version out of spare bike parts instead of using motors :D. If I make it, I'll post a picture on here.
I think when you put a rubber feet on his legs it will add more grip to it.i mean a bigger grip, not that small white thing :p

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Bio: Mechanical Engineer, photographer
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