PlayK'NEX by





Introduction: KnexBeest

Step 1: Legs.

The legs are the most important part of the beest, they dictate its walking and its height.
Theo Jansen used an genetic selection algorithm to determine the right proportions for each part of the leg. Here we are just using standard knex parts (as you will see later, the parts used in the example legs are different from the ones used in the actual beest, but the proportions are the same).

This part was reversed engineered from the following:
(notice the bottom triangle is different from the top one)

Step 2: Legs: Triangles

Build bottom and top triangles. Notice the blue part on the bottom triangle.

Step 3: Legs: Triangle Links

Build the connectors and connect them between the top and bottom triangle, this connectors go on top of the triangles and are joined by a rod as you can see in the pictures.
The yellow and green pieces on the second picture are just stoppers for the rod connecting them.

Step 4: Legs: Outside Joint

Now we need to connect the triangles to the crankshaft, we do this through the outside joints, which give the legs its 'insect-like' look.

The outside joint must be connected directly to the triangles and not to the vertical connectors, otherwise the leg will lack structure and wont be able to stand on its own.

Step 5: Feet

The feet are one also one of the most interesting parts of the beests, they were designed for being able to walk into soft surfaces like sand (or rugs and carpets in our case) and being able to stand while the legs are flexed. If we don't use a leg like this the beest would have a hard time balancing itself, before I introduced those legs it kept slipping everywhere and always ended up falling.

Its important to remark the importance of the green part and the blue rod, these pieces prevent the feet from rotating, if the feet rotate it will lose balance and eventually cause the animaris to fall.

Step 6: Crankshaft Frame

This part needs to be drastically improved, the crankshaft is made to be as simple and light as posible, but maybe because of this it tends to bend more than its necessary making the beest clumsy and slow.

Also its kinda hard to make the beest move because the crankshaft needs a lot of force for being able to move, my original idea was to mount a motor for giving it a walk-through-wire control, but i haven't found a way to mount it or a motor that can give enough torque to move it. I have tried gears without any luck.

If any one knows how to improve this part and automate it, please post a comment, i would love to give this animal RC control (or maybe a pid controller and a bunch of sensors for making it an actual robot).Crankshaft detail

Step 7: Join Everything Together and PLAY.

The last step is to join everything together (first picture), first join two legs together through a white piece, do the same for the other two, then join them together in the crankshaft.

Now as you do this you will notice that the legs tend to bend and stray, for preventing this we need to join them as in the second picture, notice the yellow bar between the legs (where there are a lot of yellow pieces) this structure connects the top triangle rod with another leg and the frame.

As you can see in the fourth pic, this connector also allows us to adjust the distance between each pair of legs, this is important because the feet need space for walking and if we keep this distance too short the feet will join and cause the beest to trip and fall.

The last picture shows how to make the animal walk, you need to twist the crankshaft and it will walk, you can see the legs bending and this movement will cause the whole structure to move forward.

This animal still needs some improvement, specially on the crankshaft and on the amount of pieces needed, but it functions as a good basis for other proyects, later i will post how i transformed this beest into a laptop stand and how using just the feet i made an little robot crawler.

Any comments are truly appreciated and please let me know if you build one of these which steps need further explanation, which parts you feel need revision and specially if you know how to mount an futaba servo to it please tell me, i would like to make this animal bigger and stronger, and i know the instructables community can help me.



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     do you have to have those specific rods to create the beest

    I'm making one of these too! Here's a video i made a while back.

    Can you make a Instructable of your design?

    (He moves a lot more natural)

    I think you need to re-upload that video - all I got was bunch of random text characters, not even media player starting.

    same here! but is there like a program i need to run these things cause everything i try through that link leads to the random text

    If it works, it should work in Windows Media Player. If you don't have it, I think it's a free download (it cam bundled in my software).