Saturday, September 2, 2000

EightLegs

After building my rather fast walker, Stampe, I wanted to make a walker that could turn. So with stampe standing there on the table with it's simple leg design I started building a similar structure but this time geared down some and with eight legs.

The plan was to make a walker that could steer like a tank does by driving one side of the propulsion system in one direction and the other in opposite. It worked quite well I must say.

I attached a radio control so that I could drive around the model as I wanted to. My sisters six year old boy had much fun with this model when he borrowed it once.

Facts

This model uses two geared down 9V motors. The motors are controlled by polarity switches that in turn are controlled by the servos I added for remote control.

The walker is rather slow, I never clocked it though. But it moves too fast in some situations, as you'll see if you read all my comments on the pictures further down on this page and on page two.


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Full frontal. The black non-LEGO box in the center of the page is the receiver for the radio control.




Looking at the back we can't see anything special since the picture quality from my video camera ain't much to brag about...

On a completely different note; My spell checker lives havoc for me for using the word "ain't" so much so I had to check it in my dictionary. Now I feel like apologizing for using such a slipshod selection of words :)





Lowering the walkers center of gravity by tipping it on it's side we can see the bottom. Worth noticing are the two white "slip" gears I use to save my motors. These are also guilty for some of the low gear ratio. They slipped to much when I placed the gears the other way around (the z24 slip on the motor and the z16 on the drive axis) so this is how it had to be (with out too much hassle, of course).




Removing much of the bricks on the top displays both drive trains. As mentioned the motors have z16 gears that drive the z24 slip gears on the drive axis. The drive axis then drives the legs via a worm gear/z24 combination. Hence the low gear ratio.




During filming/documenting this walker I accidentally drove off the edge of the shelf I had the walker on. It resulted in a 58 cm (two foot) drop to the floor. The drivers got bruised but no other LEGO was harmed.





Being such cowards the drivers refused sitting in the vehicle again.




Here's that motor with the z16 and z24 slip gear again.




This walker has a pretty OK ground clearance. I think it would have been more stable if I had used shorter beams... Let's call this one the SUV-version :)




Another shot of the guts. Motors taken out of play... The drive axis drive the worm gears that forces some z24 gears move about. On the same axis as the later z24 gear is a z16 that's part of the z16 stacks..




Another view...




Taking the two halves apart this is what one drive train configuration looks like.




Looking at the z16 stack this is what we see... The cross axles at the top and bottom z16 gears drive #4 liftarms that make the leg move about.




Looking at said liftarms you can see how they interact with the legs. The legs are made from ordinary 1x16 beams. The liftarms are mounted with 180 degree separation from each other, thus when one leg moves down the other leg is moving up, despite the fact that they both rotate in the same direction.




This is what it looks like when the legs are as far apart as they can be.




In the middle of a step.




Another angle.




Putting the legs together the walker looks like this...




A close up on the servo. Note the dark gray 3/4 pins on the sides of the servo. This makes it a snug fit. I use rubber bands to hold the servos in place. It works well enough to drive the walker of a 58 cm (about two feet) drop, as already mentioned. I only had to put some pieces in place after said crash. The servos was still in place :)




This is how the servo interacts with the polarity switch. This can be done in several ways. I use another technique on my Lynx Mk. I tank.




Continuing our survey on the servos, here's another view. Note the on-off switch for the radio control equipment, to the left in the picture.




Don't ask me why I have such a fetish for photoing the On-Off switch, but here it is again. Perhaps I'm just amazed it fits so perfect there...




Here is a overview of most of the radio control equipment. In the front is the receiver, then the blue pipe that contains the antenna and the two servos. The battery pack for the radio equipment is located in the trunk and can't be seen in this picture.

If your feeling sick about all these non-LEGO element I don't think you'll like the following pictures...





...because this is what I found when I took the walker apart. Small heaps of ABS dust. The wear on my precious bricks *grasps after something to hold so I won't fall and hurt myself*

I reccon I won't be considered a LEGO purist after this, first I add non-LEGO parts then I proceed to make heavy customizations on the bricks. At least I used LEGO to customize them ,)





The other side of the drivetrain had similar heaps. Cool :)




More ABS dust heaps...




This is the last picture I took of the walker and also the last I'll display here. Strange enough after cleaning the parts up I couldn't tell there had been wear enough to create dust heaps.

Friday, September 1, 2000

Stampe

Stampe is my first walker. I decided to build a walker after seeing some walkers OnLine. I wanted to build a walker that could walk fast. All walkers OnLine was really slow.

I though that the key to speed should be simplicity and low weight, hence my design.

I skipped "weight shifting" and such techniques and went for big feet, huge even.

Even if the walker fall on it's side it can still crawl so it feels very stubborn and it seems to arrive where it's heading no matter what. It can even climb doorsteps with out falling over, at least sometimes ,)

The name "Stampe" comes from the Swedish word "stamp" or stomp in English. So to be international I should have named it "Stompy" :) I choose that name since it stomps it way forth and is pretty loud.

The whole walker uses but seven gears.


The movies are in real-time and not speeded up.

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Starting with a overview picture. As you can see it's a simple walker indeed.




It can use an external power source to allow some remote control or...




...use an internal power source. It adds some weight and slows the walker down a little. I added the extra pieces on top so that I could fetch the walker in something when it ran away using internal power. I tried to grab it by the top drive axis first and it jammed my finger pretty bad :(




Here is a close up of the internal battery source.




This picture displays the construction of the legs. It uses three #4 liftarms per leg. The two liftarms at the top is powered and the third at the bottom is support only.




I also added a pair of liftarms on the outside of the leg for more support. The walker could run with out out these but sometimes it jammed.

Note that the two supporting liftarms are displaced with 90 degree.





I caught Stampe in the middle of one of his stomps.




Stampe running straight towards the camera.

Note that the strange angle is due to the camera man running away, not a try to fool you so that you wont notice how unparalleled Stampes feet is when he stomps...





Here is a pic showing the internals of Stampe. As you can see he's really simple and straight forward built.

The gear ratio is: z8 -> z24 -- z16 -> #4 liftarm.