BrickBear

Progress of today, finalised the connection of the gearbox, built the rear panelling around it for a more compact length, attached the legs and began adding the stoppers in a different position. Once I attach the head mechanism for balance, the xl motor and AAA battery box it should be ready for testing next weekend or possibly the one after that. Final stretch!

Thanks, I was motivated by the tedium of reconstruction :D I should add it has made the top of the structure a little wider but this is not a worry as it only 9 beams wide and does not affect leg movement or bodywork, in fact it actually provides more attachment points, hoping it makes things easier as a result

Okay so I added/am adding a feature that enhances the mechanism somewhat, this required removal of the legs but essentially makes calibration of the lego positions much easier: As i’m sure you’re all aware, working with worm gears requires keeping them strongly held within a tough frame, unfortunately however that means it’s a pain to adjust their position if you find something isn’t quite right. Now, with this small gearbox system allowing me to unite and separate the drive from one of the pairs of legs, I can freely rotate one pair to adjust their positions slightly and perfect the movement of the legs relative to each other without taking things apart to adjust things. Perfect. Secondly it has caused me to strengthen things even further and thirdly it does not take up much more vertical space. Win win.

It breaks up the monotony of redesigning the system each time I run into an obstacle. But also as the key problems have been fixed (the feet that are not raised being flush with each other on the floor, the strength of the springs to hold up the weight) it (the mechanism) is essentially finished, in the pic below you can see it was nearly there before I had to fix the aforementioned issues. I reckon i’ll get it walking next weekend. Balance ✅ Strength ✅ Bend ✅

It is great to finally be adding bodywork where the shape and design is somewhat a good compromise between accurate and possible (what with the gears and movement being quite limiting). Admittedly I did not work very much on it this weekend as I was working on another non lego project. So this much progress in such a short time is good.

Thanks, though i’m afraid from what I can tell the gait is the same as the other lego motorised AT-AT. But I have news. So I ran into a problem where the positions of the feet were not at an angle such that all feet that were supposed to be on the ground at a point in time were not flush. I have since changed that, the mechanism remains similar otherwise. I believe I am on the last stretch though to getting a moving machine. I intend to use the head turning left and right for balance too so that mechanism will have to be made. Progress though, is happening.

So i’m using the 75054 AT-AT set. But i’m making adjustments to make it more accurate (more cockpit space for example). The goal is once i’ve finished the mechanism to isolate all the pieces that come with 75054 and then only use those for the body (i’ve made a more accurate version before just from said pieces). All the while making sure weight distribution is good

Akk I’ve just noticed, the weight at the front is a bit much for the position of the springs, gonna need to adjust that.

Ok I had to rework the gears of the legs, unfortunately the difference between the 20 tooth bevel gear and the 28 tooth bevel gear caused the legs to bend too far causing strain on the mechanism and knee stopper, so I changed it to 40 tooth straight gear and the 8 tooth straight gear but that was too little bend. I’ve now landed on 36 tooth and 12 tooth combination which is perfect and I sorted the balancing issue with the use of the head movement where it moves to the side of the body that does not have its leg lifted, this adds more weight to the limbs touching the ground.

All four legs added, Struggling a little with its balance despite it having three feet on ground

Update time, ordered some new bevel gears from bricklink. The good thing about these ones is they have three connecting points within them much like the old spur gears. This means I can connect it directly to the legs and simplify the bending mechanism greatly. The one downside is due to its size the gear has to be attached half a beam away, this allows the liftarm connected to the orange cam to not bump into it. However the connection remains strong which is great and the leg bends well.

Much better, as you can see the leg rotates on the centre beam and the mechanism for pushing and pulling the leg is placed inside, this has allowed me to bring the legs together, which i assume will make it more stable as the centre of gravity from a raised foot is closer to the other feet than it was before. The last remaining problem is stopping the knee from bending when the leg is pushed backwards and it succumbs to the weight of the walker, I plan to introduce a stopper at the top of the leg to prevent this from happening so that when the leg faces back, the beams that go up and down parallel to each other to cause the bending can only be straight. Incidentally I believe this new system where the leg is connected both inside and out will reduce wobble because it initially had a terrible lean towards whichever leg was lifted up. This has sacrificed my ability to hide stuff on the rear of the leg but for the most part it is possible to cover all this up.

Okay, that was not the final iteration, I discovered a mistake in the placement of the leg on the ankle, the leg is three beams wide and the connection should have been in the centre, however I hadn’t done that so when it came to testing all four legs, there was a point where a leg would be too long. Likewise I have to work on balancing it so it can be stable on just three legs.

Thanks! 10 years of working on walking mechanisms have led to this moment. Hoping that it’ll work!

Thanks! Hopefully it’ll work!

I think this is the final leg iteration, it bends adequately, the “hip” raises up and down completely and the connections are fairly strong, the final bonus features are that I managed to slim the leg down by a whole technic bar so now each leg will be the same thickness as the original 75054 Lego AT-AT, the dish at the top rotates and the grey bricks with technic holes move up down like in the actual actuators in the AT-AT walker. When the other three legs are attached it will be the day walking tests commence, hopefully due to the hard suspension used on the hips all four legs will be able to support the weight of a battery box and motor. I should be able to implement mild steering too and with plenty of space for mini figs owing to the compact gearing.

Latest update, made the knee bending mechanism better, this is not the latest image but essentially what i’m trying to achieve. My current setup has the white quarter circle liftarm replaced with a 2x1 cylinder attached to one of the beams which either gets pressed down or lifted up by a stopper, however this while working is unsatisfactory as its not as strong a connection. The problem with the white liftarm was that the rotation movement was ever so slightly too far for the leg to go down properly, so the quest continues…

Thanks! I’m going to release instructions when I’m done. I just have to figure out the best software to do that as I’ll need to compress the springs in the mechanism to show things accurately. It’s genuinely exciting to see it come to fruition and to hear positive feedback too!

I have got it to work and it has a kind of nice mechanical movement to it, I just need to refine the leg bending mechanism as you can see a simple yet fairly strong structure has been added to the top of the previously posted ankle mechanism, this joins one point of the leg with another and has a mechanism for forward and backward movement, as the ankle lifts up the leg bends due to the fact that one connection point is raised higher than the other and as it returns down it unbends (I do need to tweak things to male the leg bending a bit bendier), then it slides back, the solution turned out to be surprisingly simple and lightweight in the end however will need refinement to make it more compact and for the sliding part to be made more secure. Here is a gif as well:

Ankle Movement Mechanism, springs push beam down, cams push up, compact, simple, includes rotating middle to allow for gentle steering. Beige bevel gear on the right lower part of the mechanism is just me figuring out how to make legs move and not a required part of up down mechanism.

Kinda like this?

I have a fair amount of technic for this project I think. I’ve taken apart 6x6 all terrain tow truck and airport fire truck for this as well as have a bunch of technic from the 80s onward (my cousins old lego) to use. The only parts I don’t have amazingly are shock absorbers or pnuematics. On another note I think I know what you mean, i’m gonna draw a little diagram but first I got to remember how to upload to flickr. Thankyou,

That’s actually really helpful, I admit an image might help to visualise some of the rack and pinion + gearbox stuff but I can easily picture the 3/4 cam wheel pressing down on a beam that is pushed upward by a medium-hard shock absorber. Pnuematics would be cool (perhaps even linear actuators could work as I do have those)? You’ve definitely given me some food for thought. edit: I’ve ordered some cams and hard shock absorbers. follow up question, the hips of an at-at from what I can tell move in a up down, level, down, (repeat) motion, to accommodate the legs bending (keep the at-at’s body level. Do you think it necessary to modify the cam to reflect this? Or should I consider that a relatively minor unnecessary aspect?

Hello, this is my first proper thread so forgive me if it’s a little amateurish in layout. With that said i’d like to begin by saying i’ve been working on this project on and off for a few years to get my 75054 AT-AT walking, having tried out the mechanism for the official LEGO walking AT-AT i’ve found that it is not stable enough nor satisfying. Since then I have been through multiple iterations of trying to get each leg moving but with only one off the ground at a time. As you can see in the pic from DK’s StarWars Vehicles book the mechanism for connecting and moving the lower leg relative to the upper leg seems to be similarly joined enough that it can be replicated using a linkage but making those linkages move in the correct sequence is the difficult part. The ankle on an AT-AT keeps three legs at a time level in the ground as well as lifts one other leg by moving it up when it takes a step. I have only ever found one person who has managed this in a non LEGO model so it’s possible: https://www.youtube.com/watch?time_continue=3&v=34tgu7ULkeM&embeds_referring_euri=https%3A%2F%2Fwww.google.co.uk%2F&source_ve_path=Mjg2NjY&feature=emb_logo That was 15 years ago. Here are some of my attempts: These two images use two sets of half beams to raise, lower and flatten the beams holding the leg, allowing up down movement, connected to the lower half beams are some linkages to move the leg back and forth, the fault of this one is it was not smooth nor stable. front Back (blue and red beams provide strength) This mechanism uses clutch gears going in a forward direction to move the bars down, half beams make them move up and down in turn, this reduced vertical space taken up, the failure of this is lack of connection points and strength as well as clutch gears probably not being able to support the weight. This was the most promising one, strong too but was unfortunately not quite walking in the right motion, it was not fully stable either. From further study I have noticed that the legs only bend in one direction so i’ve placed a stopper on each one to mimic this, I imagine this will add to the challenge. But i’ve seen people on eurobricks work magic with technic so I figured I should ask here for some help to find a solution.

Hello, my name is *checks username* BrickBear! I’m a big fan of StarWars, Batman and Technic. My main reason for interest in Batman sets is I’m an artist/illustrator with a love of comics and especially dc. So it stands to reason that I enjoy collecting the various vehicles, villains and heroes. I’ve illustrated 3 short unpublished Graphic Novels/comics, some completely illustrated by hand. As an artist I consider Lego an extension of “my practice” and I actually was one of the winners of this competition (although I think half the competition were disqualified for not fulfilling the photograph requirements so there’s that): https://www.lego.com/en-gb/my-starry-night-lego-build. As well as my creative side I also have a very mechanical side which is why I also enjoy technic, for the past six years I’ve been fiddling about with two Lego Technic sets, airport fire truck and 6x6 all terrain tow truck to make a crane and digger. I always try to make things as compact as possible and often things take me many iterations but I think I’m arriving at something to be satisfied with, I also enjoy mini Lego technic sets as I like to challenge myself to come up with a third model. I always give myself a similar challenge when it comes to Star Wars sets, I’ll often find there’s an aspect missing and see if I can figure out a way to include that aspect using just the pieces that came with (like retractable landing gear or more space in a cockpit). One modification I’m particularly proud of is this function I added to the 20th anniversary slave 1, I added manually opening side panels that can be closed seamlessly with the push of a button, oh! and gravity affected rotating guns. My current project is attempting to emulate the walk cycle/gait? of an AT-AT, I’ve been through many iterations and decided it might be time to seek assistance. I look forward to participating on Eurobricks after 10 years of just reading and learning from the experts on here.