Could Alien Tripods really walk Robot

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Day of the Tripods was originally an HG Wells Novel written in around 1897. There have been many adaptations since including a film in 1953 and another remake featuring Tom Cruise in 2005, and many other TV series and other media.
But can Tripods really walk? They only have three legs which means they have to stand on two legs while taking a step with the other leg.
I decided to build a 3D printed tripod robot which can walk along - calculating inverse kinematics and defining the gait.
CAD and Code: github.com/XRobots/TriPods
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[@RuthlessMojo]

Now the aliens have the STL’s and the open source code to build these tripods. Thanks James. You have ensured our destruction.

[@grndkntrl]

If aliens can manage to cross the vastness of interstellar space, then their technological superiority is already so far advanced that they really aren't in need of our help to come up with a viable walking tripod robot. 😂🤣

[@Sphendrana]

Good, I'm looking forward to it. -checks watch- aaaaany time now....

[@randomrant3886]

I think you meant to add "May the Emperor forgive you because I will not you filthy Xeno."

[@Pretzel_God]

Hail the tripod

[@euanmcgill918]

I for one welcome our tripod overlords

[@randomrant3886]

Day of the Triffids was the one where plants eat people. War of the worlds was the HG Wells story. Sorry if you have heard this too much already.

[@brucebaxter6923]

Lol. I was going to make a walking triffid joke.

[@djmips]

Don't humour him - he'll keep doing the annoying mistakes on purpose.

[@ulob]

He's talking about Wells's "Day of the Tripods" which... I haven't read yet

[@DrWhom]

@@djmips he is saying at at now, like a normal person!

[@molitovv]

He is making deliberate mistakes to drive engagement, can’t blame him

[@DanFitz777]

Striders from Half Life 2 have the most lifelike animation, but I don't know if anyone has simulated if it would actually work. My intuition is that the longer the legs and the taller the robot, the easier it will be to balance. It's easier to balance a tall poll from the bottom than a short poll.

[@lnhp5592]

i honestly think the strider's walk-cycle might be the best thing for that. Two legs on the "front" and a back leg that moves right behind them.

[@backgammonbacon]

Probably get deleted. kzbin.info/www/bejne/aJmumqShqJuEqpY There are loads of sane working tripod examples on youtube too. James did the whole "I did research that backed up my agenda and nothing else" thing that seems to be common now. Abuse of evidence like this is doing the world no favours, thought James was better than this but here we are.

[@pauldeddens5349]

With Striders, they have the benefit of stabby stabby feet. Which allows them to pivot and rotate them inwards to provide leverage as their moving foot finds ground. Big flat feet would actually hinder them more than help them. They need that twisting to move efficiently, especially at such a large size. With Hunters, its a matter of muscle and balance. Hunters seem to have bulkier legs with alot of muscle inside of them. They could likely hold themselves up with just a single leg, atleast for a moment. Unlike Striders, they have more blunted feet, and rely more on their complex digitigrade limbs to allow for their movement.

[@ernestoendean-hughes1328]

The striders feel like a love letter to war of the worlds they make awesome creatures they give me the same vibes as well Yes I know they were inspired by the tripods

[@homieboi5352]

I wonder if James ever played the half life franchise…

[@CoolAsFreya]

James demonstrating his ideas for the tripod bot's gait by using a pole with a shoe was hilarious!

[@sarowie]

it also points out the absurdity: Walking with 4 legs is trivial. Walking on 2 legs is human. Walking with 3 legs? that is messy!

[@tannerbass7146]

Having grown up in rural America, I've seen more than a few dogs and cats with three legs 😥 After a brief learning period, they can usually walk and run just as fast as they did before.

[@kaiwheeler64]

It's better than eating the whole animal I guess... Nature's successful tripods inspire.

[@theperfectbotsteve4916]

the one good thing about them is when I see one I know all the dogs on that street learned a valuable lesson about why you don't play in traffic

[@Mistner]

​@@2000jagoi mean it kinda is... Meh.

[@freedomofmotion]

@@2000jago You can apply the locomotion that these animals use to a robot .....

[@supercool5454]

​@@2000jagoa video about how to make a robot walk on three legs can't draw any example from nature because there totally is not any parallel between a three legged cat or dog and a three legged robot.

[@ivansdaddy]

Walking is usually described as falling forward and catching yourself, while James' gate seems to do the opposite, catching up from the rear direction...

[@The-realness-is-baffling]

I just want to say, your pfp looks like my grandpa who has sadly passed away, thank you for giving me someone who looks like him so i can remember his face easier. Thank you 😊

[@peregreena9046]

He's thinking in terms of leg and foot position. The trick is to think in terms of momentum.

[@Lumibear.]

There was a BBC Series called The Tripods, which was War Of The Worlds The Children’s Drama Series in all but name, they managed pretty convincing looking walking tripod models and a three legged alien costume that to this day I find hard to understand how it walked. Worth a look for ideas?

[@TinyMaths]

I've seen a couple of three-legged dogs in my lifetime and also one cat; they seemed to have walking and running down pretty well given their limitations. But the body shape is obviously very different and I suppose that might be a contributing factor to how the cats/dogs manage to function despite their limitations. Anyway, I love the way the tripod moves around while stationary, it's pretty surreal.

[@RND_ADV_X]

If you can't figure out how to walk with three legs, just imagine how much harder it would be to walk with only two! How are you going to hold your torso up, WITH ONLY ONE LEG!? 😂😂😂

[@0v_x0]

Human proprioception is ridiculously complex though... (#thatsthejoke)

[@segue2ant395]

Thanks. Now I'm gonna have to think before standing up.

[@RND_ADV_X]

@@segue2ant395 I was going to say he should watch videos of three legged dogs and cats who overcame their limits, but this felt funnier to me?

[@davidaugustofc2574]

He's got a pendulum between his legs at least

[@TheObliteratorOfWorlds]

You got a point

[@TimoNoko]

Pierson's Puppeteer has one back leg, which twice as strong as two front legs. It is moving like kangoroo and can be quite fast.

[@HVM_fi]

Niven fan spotted. Simone Giertz dog have three legs too, and bonus she is real.

[@r0bhumm]

I can’t remember where, but I do remember seeing an actor with his two legs bound together and a couple of crutches absolutely throwing himself around a stage. Very fluid movements.B

[@HVM_fi]

@@r0bhumm Was it 1984 Know Space based stage play called "Acts of Rishathra"?

[@r0cketplumber]

@@r0bhumm Another idea for Josh Sundquist.

[@EN-sc9yh]

@@r0bhumm Sounds like Jim Henson's "Dark Crystal" The striders

[@pieterpennings9371]

i so appreciate you showing the trigonometry and sharing the code. im working on a hexapod at the moment and it's amazing being able to reference seeing someone make the steps on paper.

[@k_the_v]

Also @James Bruton: ive always wondered why more robots dont have simple weight sensors all over... Wouldn't it help greatly if the robot knew its weight and from there could know how much of that weight is on each leg? Combined with gyro stabilisation, it could allow the robot to balance on One leg.

[@euanmcgill918]

I remember reading the Rama series by Arthur C Clarke, in which he describes tripod robots, and their motion was more of a rotational gait. Made me think that if your robot walks in a circle naturally maybe use that to your advantage?

[@NeilOKeefePrivate]

Exactly what I was thinking.

[@ramonasagan8148]

came here for this comment.

[@alunthomas1036]

It's been years since l read it, but if I remember correctly, they keep one leg on the ground and spin to bring the next one into place. I think they reversed their spin every few steps (3?). They were so fast that the humans had to film them to work out how they moved.

[@euanmcgill918]

@@alunthomas1036 yep, that's what I remember too

[@thehighseer23]

​@alunthomas1036 Exactly... came here to wonder aloud why no-one ever depicts the tripods moving as described in the novel. If I remember correctly, they move very fast and destroy trees from their movement as they pass. They are likened to a "milking stool tilted and bowled violently across the ground" which seems to describe a rotational movement. Even supposing the gait is not rotational, the tripods have never seemed as swift or violent as they should be. I hope one day to see this, but at this point I'm not holding my breath.

[@k_the_v]

That 4-gyro two legged robot is the most convincing I've ever seen! It looks like a design that could eventually become a true home domestic robot one day. Why aren't there more 4- gyros out there!?

[@sarowie]

I would guess that using 4 gyros uses a lot of energy

[@k_the_v]

@@sarowie why though? They're not even stepper motors, just free spinning gyros with angular sensors

[@ulforcemegamon3094]

@@k_the_v you are right , they don't use lots of energy , they are control moment gyroscopes , which has the advantage of not having a limit in the amount of torque generated when it comes to rpm , i mean , a normal gyro can only spin so fast and provide a maximum amount of torque given a certain rpm , even if you double the rpm , the torque won't increase , that is not the case with control moment gyroscopes , as they provide higher torque the higher the rpm is . Regarding why they aren't more common i Will say some reasons that i can think of : 1)they aren't that humanoid 2) having these 4 gyros makes it extremely noisy , you would need to cover it with a soundproof material to bring it to acceptable levels of sound 3) is not a common technology in the field : control moment gyroscopes are mostly used in satellites and some submarines , they aren't used for walking robots (last time i checked only two walking robots use CMG's ) , so is tech that wasn't applied to that field until very recently 4) is not super safe : CMG's are basically flywheels spinning at high rpm , meaning that handling these without care can be very dangerous 5) not readily avalaible : while there are CMG's for satellites , they are quite expensive and not made for walking robots , the CMG's that the robot uses are custom-made. I agree with you that they should be more common , these CMG's are so damn good they are able to balance a 34kg (yes that robot weight that much) robot that is bipedal with 2 dof in the legs (2 dof leg in a biped would be extremely hard to balance , that is why most have 3 dof ) , it seems like the ideal way to upscale a bipedal robot without having to worry that much about balance

[@burntalive]

Looking forward to v2 of this project! The Half Life Striders were always such a super cool concept to me.

[@storminmormin14]

“The Day of the Tripods” isn’t how I know the story. I know it as “War of the Worlds”. I know of a different sci-fi series called “the tripods” that takes place after an alien invasion.

[@LoganKearsley]

He's making a joke about confusing War of the Worlds with Day of the Triffids.

[@djmips]

Don't humour him - he'll keep doing the annoying mistakes on purpose.

[@0v_x0]

I read the tripods series back in middle school and this video triggered some strong memories. I'm now tempted to re-read them decades later. Alas it seems my audible subscription timed out and they took all my credits. That never happened before so I guess it's customer service time soon. But yeah I really enjoyed that series back in the day.

[@SmoMo_]

@@djmipswhat mistake? “Day of the tripods” was the short story by HGWells that was originally serialised in the Telegraph newspaper. It was the success of that short story that led Wells to expand it into the novel War of The Worlds. And in the original novel The Martians inside the Tripods were ‘plant like creatures with carnivorous spikes resembling teeth” that indeed did eat people. Presumably inspired by the Venus fly trap.

[@Frenchtanker92]

​@@SmoMo_the martians were not inspired by Venus flytraps they were inspired by cephalopods like octopus and squid. I don't know where you got that they were like plants when the book said "A big greyish rounded bulk, the size, perhaps, of a bear" and "from which other tentacles were now projecting" that doesn't sound like a plant, or even a carnivorous plant.

[@andrewholdaway813]

The biggest problem with creating specifically H G Wells' tripods is that he is quite specific that they made no use of the wheel and "singularly little" use of the fixed pivot confined to a single plane. _"Almost all the joints of the machinery present a complicated system of sliding parts moving over small but beautifully curved friction bearings."_

[@IsaacKuo]

That sounds like an extremely interesting engineering challenge that we have only developed the tools to accomplish in this millenium. I'm talking 3D printing to create such mechanisms, and genetic algorithms to design such mechanisms.

[@segue2ant395]

Love the idea of gyro-stablising with a gyro pivoting to the two grounded legs. VERY clever. Also as a big fan of classic scifi, the Day of the Tripods/War of the Triffids thing had me. I almost commented there and then lol

[@JinKee]

I friggin love John Christopher's Tripods Trilogy and the BBC TV series.

[@Redact63Lluks]

I always figured they had some kind of massive gyro stabilizer.

[@vaisakhkm783]

I thought it too, but it would have been cool without any gyroscopic stabiliaztion... just measuring the angles... i always surpriced by how humans do it... thier brain must have so much compute power and also super fast

[@typha]

No to mention they would have a massive amount of inertia, and other effects of scaling. So long as one or two of their legs were touching the ground to keep them from falling straight down, it would take a longer time for a tripod to fall a certain proportion of its height compared to a smaller one (actually that's still true even if all of the legs were off the ground).

[@jonathanjames9184]

Well, if we're keeping lore accurate, they don't use wheels of any kind (if I remember correctly). The Martians hadn't invented the wheel, emphasizing how different their development was to our's.

[@deanallenjones]

An amazing video, I often wondered why people never model a 3 legged machine on a para athlete who uses two crutches and one leg. I can outrun most able bodied folks and remain perfectly balanced :)

[@rakninja]

not radially symmetrical. you then get a bilaterally symmetrical robot with one leg and two long arms. part of the design was trying to recreate the kind of tripod walkers dreamed up by welles. i do imagine the "one short leg, two long ones" design that moves the outside legs in unison, then swings the middle one forward to complete the gait would be a lot easier to design and build.

[@marc.lepage]

I love the idea of a tripod, often wondered myself how to make one.

[@KaiserSaucy]

Can’t believe I’ve grown up my whole life with War Of The Worlds, watching numerous iterations of the tripods from Jeff Lynne to Tom Cruise & never until today stopped to think about how tf the tripods stayed upright & what a wholly impractical design that was! Good on you James for doing the difficult part to try to solve it in a real world manner. 👏👏👏

[@AaronCZim]

I'm glad you built the second walking method where the tripod balances on two legs at a time for walking because before long energy efficiency and longevity should be considered and the second walking method would prove superior. Balancing on two legs at a time would allow for slower walking speeds and I think that would be more energy efficient, and any of the other KZbinrs' tripods you showed were scraping there feet on the ground which isn't good for longevity. Your work is always very impressive!

[@sky173]

Great video. There were 'tripods' in the book series starting with 'The White Mountains".

[@paluxyl.8682]

I remember the Tripods tv series .. I had back in the days nightmares of this show , lol I can't remember anymore , was the Tripods able to fly ?

[@jacobdegeling]

Was that the one with the character called beanpole?

[@sky173]

@@jacobdegeling Indeed. It was a good series.

[@jacobdegeling]

@@sky173 thanks for reminding me, I want to read it again now!

[@Rickoshay]

Maybe with the third leg trailing - alternate between the right and left leg moving forward first - instead of the right leg always moving forward before the left. This may help negate the imparted rotational velocity.

[@ritinkornas5336]

It's been a while since I've been really excited by on of your project and not just midly interested... but I'm really looking forward to the updated version with the gyro on top! looks very promising :)

[@dumbtex6107]

Really enjoyed this project, absolutely brilliant as usual James! ❤

[@freedomofmotion]

Crutch walking is the most effective method for tripods to move. There's a mech unit in earth 2150 that uses this type of locomotion.

[@brucebaxter6923]

True. I had seen wheel spinning versions but crutch would be better. Realistically I was thinking of just using weight shift and sliding the lightest leg

[@segue2ant395]

I think this was also how TARS sometimes moved in 'Interstellar' - it struck me as a fairly straightforward locomotion method, all things considered.

[@orbismworldbuilding8428]

Yeah that or a gait where it rotates with each step These stubby legs don't work well with tripods though, unless you're willing to shuffle around but efficient walking needs long legs and actually use the angular momentum or pendulum like motions of the legs

[@gametec_live]

How many sponsors and ads do you want in one video? James: YES!

[@sock501]

This is awesome! I’d love to see this project continue.

[@cravensean]

As I recall, in the original novel, Wells described the tripods as perpetually tottering, like a three-legged stool about to fall. His description made me wonder if a gyroscopic stabilizer might not be involved. Fictionally, that is.

[@emizaquel8779]

I always assumed that these things were buoyant in air and were pulling themselves towards the ground with sticky appendages

[@Handelsbilanzdefizit]

Of course, Tripods can really walk. I saw them live, in Half-Life2

[@marijandesin8226]

The way I see it working would be to move the hind leg forward as the balance shifts forward while the front two legs act as pole vaults The legs could be flexible like Dr. Octavius tentacles as the length needs to be able to expanded almost 50%

[@charetjc]

I'm curious if using strain gauges on the legs would allow the robot to sense the weight on each leg and adjust it's pose during a gait to minimize the weight on the moving leg.

[@ZCJKF13GDG4]

It would be cool to do some fancy genetic algorithm stuff to have one of these freaky little critters figure out how to walk by itself

[@herrakaarme]

It should be quite doable, remote controlled by a PC with a good graphics card doing the machine learning. Not my field of expertise, though. But when I started watching this video, I actually expected talk about making it learn how to walk on its own, in a manner of speaking. AI is so pop these days, after all.

[@Aaa-vp6ug]

@@herrakaarmeI think training it with a simulator first would work

[@timontherocks7521]

I think these ficticious tripods are a symbolic reduction of spiders. Four represent our four legged friends and five are already quite complex for any abstract symbolism. To avoid that they look like critters and to give them some authority they got long legs, which makes them look a bit like daddy longlegs. I suppose on three legs they can never achieve a spooky, very smooth movement.

[@zenithparsec]

I imagine a three-legged robot could scurry quite quickly, or walk like a person two legs, but just insert the third leg when changing directions or when it helps them maintain stability.

[@sarowie]

he is trying implement a static or semistatic walk, where the robot is stable (or semi stable) in every moment. With dynamic walking - meaning using the momentum of each step - I think one could develop an impressive gait. Note that this would not be easy. Main issue: The transition from static to dynamic walking is messier then pure static and pure dynamic walking. You can not incrementally cross from static to dynamic; you need to attempt dynamic walking directly, which is not issue.

[@ragnkja]

Why would three legs be less able to walk steadily than two legs?

[@zenithparsec]

@@ragnkja You have more things moving at the same time in different directions with 3 legs. Each moving part affects the center of mass too, which you need for balance. So overall, there is more calculating when you have more legs doing different things.

[@ragnkja]

@@zenithparsec I’m not disagreeing that it’s harder to calculate, but that shouldn’t make it *inherently* less stable.

[@kirbyfinety]

You are amazing. The way you make your videos show you are having fun making these educational masterpieces. You are one of the best KZbin channels on here. You are a blessing to this world.

[@ProbablyH1]

this guy is really good at explaining complicated sounding things in a simple way

[@markstevensfpv3722]

Nice one James 👊 I’d like to see the next iteration of the robot dog 😆

[@onesimpleclik]

love the design!

[@shedrage9636]

Can’t wait for the next version of this! ❤

[@IsaacKuo]

IIRC, the three legged creatures in Tripods ran with a rotating motion. Imagine a tilted wine barrel doing a "rim roll". The creature would move like that, with one foot underneath as the other two feet swung around. I'm not sure how the heck you'd program a three legged robot to accomplish that "rim roll" motion, but I imagine it would end up a lot faster and more elegant than this robot's clumsy walking.

[@ashley-r-pollard]

I came here to say this too. In the original the motion is described as: "And this Thing I saw! How can I describe it? A monstrous tripod, higher than many houses, striding over the young pine-trees, and smashing them aside in its career; a walking engine of glittering metal, striding now across the heather; articulate ropes of steel dangling from it, and the clattering tumult of its passage mingling with the riot of the thunder. A flash, and it came out vividly, heeling over one way with two feet in the air, to vanish and reappear almost instantly as it seemed, with the next flash, a hundred yards nearer. Can you imagine a milking-stool tilted and bowled violently along the ground? That was the impression those instant flashes gave. But instead of a milking-stool imagine it a great body of machinery on a tripod stand."

[@MikeStavola]

When I was a kid, I made a physics model of a tripod and put a gyroscope in the body. It could balance on one leg if it were set up right, and if you had a gimbaled gyroscope, the body could move semi-independently of the legs.

[@ChristieNel]

I'd like to see the tripod from Rama, which moves by spinning asymmetrically in a continuous, off balance, falling motion, as I understand it. I've never seen anyone attempt it. There's also the STriDER robot by RoMeLa that's worth looking at.

[@segue2ant395]

Yes! I always imagined it as behaving like an off-balance spinning top - pinching its legs together into a point to spin and perambulate, spreading them only to stand still.

[@ChristieNel]

@@segue2ant395 I don't think it would work if the legs are brought to a point, since the radius of the "wheel" would be zero, but definitely closer together, rather than like spokes on a wagon-wheel. Boy, I'd love to see this thing, even if just animated.

[@Project-Air]

1:05 Nice to see your dancing finally televised on KZbin, James 😅

[@JessWLStuart]

Wow! Amazing work! Your engineering skills are amazing to me!

[@PMX]

"You should also watch 'War of the Words' which is the one where plants come alive and..." Ok, so you are trolling... You are perfectly aware that "War of the Worlds" is H.G. Wells book/movies (it's even right there in the wikipedia article you show...), and "*Day* of the *Triffids*" is the one about plants so... is this just to get engagement in the form of comments pointing this out? Then you succeeded I guess...

[@nowymail]

A magazine that contains a tiny bit of a model?On their site they never tell you how many magazines you have to buy. It's 21 magazines, containing 2-6 assembly stages. Total assembly stages are 115. It is around 200 ponuds (deliberate typo because YT algorithms). A bit much for a plastic toy. I assume all the info (text and pictures) in the magazines you can find online on fan forums and extended DVDs. I am quite certain there is not anything new in them.

[@DrWhom]

I so hate that

[@ReiverBlue1971]

Two feet: Walk, run. Four legs: Walk, trot, canter, gallop. Three legs: Walk, stride and run (same number of modes as the number of legs....I wonder if it holds further on?). I studied a tripedal motion set for animating my own CG Fighting Machine in 3DS Max

[@ldcent8482]

3:20 I am impressed at how loud that 'c' was. Thought for sure it was a cut at first.

[@W01demar]

Hey, i think it would be awesome to see how AI will resolve this by self learning. I saw different videos where ai learn to walk, maybe you could collaborate with one of guys who does this sort of thing and make a video about tripods leaning to walk via machine learning and then taking his actions into account you could improve this robot, that would be awesome.

[@RogerS1978]

I second this, can think of a couple of ways to solve it but don't look like the tripods walking, AI could help a lot

[@jdlessl]

AI is probably overkill for something like that, some bog standard genetic algorithm would develop some graceful gaits in no time.

[@W01demar]

​@@jdlessl my point is not "to use ai to resolve this problem" , more like to see the path of ai learning to do this and to see how will look it's scucessfull walking. After you said that now i want to see how will look the solution you proposed vs ai in efficiency :D Anyway i mean this just for fun, without real scope)

[@RogerS1978]

@@jdlessl Probably but it would be fun to see what insane idea's it comes up with. Also you with an AI expert , would be dangerous and good youtube...Skynet here we come :D

[@Clayne151]

I thought the same thing, and than it occured to me to just test how NI would solve it. So I got down on one feet and two hands and started "walking" without thinking too much about it. So what I naturally did was first walk forward with the hands, and than quickly pulled forward the foot, making a small hop. So combining two different modes of locomotion. That's of course because balancing on one hand and one foot is easy, but balancing on two hands while still able to reach the floor with one foot is not 😅 So, for a symmetrical walker that gives two possible modes for walking: - Balance the body above two legs, move the third. Repeat. - Quickly hopping one leg at the time forward. The first is more efficient and precise for slow walking, the second should be possible to be scaled up to a gallop.

[@huyked]

Well, if bipods like us can walk, why not tripods?

[@nxpnsv]

The broom&sock dance is so good!😀

[@SLAVKINGRED]

this is a cool video, love your projects,

[@kamikeserpentail3778]

My thought for an approach is actually to rotate the whole bottom while a top part remains facing forward. Essentially it would have its weight on two legs as the third makes a move, with it shifting its weight onto any leg that just moved and the one that isn't meant to move next. Steps wouldn't try to keep the bottom oriented the same, they would use the rotation so each leg would be at the front at a different point. I think this translates into some of the steps moving backward a bit for balance, but the steps forward could be bigger to ensure forward motion is maintained.

[@Rebar77_real]

Next one will have to be an omni-wheel on the end of a stick! Neat stuff, sir!

[@lopaka76]

To me, it looks like the forward leg needs to extend at 22.5° or 45° and then pull the body forward, while the back legs pivot on ball and socket joints as they move forward. But this also needs to happen for the other two legs if a tripod will want to move in 360° field of motion. I would think the gyroscopes will help with the balance as it turns. Sorry if my description isn't clear. First time watching one of your videos, looking forward to seeing more. Any fan of Bender and Johnny 5 can't be that bad, lol.

[@GabrielLeite123456789]

I need to see more of this!

[@Recon-WallBanger]

It could also be the fact that some Tripod aliens basically stick their feet onto the ground. In the 2005 WOTW movie, you can sometimes see that the tripod mechs have strange suction feet. In Half-Life 2, the striders use pegs that stab into the ground for grip (They also use them to stab enemies as well.)

[@Jugbot]

The best way to think of it is that one of the legs acts as the "tail" which is used to balance while walking with another two.

[@user-mu7tz3in7t]

I need to get a bit more into your work. It looks quite impressive.

[@rodshoaf]

What a weird idea for a video... ever see a 3 legged dog before? They get around pretty good!

[@TimothyGraupmann]

There's a French version of "War of the Worlds" where the aliens use Spot Robots with cattle prods. It was too scary I couldn't finish the first season.

[@maxinai_]

1:00 Wow, very funny and also intuitive way to show the movements!

[@bow-tiedengineer4453]

To make it go straight, you could have it reverse the leg order with each step, so going 1, 2, 3, 1, 3, 2 for the step order. That should counteract the rotation.

[@matteomascaropennacchi2220]

I Love how U created the Tripod and his new ways tô walk

[@budgiefriend]

Great presentation.👍

[@nidodson]

A 3 legged creature sprinting would likely spin or, more likely, have a stronger dominant leg and 2 weaker ones and run. A walk would be like a weaving pattern, 2 down back most one moving to front most, or like someone with a broken leg on crutches. All would be interesting methods to watch attempted.

[@kaosthecosmicreviewer1055]

🎵"The chances of anything coming from mars are a million to one he said." Music "The chances of anything coming from mars are a million to one, but still they come." 🎵

[@MattyCanny]

Its very cool. It would be interesting if the legs had pens on the end, and you could see the pattern of the footprints it makes, and whether it is reliably making the same step size each time. Another idea could be to let it run through a puddle of paint on white paper.

[@blue-cloud-studios]

idk why but elmo just quietly staring at you in the back is pure gold lol

[@ptolemythespacenerd]

This is seriously impressive!

[@lucasmandato4910]

love your content, i imagine that if you are able to calculate the axis inertia and mass vector form in ground direction, form a point where it intersects with the ground, than you could position two feet in a line that intersects the point, move the other feet, then do the cycle again, making the sure that the feet who moved in the previous cycle stay "still"... i bet this will make the gyros obsolete in this build...longer leg bits would help in this scenario, as the bot would have more freedom to choose where the tips go...

[@lucasmandato4910]

and thinking more about, you can use the weight of the robot to control the vector before taking the step...so it leans in a certain way, taking in count the desired axis position in the next three foot part of the step, like "lean to next balance, move a feet to intersecting line"

[@MarkWladika]

Arthur C. Clarke in "Rendezvous with Rama" describes a possible approach to tripods: "After regarding them passively for several minutes, the creature suddenly moved, and now they could understand why they had failed to observe its arrival. It was fast, and it covered the ground with such an extraordinary spinning motion that the human eye and mind had real difficulty in following it....each leg in turn acted as a pivot around which the creature whirled its body... it also seemed to him that every few 'steps' it reversed its direction of spin, while the three whips flickered over the ground like lightning as it moved."

[@bigmac1598]

Would adding one or more gyroscopes help to keep the body at a height while moving in a direction?

[@johnd324]

Kangaroos walk on 2 legs + 1 tail when they are not skipping. The tail serves as a third leg and a counter balance.

[@Ithirahad]

I always imagined a big tripod walker would use a wide stance and utilize the moving leg to tip itself and rear up in the opposite direction before taking a step, giving the computer or pilot (or whatever sort of cogitator is controlling the thing) plenty of time to look for somewhere stable to plant the foot.

[@gurdimeikenskjaldi5060]

interesting video! I'd like to mention a thing from the original H.G. Wells novel maybe not many know (me too till few years ago). The tripods' walk motion isn't described in terms of comparisons with insects, but rather as a sort of circular very fast sequence where only one leg is on the ground for few moments. To use the same image as the writer, it's like one makes a 3 legged stool rotate on itself pivoting on one leg per time. Very bizarre image, dunno how realistic, but I wanted to add this tidbito of information cause it sounded very unique ^^ (also that implies that probably the tripod could actually move ... well not in a really agile way, but surely faster than how they are usually portrayed)

[@theoverseer8568]

The tri pod design would make a good hand of sorts

[@Avaruusmurkku]

It's always a control problem. You can have stupidly rickety walking contraptions as long as you have sophisticated control over the limbs. You can see this with how children aged 3 to 6 walk. They constantly look like they're about to trip because they haven't completely mastered limb movement yet.

[@RArecordingsRickValcon]

the original book explains that it's walking motion was like a milking stool slightly tilted so it would fling around the axis of one leg with 2 legs in the air.. Don't know how that would work though because it would need to balance without a gyroscope since the Martians didn't make use of the wheel. A nice nod in the 2005 movie about this fact comes when one of the Aliens turns the wheel of the bicycle in the house and looks at it with interest.

[@G33v3s]

The Day of the Tripods, well played sir, well played!

[@thehighseer23]

I came here to wonder aloud why no-one ever depicts the tripods moving as described in the novel. If I remember correctly, they move very fast and destroy trees from their movement as they pass. They are likened to a "milking stool tilted and bowled violently across the ground" which seems to describe a rotational movement. Even supposing the gait is not rotational, the tripods have never seemed as swift or violent as they should be. I hope one day to see this, but at this point I'm not holding my breath.

[@lokonu]

this is awesome!

[@mundanestuff]

For one glorious night we had a three legged cat. He was a free soul, didn't like being cooped up in the house, and ran away from our cousins' home and was gone, we advertised for the lost tripod cat and literally a month later, our cousins had moved away, but someone caught him. He was thin, had a single puncture wound to his left hip, but otherwise seemed happy to be back indoors and fed and craved attention. Our cousins took him back, but a few months later he ran away again and was never recovered (we suspect a neighbor of theirs cat-napped him because he was so affectionate). He could walk just fine. In slow walking, he hopped, front, rear right, rear left, front, rear right, rear left, etc. In fast mode, he ran front/rear/front/rear.

[@joejoejoejoejoejoe4391]

"we come to take over your planet, but don't run away in a clockwise direction,oh, and we don't like stairs either..."

[@Strixx23]

The gait seems to have a - Right Leg, Left Leg, Back Leg cycle? Could it be programmed to reverse the right and left leg sequence each cycle so it would pull left then right? That could correct it’s tendency to walk in circles? (Right leg, Left leg, Back leg, Left leg, Right Leg, Back leg etc)

[@boxmatthewj]

Yes this was exactly what I was going to suggest. Alternate the right and left leg following the movement of back leg

[@r0cketplumber]

In the first few seconds, I remembered Larry Niven's "Grendel", where the antagonist's ship's third leg is damaged and the gyros give out- "Bey! What'll I DO?"

[@partciudgam8478]

there was a robot called strider, it swung it's third leg under the other two (like a swing) and rotated it's whole chassis to achieve so, another idea would be to give the foot fingers that allowed them to be a smaller triangle themselves, so your robot could passively balance over one of its legs while moving the other(s), ideally would be to move the center of gravity to a hexagon formed by two legs (and their fingers) while moving the other leg.

[@ASingleApe]

I recommend looking at the strider and hunters from halflifie. The strider is best for large scale but the hunters move extremely smoothly and realistically for having 3 legs

[@13thravenpurple94]

Great video Thank you

[@nickk6518]

Fun fact 1: H. G. Wells also wrote The Invisible Man during his 18 month residence in Maybury Road, Woking and, as well as the Martian Machine and cylinder, there is also a seven foot bronze statue of a seated H .G. Wells farther down the old Chobham Road. Fun fact 2: H. G. Wells was a memeber of the Woking Cycling Club.

[@fredblonder7850]

In the book, only the War Machines had three legs. There were also construction machines that had five legs.

[@empathon]

Next challenge, imagine if a creature with only two legs could walk 🤔

[@DanslatetedeFrancky]

Respect sir ! It's very very very interesting !

[@TheUnknownPrime]

There's tripod robots in the video game The Outer Worlds that walk by using the second option, using the front foot and one of the back legs to balance while the other back leg steps forward, then it repositions the front leg and steps forward with the other back leg and so on.

[@mbusbridge1]

H.G. Wells wrote The War of the Worlds, with several film adaptions and radio shows. John Christopher wrote 4 books about Triopds and the BBC made a television adaptation of the trilogy (prequel hadn't yet been released) I'd suggest that you give them a read if you have the time, growing up those were a great read. I've always wondered how those things walked about.

[@gt1man931]

Not gonna lie, triffids scared the shit out of me back in the day. They did the atmosphere right for a low budget show.