Building a Real Life Claptrap Robot | Pt. 1

have you ever wanted a robot friend you know that iconic robot from your childhood that you always wished that you could bring to life if only there were some sort of YouTube channel dedicated to bringing those types of things into reality now I'm not talking about those guys I I can't afford to build any of those robots I'm talking about this guy right here and you might think that clap trap is just a pathetic box on a wheel with spindly fragile little arms and a sad simple lens for an eye incapable of expressing deep emotion and you'd be right but behind all of that is a remarkably complex machine actually the game model is pretty simple there's not a whole lot going on in there but in my design my clap trap will be a bit more complicated because I am attempting to build my very own self-balancing clap trap robot now even if you've never played the Borderlands franchise hopefully that entices you because it turns out building a unicycle robot is really hard in fact it's so hard that I've split up into 10 smaller problems that I need to solve in order to bring him to life so let's talk about the first problem which is balance how is he going to balance on one wheel so in order for a clap trap to balance I need a special kind of wheel and I've got it right here this is a 10in hub motor rated for 800 watts and this is basically an electric go-kart wheel and what's special about this is that the motor is built into the Hub and Hub motor which means I don't have to worry about any sort of uh transmission or anything like that now originally I wanted to use an actual onewheel because hey I'm building a onewheel robot why don't I just use something off the shelf well it turns out those are really expensive even used so I ordered the finest 10-in H motor that I could find for $150 and now that I've got the motor figured out I can scale the rest of his body and start designing his chassis since this gives us a scale for his design so each side of the motor is is mounted to a right angle bracket that mounts to a spacer that bolts to a hefty base plate this is already a departure from the game because as you can see clap drop has a noticeably soft and dynamic suspension but this is a prototype and the simplest option is just to have him rigidly coupled to his frame I'll worry about a suspension later and I think it'll work just fine but this is only the first piece of the puzzle because he's a mono wheel and he needs to turn in place but how do I even do that if we watch clap trap in game you'll notice he's able to turn in place without moving against anything which is seemingly impossible but it can be done it turns out this need to rotate against something without pushing against anything is a common problem and it's already been solved if you just don't see the solution often here on Earth there's no ground to rotate against in space and satellites need to orient themselves all the time now you might think that uh they use gas thrusters and of course they do and usually see this depicted in TV and movies s because it looks dramatic but that's not practical all the time because if you're using a Thruster you're ejecting something and that something is a finite resource ideally you could convert electrical power into a torque that could change your angular momentum and position you precisely and there is a device that does just that and it's called a reaction wheel in simple terms a reaction wheel is just a rotating mass that spins opposite the direction you want something to spin due to conservation of angular momentum if you have that rotating Mass attached to your chassis and rotated clockwise the chassis will move counterclockwise there's more to than that that obviously it depends on how fast you're accelerating the mass and size of the reaction wheel and the mass and size of the thing you're trying to rotate but that's the gist of what I'm trying to accomplish and it's a proven mechanism for getting things to turn in place and for my Reaction Wheel I went with this off-the-shelf drum Brak which is Affordable and it's heavy and it's designed uh almost deally as a Reaction Wheel even though that's not the point it's got a nice mounting pattern so I can create a hub which is important because I've got this mounted at the top of clap trap's head and that connects to a long shaft which connects to a pulley which connects to a timing belt which is coupled to a motor this configuration does two things one it allows me to swap out Motors or transmission ratio so I can see what works also it keeps the Reaction Wheel at the top of clap trap's head which is important because it means he'll have more more inertia which means he'll fall over slower and that will mean he'll be easier to balance so obviously I'm not the first person to design a unicycle robot and most people when they want to stabilize the robot in roll they just use a Reaction Wheel that's in line with that roll axis so that's totally plausible and uh elegant but reaction Wheels aren't the most efficient and I want this build to be an excuse to learn a lot of new things so I'm going to use a different mechanism that is a bit more complicated but I think looks really cool and it's called a CMG to explain let's take a look at a model if I spin up a flywheel and put that on a gimbal we've now got a gyroscope if we can actively control that gimbal we've got a control moment gyroscope or an SG CMG and if we have a pair of SG cmgs where the gyroscopes are rotating and opposite directions and the gimbals move in opposite directions we could create a torque perpendicular to the axis of the gimbal in One Direction depending on which way we're accelerating them in the scissor pair which in my case would be clap traps roll axis now there's a lot more to this than I'm covering but it would take an entire dedicated video to explain how and why this works and if you want to learn more about control moment gyroscopes in a separate video for my design let me know in the comments below so how am I going to make my own control moment gyroscope well I've already got this nice beautiful brushless DC motor and this is powerful and compact packed but it doesn't have a lot of moment of inertia it's not designed to so I want to add a flywheel so there's a larger uh rotating mass now initially I thought I was just going to use some off-the-shelf flywheels this is a motorcycle flywheel and it's nice and compact but uh I want the motor to fit inside the flywheel because I want this to be as thin as possible because I want more room for activities inside my chassis there's a lot going on in there ideally I could turn down uh this flywheel but I don't have a metal lathe I have something better the combined manufacturing output of today's sponsor jlc PCB and so do you now in addition to offering highquality pcbs and stencils they also offer Cutting Edge 3D printing and CNC Services obviously I was enticed by the CNC services so I asked jlcpcb if they could help me out and they sent over these beautiful brass flywheels and they're absolutely gorgeous but they might look right but are they dimensionally accurate that's really important so let's bust out the calipers that's all with intolerance and more importantly look at that it's just so clean I'm really excited to test these out and this is absolutely not something I could fabricate in my home shop so if you are constrained by your own tools and just want someone else to make professional uh perfect parts for you go ahead and check out my link in description for jlcpcb thanks again guys for sponsoring this video and thank you for the flywheels let's get back to our design of clap trap okay so now that I figured out most of the core balancing mechanisms that take up a lot of the space in this chassis I can focus on the important but still functional aspects of clap trap's design like his eye now his eye is pretty straightforward and I've split my design into three key Parts we've got the lens L Body itself the hemispherical base and the pan and tilt mechanism but how's it actually broken down the lens body is a 3D printed tube with a lip that retains the lens itself the tube has large inner threads for an inner plate this plate acts as a mount for the inner main eye led the threads will allow me to dial in the distance between the LED and the lens so that I get just the right amount of diffusion now the lens itself isn't directly attached to the hemispherical base and that's for good reason because clap trap is going to fall and bump into things a lot I've designed this in a special way to add a little bit of shock absorption so I added five Springs to the rear of the lens body that line up with the base of his eye this way his eye can take at least some impact without just shattering how well would this actually work I don't know but uh it can't hurt can it now at the base we've got the pan and tilt mechanism so the eye and hemisphere assembly is mounted on a universal joint and that is attached to crank arms that are attached to servos this is pretty much the exact same mechanical setup I used in wheatley's eye and face design so I know it will work just fine this one's just a bit more robust because his eye is a lot larger and heavier next up we've got another important feature of clap trap's aesthetic and that is his disc drive now I call it a disc drive but I don't recall ever actually seeing him put a disc in there he usually just pops it out to express himself or to retrieve stored items like Echo devices from within his body but it's important and I want to create a motorized version for my clap trap so here's how I broke that down I split the mechanism into three main parts we've got the rigid door assembly with the front face and label insert this mounts to two long 3D printed strips that are attached to drawer slides there's also a plate to cross brace the two slides so that there's minimal twisting one slide has a herring bone gear rack that mates with the pinion gear on a Servo motor that tucks away neatly and this 3D printed block mounted at the base of the chassis the rack extends almost all the way out the rear so that I get the maximum amount of travel now this is only one of the linear mechanisms that I've designed in clap trap's body the other being his antenna mechanism clap trap's antenna is an iconic part of his character model and while it doesn't do much it does light up and it does extend and retract depending on whether or not clap traps scared or powered down and I wanted to incorporate that to my design because it's not too complicated and I don't have to reinvent anything I'm basically just using the same linear mechanism design you'd find in the z-axis of a 3D printer and in my model I've got the antenna itself which rides on a linear bearing that's fixed at the top of clap trap's head the antenna mounts to a carriage that has a flanged lead screw nut and another linear bearing that rides on a steel rod that is fixed to the chassis when the lead screw rotates I can move the carriage and antenna up or down to drive the lead screw I've coupled it to another Servo that mounts to a 3D printed piece that fixes it to the chassis to keep things tidy this piece also secures the motor for another key feature his kickstand all right I get it clap trap is never modeled with a kickstand but he's a balancing robot and that means when he's powered down he needs some way to stay upright in the game he just retracts his wheel into his body and I actually think that's mechanically plausible but that's really complicated and not something I going to do in the very first prototype so I need to have another way to keep him upright and I designed a motorized kick stand that I think will do the job in my design I've modeled this 180° hinge mechanism that is mounted to a door over his rear body panel this door has a cylindrical rubber bumper so that it has some grip when deployed on the ground and the attachment points are made of TPU so it's a little bit flexible the hinge mechanism is pretty much symmetrical on the other side except that there's just a set of bearings instead of a motor is this accurate to the game model no but I need it and more importantly it looks cool the next iconic element of clap trop's design I need to figure out is his hand assembly and thankfully his hands aren't that mechanically complicated he doesn't have fingers or anything like that he just has these two little flaps and unfortunately they don't have any modeled Motors just like most video game robots so I need to figure out a way to actuate these that hides the motor somewhere else because I don't have room to stick a motor in the actual joint I've gone ahead and added gear tee to the base of each flap this way they move together and I'll only need to actuate one side to open or close his hands to actually make the paddles move I've added a weak extension spring to one side that mounts inside his wrist the distance from the mounting point on the wrist and the hand is longer than the spring itself so that it's always spring-loaded closed to make it open I've wrapped a Kevlar cable around on the other handle and over the steel guide pin so the cable is more aligned with the hollow tube of his forearm this cable goes through the tube into his elbow and out his shoulder up to a small motor with the pulley when the cable's retracted his hand opens and when it's relaxed the spring takes up the slack and his hand closes now I've got a lightweight and compact hand mechanism that is easy to control and more importantly hides the motor somewhere else this is clap trap's bicep impressive Ive right but it gets the job done and that job is to resist the everpresent crushing force of gravity because I need a mechanism just like the hand that hides the motor somewhere else but the elbow is a little bit different here we've got clap traps upper arm and forearm the elbow itself is this little clevis assembly there are bearings that press fit on either side of the clevis and screws that ride in the bearings that screw into the forearm allowing it to swivel freely to actuate this assembly I'm I've designed a fixed Anchor Point on the inside of the forearm a guide at the base of the upper arm and a sliding anchor that rides in a dovetail on the sheath of the upper arm a steel cable attaches to the forearm anchor Loops under the guide and attaches to clap Shop's bicep spring which attaches to the sliding anchor that anchor has a small set screw so that I can adjust the tension on the spring and get just enough Force to counterbalance the weight of his hand and forearm so now it's spring-loaded closed but to extend his elbow I've designed a path for another Kev cable that wraps around the elbow pin and down into his upper arm so that it can be driven by a larger Servo in the shoulder just like the hand mechanism moving up the arm we come to the most mechanically complex part of the design clap trap's shoulder or his armpit depending on how you look at it and it has a differential mechanism but probably not one that you've seen before in my case the output shaft is this metal tube with a miter gear fixed on one end this tube rests on two bearings mounted in this large u-shaped bracket which rotates on the input shafts which each have their own miter gear there isn't enough room for a motor to attach directly to the input shafts so each shaft has a pulley that is driven by a timing belt that connects to the motor shaft when I rotate the arm both of the input shafts are moving clockwise and when I lift the arm up they're rotating in different directions this does make it more complicated to assemble and program but once again it looks cool and it will make him more powerful so I think this is the better option this is really just an overview you tell me in the comments which part of this design you'd like me to expand on and I'll make a dedicated video about it but I'm going to be making multiple videos because there's so many things to explain and explore when building a large scale unicycle robot and as always thank you to my patrons for supporting me I know my upload schedule is not really a schedule and uh yeah subscribe stick around for the next one and I'll see you guys in in the next one bye

Channel: Mr. Volt

Views: 34,086

Keywords: claptrap, borderlands, robot

Id: _r0qwPJESvo

Length: 16min 1sec (961 seconds)

Published: Tue Jul 02 2024