Really Useful AI Robot Build #1

this is part one of building a really useful robot that can do practical tasks in the home or office if you've been watching my channel for a while though you know that i've built several other robots and i've got some of them here i previously demoed the robotis turtlebot which runs rolls of the robot operating system and that uses a laser scanner to map and navigate its environment and of course that's a kit off the shelf so it works really well i then went on to build my own ros robot that again uses a laser and a raspberry pi running roz and that just about works okay the map's not too bad and the navigation works sometimes but it's not very good that's due to a multitude of reasons all the way through from the hardware build all the way through to the software configuration so the next version's gonna be much better i also built a tracked robot and that can navigate using vision using a deep learning model from nvidia which i retrained using transfer learning to look at specific markers that it navigates between and of course there's opendog which works pretty well on four legs although it's not really ready for practical tasks at the moment and it needs a little bit more work doing on it so for this project we're going to build another wheeled robot that i can use for ongoing development of intelligent robots that's robust and reliable but also big enough that it's got an arm and it can reach the table so we can literally say hey robot go over to that table and go and get that cup and it knows what you're talking about it can navigate to the table using mapping and navigation in ros potentially and it can also recognize cups using a deep learning model or whatever we want it to go and get it knows the kinematics for his arm so you can grab the thing and bring it back to you so all these projects are open source and you can find them on my github and the links in the description to this video if you'd like to support me through patreon or youtube channel membership then those links are in the description as well patrons and youtube channel members get all the videos up to a week early and also sneak peeks and you can be part of that discussion but let's get started [Music] [Music] i said it was going to be substantial didn't i it's about 450 millimeters in diameter and the wheel's about 200 millimeters in diameter so thanks to 3d fuel for providing the filament for this project check out 3d 3dfuel.com right we've got some other parts here that i've made as well and all of this assembles so let's have a look at how it goes together first of all my wheels are made in several pieces so we've got a rigid pla hub here and i've got these keys on that hold the tyre on that is printed in a flexible tpu and that of course has the same indents on so that it doesn't slip on there and it won't slip off the hub we've then got a 3d printed t5 pulley and all three of those go together to make the completed wheel and that's going to ride on bearings driven directly by a belt drive the main base of the robot is printed in four parts and these are printed on the lulzbot more struder with a 1.2 mil nozzle so each section only took 12 hours and weighs about 600 or 700 grams so the whole thing's pretty substantial it's held together with these blue plates inside that you can just about see which are screwed on the inside so that should hold it together but there's still a little bit of wobble in there so on the bottom we've got some extrusions so those fit onto the bottom there which means that the whole robot rests on these and these are going to hold the axle and all of the stuff for the wheels so those are held on with some more blue plates that are bolted onto the extrusion and screwed onto the plastic and the back ones are slightly different they've got a piece on which we'll discuss in a moment so those are all bolted on at each end and now that is incredibly rigid i don't think i can move that feels incredibly substantial and obviously with a metal in makes a bit more bottom heavy so obviously it goes that way up with the wheels on the axle mounted on those extrusions as well as two casters so let's see how that fits together this is the main axle that runs through the robot and we've got this interesting looking mechanism here which has got a pivot in the middle so one side is going to be fixed to the robot in the base and the other side is going to pivot up and that's going to make a suspension arm and each one of those is going to have a little caster fitted but on the other side on each end of that is another block with a hole in and that's going to hold this down to the 2020 extrusion as well as these two holes here bolted down and obviously the big wheels go on the end so that's bolted in there and this side is on a hinge so that it can hinge up and that's going to be the suspension arm so if we run over a bump we don't get grounded so my wheels are on those are the main drive wheels of course and we've got the two casters now one of these is fixed and one is on that sprung suspension arm and that'll get sprung this way and i've left holes here to put the springs in which i haven't got yet so that it's sprung flat but it can go and do its suspension thing if the thing runs over bumps the main drive wheels each have a bearing one in the front and one in the back just like a skateboard wheel and a bushing so it fits the axle perfectly and the axle is fixed and the wheel is driven by its own pulley we've got these collar clamps which fit on and those are 3d printed just to stop the wheels falling off earlier on you might have noticed this hole that i left in one of the pieces and that is for the base of this 2080 extrusion which is what the body is going to go on and an arm on top which is going to ride up and down so that it can come right down and the arm can reach the ground or it can go right up and it can reach tabletops it's also going to be a head of the robot with cameras and sensors and things like that in there and that's going to be driven probably by a ball screw and another motor of course that's going to be cross braced on the top because it's only sat in that hole at the moment with some shims to make it the right size so we're going to have more base of this robot that's going to mount the laser scanner on the front really low down and a control panel and other things the next part of the build is going to be putting the drivetrain and the motors in but before we do that it's time for a quick ad from the video sponsor and that is brilliant i've been building things since i was a child long before the internet existed and even back in 2004 when i started building robots and writing about them on my website the internet was a very different place youtube didn't even exist so finding information was hard a platform like brilliant would have been a great help to me back then brilliant is maths and science simply done right they inspire people to 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fundamentals which is really good for brushing up on basics the first 200 people to sign up using my special link will get twenty percent off their annual subscription that's brilliant.org jamesbruton and i put that link in the video description as well so don't forget to sign up with that link soon so that you get the discount that's brilliant.org jamesbruton right let's get back to those motors and the robot drivetrain so here's my drivetrain and this is just consists of two brushless motors and these are the o-drive branded 63 74 150 kv motors that have got tons of power they're far too fast but that's going to be fine and i was going to consider a two-stage belt reduction what i'm actually going to do is just a single belt onto that wheel so this sits over the wheel arch on each side and we've just got that motor with 3d printed t5 pulley on that's just going to drive the wheel directly we've also got encoders on each one and again these are from the o drive robotics web shop those plates just bolt onto that 2016 we put in the bottom of the robot and that's the drive belt there ready to go onto the wheel well it seems to run perfectly well and those belts are nice and tight and of course we can slide that mechanism forward and back a bit to tension the belts if we need to but that seems to be working pretty well and i'm pretty happy with that i'm pretty sure these motors will be high enough power and if not we can put in another intermediate stage there's plenty of space in there for another pulley you'll also notice there's a nice notch in here to take that 2080 that goes into the hole in the base so that seems to be held on pretty well it feels pretty substantial and pretty firm we are going to have a lid on this though that comes and grips around that stick as well and you might see i've got a little bezel on here already and that's the piece that we're going to make next the top looks like four more sections which are bolted down and we'll look at that in a moment we've got a recess for a laser scanner that's going to sit in the front here to aid with the navigation under roz and we've also got a panel here i haven't designed yet and that's going to be a general control panel for things like the emergency stop the power switch and anything else that we need [Music] so right so that's the lid on i'm pretty happy with the look of this so far we've got that space for the control panel at the back and we've got the place for the laser i mentioned at the front so i'm pretty happy that it looks pretty commercial at the moment i've also added some wheel hubs there just to encapsulate that clamp that holds the wheels on so uh pretty happy with the aesthetic so far but let's have a look at how this lid is held on each of these sections has these recesses with two bolts in there the socket cap bolts and those go into these pieces these blue sections fitted into the base and they're just push fitting at the moment they're pretty tight and each one of those has a captive nut in a slot you can just see there so that i can just bolt down the lid that's most of the mechanical build done for the base at least of course there's the thing that goes on this stick we'll discuss later but for now we need to get some electronics in to drive those wheels so we're going to be running ros on it and what we really need is to be to drive a specific velocity and get the actual velocity back from the wheel encoders really accurately so in my previous robot i just had some motor encoders on the wrong end of the motor basically so that we could see how fast the wheels were going we had some hacky code that regulated the speed then we recalculated the velocity that we were traveling at from that code we've got brushless motors in this one so that opens up quite a few more possibilities yep it's an o drive 3.6 56 volt version we're just going to run on 24 volts though but that should give us more than enough power and that will control two brushes motors with encoders so that fits just on here i left some screw holes in this beam here so that we can mount stuff there's space for an optional micro controller next to it as well we'll discuss in a moment but for now there's our o drive and of course you can see the motor power wires are just each side there so you can easily bring those to the green connectors and the encoders for this are just on the back here so those wires are really accessible as well so go and plug into the o drive so that we can drive everything with encoders around this side as well i've made a battery pocket that just drops in there and that allows us to put some lipos in probably these 24 volt ones we'll get a couple of those in there for the main drive you'll notice i've got the batteries and the motors right at the front here and this stick is also offset to the front and that means that basically the robot wants to lean this way so even though we've got no springs in that suspension arm we're still taking the load off it by making everything front heavy so that means we don't need very strong springs and everything tends to lean forward anyway to drive the robot and to install ros on we're going to need a micro computer though in the previous rolls robots the turtle bot has a raspberry pi 3b plus and in my orange ros robot i put a raspberry pi for but this one we can do some much cleverer stuff so as well as running rods on it we want to do image recognition and some other things so a big thanks to nvidia for sending me the jetson xavier nx which is a massively powerful supercomputer it's also tiny i've got it here we'll have a closer look in a minute but this is basically a box of gpu that we can do deep learning models and transfer learning and those things i demoed in previous videos as well as running ros on it it's got a lot of gpu but also eight cpu calls and 16 gig of ram so let's have a closer look so that is the jetson nano or my previous tracked robot project and this is the xavier so you can see they're really similarly sized the common thing about both of them is that the actual processor is just this credit card size piece here so you could build that into your own embedded application but the development kit comes with the carrier board that's got all the ports on the xavier as well as being massively more powerful hence the fan has also got wi-fi and that's what this plastic thing is around here so we've got the wi-fi aerial there's also a slot on here i believe for an ssd i've made this carrier that's 3d printed for it just to slot into like that and that means that we can mount it in the robot so i've put that carrier a bit of a funny angle with a couple of wedges and this just slots right in here and that's a dirty hack because when the lid is on we don't want these ports to be too close to this lip here so i've just made sure it points into lots of free space so we can plug in stuff with the usb etc in terms of power supply the xavier nx ships with a 19.5 volt power brick at 2.37 amps although the actual thing will run between 9 and 20 volts and it does its own onboard 5 volt regulation so probably just pop another 12 volt battery in there so i've got a really long camera cable here and i've got a raspberry pi version 2 camera mounted at the top of the stick and the jets and nano and xavier are compatible directly with those cameras they plug straight into the carrier board and all the examples work by default with them so i've used these previously on the jetson nano track robot and a couple of other examples so one of the advantages about having this tool stick is that instead of having a floor robot with a camera looking up at things looking at everyone's chins and looking at lights in the ceiling that dazzle the camera having the camera much higher is much better because it puts it at human height this is just over four feet tall at the moment and it's probably going to get taller that means it can also look down at objects on tables i'm running the off-the-shelf detect net example that ships with the xavier and the jetson nano and we're getting around 100 frames a second there it will run much faster i'm pretty sure we're just maxing out the bandwidth for the camera here rather than the jetsons area itself so still tons of overhead for everything else it needs to do there are more mechanics to be built on this in the future we're going to have a section that actually goes up and down this stick and this is v-slot extrusion so we can use v-wheels in the grooves and drive it up and down by some means we'll have a taller head-on here with more sensors and cameras and also a robot arm so it's quite inspired by the unbounded robotics ubr-1 and the willow garage pr2 robots which both have arms obviously we can navigate with rolls with this robot to get it to go to a location then it can detect objects using the jetson inference deep learning models and then we can use the arm and the kinematics to go and grasp an object so we can actually make it do some useful things also with this stick we could have a telepresence module so we could have a screen on there for tele presence which is quite apt at this particular time of what's going on in the world for that reason we may move the jets and xavier nx further up so it actually lives nearer the sensor so we don't need all these long cables but that's something that we'll do in the future for now it'll stay in there so we can get ros on and get it navigating there probably will be another micro controller in here probably a teensy four that we can program like an arduino and use the arduino roll serial library and that'll sit in between the xavier and the hardware now we could plug the o drive straight into the xavier with usb or a serial port it might make more sense to modulize it and have some stuff running on the tnc specifically for the stuff that's up there as well if we have any more dc motors with encoders and all the arm control so i'm pretty happy with how that's turned out it looks like a pretty commercial platform to me so that looks quite good from a hardware perspective next time we'll be putting the laser on it and hopefully getting rolls running on the zapier to get it navigating so don't forget to subscribe and like the video if you liked it there'll be plenty more updates on this one and all the other projects also if you guys respond with patreon or youtube channel membership those links are in the description below and thanks again to brilliant for sponsoring this video don't forget to use my special link to get the discount alright that's all for now [Music] you

Channel: James Bruton

Views: 64,197

Rating: 4.9613686 out of 5

Keywords: AI robot, Ai robot application, deep learning, NVIDIA JETSON, NVIDIA transfer learning, deep learning model, Neural network AI robot, how to build a robot, ROS robot, autonomous robot, How to build a ROS robot, build a useful robot, domestic robot, telepresence robot, utility AI robot, building intelligent machines, Artificial intelligence robot, xrobots

Id: M9ABtlEM788

Length: 17min 21sec (1041 seconds)

Published: Mon Oct 19 2020