How To Build Your Own SolidWorks Robot!
Unfortunately due to Brexit and some.. shall we say sub-standard customer service, Eli’s arrival has been delayed :( So, to keep myself occupied in the meantime, I have began modelling his main features through the much-loved computer-aided-design package, SolidWorks! Of course this has proved difficult at times, as at the moment, I’m making approximate estimations of dimensions based on online pictures (such as the following) but bear with me as I take you through the process so far!
Also, just a little side note before we get cracking; if you’ve found yourself working remotely and using a SolidWorks on a laptop for the first time, go buy yourself a mouse right now if you don’t already have one! The amount of time (and stress) I’ve saved myself by using a mouse rather than the laptop trackpad is staggering. However if you do ever find yourself in a situation where you can’t get your hands on a mouse for a while, you can either follow the steps in the picture below (view>modify>rotate/pan/roll) or simply right click anywhere in the window and the same, helpful rotate/pan/roll options will appear.
Another alternative would be pressing ctrl + a number. Play around with these and see which orientation you get for each one, they’ll differ depending on which plane you began with etc.
Step 1 ~ Prepare!
As Benjamin Franklin once said, “By failing to prepare, you are preparing to fail” and never a truer word has been spoken! This is by far one of the most important parts of any project, especially one that needs a lot of forethought such as this. It’d be a very haphazard robot if you just created parts willy-nilly without any thought as to how big the should be relative to each other or how they would fit together.
To begin, I needed to make some sketches and get a feel for how big each component was. But where to start? Well it turns out the ultrasonic sensor provided is pretty standard and some quick google searches led me to its dimensions (45x20x15 mm). From these measurements I was able to make some approximate assumptions as to the rest of the dimensions in order to make the following (extremely primitive) drawing of some of Eli’s main features. It took a bit of playing around with dimensions to see what looked right and what didn’t but it’s definitely a great way to help establish your feel of the project on hand!
Alas, after completing my manual attempt at figuring out the dimensions, I discovered the inbuilt ‘Sketch Picture’ function in SolidWorks. It allows you to import a picture which can then be scaled and sketched over. This may have been a quicker approach to provide my foundations but sure look, I’ll know for next time! Check out the picture below for a quick overview of where to find this feature.
Making this drawing and studying online resources from a number of angles helped to me compose the following list of the main parts I was going to need.
Would definitely recommend making lists. Slowly being able to tick things off the list helps you see how far you’ve come and how much you’ve left. A great gauge for how much time you need to set aside.
P.s. please never ask me to sketch an ultrasonic sensor freehand again. Honestly, I’m not quite sure why it turned out like that either.
P.p.s. I’m not sure where I got the number 10 out of for the 11.5mm supports. I used 6.
Step 2 ~ Get Building!
With my vision for all of Eli’s shapes and sizes clear in my head I got to work with making them a reality. The drawings were enough to help me get started with the initial SolidWorks render at the very least. Of course, it will be difficult to include all the features until I actually have the parts in my hands but for now, here are some renders of the parts I have created!
Note: I’ve used Photoview 360 for these as unfortunately I haven’t yet been able to install SolidWorks 2020 from my remote working location (sigh). However, if you are lucky enough to have the latest version installed, give Visualize a go! From what I’ve heard and seen, the render quality is infinitely better. You can also use some really fun backgrounds and place your robot in all sorts of places. From the aisles of tesco to the aisle of a plane, who knows where your robot could go!
So, getting back to business! Creating most of the basic shapes was fairly straight forward simply creating sketches and using boss extrude, extruded cut and filleting. For the more complex geometries such as the tire and wheels, I found mirroring and patterns to be extremely useful and time saving. GrabCad would’ve been another time saving tool but I was determined to construct everything completely by myself. Not only was it rewarding when I finally finished intricate components like the ultrasonic sensor but it also helped me work on my SolidWorks skills and to use all the features more fluently. I’m pretty happy with the level I’ve achieved so far but ever the perfectionist, I hope to find the time to make a few more tweaks and refinements.
One detail I found particularly cumbersome was the thread pattern on the tire and from speaking with some of my classmates, I know I wasn’t the only one. I actually started off with the tire thinking it would help me refresh most of the features and surely, ‘A tire? How hard can it?’, but boyy was I wrong! For someone attempting to get back into the swing of SolidWorks there was definitely easier parts I could’ve chosen but hey, we live and we learn. It may seem simple to a more experienced user, but I spent way too long googling how to make these extrusions on a curved surface and to be honest, all I found was dead ends… nothing seemed to work. So that’s when I turned to my friend/class-mate Scott (you can follow his progress and socials @ScottTalbot on twitter!). A few tips from him and I was flying. I’m going to share the method here in case (like myself) your CAD skills are a bit rusty or maybe you’re just starting out! So…
Step 2.1
Rotate your part so that you are looking at it straight on, like so. Begin a sketch on the right plane (or whichever plane is in the centre of your tire, see picture), then begin to sketch the shapes of your grooves; I used a spline for mine.. they’re tricky but just play around with it until you get your desired shape. Only make one of each because you can pattern the rest!
Step 2.2
Once you’re happy with your design, exit the sketch, go up to ‘Insert’, ‘Curve’, ‘Projected’, as shown in the picture. From here you select your sketch and the face you wish to place it on.
Step 2.3
Next you should begin a 3D sketch, click the convert entities feature and then select your projected curve (a). You should also create a 3D directional centreline (b) for construction purposes during your boss extrude step which is coming next!
Step 2.4
Now, begin the boss extrude. Select the 3D centreline as your direction and of course your design as the selected contour then extrude to whatever depth you like and click the tick when you’re happy.
Step 2.5
Once this is complete, circular pattern your feature as usual, add a few fillets, am appearance and whatever else takes your fancy, your tire is good to go!
Hope this mini tutorial helps out anyone struggling with something similar! Let me know in the comments if it did OR if I need to make something clearer!
Step 3 ~ Bring it all together!
File > New > New Assembly is the first little step in the last overall step of any SolidWorks creation. But if you’re anything like me, you’ll probably have to go back to step two a couple of times and change a few (*cough* a lot of) dimensions.
It was a repetitive process of distance, coincident, concentric and lock mates but I got there eventually.
As you can see the basic shapes are there but there’s still a little bit of refining to do. Now that I’m getting back to grips with SolidWorks and starting to feel more comfortable with the software, I’d love to try and incorporate smaller details like wiring! But that’s a job for another day.
So as I conclude my little shpeil here, I’d like to remind you to check out my Twitter (@aoifemcl3008) for some more cool day-to-day updates!
Bye for now my fellow little Eli/engineering enthusiasts!
