Much of the design of a mech-like vehicle can be modeled and tested digitally. All types of designers have an unprecedented number of software options to choose from. Here we review a few of these options to show how our various design challenges can be overcome without leaving the office.
A Word About Licensing
Before jumping into specifics, a word about licensing and costs. Many open source software packages are available (for free), though some of the tools common to engineering are so highly specialised that there are fewer open source options. Some of these (proprietary) commercial products can be expensive. However, in an academic environment you can often find many of them already installed. Most vendors have either free options for using the software or discounted versions available for students to buy (i.e. Matlab for $99 or Autodesk Inventor suites for $150). Just make sure you don’t break a usage license by using educational software for commercial purposes.
Now back to the design discussion. Pre-production design needs can be loosely grouped into three stages: mock-up, design, test/simulate.
Tools to help pull together mock-up drawings are the most plentiful of the three stages because anyone can put a sketch on paper. But getting hand-drawn illustrations into a computer can be a chore – vector drawing programs such as Adobe Illustrator ($) or Inkscape (Free) can help make tracing easier. In this video, the artist converts a sketch into a digital drawing in Adobe Illustrator:
These mock-up images not only help to get a feel for what components will be required or where things are located – but they also provide much needed inspiration! Imagine a Kickstarter campaign without any drawings or videos to show their prototypes? It is likewise unimpressive to talk about a project to someone without the person being able to visualise any of what you are talking about.
We break down the design phase into a few stages as well. First is to design purely for visuals – this is to communicate a general concept, say, my robot has 2 legs, is tall and will crush you if you steps on you by accident. Any kind of graphic design tool will help you here. Pull up a simple web-based tool like Pixlr Editor to do a rough mock-up for a friend:
Second is to design for internals – allow you to see how parts of your creation will be assembled or laid out. Aiming to build a digital version of your shop floor, so you can see how parts are going to fit together, is important. This part is borderline on its needs for a more sophisticated modelling toolset. For free tools, like Sketchup, you can get most of what you want for a quick feel for proportions, but you’ll get frustrated when you decide to move to the next level. So don’t spend all your time on a 3D model in an app you might abandon later on.
One bonus to using Sketchup is you get access to the 3D Warehouse where others share their designs – so if you just want to get a basic robot onto your computer ASAP, you can find one there and then fiddle with it:
If you just want to see relative sizes and positions of your components, then any graphic design tool could help. However, if you want to be able to estimate how many feet of hydraulic hose you’ll need, you might want to move into a true engineering design tool or at least something that has units you can set and, ideally, includes a 3D environment.
Which brings us to the third stage for design software needs – applying specific materials and finish. Naturally here we are talking about a bot designed inside and out, in a computer model. We’ll talk about simulation in another post, but here we recommend something like Autodesk Inventor – which allows precise design in a 3D environment, including a wide (and configurable) set of materials to choose from. Furthermore, you can design with your particular material in mind, and then get a Bill of Materials list to see how much heavy metal you’re going to need! Inventor also can support not only mechanical design, but also electrical routing and more:
In our next post we’ll get more into the meat of technical modelling and simulation. Stay tuned…
In the meantime, leave a comment or Tweet us (@MInterstellar) to share more about the design tools YOU use in your projects – be they for fun, robots or general engineering.