Diary of a Student Engineer Part 4: Finishing Touches & Systematic Design

Hello, so this week I split my time between designing the mechanical attachment for the robot and putting in some final touches on my Tumbler model in SolidWorks. The quality of the SolidWorks models my classmates have been working on are of an extremely high quality, so I’d be lying if I said I wasn’t comparing my own to a few of theirs. So, in an attempt to hold my own, I’ve been adding in a few tweaks and improvements before the deadline. Some of the said improvements include adding a tire thread to the wheels, and also working a bit more on that pesky motherboard, which I don’t think I’ll ever complete. That being said, I’m also conscious of not giving too much time to perfecting the model as my attention now must divert exclusively towards the design of the mechanical attachment.

Adding the tire thread to the wheels

Systematic Design

Design has always been my favourite part of engineering, so I’m really relishing this element of creativity despite the limited scope of the design problem. My plan of attack for designing this attachment is to adopt a condensed systematic design approach which we learned about last year and hopefully develop a final solution that is robust and effective.

Given the nature of the project, I think I can safely say I can skip any standards and patent reviews (thank God!) and get right to concept development. The problem statement is a simple one:

My first step here was to abstract what I could, all the specifications for a suitable attachment that would satisfy this problem. In the end I really came up with three critical ones:

  • The attachment must have a wheel — to aid steering in a tricky environment
  • The attachment must not effect the ultrasonic sensor — essentially this means it must be small and nimble enough to fit to the tumbler without being in the line of vision of the sensor, which is critical for the robot’s navigation.
  • The attachment must be able to be made of cardboard — this is a bit of a fail-safe spec, ideally I will be able to 3-D print the final attachment but in today’s conditions, who knows.

Specifications at the top of my mind, I could then begin the creative process of quickly sketching any solution that came to mind. I must admit, the initial ideas are not pretty, but they’re effective. I think this is an important aspect of good design, I simply want my attachment to be functional and once it solves the specified problem statement, I’m happy.

A Few Sketches

Next, given the limited complexity of the design concept geometries, I decided to try them out in SolidWorks as shown. This helped me get a better feel for what works and what doesn’t. In fact, an important takeaway I got from this was the effect each design would have on the orientation of the robot when it is stopped to catch the ping pong ball. A quick sketch told me, that the robot without an attachment sits at a decline angle of approx. 23 degrees when stationary. Going forward, my plan is to develop a final solution that does not tamper too much with this decline angle so the Tumbler will stand a better chance of catching the ball.

From Paper to Computer

And so, that’s about as far as I’ve got so far. Still early days in the design process but I have a general idea of what the final product might look like as I look towards embodiment design. I think I’ll probably combine a few of my ideas as well. On top of this, I have the task of building the ping pong launcher simultaneously so stay tuned for updates on that in the coming weeks. Seeya!