Auric: Learning from testing

-


It's amazing what you learn when testing in the real world...

Auric went out for a long drive last weekend, while things went pretty well, there are always things to learn:

1.  Solving a performance problem

Halfway through the long test I noticed that Auric was pulling to the left, and I suspected a motor drive problem.  After putting the machine up on a bench for a closer look I noticed something, well, "green"
Upon closer inspection, Auric had decided to become an autonomous lawn mower and managed to wrap a 60cm grass runner around the front left drive.  Side effect was that the motor was loaded down and that caused thermal protection in the driver board to kick in.

 The final insult was when the imaging detected off-course behaviour and resulted in the motion controller trying to drive the jammed motor even harder, resulting in a vicious cycle.

 The end result of all of this is twofold.  Firstly, removing said grass solved the problem, and I wish to add "WEEDING" as a term in the robotics lexicon for the process of solving environmentally caused mechanical issues.

2.  When the board is not what it seems

Dear SparkFun, I owe you an apology.

In my last article, I wrote I was using your "Monster Moto Shield" as part of the motion controller.  Those with keen eyes will spot something completely different at the back of Auric at present.  So what happened?

 I purchased two boards from an online reseller because my usual suppliers had no stock, and it would take too long to get them from the US.  Both boards failed in exactly the same way.  The driver for motor 2 would only drive the motor in reverse.  In forward, the potential across the motor was about 0.8 volt, regardless of the motor being used. supply voltage, etc.

 I thought this was highly unlikely, so I looked closely at the boards.  While the say SparkFun on them, have the right logo and all, they don't appear exactly like the board on SparkFun's website.  The two driver chips have wildly different manufacturing ID numbers as well.

 So what did I get then?  A pair of pretty good looking knock-offs.  Oddly enough, the seller has gone to ground so I have done my money on these ones, and will stick to my preferred resellers in future.

 To meet the deadline, I switched to a Deek Robot motor driver which has got me past the deadline, but I am looking forward to getting my real Monster Shields soon!

3.  If it sticks out, it will get broken
In the interest of getting some more interesting video, I attached a Moovie Action camera from Jaycar electronics just above the front track.  This short clip clearly shows what happens when the front camera extends beyond the line of the front tracks:





Comments

Post a Comment

Popular posts from this blog

The QYT KT-7900D

-
Image
But is it any good? As you might have noticed, I am now a freshly licensed radio amateur .  As such I do need a transceiver or two in order to get on the air.  This is the story of one of my new radios. I have a limited discretionary budget to use for my new hobby, and I have to say from the outset that my lovely wife has been very supportive.  As such, I want to try and get the best value for our money.  One evening I stumbled upon this little item on Banggood for a little over $A150 including shipping.  Covering both 2m and 70cm bands with a claimed 20W output it seemed almost too good to be true.  I bought one. About ten days later a tiny package arrived for me.  At just 98mm x 43mm x 126mm the photos don't convey quite how small it actually is.  The entire case serves as a heatsink so it is heavier than it looks, but certainly not bulky. The standard power cable comes with a cigarette lighter plug.  As I intended to run it from home using a regulated PSU, I just cut the plug o
Read more

Life with Deep Racer - Part 2

-
Image
 An Update on AWS Deep Racer OK, so AWS Summit Sydney has been run and won.  Not by us however, but there are few interesting tidbits to report: The console is now widely available This is actually pretty big news, because: The console ties together Robomaker, SageMaker and everything else you need in a convenient package There are actual examples of functions included It seems to stay running now There is new firmware for the car Also important; this includes a rolling update for the Ubuntu base as well as the Deep Racer specific bits.  WiFi connection seems more reliable now as well. Our car has a new look Since my employer (Versent) was generous enough to send me to Re:Invent last year (where I got the Deep Racer), I thought it appropriate to deck it out in the company colours, and it was well-received at Summit last week.
Read more

DIY Self-Driving - Part 9 - New Imaging

-
Image
Please Note:    Unlike most of my projects which are fully complete before they are published, this project is as much a build diary as anything else.  Whilst I am attempting to clearly document the processes, this is not a step-by-step guide, and later articles may well contradict earlier instructions. If you decide you want to duplicate my build, please read through all the relevant articles before you start. We have a lot of work to do in pretty short space of time now, with new competitive opportunities in the very near future. To be honest, the line detection has simply not been good enough, and this is leading to some of the poor performance I have been experiencing with the car.  Whilst it really does work, it is not accurate enough.  There are a couple of issues here which need to be dealt with: The core processor is just not powerful enough; and The optics aren't good enough Processing As I noted in my "Next Iteration" article I am looking at othe
Read more