I’m new in this forum so excuse me if this is not the correct sub-forum to post this.
Over the past few years I have been making some small rovers (CD sized) just for the fun of building a very limited robot.
The last month I decided that it was time to start making something more complicated and after discovering this site I decided to make a hexapod. I’m no programming genius by I can program my AVRs using Bascom Basic. To start off, I ordered an SSC-32 controller (congratulation to Lynxmotion for this wonderful piece of hardware) The next step was to make a simple controller to talk to the SSC-32. Finally comes the challange of making the skeleton of the bot.
This is the reason I’m posting in this section. Since I have access to scraps of pcbs I decided to make all my brackets using these scraps. I have made a 2DOF set as shown in the picture below.
Now the questions is, do you think in your opinion that a full haxapod could be built using this technic? Will the brackets hold up?
I know that it will take some time, but I really love to make things with my hands so that will be no problem.
I think the best way to determine if they’ll be up to the task will be to make a few different types (or at least some prototype joints) and test their overall strength and rigidity, possibly to destruction. You’ll get a better feel for how much each one can take individually, and may find ways to add some strength where needed (gusseting, strengthening ribs, etc). You may find that you don’t need to strengthen them, or you might find that they fail at somewhat low load levels.
From working with copper-clad board in the past, I know that some PCB material can delaminate at points of concentrated stress, especially where it has been subjected to high heat - at solder joints, for example.
I’m not trying to dissuade you from what you’re doing - your brackets do look good, and will probably work fine for light loads up to their point of failure. I just can’t give you any real idea of what that point might be, since that will depend largely on your board material, its thickness and composition, the copper, and how well it is bonded to the surface.
the biggest limitation is your joint only has structural support on one side of the board. You need to look at adding something on the other side for support. If you use double sided copper clad then you may be able to use copper foil tape, creased in the center and then soldered over the joint. You could also use the tape to add corner gussets for twist strength as well.
Thanks for replying.
The brackets are actually very sturdy but as you say the joints were and are my main concern. The joints have been re-enforced by laying bent pins on the inner angle and then soldering over them.
But I must agree with what’s already been said. Use double sided board. Foil tape could help. Stress test your assemblies.
You might also look to using locking slots. A pair of 1/16" (board thickness) slots cut into two parts gives a sturdy joint once soldered or glued. A single sided PCB joint is bound to fail. Epoxy might even be better in that case (on bare side). Gussets to re-enforce your joints would help.
Check out my thread on Loki (a simple biped) in the projects.
