Saturday, 5 October 2013

Bench Test (No. 2)

This morning I opened up the base again to retrieve a lost nut that accidentally dropped in the other weekend back...

With the circuit board exposed, I happened to notice one of the links touching another component....  I re-positioned the link wire, and guess what....  The link was feeding into the direction control logic for the gripper stepper motor.   Hopefully a slight tweak was all that's needed to fix the problem!


The blueprints included flat washers on the PCB mounts which I added as mine was missing these...


I know... I've had bad experiences following the blueprints to the letter, but in this case, I see no reason why these washers would not help spread the load from the fastenings.   They are M3 flat washers, purchased from a local model shop.


Finally, I could replace the missing bolt on the side plate having retrieved that wild nut...



Connected the hand controller and powered up with my new power supply for bench testing....

A couple of video clips, firstly, the Gripper action now working:

video

In this clip - you'll see a problem with the Shoulder and Upper arms having tight spots causing a lot of judder.   I can see we're rubbing on the side plates at times, but I need to look at this again with fresh eyes to figure out what to do about it....

video

So, re-positioning that link certainly solved the problem with the direction control.  I don't really like these circuit boards with unshielded links running everywhere, if you have any problems in this area, I would recommend checking your not touching any neighboring components.

On the whole, I would say we're making good progress.

I'm still missing a few fastenings, so another weekend I intend to pop to a local Nut & Bolt stockist to remedy that situation.


Not a bad pose in these pictures...