Arduino Uno - TinkerKit Braccio - Initial/Safety position wrong

Other Hardware Robotics
1

Dear all,

This isn't a code or electrical issue, it's a mechanical issue with the Braccio Robot. Sorry for the long explanation, just want to make sure everything is included.

I've recently received a TinkerKit Braccio Robot and shield for my Arduino Uno. I've assembled it and followed the manual (no problems there). Now I've connected everything, loaded the example sketch "testBraccio90" which sets the robot to it's "Initial Position", or "Safety Position". As per the manual, this is the first thing to do after assembly, and I've done exactly that. Now, my problem is as follows:

The robot is not set to the correct position after the sketch is ran (which per the manual can be expected), and I want to realign the servo motors so that the robot is set in the correct position (also according to the manual). But; how to realign all the arms without disassembling most of the already assembled robot? My conclusion for now is that the motors should have been set to their initial position before mounting, since the mounting process made sure the mechanical position was correct.

So, has anyone ever realigned the servo motors on a Braccio Robot after assembly?

Thanks in advance for any pointers. All the best!

2

i have the same problem, ca someone help us ?

3

I had similar problems, but only with the last two joints (gripper and wrist rotation), so I had to take enough apart to be able to correct that. The servos are physically limited to their 180 degree area of operation, so there is no way to compensate in software other than for small errors.

I think the best position to align the servos is in the testBraccio90 position, where the arm is positioned straight up (all servos except gripper at 90 degrees) - then it is more easy to see which joints need realigning physically.

One of the bigger weaknesses of the original Braccio library is that the initial position is hard wired in the library. That is one of the reasons I wrote my own library, where the initial position can be configured as part of the startup and I prefer the "straight up" position as the arm will stay there when it is powered off.

The library I wrote is available at: GitHub - stefangs/arduino-library-braccio-robot: A small library to control the Tinkerkit Braccio robot arm