On 26 October 2015 at 15:43, Sebastian Kuzminsky <[email protected]> wrote:
> I don't understand what problem you're solving, or what your solution > entails. Can you give more details? > John has suggested some scenarios. Here is another (based on the forum query that prompted the investigation). A robot arm can be in any initial position, and it is unlikely that you can guarantee that a full motion sweep of each axis will avoid the robotic equivalent of a boom strike. The robot in question has a potentiometer in each joint as well as an encoder. Encoder edges happen at 10, 20, 30, 40, .... 360 degrees. So you can, in theory, index home with a maximum of 5 degrees motion of each joint. If the homing sequence begins with the home switch input hal-wired shut then the robot will home to the next index[1]. But each index has a different HOME_OFFSET. Now imagine that the potentiometer voltage is fed into a "lincurve"[2] with a stair-step function to give 10,20... degrees for the output, and that value is sent to the new home-offset pin. Indexis found and the system believes itself to be now homed and at the new position. I don't know if there is a way to disable the rapid-to-home move. That would mess things up. [1]For extra credit you could fiddle the switch input to force homing to the nearest index. [2]I think that, actually "orient" has exactly the correct behaviour to do this too. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
