Define working range for robot axis (not safety limits)

Hello,

I'm working on a pick & place project where the robot picks from a conveyor and deposits the products in predefined positions. The products have to be picked from a certain orientation so that they're placed correctly everytime. The coordinates and orientation are sent by a camera so I don't have the exact Status and Turn for the place the robot needs to go to pick the product.

My problem is that the controller maintains the S and T from the previous motion so sometimes it performs the shortest motion and sometimes A6 turns 360° more than it should. I want to be able to limit the motion range of axis A6 on a KR3 R540 robot so that it works between -180 and 180.

The only solution I could come up with is geometrically calculate the position of A6 on the end point and set the bit 5 of Turn so that it takes the path I prefer. This is a complicated solution because it works for this particular setup, so what I want is a way to set conditions for the motion planner to take into account. For example to choose the shortest path and disregard the previous Turn or set working limits for an axis (but not the ones that stop the robot for safety purposes). Is this possible?

I've been reading all the manuals I think can be relevant for this but I couldn't find anything.

Thanks

Yes, but one that is only suitable for these exact conditions. I'd like something more applicable to different situations.

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What does this mean, exactly? Do you mean that the robot stays physically in the last S&T combination?

Yes, the KSS manual says for SPTP motion instructions:

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If not all components of the end point are specified, the controller takes the values of the previous position for the missing components.

The start point for the motion I want to perform is completely defined with S&T, but the end point isn't because I didn't know how the robot axis would end up when picking up the object with the coordinates from the camera.

Quote from SkyeFire

And sticking to LIN motions after this "unwind" motion, so that the S&Ts that result from the camera data don't have any effect.

I didn't want to use LIN motions because they can be much slower than PTP and speed is critical in my application as one whole pick & place cycle should take just 1s.

This way the axis always "unwinds" but my problem was how to determine the optimal path for the A6 axis to take. For some end points A6 would turn 270° in one direction for example instead of 90° in the opposite direction, just to maintain the start point's Turn.

As my problem can be reduced to a 2D situation, I calculated an equation which, from the relative position of the pick location to the robot, calculates A6 (assuming A4 stays in or near 0° and knowing A1 is always positive), and I set the bit 5 of Turn accordingly. This works fine but I wanted to know if there was a more general way to solve this issue. I still have to try to implement the solution panic mode suggested but it seems that is what I was looking for.

Thanks to the both of you!