Travel Path Repeatability based on Arm position and Speed

    This would be more of a general discussion rather then a troubleshooting question. I am rather new to Kawasaki robotic systems but have 4-5 years of experience with Fanuc robotic systems. We recently had Kawasaki come in and replace a Lower Arm on a ZX300S-B001 ( Handling Tool). We then ended up having to remaster JT2 and JT3 and then had to touch up all the points due to everything being just slightly off from the variance in mastering. While working with the assembly cells OEM on touching up the points I noticed something interesting that I haven't encountered while working with Fanuc's in the past. Even though we were only making small adjustments to our original points(+-2/3mm) such as the pick and place of work, and pick and place of the various tool change heads the air moves (Jmoves) between these finer and generally Linear moves were seeing a large change/variance in the path they took, also there would a noticeable difference between Auto speed 50% versus Auto Speed 100%. The OEM explained that with moves closer to the robots base the repeatability of the path increases versus when the arm is extended out, which is the case for some of transitional air moves. Is this just a Kawasaki characteristic or have I just missed that when working and programing Fanuc's? I understand the differences in JMoves vs Lmoves, but is there repeatability difference between Joint Postions (#positionname) versus Trans positions? Is there a best practice to avoid this from occurring. I know the AS Programing Language is quite powerful and I am are of speed and accuracy commands, is there an adjustment using those commands I could use? The equipment is running and the touch ups were completed, I'm more curious now for background knowledge and for future best practices.

    The OEM would be best served with your question I think as there are a lot of factors involved...…


    However, to just add my opinion:

    - Pre E Controller were a lot worse for path deviation at speeds.

    - This is ALWAYS mentioned in Kawasaki Documentation regarding geometry change with speeds.

    - Remember OEM specs/payloads are ALWAYS based at the centre of the Flange (not away from it).

    - So EOAT and ARM Load, inertia, COG settings need to be accurate - See WEIGHT command.

    - With Tool Change, should also incorporate WEIGHT command change too.

    - Acceleration and Deceleration values are left at defaults.

    - Using incorrect Speed commands such as % instead of mm/s.

    - Using incorrect accuracy values (FINE command introduced for D+ and onwards) improved this.

    - Joint posturing/configuration (LEFTY/RIGHTY/UWRIST/DWRIST) can add enhancement.

    - Reducing the total of Joint displacements between moves can assist.

    - Try doing a comparison test between a simple BLOCK program and AS equivalent.


    Kawasaki OOBE (in my opinion) is not optimized and needs a lot of work to optimize it further.

    Authorized integrators have access to certain areas which also allow for further enhancements and also remember most of the time with air moves, attention is not made in the programming to ensure accuracy of this as this may involve increased overall cycle times and this will have an impact on path.

Advertising from our partners