Root Cause
For robots of some brands, the robot coordinate systems are not located beneath the base. This is due to the fact that, in Mech-Mind software versions before 1.8.0, the robot coordinate systems were all positioned beneath the base.
Known Robots with Similar Issues
- FANUC full series of four, five, and six-axis robots.
- YASKAWA full series of four, five, and six-axis robots.
- KAWASAKI R series of six-axis robots.
- Stäubli full series of six-axis robots.
- AUBO full series.
- HANS full series.
It is currently uncertain whether robots from other brands or models also exhibit this issue.
Among them, FANUC, YASKAWA, KAWASAKI, and Stäubli have their robot coordinate systems located in the plane of the second-axis rotation axis directly above the base. Therefore, their Z-offset value is equal to their DH1.
For AUBO and HANS, the Z-offset is the height of their bottom base metal block, approximately 5mm.
In software versions before 1.8.0, due to the aforementioned issue, there were discrepancies in the Z-values of the robot tool poses between the teach pendant and the software. In versions 1.8.0 and later, this problem has been fixed, and the issue no longer exists.
In versions before 1.8.0, during automatic calibration, the software automatically compensated for the z offset of FANUC’s full series of four, five, and six-axis robots, YASKAWA’s full series of four, five, and six-axis robots, and KAWASAKI’s R series. The results obtained from automatic calibration with these robots can be directly used. However, when using other robots with z offset, automatic calibration does not provide compensation.
In versions before 1.8.0, when using manual calibration, teaching pick points, or directly sending the vision poses calculated by Mech-Vision through a standard interface, it is necessary to manually compensate for the z offset difference. These operations are not automatically compensated by the software.