One basic item to identify in the context of robot calibration is the offsets in the joint-angle dials, whose zero does not always coincide with their nominal locations. However, when attempting to identify the joint offsets with the aid of the robot's own encoders, using self-motions, it turns out that, upon fixing the end-effector (EE) to the robot base, the offsets of the end joints cannot be identified. A set of measurements is needed in a different EE pose--position and orientation. We have established identifiability conditions and developed an identification algorithm that has undergone satisfactory tests in a dual-arm robotic workcell that is under development, as outlined in this same issue. (Figure 6.12).
Y. Gonthier, G. Bilodeau, F. Ranjbaran, J. Angeles, A. Robins (Bombardier Services)
Figure 6.12: REDIESTRO 1