Gravity vector:
Results of a validation experiment: We asked the robot to execute the reference link trajectories shown in color below (under position control mode set in FRI). In the seven following figures, we report the time evolution of the seven diagonal elements of the link inertia matrix. The data retrieved through the FRI are shown in blue; the predictions obtained using the dynamic model we have identified (along different trajectories) as evaluated on the actual link positions retrieved through the FRI are shown in green. The agreement is in practice total (the (7,7) element has a constant error in the order of 10^(-7) Kgm^2). Similarly, the next seven figures report the same comparison for the seven elements of the gravity vector.
At the bottom of the page, you can download a zipped file with the comparison plots on all the (28, in a symmetric 7x7 matrix) inertial and gravity terms.
Download all images of the validation experiment