Comments on "On adaptive inverse dynamics control of rigid robots" [with reply]

The commenters point out an error in the adaptive control approach for robotic manipulators given in the above-named work by M.W. Spong and R. Ortega (see ibid., vol.35, p.92-5, Jan. 1990). It is noted that the authors assert that their adaptive control scheme eliminates the restriction given in J.J. Craig (1986) on the estimated inertia matrix; however, the commenters point out that a form of the inverse of the estimated inertia matrix must be bounded for the acceleration to be bounded. In a reply, the authors acknowledge the error in their paper.<>