Comments on "Tracking control of a flexible robot link" [with reply]

In the work by J.H. Davis and R.M. Hirschorn (see ibid., vol.33, p.238-48, Mar. 1988), the model of a flexible slewing link is derived. The authors assert that when the equations of motion are written relative to a desired coordinate frame, then a substantial linearization of the equations results. The commenter raises some questions regarding the validity of that claim and shows that in fact the coupling between the transverse displacement of the beam and the servomotor angle was not adequately accounted for. In a reply the original authors state that their interest was primarily in the case of high-performance rapid slewing motions, for which the centrifugal effects can be expected to play a role.<>