Comments on "Computing time delay and its effects on real-time control systems"

In the above paper by Shin and Cui (see ibid., vol.3, p.218-24, 1995), the effects of computing time delay on real-time control systems were addressed qualitatively and quantitatively, where the quantitative analysis was based on an example, i.e., the computed torque control of a robot. The purpose of this letter is to point out that the results of the quantitative analysis are incorrect.