Comments on “Design and analysis of a totally decoupled 3-DOF spherical parallel manipulator” by D. Zhang and F. Zhang (Robotica, Available on CJO 19 Nov, 2010, doi:10.1017/S0263574710000652)

Abstract

D. Zhang and F. Zhang addressed the issue of designing and analyzing totally decoupled 3-DOF spherical parallel manipulators (SPMs) and concluded that the SPMs in Figs. 5(a) and 5(b) of ref. [1] are completely decoupled and fully isotropic (see Abstract, Section 5, and Conclusions in ref. [1]). This topic is of great interest to researchers working in the general area of parallel mechanisms. However, we disagree with the authors of ref. [1] on their conclusion.