... where p~, Apt, Pl and P2 are position/orientation vectors corresponding to s~, st, Sl and s2, respectively. The positions/orientations p,, Pl and P2 are those of S~, $1 and $2 in Figure 1.2, ... The velocity and force ellip- soids, and extension of grasp stability and manipulability are presented in Section 2.3. Section 2.4 presents a number of examples. Terminology and Notation: ... - s2 (1.18) where s~, Asr, Sl and s2 are velocity vectors corresponding to f~, f~, fl and f2, respectively. The velocities s~, sl and s2 are those of Z~, ~1 and E~ in Figure 1.2, respectively....