Conclusions

Abstract

It has been shown how the substitution of ordinary joints with lockable revolute joints ($\text {R}_\text {b}$ joints) or non-holonomic spherical joints ($\text {S}_\text {n}$ joints), which we have referred here to as unconventional joints, provide lower-mobility parallel robots with interesting features. One important common characteristic of this kind of robots is that they can approximate, in general, trajectories for their moving platform in a configuration space of dimension higher than the number of their continuously actuated joints. In this monograph, the kinematics of the following three robots have been analyzed: the 4$\text {R}_\text {b}$RPS spatial reconfigurable robot (Chap. 2), the 3$\text {S}_\text {n}$ PU spatial non-holonomic robot (Chaps. 4 and 5), and the S-2SPS spherical non-holonomic robot (Chaps. 6 and 7).