**7. Summary**

10 Will-be-set-by-IN-TECH

Fig. 6. Joint tracking errors when the RA-PKM is controlled by the CTC in redundant

 [rad] 

coordinates.


PKM are commonly characterized by inhomogeneous distribution of kinematic and dynamic properties within the work space, and eventually the existence of input-singularities. Actuation redundancy allows to eliminate these singularities, and thus to extend the usable workspace. The PKM motion equations are commonly formulated using a set of minimal coordinates. Moreover, actuator coordinates are usually used as minimal coordinates. Thus input-singularities are also parameterization-singularities of the PKM model, which is critical for any model-based control. In this chapter an alternative formulation of motion equations in terms of redundant actuator coordinates has been proposed, and the corresponding amended form of an augmented PD and computed torque control scheme were presented. The applicability of the proposed methods is confirmed by the experimental results for a planar redundantly actuated PKM.
