Theoretical aspects of control of the Tricept type parallel kinematic structure

The paper deals with several theoretical aspects connected with determination of positioning accuracy of parallel kinematic structures (PKS) with special regard to the Tricept type PKS. The conventional serial structures employ translate or rotational movement (or their combination) and their element are ordered in serial manner. On the other hand, parallel structures comprise a set of telescopic driving rods that are joined together via solid platform. Due to this fact, the mathematical model describing relationship between the driving actions of telescopic rods and resulting coordinates of the desired effector's endpoint is rather complex. To determine the theoretically achievable positioning accuracy of the endpoint is the main aim of the presented paper. One of the possible approaches will be discussed in details, together with presentation of sample calculations of coordinates of several selected target points within the workspace.