On some aspects of kinematic properties of parallel manipulators destined for some new applications

A designer of a robot manipulator has to select a kinematic structure, link lengths, its locations, and bearings etc. New manipulator applications for measurement of machined parts at the work-station need the investigation of components of mechanical parts and adequate (very small) mechanical hysteresis at kinematic pairs, kinematic model of the manipulator and properties of measurement transducers to obtain required performances of the robot. The paper deals with the design of a parallel manipulator POLMAN-3Lm with improved kinematic properties, i.e. with good distribution of linear resolution of the end-effector throughout its 3D workspace. An adopted mechanical system is characterized by good kinematic properties, i.e. the manipulator has good isotropicity of linear error (linear velocity) distribution in the workspace. The main advantages of this solution are simplicity and lightness of the construction.