POSITIONING ACCURACY OF NON-CONVENTIONAL PRODUCTION MACHINES

The paper deals with machines employing parallel-kinematics structures (PKS). They represent a relatively new generation of machine tools. Depending on the number of struts, the machines are referred to as hexapod or tripod machines. Such machines offer several advantages comparing to the conventional machine tools with serial kinematics, such as high flexibility, high stiffness, and high accuracy. It is very suitable for High- Speed-Machining (HSM), light machining and has received a wide interesting in manufacture industry. To achieve a desired positioning accuracy and stability, the static and dynamic properties of the machine must be searched and mathematically described. The calculation of the estimate of positioning deviation, including respective uncertainty and covariances, is much more complicated task comparing to the serial kinematics.