The positioning accuracy describes a property of moving mechanical systems, mainly in machine tools and positioning systems . It is a measure of how precisely a desired position can be approached or reached, and thus for the manufacturing accuracy that can be achieved with the machine.
A method for checking the positioning accuracy or for assessing the controller settings of a CNC machine tool is the circularity test .
The position uncertainty is a parameter for the positioning accuracy . This indicates how large the deviation of the actual position from the target position is in the direction of movement. The total permissible deviation of a movement axis is known as the position tolerance.
To determine the position uncertainty target positions are each of positive ( ) and negative ( started up) direction, and so the actual positions and measured.
The positional uncertainty of a movement axis is made up of three parts:
the systematic deviation at location x i from the target value:
the reversal range at location x i , which indicates the difference in position by approaching from positive and negative directions: