Double ball-bar measuring system and errors compensation method thereof
AssigneeNational Tsing Hua University
InventorWei-Tai Lei
Life of this patent
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Abstract
A double ball-bar measuring system includes a calibration unit, at least two double ball-bars and a measuring module. Among the double ball-bars, at least one is a measuring double ball-bar and at least one is a reference double ball-bar. The measuring double ball-bar is installed on a measurement apparatus to measure or calibrate a target machine. The reference double ball-bar is disposed on the calibration unit to measure thermal errors. When the target machine is driven for measurement or calibration, the geometric and thermal errors of the measuring double ball-bar are compensated so that the measurement apparatus can achieve highly accurate measurement.
Claims27
A double ball-bar measuring system comprising a calibration unit, at least two double ball-bars and a measuring module, among the double ball-bars at least one double ball-bar being a measuring double ball-bar and at least one double ball-bar being a reference double ball-bar, wherein:
- the calibration unit comprises at least three supporting members and provides at least two reference center distances;
- the measuring double ball-bar is installed on a measurement apparatus to measure or calibrate a target machine, and when the target machine is driven for a measurement or a calibration, the measuring double ball-bar measures a displacement amount;
- the reference double ball-bar is disposed on two supporting members of the calibration unit and measures a thermal error amount in accordance with an ambient temperature;
- and
- the measuring module processes the displacement amount and the thermal error amount, compensates the geometric and thermal errors of the measuring double ball-bar and performs measurement data processing.
An errors compensation method of a double ball-bar measuring system, comprising:
- providing a calibration unit comprising at least three supporting members and providing at least two reference center distances;
- providing at least two double ball-bars, wherein at least one double ball-bar is a measuring double ball-bar and at least one double ball-bar is a reference double ball-bar;
- disposing the measuring double ball-bar on the calibration unit and measuring at least two calibration points;
- establishing a center distance function of the measuring double ball-bar in accordance with the calibration points;
- installing the measuring double ball-bar on a measurement apparatus to measure or calibrate a target machine;
- disposing the reference double ball-bar on the calibration unit;
- driving the target machine for a measurement or a calibration;
- measuring a displacement amount of the measuring double ball-bar;
- measuring a thermal error amount of the reference double ball-bar;
- determining the center distance of the measuring double ball-bar in accordance with the center distance function and the displacement amount;
- compensating the center distance in accordance with the thermal error amount;
- and
- using the compensated center distance for further measurement data processing.
Dependencies are inferred from the claim text.