Geometric error measurement and compensation of a six-degree-of-freedom hybrid positioning stage

Author(s):  
F-S Wang ◽  
S-L Chen
2005 ◽  
Vol 127 (4) ◽  
pp. 857-865 ◽  
Author(s):  
Sang Won Lee ◽  
Rhett Mayor ◽  
Jun Ni

This paper presents the development of a six-degree-of-freedom (DOF) geometric error measurement (6GEM) system that can be applied to the simultaneous measurement of six geometric error components of the moving axes of a meso-scale machine tool (mMT). The system consists of a laser module constructed by a cube beam splitter and a pigtailed laser diode, three two-dimensional position sensitive detectors (PSDs), and an additional cube beam splitter. The laser module moving with the positioning system of the developed mMT testbed generates two perpendicular laser beams, one of which is further divided into two laser beams at the second cube beam splitter. These three laser beams are detected by the three PSDs, and the full pose of the laser module is then calculated simultaneously by forward and inverse kinematic computations. The calculated full pose of the laser module is translated into six-DOF geometric errors of the mMT testbed. A series of experiments are performed to demonstrate the effectiveness and accuracy of the proposed 6GEM system. The experimental results show that the measurement accuracy of the 6GEM system was better than ±0.6μm for translational error components and ±0.6arcsec for angular error components.


Author(s):  
Jun Zha

Abstract The laser tracer multi-station measurement method has outstanding performance in computerized numerical control (CNC) rotary table geometric error measurement and separation. However, external factors, such as layout, selected distance between the target mirror and measurement coordinate system, uncertainty of the length measurement, selection of measuring radii for the rotary table, and installation deviation from the target mirror center to the rotary table surface, have negative effects on the results. In this research, the position dilution of precision in the global positioning system measurement process is introduced to evaluate the influence of the laser tracers’ positions on measurement errors. The optimal measurement layout of the laser tracer is used to select the distance between the target mirror and XY plane of the laser tracer measurement coordinate system for the simulation. Then, the influence of the length measurement uncertainty on the laser tracer self-calibration and point measurement results used for calibration is examined based on the Monte Carlo simulation method. Different measurement radii in the rotary table are selected, and four-station laser tracers are used to perform the virtual measurement and evaluate the maximum uncertainty in the X, Y, and Z directions to further determine the best measurement radii of the CNC rotary table. Finally, the effects of the deviation of the target mirror installation center on the geometric error items of the CNC rotary table are quantitatively examined through a simulation. The analysis of the influencing factors in the geometric error measurement and separation process of the CNC rotary table can help further understand how the final results are formed, so as to control the influencing factors during the measurement process and finally optimize them in practice.


2019 ◽  
Vol 10 (1) ◽  
pp. 100 ◽  
Author(s):  
Chuandong Li ◽  
Xianli Liu ◽  
Rongyi Li ◽  
Shi Wu ◽  
Houwang Song

This paper presents the design of a precise “ball-column” device to efficiently and accurately measure the geometric error terms of both rotary axes of the five-axis machine tool. A geometric error measurement method of spherical contact was proposed based on the influence of the geometric error term from a five-axis machine tool rotating axis on the integrated geometric error of the machine tool. A multiple degree of freedom, step-by-step contact method based on on-machine measure for measuring the spherical center point is proposed, and the solution formula of each geometric error term of the rotating axis is established, respectively. This method can identify 12 geometric errors based on the influence of one rotating axis on another rotating axis after long term operation. The spatial error field of the five-axis machine tool was constructed by analyzing the error law of the two rotating axes of machine tools based on various positions and postures. Finally, after the comparison of the experiment, the results showed that the accuracy of the developed error measurement device reached 91.8% and the detection time was as short as 30–40 min.


Author(s):  
Shufeng Sun

To adapt the miniaturized development tendency of nanometer positioning devices, a new type of micro-displacement stage with six degree of freedom, which can implement nanometer-level ultra-precision positioning without feedback control is designed. It takes a group of piezoelectric ceramics actuators (PZTAs) connected in series as actuation unit, takes flexure hinges as elastic guide rail. To overcome the non-linearity and hysteresis of PZTAs, binary actuation principle is adopted to control a group of actuators that work together to output many discrete, repeatable displacements. If these displacements are distributed within a scope of several microns, only simple on and off actuator commands may obtain nanometer-level repeatable positioning without feedback control. Theoretical calculation and finite element analysis (FEA) are used to design and simulate the stage. Expressions of rigidity and stress are obtained by theoretical calculation. FEA and experimental results verify the rationality and feasibility of the stage.


Procedia CIRP ◽  
2015 ◽  
Vol 27 ◽  
pp. 313-317 ◽  
Author(s):  
Zhang Zhenjiu ◽  
Ren Mingjun ◽  
Liu Mingjun ◽  
Wu xinmin ◽  
Chen yuanbo

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