A New Method for On-line Measurement of the Straightness Error of Machine Tools Using an Acceleration Sensor

2021 ◽  
Author(s):  
Kuo Liu ◽  
Yiming Cui ◽  
Zhisong Liu ◽  
Jiakun Wu ◽  
Yongqing Wang
Keyword(s):  
Machine Tools ◽  
Signal To Noise Ratio ◽  
Measurement Data ◽  
Geometric Error ◽  
Ar Model ◽  
High Signal ◽  
Line Measurement ◽  
On Line ◽  
Straightness Error ◽  
Zero Phase

Abstract In order to improve the poor efficiency in the measurement of the geometric error of machine tools’ linear axes, this paper has presented a method to measure and restructure the geometric error of linear axes that is based on accelerometers. This method takes advantage of the phenomenon that when acceleration is measured under different measuring speeds, different frequencies and amplitudes are produced. The measurement data of the high signal-to-noise ratio for various velocities was fused together and the straightness error of the measured axis was obtained by integrating the acceleration twice. In order to remove the trend terms error in the integration, a zero phase IIR Butterworth filter was designed, which guarantees the signal’s phase invariance after filtering. The data was continued with the AR model to eliminate the endpoints’ effect in the filtering. The proposed method was verified by numerical values and experiments. The results showed that the proposed method has better robustness, a wider bandwidth and a higher efficiency than the methods of measuring by laser interferometer. It is also able to measure the geometric error of linear axes with an accuracy that reaches the micron scale.

Table-Based Volumetric Error Compensation of Large Five-Axis Machine Tools

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Data Gathering ◽  
Measurement Data ◽  
Geometric Error ◽  
Compensation Method ◽  
Geometric Errors ◽  
Simultaneous Generation ◽  
Five Axis

This paper presents a geometric error compensation method for large five-axis machine tools. Compared to smaller machine tools, the longer axis travels and bigger structures of a large machine tool make them more susceptible to complicated, position-dependent geometric errors. The compensation method presented in this paper uses tool tip measurements recorded throughout the axis space to construct an explicit model of a machine tool's geometric errors from which a corresponding set of compensation tables are constructed. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. Two position-dependent geometric error models are considered in this paper. The first model utilizes a six degree-of-freedom kinematic error description at each axis. The second model is motivated by the structure of table compensation solutions and describes geometric errors as small perturbations to the axis commands. The parameters of both models are identified from the measurement data using a maximum likelihood estimator. Compensation tables are generated by projecting the error model onto the compensation space created by the compensation tables available in the machine tool controller. The first model provides a more intuitive accounting of simple geometric errors than the second; however, it also increases the complexity of projecting the errors onto compensation tables. Experimental results on a commercial five-axis machine tool are presented and analyzed. Despite significant differences in the machine tool error descriptions, both methods produce similar results, within the repeatability of the machine tool. Reasons for this result are discussed. Analysis of the models and compensation tables reveals significant complicated, and unexpected kinematic behavior in the experimental machine tool. A particular strength of the proposed methodology is the simultaneous generation of a complete set of compensation tables that accurately captures complicated kinematic errors independent of whether they arise from expected and unexpected sources.

On-line measurement data of wastewater systems via WAP mobile phones

2003 ◽  
Vol 47 (2) ◽  
pp. 205-211
Author(s):  
J. Alex ◽  
U. Jumar ◽  
M. Schütze
Keyword(s):  
Mobile Phones ◽  
Remote Monitoring ◽  
Measurement Data ◽  
Internet Technologies ◽  
Line Measurement ◽  
Spatially Distributed ◽  
Standard Application ◽  
Wastewater Systems ◽  
On Line ◽  
Plant Data

In order to support the operation of wastewater systems a system was developed which allows us to access plant data by standard mobile devices such as WAP mobile phones. This system is suited to complement the standard application of alarm and message systems based for example on SMS or pager services. This technology provides useful options for mobile remote monitoring and remote control of automated plants. This technology is particularly appropriate for the use in remote facilities where no staff is available. The technology has been implemented succesfully and shows how standard IT and Internet technologies can be utilised to support the operation of spatially distributed plants with reasonable effort. Two implementations are presented which access plant data via WAP mobile phones and via mobile pocket PCs. First application experiences are presented.

Feasibility and Performances of a New, Multiplexed, Fast and Low-Cost Fiber-Optic NIR Spectrometer for the On-Line Measurement of Sugar in Fruits

1993 ◽  
Vol 47 (7) ◽  
pp. 1079-1083 ◽  
Author(s):  
Véronique Bellon ◽  
Jean Louis Vigneau ◽  
Michel Leclercq
Keyword(s):  
Fiber Optics ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Sugar Content ◽  
Acquisition Time ◽  
Diode Array ◽  
Line Measurement ◽  
Array Technology ◽  
On Line ◽  
Good Signal

This paper describes an attempt to develop a new NIR spectrometer to sort fruits according to the sugar content in the conditioning stations. This spectrometer, ranging from 800 to 1050 nm, is based on diode array technology. It is coupled with fiber optics, which allow multiplexing; 20 fibers have been detected by the camera, showing the potential multiplexing of 20 different points. The acquisition time is 40 ms per image (i.e., 2 ms per spectrum). A good signal-to-noise ratio has been recorded in the 820–1010 nm range. This spectrometer has been tested with a set of 79 peaches. Partial least-squares processing is applied to different wavelength ranges. The best coefficient of correlation, achieved with a reduced wavelength range (from 847 to 977 nm), is 0.81, and the standard error of prediction is 1.04°Brix. With this calibration, the fruits can be sorted into three maturity classes with a reliability of 76%. This performance, as well as the other characteristics of the instrument, is in accordance with the requirements of the conditioning station managers.

An On-Line Measurement Technique for Machine Volumetric Error Compensation

1993 ◽  
Vol 115 (1) ◽  
pp. 85-92 ◽  
Author(s):  
J. Ni ◽  
S. M. Wu
Keyword(s):  
Measurement Technique ◽  
Error Compensation ◽  
Experimental Tests ◽  
Geometric Error ◽  
Degree Of Freedom ◽  
Volumetric Error ◽  
Measurement Systems ◽  
Line Measurement ◽  
Maximum Range ◽  
On Line

A hybrid on-line and off-line measurement technique is developed for machine volumetric error compensation based on a multiple-degree-of-freedom laser optical system. When implemented on a 3-axis machine up to 15 geometric error components can be measured simultaneously on-line and the remaining 6 components need to be calibrated off-line. Since the on-line measurement systems use different metrology bases, a modified volumetric error model is derived for a milling machine by considering the measurement features of the multiple-degree-of-freedom system. Through experimental tests, it was found that the discrepancy between the identified errors and the actual errors was less than 4 μm out of a maximum range of 20 μm.

Multiple Fault Diagnosis for Sheet Metal Fixtures Using Designated Component Analysis

2004 ◽  
Vol 126 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Jaime A. Camelio ◽  
S. Jack Hu
Keyword(s):  
Fault Diagnosis ◽  
Sheet Metal ◽  
Measurement Data ◽  
Component Analysis ◽  
New Approach ◽  
Multiple Fault ◽  
Sheet Metal Parts ◽  
Multiple Fault Diagnosis ◽  
Line Measurement ◽  
On Line

This paper presents a new approach to multiple fault diagnosis for sheet metal fixtures using designated component analysis (DCA). DCA first defines a set of patterns based on product/process information, then finds the significance of these patterns from the measurement data and maps them to a particular set of faults. Existing diagnostics methods has been mainly developed for rigid-body-based 3-2-1 locating scheme. Here an N-2-1 locating scheme is considered since sheet metal parts are compliant. The proposed methodology integrates on-line measurement data, part geometry, fixture layout and sensor layout in detecting simultaneous multiple fixture faults. A diagnosability discussion for the different type of faults is presented. Finally, an application of the proposed method is presented through a computer simulation.

Sign in / Sign up

Export Citation Format

Share Document