scholarly journals Dynamic error characteristics of touch trigger probes fitted to coordinate measuring machines

1998 ◽  
Vol 47 (5) ◽  
pp. 1168-1172 ◽  
Author(s):  
R.P. Johnson ◽  
Qingping Yang ◽  
C. Butler
Keyword(s):  
Dynamic Error ◽  
Coordinate Measuring Machines ◽  
Error Characteristics

Dynamic Error Prediction and Compensation of Coordinate Measuring Machines

2000 ◽  
Author(s):  
Chensong Dong ◽  
Chuck Zhang ◽  
Ben Wang ◽  
Guoxiong Zhang
Keyword(s):  
Manufacturing Industry ◽  
Systematic Approach ◽  
Laser Interferometer ◽  
Dynamic Error ◽  
Error Prediction ◽  
Coordinate Measuring Machines ◽  
Air Bearings ◽  
Touch Trigger Probe ◽  
Dynamic Errors ◽  
Measuring Tool

Abstract Coordinate measuring machines (CMMs) are already widely used as a measuring tool in the manufacturing industry. Fast probing is now the trend for next generation CMMs. However, increases in the measuring velocity of CMMs are limited by dynamic errors that occur in CMMs. In this paper, theoretical analysis and experimental research is used to create a systematic approach for modeling the dynamic errors of a touch-trigger probe CMM. First, an overall analysis of the dynamic errors of CMMs is given, and methods to improve the stiffness of air bearings are presented. Weak elements of the CMM are identified with a laser interferometer. The probing process, as conducted with a touch-trigger probe, is analyzed and dynamic errors are measured. Based on these analyses, the dynamic errors in touch-trigger probing are modeled using neural networks. In turn, dynamic errors are predicted. An approach to achieving software error compensation is discussed. Finally, the method and results from this study illustrate that it is possible to compensate for dynamic errors of CMMs.

Impact Assessment of Dynamic Characteristics on the Hydraulic Driven Machinery Operation

2018 ◽  
pp. 1-12
Author(s):  
A. D. Terenteva
Keyword(s):  
Dynamic Error ◽  
Total Error ◽  
Soil Layer ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Working Mechanism ◽  
Automated Control ◽  
Vertical Coordinate ◽  
Construction Machinery ◽  
The Difference

In civil engineering in Russia, trenching for utilities is currently under digging. To perform such works, it is necessary to use high-precision construction machinery, because inaccurate performance of works can lead to the break down of existing utilities, thereby affecting the residents of nearby houses and demanding the additional works for renewal.The most universal labour saver to perform construction works is hydraulic driven single-bucket excavators, which provide up to 38% of works. Therefore, to improve technical characteristics that affect the accuracy of the work performed is an important task.High requirements for the performance of works are defined by existing construction regulations: an allowable soil layer to remain is at most 0.05 m. To fulfil such requirements, an exact assessment of the working mechanism position and a trench profile is necessary.Examination of a manually operated digging process shows that an operator provides operations untimely, however an automated control system can solve this problem. Dynamic phenomena in the working mechanism have the greatest impact on the accuracy of the works performed.To assess the bucket digging edge position accuracy, a mathematical model of the working mechanism has been created. Based on the cycle scheme of the working process, the excessive displacements of the hydraulic cylinder rods under the load are taken into account. By the end of the cycle, the difference between the specified and obtained positions along the vertical coordinate has been 0.0892 m.A dynamic error of the hydraulic drive system of the working mechanism is considered as a sum of the error due to excessive displacements of the hydraulic cylinder rods and the error due to delay of the hydraulic drive, with the latter being calculated for the average time of delay taking into account the data available in the literature. The total error of the bucket digging edge position of the working mechanism is 0.1176 m, which is 2 times more than the value of 0.05 mConformity of all the links with specification requirements does not guarantee compliance with the required displacement accuracy of the bucket digging edge, and, thus, the soil layer to remain in the base of the trench can exceed the regulated value of 0.05 m.

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