This paper provides more details of dynamic behaviors of the feed drive system which consists of an AC servo motor and rolling elements etc. In the feed drive system, the nonlinear behaviors of the internal structure of the rolling element have an crucial influences on precise control performance. Our special interest is how to verify the fundamental data of dynamic behaviors of the feed drive system in the vicinity of a microscopic displacement. Experimental data show that the driving torque curve becomes distorted as the input amplitude of sinusoidal wave to the system gets larger, but the curve forms are independent of the input frequencies.

This force comparison was performed among IDIC (Chile), LATU (Uruguay) and CENAM (Mexico), national laboratories within the Interamerican Metrology System (SIM) region. Each laboratory used its national standard for the established measuring range. The comparison started in August 2002 and finished in September 2004. This comparison is the second part of a SIM primary standards comparison carried out with the participation of INMETRO (Brazil), INTI (Argentina) and SIC (Colombia), having CENAM as pilot laboratory, (SIM comparison number SIM 7.7). This comparison has an overlap with the force steps used in the CIPM Key Comparison CCM.F-K1.a and CCM.F-K1.b., force points 5 kN and 10 kN.
The objective of the comparison was to estimate the level of agreement for the realization of the quantity force and the uncertainty associated to its measurement in the range up to 10 kN. Two transducers (load cells) were used as transfer standards, to obtain its maximum accuracy, the comparison range was selected from 4 kN to 10 kN (starting at 40% of the full load cells range). The results obtained by the participating laboratories were in agreement according to the analysis of comparability performed by the normalized error equation and the Youden plot techniques used.

This paper presents the methodology and results of an interlaboratory comparison currently in progress for the validation of forces generated by the 5 kN force standards machine (MCCC) designed and manufactured for the Low Force Laboratory (LBF) of the Aerospace Technical Centre (CTA), Brazil. Reference forces were generated by the 5,2 kN force standards machine of the Isaac Newton Laboratory of the Technological Centre Foundation in the State of Minas Gerais (CETEC). Results obtained in the first phase of the intercomparison have shown that the errors and the best measurement capability are larger than expected. Further investigation in the MCCC initial nominal range is to be carried out in the second phase of the comparison.

Developed, put into practice and used the universal automatic system MABA-2000 for calibration of force measurement devices in accordance to ISO 376-1999, ISO 7500-1999 and manufacturer requirements. The system includes a set of load cells from 1 kN to 5 MN, amplifier DMP-40 (HBM), computer and accessories. Mathematically proved the possibility of calibration in points, which vary from series to series, proved, and confirmed the application of calculation of formulas accuracy deviation and repeatability in accordance to ISO 7500-1999. This approach increases the productivity and simplifies the calibration process. Software MABA-2000 permits to communicate the measurement line “load cell-amplifier-computer” and to perform calibration process on mode ON-LINE: input of the measurement data, indications of the deviations in real time, calculations of the uncertainties, calculations of the calibration results and output of certificate. For calibration by method of Dead Weight a computer automatically selects a set of standard weights as a function of the True Force and value of gravity acceleration. The strict and precise method of the measurement results’ rounding optimizes the value of uncertainty. Calculation of interpolation polynoms of 1^st, 2^nd, 3^rd degree is done automatically too, and does not require additional resources or time. The software MABA-2000 includes also the subroutine for the measurement load rate and calculates uncertainty in accordance to customer requirements.

The cleaning of primary platinum-iridium mass standards is traditionally achieved using the nettoyage-lavage process developed at the BIPM. This manual cleaning method is notoriously difficult to reproduce, particularly at laboratories other than the BIPM. An alternative, operator independent, method for the cleaning of primary mass standards, using UV activated ozone, has been investigated and the results are reported.