The investigation of the roll brake testers used testing for trucks has been made during year 2002. There have been developed a test trail, reported in TC-3 Congress Celle 2002. The aim of this investigation was to get information about real measurement capability of the roll brake testers used in inspection of the trucks for Finnish authority (The Finnish Vehicle Administration AKE). The usually way to calibrate roll brake tester has been to generate the reference force direct against of the force measurement transducer. This calibration does neither take in to account the mechanical construction of the rollers nor the diameters of them or the dynamic behaviour of the measurement. The investigation gives the information over practical uncertainty of the roll brake tester. The used comparing method has been static with the reference transducer as well quasistatic by the test trail, which makes the control of roll brake testers with the speed of normal use of a roll brake tester, about 3 km/h.

This contribution deals with possible reasons for the non-linear behaviour of piezoelectric force transducers, previously unknown.
Possible reasons are interactions between isotropic elements such as force introduction and the anisotropic piezoelectric sensor element, geometrical non-linearities of the force transducer and non-linearities of the piezoelectric material.
This paper discusses the influence of geometrical nonlinearities. A theory for analytical modelling of piezoelectric force transducers is developed and presented.

Many mechanical quantities in metrology are affected by the local gravity. Modern gravimetric methods allow to determine the local gravity value with sufficient accuracy, but the effort is still time consuming and expensive. An interpolation within available gravity databases mostly does not suffice because of an inadequate data density compared with the heterogeneous field. This study gives a short overview of today’s most important representations of the physical gravity field. The classical methods will be introduced from the perspective of the usability in metrology and compared to some strategies in synthetic gravity modeling.

The purpose of this lecture is to show the problems which must be taken into account by the designer in constuction of miniature semiconductor strain gauges for dynamic measurements of yarn tension and to give practical methods for identification of static and dynamic behaviour and a design of such transducer.

This paper describes the unique features and metrological performance of a new 55 kN / 2200 kN lever deadweight force standard machine set up recently at SPRING Singapore. It uses a novel 55 kN deadweight stack with individual mass disk drives, a single lever of 40 times multiplication ratio and a 2.2 MN tension-compression loading device. The machine is of increased capacity, with a wider force range and larger amplification ratio than previously possible. The lever machine covers force range from 10 kN up to 2200 kN in intervals of 10 kN. For the first time, a force standard machine of this type and size uses an entirely digital control system. The machine has been the subject of a comparison measurement with the PTB, preliminary results of which are given. The uncertainties of the machine were found to be within 2·10^-5 for the deadweight part and 1·10^-4 for the lever part. The system now serves as a primary force standard for Singapore.