This paper presents a new method for calibrating piezoelectric force transducers with static forces. Load cycles with pilgrim-steps and a special evaluation of the measuring results permit the determination of transducer coefficients that are independent of the linear drift of the charge amplifier. Consequently, the coefficients are independent of the measurement time and the time of load change of the force standard machine in use. It is shown that the new calibration method contributes essentially reducing the uncertainty of piezoelectric force transducers that are used in quasistatic and...
XVIII IMEKO World Congress · TC3 · 2006 · Download
An approach for calibrating a low-cost IMU is studied, requiring no mechanical platform for the accelerometer calibration and only a simple rotating table for the gyro calibration. The proposed calibration methods utilize the fact that ideally the norm of the measured output of the accelerometer and gyro cluster are equal to the magnitude of applied force and rotational velocity, respectively. This fact, together with model of the sensors is used to construct a cost function, which is minimized with respect to the unknown model parameters using Newton’s method. The performance of the...
XVIII IMEKO World Congress · TC3 · 2006 · Download
A procedure is described by which the spring constant of a microfabricated cantilever beam can be calibrated for the measurement of small forces in an atomic force microscope (AFM) or other device. The procedure utilizes dynamic force instrumented indentation to determine the mechanical properties of the beam by applying a well-characterized oscillating force and measuring resulting displacement of the system. An uncertainty analysis is carried out, and by intercomparison with the U.S. National Institute of Standards and Technology (NIST) Electrostatic Force Balance (EFB). The spring...
XVIII IMEKO World Congress · TC3 · 2006 · Download
Three Methods for evaluating the dynamic response of force transducers against varying force are described in this paper. In all methods, the inertial force of a mass is used as the known dynamic force, and this reference force is applied to a force transducer under test. The inertial force is measured highly accurately as the product of the mass and the acceleration. An aerostatic linear bearing is used to obtain linear motion with sufficiently small friction acting on the mass (i.e., the moving part of the bearing). Three experimental setups were built for the dynamic calibration against...
XVIII IMEKO World Congress · TC3 · 2006 · Download
Tuning fork type load cells are expected to have better long-term stability than conventional strain gauge type load cells. A new 50 N rated capacity load cell has been developed herein adopting a Double-Ended Tuning Fork (DETF) sensing unit. The performance of two such load cells was evaluated using the 500 N force standard machine at the National Metrology Institute of Japan (NMIJ). The DETF load cells were found to have low creep, low hysteresis and superior long-term stability.
XVIII IMEKO World Congress · TC3 · 2006 · Download
The reliability of the weighing system is becoming more and more important these years. This paper deals with a new approach to load cell soft failure prediction by the application of Grey theory. Grey theory is a theory which studies poor information and sets up a math model to simulate and predict a system behavior. Collecting the historical data of zero and sensitivity drift to set up a grey model GM (1.1) and with this model, the system can not only simulate the zero and sensitivity drifts but also calculates their possible value in the near future. Therefore, a previous action could be...
XVIII IMEKO World Congress · TC3 · 2006 · Download
This paper describes a weighing system used under the conditions in which various movements exist. These various movements are heaving motion, rolling motion, pitching motion, etc. In this paper, these various movements are collectively called as “vibration-like movement”. The term of “vibration-like moving conditions” means the conditions in which vibration-like movements exist. In the previous paper, the new weighing method was proposed. This method basically requires 4 loadcells which observe the vibration-like moving conditions. These loadcells are called as “dummy loadcell”. Installing...
XVIII IMEKO World Congress · TC3 · 2006 · Download
Luis O. Becerra, Eduardo González, Félix Pezet, José Revuelta M, José Revuelta R, Sylvia Maeda
This paper presents the results obtained from the comparison of different techniques for the weighing tests for the calibration of high capacity weighing instruments, in order to evaluate their use as a function of the amount of available weights and the required uncertainty of the instrument in their normal use.
XVIII IMEKO World Congress · TC3 · 2006 · Download
Our aim is to establish a measurement system that enables highly accurate measuring mass and length of moving products with a relatively high speed on a conveyor belt. In this paper, effectiveness of the proposed measurement system is demonstrated by an analysis of a digital image taken by a digital camera. In our experimental results, it can be found in the following: First, our discrimination method of colors is that there is no need to count the number of pixels for all three primary colors, but the only one component indicated the highest value of graduation should be counted. Second,...
XVIII IMEKO World Congress · TC3 · 2006 · Download
Gerhard Schulder, Ulrich Kolwinski, Daniel Schwind
The main purpose of the build-up system is the use in verification measurements of force standard machines up to 5MN or even higher capacity. The special design of the described build-up system allows the use of nine force transfer standards either individually, in groups of three transducers or all transducers together in three groups of three. A 9-channel digital measuring amplifier (GTM VNDigitizer 3.0) enables the user to get the readout of all transducers simultaneously.
XVIII IMEKO World Congress · TC3 · 2006 · Download