Pendulum for precision force measurement

Abstract

A pendulum and a method for correcting the restoring force of the pendulum are proposed for realizing an instrument based on the levitation mass method without the use of pneumatic linear bearings. As an example a material tester using the pendulum, which evaluates the mechanical response of general objects against impact forces, is developed. The characteristics of the restoring force are accurately determined using the same instrument under the free-swing condition without the object under test. To demonstrate the high performance of the developed instrument, the impact response of a gel block is accurately determined. The possible applications of the developed method are discussed.

Measurement of the electrical and mechanical responses of a force transducer against impact forces

“…[9][10][11] Recently, a pendulum mechanism has been developed as a substitute for the aerostatic linear bearing. 12 The inertial force of the levitated mass is measured using an optical interferometer. As for the methods proposed by the author for the dynamic force calibration of force transducers against some typical dynamic forces, such as impact force, 1 step force, 3 and oscillation force, 7 the electric responses of the force transducer against the typical varying forces are evaluated.…”

Toward dynamic force calibration

“…An algorithm of evaluating the frequency fro the waveform recorded using a digitizer has also been proposed [17]. By introducing a pendulum mechanism instead of the expensive aerostatic linear bearing and a low cost digitizer instead of the expensive electronic frequency counter, a low cost instrument based on the LMM can be developed.…”

Materials Testers Using Micro-Newton Level Forces Based on the Levitation Mass Method (LMM)

“…FUTURE PROSPECTS OF THE LMM In this section, the possible applications of the LMM in the near future are discussed. Recently, a pendulum mechanism for use as a substitute of an aerostatic linear bearing has been developed [27]. An algorithm of evaluating the frequency fro the waveform recorded using a digitizer has also been proposed [28,29].…”