Precision and Compact Dynamic Bending Tester

A method for precision force measurement by using the levitation mass method (LMM) is reviewed. In this method, a mass levitated using a pneumatic linear bearing with sufficiently small friction is made to collide with the object being tested, and the instantaneous value of the impact force is measured as the inertial force acting on the mass. The velocity and acceleration of the mass are measured using an optical interferometer. With this method, the relative combined standard uncertainty is estimated to be very small. The prospects for reducing the size and cost of the optical interferometer are also discussed.