A method is proposed for evaluating the dynamic response of force transducers to a step force. In the method, gravitational and inertial forces acting on an object, which is suddenly put on a force transducer under test, are used as the reference force. At the beginning of the evaluation, the object is suspended using a wire just above the transducer. The object is then made to fall on to the transducer by cutting the wire. To realize perpendicular motion with sufficiently small friction, a pneumatic linear bearing is used. The inertial force acting on the object is measured highly accurately by measuring the velocity of the mass using an optical interferometer.

A method for evaluating the components of the force acting on a moving part of a pneumatic linear bearing is proposed. The total force acting on the moving part is accurately measured as the inertial force using an optical interferometer. Then, the components of the force, such as the force component depending on position, the force component depending on velocity, and the force component depending on tilt angle, are evaluated using the least-squares method. In the experiment, the total force acting on the moving part is measured with the standard uncertainty of approximately 0.001 N, which corresponds to approximately 0.003% ͑30 ppm͒ of the gravitational force acting on it (Mϭ4.119 kg) of approximately 40 N ͑40 N͒. The experimentally evaluated values of these force components well coincide with the theoretically expected values.

A method for evaluating the dynamic response of force transducers against an oscillation force is proposed. In the method, a force transducer is connected to a mass by a spring, which generates the oscillating force after the mass is manually hit using a hammer. A pneumatic linear bearing is used to realize linear motion with sufficiently small friction acting on the mass, which is the moving part of the bearing. The inertial force acting on the mass is determined highly accurately by measuring the velocity of the mass using an optical interferometer.