A large range and high resolution force sensor and its application to wire-pull tests

This paper presents a new method for large range and high resolution force measurement. Unlike conventional strain-gauge-based force measurement, our method measures an external force through measuring the displacement of a movable member suspended by a compliant mechanism. The compliant mechanism is specially design to have two different stiffness values in its workspace. The low stiffness is used for small force measurement while the high stiffness is used for larger force measurement. A grating scale is attached on the movable member to measure the displacement. The major advantage of this method is that it can measure both micro and macro forces with different scales in one setup, and the output signals are digital. A force sensor prototype has been developed and applied for wire-bond pull tests.