Nonlinear Load Cell

Load cells are useful for applications ranging from material strength testing to prosthetic limb sensing, monitoring infusion pumps delivering drugs, agricultural product sorting, suction cup strength measuring, and human-robot collision force sensing. Typical linear load cells can only function over a limited force range and have limited resolution. These load cells' force vs. deflection curves behave similarly to the nonlinear energy harvester spring's curve. The value of a load cell with a nonlinear stiffness is that it can be very sensitive to small forces (i.e. the load cell deflects by a large amount so that a sensor with limited resolution can distinguish small changes in applied force) and not break for large forces. This nonlinear effect can allow a single load cell to function over large force ranges (several orders of magnitude).

Nonlinear load cells
Nonlinear Load Cells

Load cell with rigid connections
Theory and experimental data for load cell with rigid connections

Load cell with moment-complaint connections
Theory and experimental data for load cell with moment compliant rings