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 |

Theory and experimental data for load cell with rigid connections |

Theory and experimental data for load cell with moment compliant rings |