title: Detailed study of amplitude nonlinearity in piezoresistive force sensors.
abstract: This article upgrades the RC linear model presented for piezoresistive force sensors. Amplitude nonlinearity is found in sensor conductance, and a characteristic equation is formulated for modeling its response under DC-driving voltages below 1 V. The feasibility of such equation is tested on four FlexiForce model A201-100 piezoresistive sensors by varying the sourcing voltage and the applied forces. Since the characteristic equation proves to be valid, a method is presented for obtaining a specific sensitivity in sensor response by calculating the appropriate sourcing voltage and feedback resistor in the driving circuit; this provides plug-and-play capabilities to the device and reduces the start-up time of new applications where piezoresistive devices are to be used. Finally, a method for bypassing the amplitude nonlinearity is presented with the aim of reading sensor capacitance.
authors.affiliation: Centre for Automation and Robotics, UPM-CSIC, Ctra. Campo Real Km 0.2, Madrid 28500, Spain.
authors.forename: Leonel
authors.initials: L
authors.lastname: Paredes-Madrid
authors.forename: Luis
authors.initials: L
authors.lastname: Emmi
authors.forename: Elena
authors.initials: E
authors.lastname: Garcia
authors.forename: Pablo Gonzalez
authors.initials: PG
authors.lastname: de Santos
mesh_terms: D004581:Electronics; D008962:Models, Theoretical