Toward the Design of a Decoupled, Two-Dimensional, Vision-Based $μN$ Force Sensor

In this paper, we present three designs for a decoupled, two-dimensional, vision-based micro-Newton $(μN)$ force sensor for microrobotic applications. There are currently no reliable, multi-axis, commercially-available force sensors to measure forces at this scale that can be easily integrated into standard microrobotic test-beds. In our previous work, we presented a design consisting of a planar, elastic mechanism with known force-deflection characteristics. It was inspired by the designs of pre-existing micro electromechanical system suspension mechanisms. A charge-coupled device camera was used to track the deformation of the mechanism as it was used to manipulate objects in a microscale/mesoscale robotic manipulation test-bed. By observing the displacements of select points on the mechanism, the manipulation forces were estimated. In this work, we have designed a compliant mechanism with decoupled stiffness using the building block approach. By designing mechanisms with circular compliance and stiffness ellipses along with zero magnitude compliance and stiffness vectors, we are able to achieve our design requirements. Validation of this approach through the testing of macroscale prototypes and a scaled design for microrobotic applications are offered, along with a sensitivity analysis, yielding insights for microfabricating such designs.