Three-Dimensional Shape Optimized Seesaw-Type Force Sensor Fabricated with a Micro-Scale 3D Printer

This paper proposes a force sensor that utilizes three-dimensional (3D) shape optimization and 3D printing technology. Introduction of micro-scale 3D printing technology have simplified the fabrication processes of microdevices with complex geometries. At the same time, there have also been advancements in the optimization of 3D structures to achieve desirable performances. This study combined these two technologies to develop a force sensor for measuring the force of a soft actuator. The force sensor combines a typical probe geometry with a laser displacement sensor. Due to the millimeter-order scale of the sensor, the low rigidity of the resin material causes undesired torsional deformation. Through 3D shape optimization, a beam design with more than 70 % torsional displacement reduction was achieved without changes in spring constant. Furthermore, a beam printed by a micro-scale 3D printer showed elasticity. The relationship between the input force and laser displacement sensor output showed linear characteristics, indicating its suitability as a force sensor.