Maximizing the Resolution Range of Addictive-Manufactured Miniature-Scale Force-Sensing Devices for Biomedical Applications

This research presents a methodology for the design and manufacturing of miniature-scale force-sensing devices based on an additive manufactured sensor structure, coupled with strain gauge measuring elements, hereafter referred to as measuring device (MD). The proposed MD has been designed and manufactured to maximize the resolution of the steering force measurement in active needles utilized in biomedical applications. The force resolution is defined as the variation of the signal output of the four strain gauges bridge for predetermined increases of the applied force. By means of the proposed approach, the geometry and curing conditions of the sensor structure that allows achieving the maximum allowed deformation for the strain gauges, in the regions where they are installed on the sensor structure, can be defined a-priori, allowing to maximize the resolution of the measured force signal. The proposed methodology has been developed considering a sensor thickness ranging from 1 to 5mm and curing conditions varying from no curing up to 80°C for 120 minutes and showed that, by utilizing the proposed methodology, the measurable force range can be adjusted in the 0.1N~12.8N range with a relevant maximum and minimum resolutions ranging from 712.2 unit/N (force range: 0.1N~5N) to 362.2 unit/N (force range: 0.1N~12.8N), respectively.