Searching for Stiffness Singularity Using Directional Palpation by a Microfinger and its Scanning Condition Dependence

Minimally invasive treatment has recently emerged as a dominant procedure, as it reduces the patients' physical burden. However, it is still limited by the lack of tactile-sensation feedback from the invading device. We have reported a technology for conducting stiffness-singularity search in an elastic object based on palpation using a microfinger that was integrated with an artificial muscle and a tactile sensor. Here, to advance the application of the technology in medical diagnosis, we focused on tumor detection facilitated by palpation diagnosis using the microfinger. Notably, the miniaturized microfinger exhibits bending actuation, which imparts it with directivity. We have demonstrated an efficient searching method for singularities based on the directivity of the microfinger. Here, we estimated the condition dependence of the search method, as it is key to achieving the application of palpation diagnosis, and confirmed the accuracy of the proposed technology for estimating singularities. Thus, we present a highly efficient search method that offers feedback on tactile information. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.