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Saekwang Nam

Publications and source records attributed to Saekwang Nam.

3 recordsLinked to original sources

TactiVerse: Generalizing Multi-Point Tactile Sensing in Soft Robotics Using Single-Point Data

Real-time prediction of deformation in highly compliant soft materials remains a significant challenge in soft robotics. While vision-based soft tactile sensors can track internal marker displacements, learning-based models for 3D contact estimation heavily depend on their training datasets, inherently limiting their ability to generalize to complex scenarios such as multi-point sensing. To address this limitation, we introduce TactiVerse, a U-Net-based framework that formulates contact geometry estimation as a spatial heatmap prediction task. Even when trained exclusively on a limited dataset of single-point indentations, our architecture achieves highly accurate single-point sensing, yielding a superior mean absolute error of 0.0589 mm compared to the 0.0612 mm of a conventional regression-based CNN baseline. Furthermore, we demonstrate that augmenting the training dataset with multi-point contact data substantially enhances the sensor's multi-point sensing capabilities, significantly improving the overall mean MAE for two-point discrimination from 1.214 mm to 0.383 mm. By successfully extrapolating complex contact geometries from fundamental interactions, this methodology unlocks advanced multi-point and large-area shape sensing. Ultimately, it significantly streamlines the development of marker-based soft sensors, offering a highly scalable solution for real-world tactile perception.

cs.RO

TacFinRay: Soft Tactile Fin-Ray Finger with Indirect Tactile Sensing for Robust Grasping

We present a tactile-sensorized Fin-Ray finger that enables simultaneous detection of contact location and indentation depth through an indirect sensing approach. A hinge mechanism is integrated between the soft Fin-Ray structure and a rigid sensing module, allowing deformation and translation information to be transferred to a bottom crossbeam upon which are an array of marker-tipped pins based on the biomimetic structure of the TacTip vision-based tactile sensor. Deformation patterns captured by an internal camera are processed using a convolutional neural network to infer contact conditions without directly sensing the finger surface. The finger design was optimized by varying pin configurations and hinge orientations, achieving 0.1\,mm depth and 2mm location-sensing accuracies. The perception demonstrated robust generalization to various indenter shapes and sizes, which was applied to a pick-and-place task under uncertain picking positions, where the tactile feedback significantly improved placement accuracy. Overall, this work provides a lightweight, flexible, and scalable tactile sensing solution suitable for soft robotic structures where the sensing needs situating away from the contact interface.

cs.RO

StereoTacTip: Vision-based Tactile Sensing with Biomimetic Skin-Marker Arrangements

Vision-Based Tactile Sensors (VBTSs) stand out for their superior performance due to their high-information content output. Recently, marker-based VBTSs have been shown to give accurate geometry reconstruction when using stereo cameras. \uhl{However, many marker-based VBTSs use complex biomimetic skin-marker arrangements, which presents issues for the geometric reconstruction of the skin surface from the markers}. Here we investigate how the marker-based skin morphology affects stereo vision-based tactile sensing, using a novel VBTS called the StereoTacTip. To achieve accurate geometry reconstruction, we introduce: (i) stereo marker matching and tracking using a novel Delaunay-Triangulation-Ring-Coding algorithm; (ii) a refractive depth correction model that corrects the depth distortion caused by refraction in the internal media; (iii) a skin surface correction model from the marker positions, relying on an inverse calculation of normals to the skin surface; and (iv)~methods for geometry reconstruction over multiple contacts. To demonstrate these findings, we reconstruct topographic terrains on a large 3D map. Even though contributions (i) and (ii) were developed for biomimetic markers, they should improve the performance of all marker-based VBTSs. Overall, this work illustrates that a thorough understanding and evaluation of the morphologically-complex skin and marker-based tactile sensor principles are crucial for obtaining accurate geometric information.

cs.RO