Design and characterization of flexible electronic skin for robot grasping force detection
Haoyu Wang
China Agricultural University (East Campus)
DOI: https://doi.org/10.59429/esta.v13i3.15553
Keywords: flexible electronic skin; conductive hydrogel; piezoresistive sensing; grasping force detection; slippage detection; robotic grasping
Abstract
This study aims to develop and validate a flexible electronic skin for normal contact-force detection during robotic grasping. We fabricated a 4×4 piezoresistive array using a conductive hydrogel and evaluated it through static calibration, cyclic loading, curved-finger interference tests, array localization, and robotic grasping experiments. We designed a 4×4 flexible piezoresistive electronic skin based on conductive hydrogel for continuous contact-force detection, slippage recognition, and protection of fragile objects during robotic grasping. Verification covered device calibration, curved-surface interference, array positioning, and robotic grasping. Eight independent devices from two batches exhibited a stepped response in the 0–20 N range: Sensitivities of 0.05592 N−1 and 0.01758 N−1 in the 0–5 N and 5–20 N ranges, respectively, with an inversion RMSE of 0.468 N and a hysteresis error of 3.812% FS. Under a 5 N step stimulus, the system response and recovery times were 88.0 ms and 110.3 ms, respectively. After 10,000 cycles, the peak response changed by −1.882%, and baseline drift was 2.358% FS. The 4×4 array correctly localized all 48 point loads, with an average center-of-mass error of 0.391 mm. Robot testing covered 8 object types and 120 grasping operations. Overall relative steady-state force error was 3.752% ± 3.494%, and grasping success was 90.0%. Across 240 state events, recognition accuracy was 94.58%, and the F1 score for slippage recognition was 0.9167. Within the tested range, the electronic skin combined low-force sensitivity, curved-surface conformability, and array-based positioning. It supported open-loop grasping-force detection and slippage and overload alarms. Cross-object generalization and closed-loop control gains require further validation.
References
[1] Chunge Wang, Chen Liu, Fangfang Shang, et al. Tactile sensing technology in bionic skin: A review[J]. Biosensors and Bioelectronics, 2023, 220:114882.
[2] Zuqing Yuan, Guozhen Shen. Materials and device architecture towards a multimodal electronic skin[J]. Materials Today, 2023, 64:165–179.
[3] Juntian Qu, Baijin Mao, Zhenkun Li, et al. Recent Progress in Advanced Tactile Sensing Technologies for Soft Grippers[J]. Advanced Functional Materials, 2023, 33(41):2306249.
[4] Yin He, Xiaoxuan Xu, Shuang Xiao, et al. Research Progress and Application of Multimodal Flexible Sensors for Electronic Skin[J]. ACS Sensors, 2024, 9(5):2275–2293.
[5] Jian Ping Gong, Yoshimi Katsuyama, Takayuki Kurokawa, Yoshihito Osada. Double-Network Hydrogels with Extremely High Mechanical Strength[J]. Advanced Materials, 2003, 15(14):1155–1158. DOI:10.1002/adma.200304907.
[6] Hyunwoo Yuk, Baoyang Lu, Xuanhe Zhao. Hydrogel bioelectronics[J]. Chemical Society Reviews, 2019, 48:1642–1667. DOI:10.1039/C8CS00595H.