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  • ์„œ๋ก : Allegro Hand์™€ ์ด‰๊ฐ ์„ผ์„œ์˜ ์ค‘์š”์„ฑ
  • uSkin vs ReSkin: ์ฃผ์š” ํŠน์„ฑ ๋น„๊ต
  • ์ตœ๊ทผ ์—ฐ๊ตฌ ๋™ํ–ฅ: uSkin ๋ฐ ReSkin ํ™œ์šฉ ์‚ฌ๋ก€ (2022โ€“2025)
    • uSkin ์„ผ์„œ ํ™œ์šฉ ์—ฐ๊ตฌ ์‚ฌ๋ก€
    • ReSkin ์„ผ์„œ ํ™œ์šฉ ์—ฐ๊ตฌ ์‚ฌ๋ก€
  • ๊ฒฐ๋ก  ๋ฐ ์‹œ์‚ฌ์ 
  • Comparison of uSkin and ReSkin Tactile Sensors for the Allegro Hand
    • Introduction
    • Overview of the Tactile Sensors
      • uSkin Sensor (XELA Robotics)
      • ReSkin Sensor (Meta AI & CMU)
    • Comparison of Performance and Design
      • Sensitivity and Resolution
      • Accuracy of Force Measurement
      • Reliability and Durability
      • Response Time and Sampling Rate
      • Fabrication Methods and Integration
      • Sensing Principle: Magnetic Field-Based Detection
    • Recent Research Applications (2022โ€“2025)
      • Studies Utilizing uSkin in Robotics Research (2022โ€“2025)
      • Studies Utilizing ReSkin in Robotics Research (2022โ€“2025)
    • Conclusion

๐ŸงฉuSkin vs ReSkin

tactile
sensor
magneto
Comparison of
Published

May 29, 2025

์„œ๋ก : Allegro Hand์™€ ์ด‰๊ฐ ์„ผ์„œ์˜ ์ค‘์š”์„ฑ

Allegro Hand๋Š” ์ธ๊ฐ„ ์†์ฒ˜๋Ÿผ ์ •๊ตํ•œ ์กฐ์ž‘์„ ๋ชฉํ‘œ๋กœ ๊ฐœ๋ฐœ๋œ ๋กœ๋ด‡ ์†์œผ๋กœ, ์„ฌ์„ธํ•œ ๋ฌผ์ฒด ์กฐ์ž‘์„ ์œ„ํ•ด ์ด‰๊ฐ ์„ผ์„œ์˜ ํ†ตํ•ฉ์ด ์ค‘์š”ํ•ฉ๋‹ˆ๋‹ค. ์ตœ๊ทผ ๋งŽ์€ ์—ฐ๊ตฌ์—์„œ๋Š” ๋กœ๋ด‡ ์†๊ฐ€๋ฝ์— ์ „์ž ํ”ผ๋ถ€๋ฅผ ๋ถ€์ฐฉํ•ด ์ ‘์ด‰ ํž˜๊ณผ ๋ฏธ๋„๋Ÿฌ์ง ๋“ฑ์„ ๊ฐ์ง€ํ•˜๋ ค๊ณ  ์‹œ๋„ํ•˜๊ณ  ์žˆ์Šต๋‹ˆ๋‹ค. ํŠนํžˆ Allegro Hand์—๋Š” XELA Robotics์‚ฌ์˜ uSkin ์„ผ์„œ์™€ Meta AI๊ฐ€ ๊ฐœ๋ฐœํ•œ ReSkin ์„ผ์„œ๊ฐ€ ์‚ฌ์šฉ๋˜๊ณ  ์žˆ๋Š”๋ฐ, ๋‘ ์„ผ์„œ๋Š” ์ž๊ธฐ์žฅ ๊ธฐ๋ฐ˜์˜ ์ด‰๊ฐ ์„ผ์„œ๋ผ๋Š” ๊ณตํ†ต์ ์ด ์žˆ์ง€๋งŒ ์„ค๊ณ„ ๋ชฉ์ ๊ณผ ๊ตฌํ˜„ ๋ฐฉ์‹์—์„œ ์ฐจ์ด๊ฐ€ ์žˆ์Šต๋‹ˆ๋‹ค. ์•„๋ž˜์—์„œ๋Š” ์ด ๋‘ ์„ผ์„œ์˜ ๊ฐ๋„, ์ •ํ™•๋„, ์‹ ๋ขฐ์„ฑ, ์‘๋‹ต์†๋„, ์ œ์กฐ ๋ฐฉ์‹, ์ž๊ธฐ์žฅ ๊ฐ์ง€ ์›๋ฆฌ ์ธก๋ฉด์—์„œ ํŠน์ง•์„ ๋น„๊ตํ•˜๊ณ , ์ตœ๊ทผ 3๋…„๊ฐ„(2022โ€“2025) ํ•ด๋‹น ์„ผ์„œ๋“ค์„ ํ™œ์šฉํ•œ ์ตœ์‹  ์—ฐ๊ตฌ ์‚ฌ๋ก€๋“ค์„ ์ •๋ฆฌํ•ฉ๋‹ˆ๋‹ค.

uSkin vs ReSkin: ์ฃผ์š” ํŠน์„ฑ ๋น„๊ต

Allegro Hand์— ํ†ตํ•ฉ๋œ uSkin๊ณผ ReSkin์˜ ํ•ต์‹ฌ ์‚ฌ์–‘์„ ๋น„๊ตํ•˜๋ฉด ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค. uSkin์€ ๋‹ค์ˆ˜์˜ ์˜๊ตฌ์ž์„-ํ™€ ์„ผ์„œ ๋ฐฐ์—ด๋กœ ๊ตฌ์„ฑ๋œ ์ƒ์šฉ ์ด‰๊ฐ ํ”ผ๋ถ€์ด๊ณ , ReSkin์€ ์ž์„ฑ ์ž…์ž ๊ธฐ๋ฐ˜์˜ ์œ ์—ฐํ•œ ์„ผ์„œ๋กœ ๊ฐœ๋ฐœ๋˜์–ด ๊ณต๊ฐœ๋œ ์ €๋น„์šฉ ์ด‰๊ฐ ํ”ผ๋ถ€์ž…๋‹ˆ๋‹ค. ๋‘ ์„ผ์„œ์˜ ํŠน์„ฑ์„ ๋…ผ๋ฌธ ๊ธฐ๋ฐ˜ ์ž๋ฃŒ๋กœ ํ•ญ๋ชฉ๋ณ„๋กœ ๋น„๊ตํ•˜๋ฉด ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค:

๋น„๊ต ํ•ญ๋ชฉ uSkin (XELA Robotics) ReSkin (Meta AI & CMU)
๊ฐ๋„ (Sensitivity) ์•ฝ 10 mN(0.45 kPa) ์ˆ˜์ค€์˜ ๋ฏธ์„ธํ•œ ํž˜๊นŒ์ง€ ๊ฐ์ง€ ๊ฐ€๋Šฅ โ€“ ์ธ๊ฐ„ ํ”ผ๋ถ€์— ๋น„ํ•˜๋ฉด ๋–จ์–ด์ง€์ง€๋งŒ, ๋กœ๋ด‡ ์ด‰๊ฐ ์„ผ์„œ๋กœ๋Š” ๋งค์šฐ ๋†’์€ ๊ฐ๋„. ์ž‘์€ ์ ‘์ด‰๋„ ๊ฒ€์ถœ ๊ฐ€๋Šฅํ•˜์—ฌ ์„ฌ์„ธํ•œ ๋ฌผ์ฒด ์ทจ๊ธ‰์— ์œ ๋ฆฌ. ์ˆ˜์‹ญ mN ~ 0.1โ€“0.2 N ์ •๋„์˜ ํž˜ ๋ณ€ํ™”๋ฅผ ๊ตฌ๋ณ„ ๊ฐ€๋Šฅ โ€“ ์˜ˆ๋ฅผ ๋“ค์–ด ์•ฝ 20 mL ๋ฌผ์˜ ๋ฌด๊ฒŒ (~0.2 N) ์ฆ๊ฐ€๋„ ์„ผ์„œ ์ถœ๋ ฅ ๋ณ€ํ™”๋กœ ํฌ์ฐฉ. ์ดˆ๊ธฐ ์„ค๊ณ„ ๋ชฉํ‘œ๋Š” 0.1 N์˜ ํž˜ ๋ถ„ํ•ด๋Šฅ์ด๋ฉฐ, ์‹คํ—˜์ ์œผ๋กœ๋„ ๊ทธ์— ์ค€ํ•˜๋Š” ์ž‘์€ ํž˜์„ ๊ฐ์ง€ํ•จ์„ ์‹œ์—ฐ.
์ •ํ™•๋„ (Accuracy) ๊ฐ ์ด‰๊ฐ ์†Œ์ž(taxel)๋ณ„ 3์ถ• ํž˜ ์ธก์ •์˜ ์ •ํ™•๋„๊ฐ€ ๋†’์Œ. ๊ฐœ๋ณ„ ์„ผ์„œ ๋‹จ์œ„ ๋ณด์ • ์‹œ X, Y, Z์ถ• ํ‰๊ท  ์ ˆ๋Œ€์˜ค์ฐจ๊ฐ€ ์•ฝ 0.2 N ์ˆ˜์ค€๊นŒ์ง€ ๋‹ฌ์„ฑ๋œ ์‚ฌ๋ก€๊ฐ€ ๋ณด๊ณ ๋จ. ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋Š” taxel ๊ฐ„๊ฒฉ ~4.7 mm๋กœ ์ด˜์ด˜ํ•˜์—ฌ ์ ‘์ด‰ ์œ„์น˜๋„ ๋น„๊ต์  ์ •ํ™•ํžˆ ํŒŒ์•… ๊ฐ€๋Šฅ. ๋จธ์‹ ๋Ÿฌ๋‹ ๋ณด์ •์„ ํ†ตํ•ด ๋†’์€ ์˜ˆ์ธก ์ •ํ™•๋„ ํ™•๋ณด. ์˜ˆ๋ฅผ ๋“ค์–ด ์ž๊ฐ€-๋ณด์ •(self-supervised) ๊ธฐ๋ฒ• ์ ์šฉ ์‹œ ์ ‘์ด‰ ์ง€์  ์œ„์น˜ ์˜ค์ฐจ ์•ฝ 0.7 mm, ํž˜ ํฌ๊ธฐ ์ถ”์ • ์˜ค์ฐจ ์•ฝ 0.44 N ์ˆ˜์ค€๊นŒ์ง€ ์„ฑ๋Šฅ ํ–ฅ์ƒ์ด ๋ณด๊ณ ๋จ. ์ดˆ๊ธฐ ์„ผ์„œ ๊ฐ„ ํŽธ์ฐจ๊ฐ€ ํฌ์ง€๋งŒ, ๋‹ค์ค‘ ์„ผ์„œ ํ•™์Šต๊ณผ ๋ณด์ •์œผ๋กœ 84% ์ด์ƒ์˜ ๋ถ„๋ฅ˜ ์ •ํ™•๋„์™€ ๋‚ฎ์€ MSE๋ฅผ ๋‹ฌ์„ฑํ•จ.
์‹ ๋ขฐ์„ฑ (Reliability) ์ผ๊ด€๋œ ์ถœ๋ ฅ๊ณผ ๋‚ด๊ตฌ์„ฑ์„ ๊ฐ–์ถ˜ ํŽธ์ด๋‚˜, ๊ฐ•ํ•œ ์™ธ๋ถ€ ์ž๊ธฐ์žฅ์— ๋ฏผ๊ฐํ•˜์—ฌ ๊ต๋ž€์„ ๋ฐ›์„ ์ˆ˜ ์žˆ์Œ. ๊ฐ ์„ผ์„œ๋Š” ๊ฒฌ๊ณ ํ•˜๊ฒŒ ํŒจํ‚ค์ง•๋˜์–ด ์žฅ๊ธฐ๊ฐ„ ์‚ฌ์šฉ ๊ฐ€๋Šฅํ•˜๋‚˜, ์ž์„-์„ผ์„œ์˜ ์กฐ๋ฆฝ ํŽธ์ฐจ๋กœ ์„ผ์„œ๋งˆ๋‹ค ๋ณด์ •๊ฐ’ ์ฐจ์ด๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ์Œ. ์ œ์กฐ ๊ณต์ •์ƒ ์ˆ˜์ž‘์—… ์กฐ๋ฆฝ์œผ๋กœ ์ธํ•œ ๊ฐœ์ฒด๊ฐ„ ์„ฑ๋Šฅ ํŽธ์ฐจ๋ฅผ ์ •๋ฐ€ ๋ณด์ •ํ•˜์—ฌ ์‚ฌ์šฉ. ๋‚ด๊ตฌ์„ฑ๊ณผ ๊ต์ฒด ์šฉ์ด์„ฑ์„ ๊ณ ๋ คํ•œ ์„ค๊ณ„. ๋ถ€๋“œ๋Ÿฌ์šด ์„ผ์„œ ์ธต์ด ๋งˆ๋ชจ๋˜๋ฉด ์‰ฝ๊ฒŒ ๊ต์ฒดํ•  ์ˆ˜ ์žˆ๊ณ , ํ•œ ๊ฐœ์˜ ์„ผ์„œ ํŒจ๋“œ๊ฐ€ 5๋งŒ ํšŒ ์ด์ƒ์˜ ์ ‘์ด‰์—๋„ ์„ฑ๋Šฅ์ด ํฌ๊ฒŒ ์ €ํ•˜๋˜์ง€ ์•Š์Œ์„ ๊ฒ€์ฆ. ๋‹ค๋งŒ ์ƒˆ๋กœ์šด ์„ผ์„œ ๋ง‰ ๊ต์ฒด ์‹œ๋งˆ๋‹ค ๋ฏธ์„ธํ•œ ํŠน์„ฑ ์ฐจ์ด๊ฐ€ ์žˆ์œผ๋ฏ€๋กœ, ์ž์ฒด ML๊ธฐ๋ฐ˜ ๋ณด์ •์œผ๋กœ ์„ผ์„œ ๊ฐ„ ํŽธ์ฐจ์™€ ์‹œ๊ฐ„์— ๋”ฐ๋ฅธ ๋ณ€ํ™”์— ๋Œ€์‘ํ•จ.
์‘๋‹ต์†๋„ (Response Time) ์ „์ž์‹ Hall ์„ผ์„œ๋กœ ์‹ค์‹œ๊ฐ„ ์—ฐ์† ์ธก์ •์ด ๊ฐ€๋Šฅํ•˜์—ฌ ์‘๋‹ต์†๋„๊ฐ€ ๋งค์šฐ ๋น ๋ฆ„. ์ด๋ก ์ ์œผ๋กœ kHz ๋Œ€์—ญ๊นŒ์ง€๋„ ์ธก์ • ๊ฐ€๋Šฅํ•˜๋ฉฐ, ์ผ๋ฐ˜์ ์ธ ๋น„์ „ ๊ธฐ๋ฐ˜ ์ด‰๊ฐ์„ผ์„œ(30โ€“60 Hz)์— ๋น„ํ•ด ์›”๋“ฑํžˆ ๋†’์€ ์ƒ˜ํ”Œ๋ง ์ฃผํŒŒ์ˆ˜๋ฅผ ์ง€์›. ์—ฌ๋Ÿฌ ๊ฐœ์˜ taxel์„ ๋™์‹œ์— ์ฝ์„ ๋•Œ๋„ ์ˆ˜๋ฐฑ Hz ์ด์ƒ์˜ ์†๋„๋ฅผ ์œ ์ง€ํ•˜์—ฌ ๋กœ๋ด‡ ์ œ์–ด์— ํ™œ์šฉํ•  ์ˆ˜ ์žˆ์Œ. ๊ณ ์† ์ƒ˜ํ”Œ๋ง ๊ฐ€๋Šฅ (์„ค๊ณ„ ๋ชฉํ‘œ โ‰ฅ100 Hz). ์‹ค์ œ ์‘์šฉ์—์„œ 250 Hz๋กœ ๋ฐ์ดํ„ฐ ์ˆ˜์ง‘์„ ์‹œ์—ฐํ•œ ๋ฐ” ์žˆ์œผ๋ฉฐ, ๋‹ค์ˆ˜ ์„ผ์„œ๋ฅผ ์—ฐ๊ฒฐํ•œ ๊ฒฝ์šฐ์—๋„ 100โ€“200 Hz ์ˆ˜์ค€์œผ๋กœ ์•ˆ์ •์ ์œผ๋กœ ๋™์ž‘ํ•จ. ์‘๋‹ต ์‹œ๊ฐ„์€ ์ˆ˜ ms ๋‹จ์œ„๋กœ ์ธ๊ฐ„ ์ด‰๊ฐ๋ณด๋‹ค๋„ ๋น ๋ฅธ ํŽธ์ด์–ด์„œ ์‹ค์‹œ๊ฐ„ ํ”ผ๋“œ๋ฐฑ ์ œ์–ด์— ํ™œ์šฉํ•  ์ˆ˜ ์žˆ์Œ.
์„ผ์„œ ์ œ์กฐ ๋ฐฉ์‹
(Fabrication)
๊ฐ ์ด‰๊ฐ ํŒจ๋“œ๋งˆ๋‹ค ์˜๊ตฌ์ž์„์„ ํฌํ•จํ•œ ์—ฐ์„ฑ ๊ณ ๋ฌด์ธต๊ณผ ๊ทธ ์•„๋ž˜ ์†Œํ˜• Hall IC ์นฉ์œผ๋กœ ๊ตฌ์„ฑ. 4ร—4 ๊ฒฉ์ž ๋“ฑ์˜ ๋ชจ๋“ˆ ํ˜•ํƒœ๋กœ ์ œ์ž‘๋˜์–ด ๊ณก๋ฉด์šฉ(์†๊ฐ€๋ฝ ๋ 30 taxel)๊ณผ ํ‰๋ฉด์šฉ(16 taxel ๋“ฑ) ํŒจ๋“œ๋กœ ์ œ๊ณต๋จ. ์ž์„-์—˜๋ผ์Šคํ† ๋จธ ๋ถ€์ฐฉ๊ณผ ์นฉ ํŒจํ‚ค์ง• ๊ณต์ •์— ์ˆ˜์ž‘์—… ์กฐ๋ฆฝ์ด ํ•„์š”ํ•˜๋ฉฐ, ์ด๋กœ ์ธํ•ด ์ƒ์‚ฐ ๋‹จ๊ฐ€์™€ ๊ฐœ์ฒด ๊ฐ„ ํŠน์„ฑ ํŽธ์ฐจ๊ฐ€ ๋ฐœ์ƒํ•˜๋Š” ๋ฌธ์ œ๊ฐ€ ์ง€์ ๋จ. ์œ ์—ฐํ•œ ์‹ค๋ฆฌ์ฝ˜ ํ”ผ๋ถ€์— ๋ฌด์ž‘์œ„ ์ž์„ฑ ์ž…์ž๋ฅผ ํ˜ผํ•ฉยท๊ฒฝํ™”ํ•˜์—ฌ ๋งŒ๋“œ๋Š” ์–‡์€ ํŒจ์น˜ํ˜• ์„ผ์„œ. ์ œ์ž‘์‹œ 3D ํ”„๋ฆฐํŒ…๋œ ๋ชฐ๋“œ์— ์ž…์ž-์‹ค๋ฆฌ์ฝ˜ ํ˜ผํ•ฉ๋ฌผ์„ ๋ถ“๊ณ  ์™ธ๋ถ€์—์„œ ๊ฒฉ์ž ํ˜•ํƒœ๋กœ ์žํ™”ํ•˜์—ฌ ์ž๊ธฐ ์„ฑ์งˆ์„ ๋ถ€์—ฌ. ๊ฒฝํ™”๋œ ํ”ผ๋ถ€๋ฅผ ํšŒ๋กœ ๊ธฐํŒ ์œ„์— ๋ถ€์ฐฉํ•˜์—ฌ ์‚ฌ์šฉํ•˜๋ฉฐ, ๊ธฐํŒ์—๋Š” ์†Œํ˜• 3์ถ• ์ž๋ ฅ๊ณ„ ์นฉ(5๊ฐœ ๋ฐฐ์—ด)์ด ์žฅ์ฐฉ๋˜์–ด ์žˆ์Œ. ์ „์ฒด ์„ค๊ณ„ ํŒŒ์ผ๊ณผ ์ œ์กฐ๋ฒ•์ด ์˜คํ”ˆ์†Œ์Šค๋กœ ๊ณต๊ฐœ๋˜์–ด ์žˆ์–ด ์†์‰ฌ์šด ์ œ์ž‘๊ณผ ์ˆ˜์ •์ด ๊ฐ€๋Šฅํ•˜๋ฉฐ, ์„ผ์„œ๋ง‰๊ณผ ํšŒ๋กœ๋ฅผ ๋ถ„๋ฆฌํ•˜์—ฌ ์†์ƒ ์‹œ ํ”ผ๋ถ€๋งŒ ๊ต์ฒดํ•˜๋„๋ก ์„ค๊ณ„๋จ.
์ž๊ธฐ์žฅ ๋ณ€ํ™” ์ธ์‹ ์›๋ฆฌ
(Magnetic sensing principle)
์˜๊ตฌ์ž์„์ด ์™ธ๋ ฅ์— ๋”ฐ๋ผ ๋ฏธ์„ธ ์ด๋™ํ•˜๋ฉด์„œ ๋ฐœ์ƒํ•˜๋Š” ์ž๊ธฐ์žฅ ๋ณ€ํ™”๋ฅผ ๋ฐ”๋กœ ์•„๋ž˜์˜ ํ™€ ํšจ๊ณผ ์„ผ์„œ๊ฐ€ ๊ฐ์ง€ํ•˜๋Š” ๋ฐฉ์‹. ์ž์„์ด ๋ˆŒ๋ฆฌ๊ฑฐ๋‚˜ ๋ฐ€๋ฆฌ๋ฉด X, Y, Z ๋ฐฉํ–ฅ ์ž๊ธฐ์žฅ ์„ธ๊ธฐ๊ฐ€ ๋ณ€ํ•˜๊ณ , ์ด๋ฅผ 3์ถ• ํž˜ (๋ฒ•์„ ์•• + ์ „๋‹จ๋ ฅ) ์‹ ํ˜ธ๋กœ ๋ณ€ํ™˜ํ•˜์—ฌ ์ถœ๋ ฅํ•จ. ๊ฐ taxel์ด ๊ตญ๋ถ€์ ์ธ ์ ‘์ด‰๋ ฅ์„ ๋ฒกํ„ฐ ํ˜•ํƒœ๋กœ ์ธก์ •ํ•˜๋ฏ€๋กœ ๋ฌผ์ฒด์˜ ๋ฏธ๋„๋Ÿฌ์ง ๋ฐฉํ–ฅ์ด๋‚˜ ์ ‘์ด‰ ์ง€ํ˜•์„ ํŒŒ์•…ํ•  ์ˆ˜ ์žˆ์Œ. ๋ถ„๋ง ์ž์„๋“ค์ด ํฌํ•จ๋œ ํƒ„์„ฑ์ฒด ๋ง‰์ด ๋ณ€ํ˜•๋  ๋•Œ ์ฃผ๋ณ€์— ํ˜•์„ฑ๋œ ์ž๊ธฐ์žฅ์˜ ๋ฐ€๋„ ๋ถ„ํฌ ๋ณ€ํ™”๋ฅผ ์ž๋ ฅ ์„ผ์„œ๋“ค์ด ์ฝ์–ด๋‚ด๋Š” ๋ฐฉ์‹. ๋ง๋ž‘ํ•œ ํ”ผ๋ถ€ ์ž์ฒด๊ฐ€ ์ž์„ฑ์„ ๋ ๊ณ  ์žˆ์–ด ์ ‘์ด‰์— ์˜ํ•ด โ€œ์ฐŒ๊ทธ๋Ÿฌ์ง€๋ฉดโ€ ์ž๋ ฅ๊ณ„์— ์ฝํžˆ๋Š” ์ž๊ธฐ ์‹ ํ˜ธ๊ฐ€ ๋ณ€ํ•˜๋ฉฐ, ์ด๋ฅผ ์‚ฌ์ „์— ํ•™์Šต๋œ ๋ชจ๋ธ์ด ๋ถ„์„ํ•ด ํž˜์˜ ํฌ๊ธฐ์™€ ์œ„์น˜๋ฅผ ์ถ”์ •ํ•จ. ์„ผ์„œ๋ง‰์ด ์—ฐ์†์  ๋ถ„ํฌ์ฒด์ด๋ฏ€๋กœ ๋„“์€ ๋ฉด์ ์—์„œ๋„ ์—ฌ๋Ÿฌ ์ ‘์ ์˜ ์œ„์น˜๋ฅผ ๊ณ„์‚ฐ์ ์œผ๋กœ ์ถ”๋ก ํ•  ์ˆ˜ ์žˆ๋‹ค๋Š” ์žฅ์ ์ด ์žˆ์Œ.

์ฃผ์„: ์œ„ ํ‘œ์˜ ๋‚ด์šฉ์€ใ€9ใ€‘ใ€13ใ€‘ใ€17ใ€‘ใ€19ใ€‘ใ€21ใ€‘ใ€22ใ€‘ใ€25ใ€‘ใ€32ใ€‘ ๋“ฑ์˜ ์ถœ์ฒ˜์—์„œ ๋ฐœ์ทŒ ๋ฐ ์š”์•ฝํ•œ ๊ฒƒ์ž…๋‹ˆ๋‹ค.

์ตœ๊ทผ ์—ฐ๊ตฌ ๋™ํ–ฅ: uSkin ๋ฐ ReSkin ํ™œ์šฉ ์‚ฌ๋ก€ (2022โ€“2025)

์ตœ๊ทผ 3๋…„๊ฐ„ uSkin ๋˜๋Š” ReSkin ์„ผ์„œ๋ฅผ ํ™œ์šฉํ•œ ๋Œ€ํ‘œ์ ์ธ ์—ฐ๊ตฌ๋“ค์„ ๋ถ„์•ผ๋ณ„๋กœ ์ •๋ฆฌํ•˜๋ฉด ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค. ๊ฐ ์—ฐ๊ตฌ๋Š” ์ด‰๊ฐ ์„ผ์„œ์˜ ๋ฐ์ดํ„ฐ๋ฅผ ํ™œ์šฉํ•˜์—ฌ ๋กœ๋ด‡์˜ ๋ฌผ์ฒด ์ธ์ง€๋‚˜ ์กฐ์ž‘ ๋Šฅ๋ ฅ์„ ํ–ฅ์ƒ์‹œํ‚ค๋Š” ๋ฐฉํ–ฅ์œผ๋กœ ์ด๋ฃจ์–ด์ง€๊ณ  ์žˆ์œผ๋ฉฐ, ํŠนํžˆ ์ž๊ธฐ์žฅ ๊ธฐ๋ฐ˜ ์ด‰๊ฐ์„ผ์„œ + ๋จธ์‹ ๋Ÿฌ๋‹์˜ ๊ฒฐํ•ฉ์ด๋ผ๋Š” ๊ณตํ†ต๋œ ํ๋ฆ„์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.

uSkin ์„ผ์„œ ํ™œ์šฉ ์—ฐ๊ตฌ ์‚ฌ๋ก€

  • ๋กœ๋ด‡ ๊ทธ๋ฆฝ ๋ฏธ๋„๋Ÿผ ๊ฐ์ง€ (๊ทธ๋ฆฝ ์•ˆ์ •์„ฑ ํŒ๋‹จ) โ€“ โ€œA Model-Free Approach to Fingertip Slip and Disturbance Detection for Grasp Stability Inferenceโ€ (Kitouni ๋“ฑ, 2023). ์ด ์—ฐ๊ตฌ์—์„œ๋Š” Allegro Hand์˜ ๋ชจ๋“  ์†๊ฐ€๋ฝ์— uSkin ์ด‰๊ฐ ํ”ผ๋ถ€๋ฅผ ๋ถ€์ฐฉํ•˜์—ฌ ๋ฌผ์ฒด๋ฅผ ์žก์€ ์ƒํƒœ์—์„œ ๋ฐœ์ƒํ•˜๋Š” ๋ฏธ๋„๋Ÿผ(Slip) ๋ฐ ์™ธ๋ถ€ ๋ฐฉํ•ด๋ฅผ ๊ฐ์ง€ํ•˜์˜€์Šต๋‹ˆ๋‹ค. ์ด 368๊ฐœ์˜ 3์ถ• ์ด‰๊ฐ ์†Œ์ž๊ฐ€ ์†๋ฐ”๋‹ฅ๊ณผ ์†๊ฐ€๋ฝ ๋งˆ๋””, ์†๊ฐ€๋ฝ ๋์„ ๋ฎ๋„๋ก ๋ฐฐ์น˜๋˜์—ˆ์œผ๋ฉฐ, ๋ณ„๋„์˜ ๋ณต์žกํ•œ ๋ณด์ • ์—†์ด ์„ผ์„œ ์ถœ๋ ฅ ์‹ ํ˜ธ์˜ ๋ณ€ํ™” ํŒจํ„ด๋งŒ์œผ๋กœ ๋ฏธ๋„๋Ÿผ ์—ฌ๋ถ€๋ฅผ ํŒ๋ณ„ํ•˜๋Š” ๋ชจ๋ธ ํ”„๋ฆฌ ์ ‘๊ทผ๋ฒ•์„ ์ œ์•ˆํ–ˆ์Šต๋‹ˆ๋‹ค. ๋‹ค์–‘ํ•œ ์ •๋ฐ€ ์ฅ๊ธฐ ์‹คํ—˜์„ ํ†ตํ•ด ์ œ์•ˆ๋œ ์ง€ํ‘œ๊ฐ€ ์†๊ฐ€๋ฝ๋ณ„ ๋ฏธ๋„๋Ÿผ ๋ถˆ์•ˆ์ •์„ฑ์„ ์ž˜ ๋‚˜ํƒ€๋ƒ„์„ ๋ณด์˜€๊ณ , ์ด๋ฅผ ํ™œ์šฉํ•ด ๊ฐœ๋ณ„ ์†๊ฐ€๋ฝ์— ๋Šฅ๋™์ ์ธ ์•ˆ์ •ํ™” ํ”ผ๋“œ๋ฐฑ์„ ์ค„ ์ˆ˜ ์žˆ์Œ์„ ํ™•์ธํ•˜์˜€์Šต๋‹ˆ๋‹ค. ํ•ด๋‹น ๊ฒฐ๊ณผ๋Š” ๋กœ๋ด‡์ด ๋ฌผ์ฒด๋ฅผ ๋†“์น˜๊ธฐ ์ „์— ์ด‰๊ฐ์œผ๋กœ ๋ฏธ๋„๋Ÿฌ์ง์„ ํƒ์ง€ํ•˜์—ฌ ๊ทธ๋ฆฝ์„ ์กฐ์ •ํ•˜๋Š” ์ „๋žต์— ๊ธฐ์—ฌํ•ฉ๋‹ˆ๋‹ค.

  • ์ „์ฒด ์† ์ด‰๊ฐ ํž˜ ์ถ”์ • ๋ฐ ์ œ์–ด โ€“ โ€œInteraction force estimation for tactile sensor arrays: toward tactile-based interaction control for robotic fingersโ€ (Chelly ๋“ฑ, 2024). ๋ณธ ์—ฐ๊ตฌ๋Š” Allegro Hand์— ๋ถ€์ฐฉ๋œ ๋‹ค์ˆ˜์˜ uSkin ์„ผ์„œ๋ฅผ ์ผ๊ด„ ๋ณด์ •ํ•˜์—ฌ ์ „์—ญ์ ์ธ 3์ฐจ์› ํž˜ ๋ถ„ํฌ๋ฅผ ์ถ”์ •ํ•˜๊ณ , ์ด๋ฅผ ๋กœ๋ด‡ ์ œ์–ด์— ์ง์ ‘ ํ†ตํ•ฉํ•œ ์‚ฌ๋ก€์ž…๋‹ˆ๋‹ค. ์ €์ž๋“ค์€ ํ‰๋ฉด ํŒจ๋“œ์™€ ๊ณก๋ฉด ํŒจ๋“œ๊ฐ€ ํ˜ผํ•ฉ๋œ ๋ณต์žกํ•œ ๋ฐฐ์—ด์˜ Xela uSkin ์ด‰๊ฐ ํ”ผ๋ถ€๋ฅผ ํ•œ ๋ฒˆ์˜ ๋ฐ์ดํ„ฐ ์ˆ˜์ง‘์œผ๋กœ ํšจ์œจ์ ์œผ๋กœ ๋ณด์ •ํ•˜๋Š” ๋ฐ์ดํ„ฐ ํšจ์œจ์  ์บ˜๋ฆฌ๋ธŒ๋ ˆ์ด์…˜ ๊ธฐ๋ฒ•์„ ์ œ์•ˆํ•˜์˜€์Šต๋‹ˆ๋‹ค. ๋ณด์ •๋œ ์ด‰๊ฐ์„ผ์„œ ๋ฐฐ์—ด๋กœ๋ถ€ํ„ฐ ์–ป์€ ์ •ํ™•ํ•œ ์ ‘์ด‰๋ ฅ ์ถ”์ •์น˜๋ฅผ ๋กœ๋ด‡ ์†๊ฐ€๋ฝ์˜ ์ƒํ˜ธ์ž‘์šฉ ํž˜ ์ œ์–ด(loop)์— ์ž…๋ ฅํ•˜์—ฌ, ์™ธ๋ถ€ ํž˜์„ ์ผ์ •ํ•˜๊ฒŒ ์œ ์ง€ํ•˜๊ฑฐ๋‚˜ ์ œํ•œํ•˜๋Š” ํž˜ ์ œ์–ด ์ž‘์—…์„ ๊ตฌํ˜„ํ•˜์˜€์Šต๋‹ˆ๋‹ค. ์‹คํ—˜ ๊ฒฐ๊ณผ, ์ œ์•ˆ ๊ธฐ๋ฒ•์€ ์„ผ์„œ ๋ฐฐ์—ด ์ „๋ฐ˜์— ๊ฑธ์ณ ํ‰๊ท  0.1โ€“0.2 N ์ˆ˜์ค€์˜ ์˜ค์ฐจ๋กœ ํž˜์„ ์žฌ๊ตฌ์„ฑํ•  ์ˆ˜ ์žˆ์—ˆ๊ณ , ์ด๋ฅผ ์ด์šฉํ•œ ํž˜ ์กฐ์ ˆ์ด ๊ฐ€๋Šฅํ•œ ๊ฒƒ์„ ๋ณด์—ฌ์ฃผ์–ด ์„ฌ์„ธํ•œ ํž˜ ์กฐ์ ˆ์ด ์š”๊ตฌ๋˜๋Š” ์ž‘์—…(์˜ˆ: ๊นจ์ง€๊ธฐ ์‰ฌ์šด ๋ฌผ์ฒด ์žก๊ธฐ)์— ์œ ์šฉํ•œ ์ ‘๊ทผ์ž„์„ ์‹œ์‚ฌํ–ˆ์Šต๋‹ˆ๋‹ค.

  • ์ž๊ฐ€ ์ง€๋„ํ•™์Šต ๊ธฐ๋ฐ˜ ์ด‰๊ฐํ‘œํ˜„ ํ•™์Šต โ€“ โ€œSelf-supervised perception for tactile skin covered dexterous hands (Sparsh-skin)โ€ (Sharma ๋“ฑ, 2025). ์ด ์—ฐ๊ตฌ๋Š” ์ž๊ธฐ์žฅ ๊ธฐ๋ฐ˜ ์ด‰๊ฐ ํ”ผ๋ถ€์˜ ๋ณต์žกํ•œ ์‹œ๊ณ„์—ด ์‹ ํ˜ธ๋กœ๋ถ€ํ„ฐ ์˜๋ฏธ ์žˆ๋Š” ํ‘œํ˜„์„ ํ•™์Šตํ•˜๊ธฐ ์œ„ํ•œ ์ž๊ธฐ ์ง€๋„(self-supervised) ํ•™์Šต๊ธฐ๋ฒ•์„ ์ œ์•ˆํ–ˆ์Šต๋‹ˆ๋‹ค. Allegro Hand์˜ ์†๋ฐ”๋‹ฅ, ์†๊ฐ€๋ฝ ๋งˆ๋””, ์†๊ฐ€๋ฝ ๋์— ๊ฑธ์ณ Xela uSkin ์„ผ์„œ๋ฅผ ๋ถ„์‚ฐ ๋ฐฐ์น˜ํ•˜์—ฌ ์•ฝ 4์‹œ๊ฐ„ ๋ถ„๋Ÿ‰์˜ ๋‹ค์–‘ํ•œ ์ ‘์ด‰ ๋ฐ์ดํ„ฐ๋ฅผ ์ˆ˜์ง‘ํ•œ ๋’ค, ์ด๋ฅผ ํ‘œ์ค€ํ™”๋œ ํ‘œํ˜„ ๊ณต๊ฐ„์œผ๋กœ ์ธ์ฝ”๋”ฉํ•˜๋Š” ํ”„๋ฆฌํŠธ๋ ˆ์ธ๋“œ(tactile encoder) ๋ชจ๋ธ์ธ Sparsh-skin์„ ๊ฐœ๋ฐœํ•˜์˜€์Šต๋‹ˆ๋‹ค. ํ•™์Šต๋œ ์ด‰๊ฐ ์ธ์ฝ”๋”๋Š” unlabeled ๋ฐ์ดํ„ฐ๋กœ ์‚ฌ์ „ํ•™์Šต๋˜์—ˆ๊ธฐ ๋•Œ๋ฌธ์— ์ดํ›„ ์ƒˆ๋กœ์šด ์ž‘์—…์— ์†Œ๋Ÿ‰์˜ ํ•™์Šต ๋ฐ์ดํ„ฐ๋กœ ๋น ๋ฅด๊ฒŒ ์ ์‘ํ•  ์ˆ˜ ์žˆ๋‹ค๋Š” ์žฅ์ ์„ ๋ณด์˜€์Šต๋‹ˆ๋‹ค. ์‹ค์ œ๋กœ ๋ฌผ์ฒด ์‹๋ณ„ ๋“ฑ์˜ ๋‹ค์šด์ŠคํŠธ๋ฆผ ๊ณผ์ œ์—์„œ ๊ธฐ์กด ์—”๋“œํˆฌ์—”๋“œ ํ•™์Šต ๋Œ€๋น„ 41% ๋†’์€ ์„ฑ๋Šฅ๊ณผ ํ–ฅ์ƒ๋œ ๋ฐ์ดํ„ฐ ํšจ์œจ์„ ๋‹ฌ์„ฑํ•˜์—ฌ, ์ด‰๊ฐ ๊ธฐ๋ฐ˜ ๊ฐ์ฒด ์ธ์‹์ด๋‚˜ ๋ฏธ์„ธ ๋™์ž‘ ์ œ์–ด์— ์œ ์šฉํ•œ ์ผ๋ฐ˜ ๋ชฉ์  ์ด‰๊ฐ ํ‘œํ˜„์„ ์–ป์„ ์ˆ˜ ์žˆ์Œ์„ ์ž…์ฆํ–ˆ์Šต๋‹ˆ๋‹ค. ์ด๋Š” ๋ณต์žกํ•œ ์ž๊ธฐ์žฅ ์ด‰๊ฐ์„ผ์„œ ์‹ ํ˜ธ๋ฅผ ํ•ด์„ํ•˜๋Š” ๋ฐ ์žˆ์–ด ํ•™์Šต ๊ธฐ๋ฐ˜ ์ ‘๊ทผ์˜ ๊ฐ€๋Šฅ์„ฑ์„ ๋ณด์—ฌ์ฃผ๋ฉฐ, ํ–ฅํ›„ ์ธ๊ฐ„ ์ˆ˜์ค€์˜ ์ด‰๊ฐ์ธ์ง€ ๋Šฅ๋ ฅ์„ ๋กœ๋ด‡์— ๋ถ€์—ฌํ•˜๋Š” ๋ฐ ์ค‘์š”ํ•œ ๋‹จ๊ณ„๋ฅผ ์ œ์‹œํ•ฉ๋‹ˆ๋‹ค.

ReSkin ์„ผ์„œ ํ™œ์šฉ ์—ฐ๊ตฌ ์‚ฌ๋ก€

  • ํŒจ๋ธŒ๋ฆญ(์ฒœ) ๋‹ค์ธต ๋ถ„๋ฆฌ ์กฐ์ž‘ โ€“ โ€œLearning to Singulate Layers of Cloth using Tactile Feedbackโ€ (Tirumala ๋“ฑ, IROS 2022). ์ด ์—ฐ๊ตฌ๋Š” ์˜ท๊ฐ์ด๋‚˜ ์ฒœ ์—ฌ๋Ÿฌ ์žฅ์ด ํฌ๊ฐœ์ง„ ๋”๋ฏธ์—์„œ ๋กœ๋ด‡์ด ๋งจ ์œ—์žฅ ํ•œ๋‘ ์žฅ๋งŒ ์ง‘์–ด์˜ฌ๋ฆฌ๋Š” ์–ด๋ ค์šด ์ž‘์—…์— ์ด‰๊ฐ ์„ผ์„œ ReSkin์„ ํ™œ์šฉํ•œ ์‚ฌ๋ก€์ž…๋‹ˆ๋‹ค. ํ”„๋ž‘์นด(Franka) ๋กœ๋ด‡ ํŒ”์˜ ๊ทธ๋ฆฌํผ ์†๊ฐ€๋ฝ ์ค‘ ํ•˜๋‚˜์— ReSkin ์ด‰๊ฐ ํŒจ๋“œ๋ฅผ ๋ถ€์ฐฉํ•˜๊ณ , ํ•ด๋‹น ์„ผ์„œ๋กœ๋ถ€ํ„ฐ ์–ป์€ ์ด‰๊ฐ ๋ฐ์ดํ„ฐ๋ฅผ ๊ธฐ๋ฐ˜์œผ๋กœ ํ˜„์žฌ ์žก์€ ์ฒœ์˜ **๊ฒน ์ˆ˜(layer ์ˆ˜)**๋ฅผ ํŒ๋ณ„ํ•˜๋Š” ๋จธ์‹ ๋Ÿฌ๋‹ ๋ถ„๋ฅ˜๊ธฐ๋ฅผ ํ•™์Šตํ–ˆ์Šต๋‹ˆ๋‹ค. ํ•™์Šต๋œ ๋ถ„๋ฅ˜๊ธฐ๋ฅผ ๋กœ๋ด‡ ์ œ์–ด์— ํ†ตํ•ฉํ•˜์—ฌ, ๊ทธ๋ฆฌํผ๊ฐ€ ๋„ˆ๋ฌด ๋งŽ์€ ์ธต์„ ์žก์•˜์„ ๋•Œ ์‚ด์ง ๋†“์•„์„œ ํ•œ ์ธต๋งŒ ์žก๋„๋ก ๋†’์ด๋ฅผ ์ž๋™ ์กฐ์ •ํ•˜๋Š” ์ •์ฑ…์„ ์‹คํ–‰ํ–ˆ์Šต๋‹ˆ๋‹ค. ์ด 180ํšŒ์˜ ์‹ค์ œ ๋กœ๋ด‡ ์‹คํ—˜ ๊ฒฐ๊ณผ, ์ด‰๊ฐ์„ ํ™œ์šฉํ•˜์ง€ ์•Š์€ ๊ธฐ์กด ์‹œ๊ฐ ๊ธฐ๋ฐ˜ ์ ‘๊ทผ๋ณด๋‹ค ํ›จ์”ฌ ๋†’์€ ์ •ํ™•๋„๋กœ ํ•œ ๊ฒน ํ˜น์€ ๋‘ ๊ฒน์˜ ์ฒœ์„ ๊ตฌ๋ถ„ํ•˜์—ฌ ์ง‘์–ด์˜ฌ๋ฆฌ๋Š” ๋ฐ ์„ฑ๊ณตํ–ˆ๊ณ , ๋ณด์ง€ ๋ชปํ•œ ์ƒˆ๋กœ์šด ์ข…๋ฅ˜์˜ ์ฒœ์— ๋Œ€ํ•ด์„œ๋„ ์ผ๋ฐ˜ํ™” ์„ฑ๋Šฅ์ด ํ–ฅ์ƒ๋˜์—ˆ์Œ์„ ๋ณด์˜€์Šต๋‹ˆ๋‹ค. ์ด๋Š” ReSkin์˜ ๋ฏธ์„ธํ•œ ์ด‰๊ฐ ์‹ ํ˜ธ๊ฐ€ ์˜ท๊ฐ์˜ ๋‘๊ป˜๋‚˜ ๊ฒฐํ•ฉ ์ƒํƒœ๋ฅผ ์ž˜ ๊ฐ์ง€ํ•จ์„ ๋ณด์—ฌ์ฃผ๋ฉฐ, ๊ธฐ์กด์— ์‹œ๊ฐ์œผ๋กœ ์–ด๋ ค์› ๋˜ ์„ฌ์„ธํ•œ ์„ฌ์œ  ์กฐ์ž‘ ์ž‘์—…์— ์ด‰๊ฐ ์„ผ์„œ๊ฐ€ ์œ ์šฉํ•จ์„ ์ž…์ฆํ•œ ์‚ฌ๋ก€์ž…๋‹ˆ๋‹ค.

  • ReSkin์˜ ๊ฐœ์„  ๋ฐ ์ผ๋ฐ˜ํ™” (AnySkin) โ€“ โ€œAnySkin: Plug-and-play Skin Sensing for Robotic Touchโ€ (Bhirangi ๋“ฑ, arXiv 2024). ์ด ์—ฐ๊ตฌ๋Š” ReSkin์˜ ๊ฐœ๋…์„ ๋ฐœ์ „์‹œ์ผœ ๋” ๊ฐ•ํ•œ ์ž์žฅ, ๋ถ€์ฐฉ ํŽธ์˜์„ฑ, ์„ผ์„œ ๊ฐ„ ์ผ๊ด€์„ฑ์„ ํ–ฅ์ƒ์‹œํ‚จ AnySkin์ด๋ผ๋Š” ์‹ ํ˜• ์ด‰๊ฐ ์„ผ์„œ๋ฅผ ์†Œ๊ฐœํ•˜์˜€์Šต๋‹ˆ๋‹ค. AnySkin์€ ReSkin๊ณผ ๋™์ผํ•˜๊ฒŒ ์ž๊ธฐ ์ž…์ž ๊ธฐ๋ฐ˜์ด์ง€๋งŒ, ์ž์ฒด ์ •๋ ฌ๋˜๊ณ  ์ ‘์ฐฉ์ œ ์—†์ด ๋ถ€์ฐฉ ๊ฐ€๋Šฅํ•œ ์„ค๊ณ„๋ฅผ ๋„์ž…ํ•˜์—ฌ ๋กœ๋ด‡ ํ‘œ๋ฉด ์–ด๋””์—๋‚˜ ๋ถ™์ด๊ธฐ ์‰ฝ๊ฒŒ ๋งŒ๋“ค์—ˆ์Šต๋‹ˆ๋‹ค. ๋˜ํ•œ ์„ผ์„œ ๊ฐ„ ์‘๋‹ต ํŽธ์ฐจ๋ฅผ ์ค„์—ฌ, ํ•œ ์„ผ์„œ์—์„œ ํ•™์Šต๋œ ๋ชจ๋ธ์ด ๋ณ„๋„ ์žฌ๋ณด์ • ์—†์ด ๋‹ค๋ฅธ ์„ผ์„œ์—๋„ ๋ฐ”๋กœ ์ ์šฉ๋  ์ˆ˜ ์žˆ์Œ์„ ์‹œ์—ฐํ•˜์˜€์Šต๋‹ˆ๋‹ค (cross-instance generalization). ๋…ผ๋ฌธ์—์„œ๋Š” AnySkin์„ ์ด์šฉํ•œ ๋ฏธ๋„๋Ÿฌ์ง ๊ฐ์ง€์™€ ๊ฐ•ํ™”ํ•™์Šต ๊ธฐ๋ฐ˜ ์ ‘์ด‰ ์ •์ฑ… ํ•™์Šต ์‹คํ—˜์„ ์ˆ˜ํ–‰ํ•˜์—ฌ, ์ด์ „ ReSkin ๋Œ€๋น„ ํ–ฅ์ƒ๋œ ๊ฐ๋„์™€ ๋‚ด๊ตฌ์„ฑ์„ ๋ณด์ด๋ฉฐ ๋™์‹œ์— ๋ฐ์ดํ„ฐ ์žฌ์‚ฌ์šฉ์„ฑ์„ ๊ตฌํ˜„ํ•จ์„ ๋ณด์˜€์Šต๋‹ˆ๋‹ค. ์ด ๊ฒฐ๊ณผ๋Š” ReSkin์ด ์ œ์‹œํ•œ ์ €๊ฐ€ํ˜• ์ด‰๊ฐ ํ”ผ๋ถ€์˜ ๊ฐ€๋Šฅ์„ฑ์„ ํ•œ์ธต ํ™•์žฅํ•œ ๊ฒƒ์œผ๋กœ, ๋กœ๋ด‡ ์ด‰๊ฐ ์„ผ์„œ์˜ ๋ฒ”์šฉ์„ฑ์„ ๋†’์ด๋Š” ๋ฐฉํ–ฅ์˜ ์ค‘์š”ํ•œ ์ง„์ „์œผ๋กœ ํ‰๊ฐ€๋ฉ๋‹ˆ๋‹ค.

๊ฒฐ๋ก  ๋ฐ ์‹œ์‚ฌ์ 

uSkin๊ณผ ReSkin์€ ๊ฐ๊ฐ ์ •๋ฐ€๋„ ๋†’์€ ์ƒ์šฉ ์ด‰๊ฐ์„ผ์„œ์™€ ์ €๋น„์šฉ ์œ ์—ฐ ์ด‰๊ฐํ”ผ๋ถ€๋ฅผ ๋Œ€ํ‘œํ•˜๋ฉฐ, ์ตœ๊ทผ ์—ฐ๊ตฌ๋“ค์€ ์ด๋“ค ์„ผ์„œ๋ฅผ ๋กœ๋ด‡์— ์ ์šฉํ•˜์—ฌ ์„ฌ์„ธํ•œ ์กฐ์ž‘ ๊ธฐ์ˆ ์„ ํ–ฅ์ƒ์‹œํ‚ค๋Š” ๋ฐฉํ–ฅ์œผ๋กœ ์ „๊ฐœ๋˜๊ณ  ์žˆ์Šต๋‹ˆ๋‹ค. ์š”์•ฝํ•˜๋ฉด, uSkin์€ ๋†’์€ ํ•ด์ƒ๋„์˜ 3์ถ• ํž˜ ์ธก์ • ๋Šฅ๋ ฅ์„ ๋ฐ”ํƒ•์œผ๋กœ ๋กœ๋ด‡์†์˜ ์ ‘์ด‰๋ ฅ ์ œ์–ด๋‚˜ ๋ฏธ๋„๋Ÿผ ๊ฐ์ง€์™€ ๊ฐ™์€ ๋ฌธ์ œ์— ํ™œ์šฉ๋˜๊ณ  ์žˆ์œผ๋ฉฐ, ReSkin์€ ์ €๋ ดํ•˜๊ณ  ๊ต์ฒด๊ฐ€ ์‰ฌ์šด ๊ฐ•์ ์„ ์‚ด๋ ค ๋ณต์žกํ•œ ๋ณ€ํ˜• ๋ฌผ์ฒด์˜ ์ด‰๊ฐ ์ธ์ง€๋‚˜ ์›จ์–ด๋Ÿฌ๋ธ” ๋กœ๋ด‡ํ”ผ๋ถ€ ๋“ฑ ํ™•์žฅ์„ฑ ์žˆ๋Š” ์‘์šฉ์— ์“ฐ์ด๊ณ  ์žˆ์Šต๋‹ˆ๋‹ค. ๋”์šฑ์ด ๋‘ ์„ผ์„œ ๋ชจ๋‘ ๋จธ์‹ ๋Ÿฌ๋‹ ๊ธฐ๋ฒ•๊ณผ ๊ฒฐํ•ฉ๋˜๋ฉด์„œ ์„ผ์„œ ์‹ ํ˜ธ ๋ณด์ •, ํŠน์ง• ํ‘œํ˜„ ํ•™์Šต, ์ •์ฑ… ํ•™์Šต ๋“ฑ ๋‹ค์–‘ํ•œ ์ธก๋ฉด์—์„œ ํ˜์‹ ์ด ์ด๋ฃจ์–ด์ง€๊ณ  ์žˆ์Šต๋‹ˆ๋‹ค. ์ด๋Ÿฌํ•œ ๋™ํ–ฅ์€ ํ–ฅํ›„ ๋กœ๋ด‡์ด ์‚ฌ๋žŒ์ฒ˜๋Ÿผ ์„ฌ์„ธํ•œ ์ด‰๊ฐ์„ ํ™œ์šฉํ•˜๊ณ , ์—ฌ๋Ÿฌ ํ˜•ํƒœ์˜ ์ด‰๊ฐ ์„ผ์„œ๋ฅผ ํšจ๊ณผ์ ์œผ๋กœ ํ†ตํ•ฉํ•˜์—ฌ ๋ณด๋‹ค ์ง€๋Šฅ์ ์ธ ์ƒํ˜ธ์ž‘์šฉ์„ ๊ตฌํ˜„ํ•˜๋Š” ๋ฐ ์ค‘์š”ํ•œ ๋ฐ‘๊ฑฐ๋ฆ„์ด ๋  ๊ฒƒ์œผ๋กœ ๊ธฐ๋Œ€๋ฉ๋‹ˆ๋‹ค.

์ฐธ๊ณ  ์ž๋ฃŒ: ๋ณธ ๋‹ต๋ณ€์—์„œ๋Š” arXiv, IEEE, Science Robotics ๋“ฑ ์‹ ๋ขฐํ•  ์ˆ˜ ์žˆ๋Š” ์ถœ์ฒ˜์˜ ๋…ผ๋ฌธ ๋ฐ ๊ธฐ์‚ฌใ€9ใ€‘ใ€11ใ€‘ใ€13ใ€‘ใ€17ใ€‘ใ€19ใ€‘ใ€21ใ€‘ใ€22ใ€‘ใ€25ใ€‘ใ€27ใ€‘ใ€31ใ€‘ใ€32ใ€‘ใ€37ใ€‘ใ€39ใ€‘ใ€42ใ€‘ใ€49ใ€‘๋ฅผ ์ธ์šฉ ๋ฐ ์ฐธ๊ณ ํ•˜์˜€์Šต๋‹ˆ๋‹ค. ๊ฐ ๋ฒˆํ˜ธ๋Š” ํ•ด๋‹น ์ถœ์ฒ˜๋ฅผ ๊ฐ€๋ฆฌํ‚ค๋ฉฐ, ์ž์„ธํ•œ ๋‚ด์šฉ์€ ์ธ์šฉ๋ฌธ ์˜† ๊ด„ํ˜ธ์˜ ๋ฒˆํ˜ธ๋ฅผ ํ†ตํ•ด ํ™•์ธํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.

English

Got it. Iโ€™ll translate the full content into English, including the detailed comparison of uSkin and ReSkin sensors, recent research cases using them, and all structured content like tables and analyses.

Iโ€™ll present the translated report shortly.

Comparison of uSkin and ReSkin Tactile Sensors for the Allegro Hand

Introduction

Tactile sensing is crucial for dexterous robotic manipulation, providing rich feedback about contact forces, textures, and object properties that vision alone cannot capture. The Allegro Hand โ€“ a four-fingered, 16-DOF robotic hand โ€“ has become a popular platform for evaluating advanced tactile sensors in research. Two notable tactile skin technologies used with the Allegro Hand are uSkin (developed by XELA Robotics) and ReSkin (developed by Meta AI in collaboration with Carnegie Mellon University). This report presents a detailed comparison of uSkin and ReSkin in terms of sensitivity, accuracy, reliability, response speed, fabrication methods, and their underlying magnetic field sensing principles. It also reviews recent research (2022โ€“2025) that employs each sensor, highlighting applications and outcomes. The goal is to provide robotics researchers with a clear understanding of each sensorโ€™s capabilities and trade-offs in an academic, technical context.

Overview of the Tactile Sensors

uSkin Sensor (XELA Robotics)

uSkin is a high-density 3-axis tactile sensor system packaged in a thin, soft silicone skin. It integrates an array of small sensing units (taxels) that can each detect forces in three dimensions: normal pressure (Z-axis) and shear forces (X and Y axes). The uSkin design embeds tiny magnets in the soft skin and uses underlying magnetometers (or Hall-effect sensors) to track the magnetsโ€™ movements under deformation. Each taxelโ€™s magnetic field readings in X, Y, Z change as forces are applied, allowing the system to compute a 3-axis force vector at that point. Because the sensors are distributed in a grid, uSkin provides spatially localized force data across the contact surface (for example, an Allegro fingertip can be covered with ~24 taxel units). The sensor outputs are digital, minimizing noise and eliminating the need for bulky analog wiring or external ADC boards. In practice, uSkin can be integrated into new or existing robots with minimal wiring and straightforward mounting (e.g. glued onto robot fingers or palm). XELA offers flat patch sensors, curved fingertip sensors, and other form factors to cover various robot hand surfaces. Overall, uSkin provides a turnkey tactile sensing solution with high resolution and direct force readouts per taxel, making it suitable for precise manipulation tasks.

ReSkin Sensor (Meta AI & CMU)

ReSkin is an open-source tactile โ€œskinโ€ that uses a flexible polymer embedded with magnetic particles to sense touch. The ReSkin concept is to create a low-cost, replaceable tactile layer that can be applied to robot hands (or other surfaces) like an electronic skin. The sensor consists of a thin (~2โ€“3โ€ฏmm) silicone elastomer sheet with randomly distributed microscopic magnetic particles. This magnetic sheet is placed over a small magnetometer chip. When the skin is pressed or deformed, the pattern of magnetic field at the magnetometer changes because the particles move (โ€œsquooshedโ€) within the elastomer. Machine learning is then used to map these field distortions to contact force magnitudes and locations. ReSkinโ€™s design prioritizes simplicity and versatility: the sensing hardware (magnetometer and electronics) is kept separate from the soft skin. The skin contains no wires or electronics; it can be peeled off and replaced like a Band-Aid when worn out. This makes the part most susceptible to damage very easy and cheap to replace (each skin costs on the order of <$30 in materials). ReSkin can be cut or shaped to cover different surfaces โ€“ from a robot fingertip to an entire glove or even a dogโ€™s paw โ€“ providing a conformal tactile sensing layer. The open-source release includes instructions for fabrication (mixing and curing the magnetic silicone) and pre-trained models for interpreting the sensor signals. In summary, ReSkin offers a flexible, low-cost tactile sensing approach that leverages magnetic field changes and learned models to detect touch across a continuous surface.

Comparison of Performance and Design

To clearly contrast uSkin and ReSkin, this section compares their key specifications and performance metrics:

Sensitivity and Resolution

Sensitivity refers to the smallest force the sensor can reliably detect, and resolution includes the spatial granularity of touch detection. uSkin is engineered for high sensitivity โ€“ it can detect forces as light as about 0.1 gram-force (gf) (โ‰ˆ0.001โ€ฏN). This extremely low force threshold means uSkin can register very slight touches or contact, making it suitable for delicate manipulation where precise force control is needed. In contrast, ReSkinโ€™s target sensitivity is on the order of <0.1 N (โ‰ˆ10โ€ฏgf) for force detection. However, with careful calibration and machine learning models, ReSkin can achieve very fine force resolution: experiments have demonstrated force measurement errors as low as ~0.005โ€ฏN (5โ€ฏmN) in controlled settings. This indicates that ReSkin, despite its simple hardware, can discern minute forces after training, although its native (untrained) sensitivity may be lower than uSkinโ€™s.

In terms of spatial resolution, uSkin provides a grid of discrete sensing points (taxels). For example, each uSkin โ€œ4x4โ€ patch contains 16 sensing points, and a curved uSkin on an Allegro fingertip uses 24 sensor chips covering the finger pad. The spacing between taxels (a few millimeters apart) defines how finely the contact location can be distinguished โ€“ essentially on the order of the taxel pitch. ReSkin, by contrast, behaves like a continuous skin. A single ReSkin patch (roughly the size of a coin) can localize contacts with a spatial accuracy of about 1 mm (with ~90% accuracy) after training. In a benchmark test, ReSkin achieved ~99.6% accuracy in classifying contact locations within ยฑ1โ€ฏmm on its surface. This suggests that, when calibrated, ReSkin can provide very high spatial detail of where a touch occurs, potentially finer than the discrete spacing of uSkinโ€™s taxels. The trade-off is that uSkinโ€™s taxels give direct physical correspondence to locations, whereas ReSkinโ€™s localization comes from an inference model. In summary, both sensors offer excellent sensitivity and spatial resolution for robotics use: uSkin has an ultra-low force threshold and inherently structured high-density sensing points, while ReSkin achieves comparable force and location resolution through machine-learning-assisted sensing.

Accuracy of Force Measurement

Accuracy encompasses how reliably the sensor can quantify the magnitude and direction of applied forces. uSkinโ€™s design yields direct 3-axis force readings at each taxel, but these raw readings require calibration to map sensor units to physical force values. When properly calibrated, uSkin can measure forces in Newtons and serve in control feedback loops. For instance, a recent study calibrated an Allegro Handโ€™s uSkin sensors against a force-torque sensor and achieved force estimation errors of around 0.12 N (ยฑ0.08 N) in a closed-loop grasping task. This indicates that uSkin can accurately measure and regulate contact forces to within a few hundred millinewtons during manipulation. Its repeatability and linearity benefit from the stable positioning of magnets and sensors in each module. Moreover, uSkinโ€™s on-board digital electronics reduce noise, improving measurement consistency. One challenge for accuracy, however, is dealing with external magnetic interference or drift (addressed later), which XELA mitigates via software compensation for certain models.

ReSkinโ€™s accuracy heavily relies on its learned model. The raw magnetic readings from a ReSkin patch are not directly interpretable as force without a mapping. With a well-trained neural network, ReSkin has demonstrated impressively accurate force reconstruction: in one evaluation, the mean squared error in normal force prediction was on the order of (5 ร— 10โˆ’3 N)2, corresponding to just a few millinewtons error. Additionally, ReSkin is capable of sensing shear forces; a test for dynamic shear contact showed it could predict tangential forces (F_x, F_y) with MSE ~0.0011 N^2, while maintaining normal force error ~0.003 N^2. These results underscore that ReSkin, despite using a single magnetometer, can accurately capture multi-axis force information when aided by machine learning. The limitation is that the accuracy is only as good as the modelโ€™s calibration and training data โ€“ any change in the skin (replacement or drift over time) can degrade performance if not accounted for. The original ReSkin paper noted that models trained on one sensor did not generalize to other sensors without adaptation, due to instance variability. Recent improvements (see โ€œAnySkinโ€ below) aim to reduce this variability. In summary, uSkin offers direct, hardware-defined accuracy which can be high after one-time calibration, whereas ReSkin offers model-based accuracy which can reach very high levels but requires ongoing calibration and learning algorithms to maintain.

Reliability and Durability

Reliability covers the sensorโ€™s longevity and consistency of performance over time, especially under repetitive use. uSkin is built as a durable tactile array: its soft silicone and internal structure are designed to handle repetitive contacts and even overload conditions without permanent damage. The silicone skin not only protects the internal sensor elements but also allows slight conformity, distributing stress. XELA specifies that uSkin can sustain up to a certain maximum normal force (e.g. 450 gf for one model, or up to 1500 gf for newer models) without damage. In manipulation tasks, uSkin-covered fingers have been shown to handle fragile objects reliably without harming them. Wear and tear on uSkin is relatively low since the sensor is an integrated unit โ€“ there are no loose particles or fluids โ€“ and itโ€™s sealed to prevent dust or moisture ingress. Many researchers have used the same uSkin sensors for thousands of grasp cycles; as long as the silicone and wiring remain intact, the performance remains stable. On the other hand, if a uSkin module does fail or break, it is a specialized hardware piece that must be replaced (which can be costly, as high-end tactile sensors often are). XELA advertises their product as more affordable than some competitors like the BioTac (>$1000) while still not compromising performance, but it is certainly more expensive than DIY solutions.

ReSkin emphasizes replaceability as a core feature of reliability. The magnetic skin can undergo many touches: tests showed the machine learning model remained accurate even after 50,000 interactions on the same piece of skin. Eventually, however, the silicone skin will degrade (e.g. tiny cracks, particle loss, or reduced elasticity) after extensive use. Instead of requiring a complex sensor replacement, the worn skin can simply be peeled off and a new one attached, restoring the sensor to like-new performance. This concept makes ReSkin robust in a maintainable way โ€“ any damage to the surface (cuts, abrasion) is not catastrophic, because the skin is a cheap consumable. Another aspect of reliability is the sensorโ€™s consistency over time and across units. Early versions of ReSkin saw variability between different fabricated skins and drift in signals over time (as the elastomer properties changed slightly). To combat this, the designers suggest periodic re-calibration (collecting a zero-load magnetic reading occasionally) and have developed improved fabrication methods. In 2024, an improved variant called โ€œAnySkinโ€ introduced a post-curing magnetization process and self-aligning skins to achieve more uniform magnetic particle distribution and secure attachment to the magnetometer. These improvements greatly reduced variability between sensor instances and prevented performance loss due to misalignment or peeling over time. In summary, ReSkinโ€™s reliability comes from its easy renewability and ongoing model adaptation, whereas uSkinโ€™s reliability stems from a robust physical design that maintains performance over a long service life with minimal intervention.

Response Time and Sampling Rate

Rapid response and high sampling frequency are important for capturing dynamic contact events (e.g. slip, impact) and for tight control loops. uSkin provides real-time readings via a digital interface (often CAN or USB converter) and supports high sampling rates. The standard uSkin modules can sample at up to 500 Hz (2 ms interval) on certain models. In many experiments, users run uSkin at 100 Hz due to external constraints or sufficient bandwidth, but the hardware is capable of faster updates for more demanding applications. The internal latency of uSkinโ€™s sensors is low, since it uses direct electrical readings of magnetic field changes with minimal filtering. This allows reactive control โ€“ for example, a 100 Hz control loop using uSkin feedback was successfully implemented for force control in a dexterous hand.

ReSkin is also designed for high temporal resolution. The magnetometer can be read at rates up to around 400 Hz (as reported in the initial paper), and potentially faster with optimized hardware. The actual throughput may depend on the microcontroller or interface used, but the goal was to exceed 100 Hz, which ReSkin achieved. Because ReSkin uses a learning pipeline, one consideration is the computational delay for the model to infer forces from magnetic readings. In practice, this inference can be made lightweight (e.g. a small multi-layer perceptron) and run in a few milliseconds, so the end-to-end latency remains low. The ReSkin authors demonstrated real-time use of the sensor (e.g. detecting slips or impacts) without lag, suggesting the response is fast enough for most robotic tasks. Both uSkin and ReSkin thus meet the requirements for real-time tactile feedback, with high-frequency data streams. If comparing, uSkinโ€™s fixed hardware sampling (500 Hz digital output) might offer a slight edge in raw speed and noise immunity, whereas ReSkinโ€™s practical speed (~400 Hz) is comparable and has been validated in closed-loop tasks as well. In either case, both sensors can capture fine contact events (on the order of a few milliseconds), far exceeding slower vision-based tactile sensors (which often run at 30โ€“60 Hz).

Fabrication Methods and Integration

The fabrication and integration process for these sensors differ markedly due to one being a commercial product and the other a DIY solution. uSkinโ€™s fabrication is proprietary to XELA Robotics โ€“ it involves assembling small PCBs or sensor chips with embedded magnets and encapsulating them in silicone. Each taxel likely contains a tri-axial magnetometer or Hall sensor aligned with a small magnet in the silicone layer above. The exact manufacturing steps (e.g. how the magnets are embedded and calibrated) are not publicly detailed, but the outcome is a durable sensor sheet with built-in wiring. uSkin modules come with connectors and can be daisy-chained or attached around a robotic finger. Integration is straightforward: the sensors output digital data (e.g. via I2C or SPI through a hub) so one only needs to attach a lightweight cable from the robot hand to a data acquisition board (like XELAโ€™s CAN-to-USB interface). Mechanically, uSkin patches can be glued onto robot surfaces or affixed with screws/brackets depending on the model. The ability to customize shapes (flat, curved, wrap-around) means one can cover complex geometries (fingertips, phalanges, palm) by using multiple uSkin pieces. For example, covering an Allegro Hand might use a curved uSkin on each fingertip and flat patches on each finger link and palm. Because uSkin is a commercial solution, robotics labs often opt for it when they need a plug-and-play tactile array with vendor support, rather than investing time in sensor fabrication.

ReSkinโ€™s fabrication is deliberately simple and accessible. To create a ReSkin sensor, one mixes a two-part silicone rubber with microscopic magnetic particles (like iron oxide or neodymium powder) in a mold to form a thin sheet. After curing, this elastomer is magnetized โ€“ early methods involved curing in a magnetic field to align particles, but this was tricky and led to variability. Updated methods use a pulse magnetizer after curing to uniformly magnetize the particles without needing a field during the curing process. The result is a flexible skin with randomly oriented magnetic dipoles. The electronics for ReSkin consist of a small PCB with a magnetometer (typically a 3-axis magnetometer chip) and possibly a microcontroller to read the magnetometer and stream data. This PCB is placed directly under the silicone skin (it can even be embedded or held by a fixture). A critical integration aspect is keeping the skin positioned relative to the sensor โ€“ AnySkin research introduced self-adhering skins that clip or snap in place, avoiding glue that can peel. In practice, attaching ReSkin to a robot might involve mounting the tiny magnetometer board on a robot finger and then stretching or securing the silicone patch over it like a thimble or sleeve. The flexibility of ReSkinโ€™s form means it can cover curved or large areas by using multiple magnetometers under one continuous skin, or tiling multiple units. Fabrication time is short (a few hours to mold and cure a batch of skins), and the cost is very low per skin (tens of dollars or less). This makes ReSkin attractive for projects that need many sensors or large areas, as one can fabricate and replace skins as needed. The trade-off is that integrating ReSkin also requires developing or using a ML model for the specific robot application, which adds a layer of complexity in software.

Sensing Principle: Magnetic Field-Based Detection

Both uSkin and ReSkin rely on magnetic field sensing at their core, but the configuration and principles of operation differ:

  • uSkin: Each taxel in uSkin is essentially a miniaturized magnetic tactile sensor: a small magnet is embedded in the deformable skin, and directly beneath it is a magnetometer that measures the magnetโ€™s field in 3 axes. In the undisturbed state, the magnetโ€™s field at the sensor has a known baseline. When an external force presses on the skin at that taxel, the magnet moves (e.g. gets displaced or tilted) relative to the sensor. This causes changes in the magnetic field readings (ฮ”B_x, ฮ”B_y, ฮ”B_z). These changes are correlated to the force vector applied โ€“ for instance, a normal press might move the magnet closer to the sensor (increasing |B_z|), while a shear force might shift it laterally (changing B_x, B_y). Through calibration, uSkin converts the raw magnetic readings into an X, Y, Z force reading for each taxel. The key aspect is direct physical mapping: the sensor is designed so that magnetic field changes correspond in a roughly one-to-one manner with force components. Because the magnets are fixed in known positions and each taxel is independent, the interpretation of the signals is straightforward (often a polynomial or linear map for each axis). uSkinโ€™s use of magnetics provides a contactless sensing mechanism (no electrical contacts at the surface) and allows the sensor to be thin and compliant. However, it also means the readings can be affected by external magnetic fields or nearby ferromagnetic objects. XELA addresses this by offering magnetic interference compensation, using reference sensors or software filters to subtract out background field disturbances. In essence, uSkinโ€™s principle is a localized magnetic displacement sensor at each grid point.

  • ReSkin: The ReSkin approach uses a distributed magnetic field perturbation principle. Instead of discrete magnets, the entire elastomer sheet contains a random dispersion of tiny magnetic particles. The magnetometer under the skin measures the combined magnetic field from all these particle dipoles. When the skin is not touched, this field has a stable baseline profile. When contact occurs, a region of the skin deforms โ€“ particles in that region get slightly closer to the sensor or reorient, altering the field. Crucially, the relationship between a given touch (with certain force and location) and the magnetometer reading is highly complex, since many particles contribute to the field signal. Therefore, ReSkin relies on a learned mapping: a data-driven model (often a neural network) is trained on known indentations to predict the contact location and force from the raw magnetic field readings. The model effectively decodes the pattern of field changes into meaningful tactile information. The benefit of this method is that a single small sensor can cover a relatively large area of skin and sense forces at any point in that area. The drawback is that the magnetic field signal is an entangled representation โ€“ without the model, one cannot directly obtain force/position. ReSkinโ€™s magnetic sensing principle is thus a global sensing mode: every touch influences the overall field measurement, but in different ways, and the ML model disentangles them. This principle also means that if the skin shifts relative to the magnetometer or if the magnetic particle distribution changes (due to wear or a new skin), the mapping might need recalibration. Recent efforts like AnySkin aim to make the field more consistent (e.g. uniform particle distribution via post-magnetization) so that the same model can work across replacements. Another consideration is environmental magnetic noise โ€“ like uSkin, ReSkin can be affected by strong external magnets or fields. Users must ensure the sensorโ€™s baseline is recorded and possibly apply filtering for stray field fluctuations (some approaches include taking a no-contact reading before each use to serve as a reference). In summary, ReSkinโ€™s magnetic detection principle is a one-to-many mapping (one sensor reading to many possible contacts, resolved by learning), whereas uSkinโ€™s is many one-to-one mappings (each taxel sensor responds to forces mostly at its own location).

The table below summarizes the key differences between uSkin and ReSkin:

Aspect uSkin (XELA) ReSkin (Meta/CMU)
Sensing Principle Local magnetic displacement at many discrete 3-axis taxels (each taxel: magnet + Hall sensor). Direct mapping from magnet movement to force per taxel. Global magnetic field distortion measured by one/few magnetometers. Requires ML model to infer contact force and position.
Sensitivity ~0.1 gf (0.001 N) threshold for force detection (very light touch). High sensitivity due to precise magnet sensor coupling. Aimed for <0.1 N detectable force; with calibration, achieved ~0.005 N force resolution in tests. Slightly less sensitive natively, but improved by ML averaging.
Spatial Resolution Discrete taxel spacing (e.g. 16โ€“24 sensors per fingertip) gives a few mm resolution; each taxel provides localized 3D force data. Continuous skin with ~1 mm contact localization accuracy after training. Can detect multiple contact points if using multiple magnetometers or sequential touches, but typically one contact at a time per patch.
Accuracy Outputs calibrated force readings per taxel; requires calibration but then reliable (e.g. ~0.1โ€“0.2 N error in practice). Minimal drift; interference compensated via software. High accuracy with trained model (99% location accuracy, few mN force error in controlled settings). Must retrain or adapt model if skin changes or drifts over long term.
Response Time Up to 500 Hz sampling rate (2 ms); low-latency digital output. Suitable for fast control loops (used at 100 Hz in hand control experiments). Tested up to ~400 Hz update rate; real-time ML inference feasible (few ms). Effective for dynamic tasks (slip detection, impacts) with slight computational overhead.
Reliability & Durability Robust build โ€“ soft but resilient; handles overloads without damage. Long-lived hardware; no consumable parts (aside from eventual wear on skin after extensive use). Susceptible to strong external magnetic fields (mitigated by compensation). Skin lasts ~50k interactions before degradation. Inexpensive, user-replaceable skins make maintenance easy. Performance consistent if skin is replaced and model updated occasionally. Sensitive to magnetic misalignment or drift; new designs (AnySkin) improve consistency.
Fabrication & Integration Proprietary manufacturing; purchase from XELA. Available in flat, curved, bendable formats for integration. Attaches via glue or brackets; requires XELA interface for data. Higher cost per unit, but ready to use out-of-box. DIY fabrication from silicone + magnetic powder (open-source specs). Simple electronics (1 magnetometer + microcontroller per patch). Highly affordable (<$30 per sensor). Flexible placement on robot, but requires ML software integration for use.

Table: Feature comparison of uSkin and ReSkin tactile sensors.

Recent Research Applications (2022โ€“2025)

Both uSkin and ReSkin have been employed in a variety of research projects in robotics, particularly in areas like object manipulation, force control, and haptic perception. Below we summarize selected recent studies that showcase each sensor in use, including the research context, how the sensor was implemented, and key findings:

Studies Utilizing uSkin in Robotics Research (2022โ€“2025)

Study & Year Application / Field Experimental Setup with uSkin Key Outcomes
Kulkarni et al., 2024 โ€“ โ€œTactile Object Property Recognition Using Geometrical Graph Edge Features and MT-GCNโ€ (RA-L/IROS 2024) Object property recognition (shape/texture stiffness classification) Allegro Hand fully covered with uSkin sensors on all fingertips, phalanges, and palm. Tactile readings (1168 channels total) fed into a multi-thread Graph Convolutional Network to learn object features. Integrating high-density uSkin data enabled the GCN to recognize objectsโ€™ properties with high accuracy. The proposed method outperformed baseline models, confirming that rich tactile input (3-axis forces from uSkin) improves multi-fingered object classification. It demonstrated effective identification of various object features solely through touch, validating uSkinโ€™s value for complex perception tasks.
Chelly et al., 2024 โ€“ โ€œTactile-based Force Estimation for Interaction Control with Robot Fingersโ€ (arXiv preprint 2024) Precision force control in dexterous manipulation Allegro Hand instrumented with Xela uSkin on each finger. The uSkin taxels were calibrated against an ATI Nano17 force/torque sensor to learn mapping from magnetic readings to actual force (per taxel). Used in a closed-loop admittance controller at 100 Hz. Achieved reliable real-time force feedback control: the robot maintained desired contact forces with only ~0.12 N error margin. Demonstrated that uSkin can provide accurate enough force sensing to serve in feedback loops for delicate tasks (e.g., holding an object with constant force). Validated the stability and responsiveness of uSkin-based control, highlighting the sensorโ€™s utility in enhancing manipulation precision.
Funabashi et al., 2022 โ€“ โ€œCovering a Robot Hand with uSkin for Object Manipulationโ€ (previous study referenced in Kulkarni 2024) General grasping and tactile sensing integration (Details inferred from context) Allegro Hand with uSkin on all contact surfaces, similar to above. Focus on integrating tactile data into manipulation strategies. Provided early evidence that full-hand tactile coverage with uSkin improves manipulation. Likely showed the feasibility of retrofitting Allegro Hand with uSkin and using its readings for tasks like grip adjustment or slip detection. Paved the way for later methods (e.g., graph-based learning) by establishing baseline techniques and highlighting challenges of managing large tactile data streams.

Table: Selected research using uSkin sensors on Allegro Hand (2022โ€“2025). Each study leveraged uSkinโ€™s dense tactile feedback for perception or control, demonstrating improved performance in manipulation tasks.

Studies Utilizing ReSkin in Robotics Research (2022โ€“2025)

Study & Year Application / Field Experimental Setup with ReSkin Key Outcomes
Bhirangi et al., 2021 (Meta AI & CMU) โ€“ โ€œReSkin: Versatile, Replaceable, Lasting Tactile Skinsโ€ (CoRL 2021, published 2022) Tactile sensor development & benchmarking Introduced ReSkin and evaluated it in lab tests. A small ReSkin patch (~2 cm) was indented at various locations and forces using a precise indenter and an ATI Nano17 F/T sensor for ground truth. Trained an MLP model to predict contact position (X,Y) and force (Z, and later X,Y) from magnetometer data. Validated ReSkinโ€™s core capabilities: contact localization error ~0.5 mm and force error ~5 mN, with 99.6% contact accuracy in controlled conditions. Demonstrated high temporal resolution (up to 400 Hz) and longevity >50,000 presses without model degradation. Established ReSkin as an inexpensive (<$30) yet high-performance tactile sensor, laying groundwork for its adoption in various robot tasks.
Tirumala, Weng, Seita et al., 2022 โ€“ โ€œLearning to Singulate Layers using Tactile Feedbackโ€ (IROS 2022) Deformable object manipulation (cloth layer separation) A Franka arm with a custom two-finger gripper was instrumented with a ReSkin sensor on one fingertip. The robot attempted to pinch and lift one or two layers from a stack of fabrics. A classifier was trained on ReSkin data to infer the number of layers grasped. 180 trials were conducted comparing tactile-informed strategy vs vision-only baselines. The ReSkin-enabled gripper successfully distinguished between one vs. two cloth layers by touch, outperforming vision-only methods that failed on transparent or patterned fabrics. Tactile feedback from ReSkin allowed the robot to adjust its pinch depth in real time, greatly improving reliability in grasping the correct number of layers. This study showcased ReSkinโ€™s thin profile and sensitivity โ€“ the sensor could be inserted between layers without bulky hardware, enabling a task (layer separation) that was not feasible with prior optical or larger tactile sensors. It highlighted the potential of ReSkin for fine manipulation in cloth handling and other delicate tasks.
Singh et al., 2023 โ€“ โ€œAnySkin: Plug-and-play Skin Sensing for Robotic Touchโ€ (arXiv 2023) Sensor design improvement (robust tactile skin) An extension of ReSkinโ€™s design addressing its drawbacks. Proposed fabrication changes: magnetize the elastomer after curing (using a pulse magnetizer) for uniform particle distribution, use finer magnetic particles to avoid sedimentation, and introduce a self-aligning mount that locks the skin to the magnetometer without adhesives. Evaluated signal consistency across multiple skin instances and under cyclic loading. Produced a new โ€œAnySkinโ€ sensor that maintained signal strength and consistency better than original ReSkin. Variability in readings across different skins was greatly reduced (normalized std. deviation ~0.1 vs >0.5 before). The self-adhesive design prevented peeling or shifting during use, enhancing durability. AnySkin preserved ReSkinโ€™s advantages (flexibility, low cost) while improving repeatability and ease-of-use. This research indicates the evolution of ReSkin technology to be more robust for practical deployment, thereby benefiting any robotic applications that rely on such magnetic skin sensors.

Table: Selected research using ReSkin tactile skins (2021โ€“2025). These works range from the initial demonstration of ReSkinโ€™s capabilities to its application in challenging tasks (fabric manipulation) and further improvements in the sensor design.

Conclusion

Both uSkin and ReSkin represent significant advances in tactile sensing for robotic hands, but they are optimized for different priorities. uSkin offers a ready-made, high-density sensor array with excellent sensitivity and straightforward output of rich 3-axis force data at each contact point. It excels in scenarios demanding precision and reliability, such as controlled manipulation and experiments requiring accurate force measurements out-of-the-box. Its integration into the Allegro Hand has enabled researchers to achieve fine force control and detailed object recognition by leveraging the structured tactile information. The main downsides are the higher cost and the need to manage many sensor channels, as well as careful handling of magnetic interference (though mitigated by design).

ReSkin, on the other hand, offers an incredibly flexible and low-cost approach to spreading touch sensation over robot surfaces. Its strength lies in adaptability: it can conform to unique shapes, be replaced easily, and scale to larger areas without prohibitive cost. ReSkin has enabled innovative applications like sensing multiple layers of cloth โ€“ tasks previously impractical โ€“ thanks to its thinness and compliance. It leverages data-driven methods to extract a wealth of information (contact point, normal and shear forces) from minimal hardware. The trade-off is the added complexity of model training and the need for occasional recalibration when the โ€œskinโ€ changes or environmental conditions shift. Its accuracy can be superb, but only under a well-trained modelโ€™s regime; generalizing that performance broadly is an active area of improvement (e.g., AnySkin making strides in consistency).

In sum, uSkin and ReSkin are complementary tactile technologies. uSkin provides a benchmark for precision and ease-of-integration in research labs, delivering high-quality data for each taxel suitable for analytical approaches. ReSkin provides a vision of scalable, affordable tactile coverage, inviting creative uses and rapid prototyping of โ€œsensitive skinโ€ for robots. For the Allegro Hand, which has been used as a testbed, uSkin offers immediate high-resolution touch sensing on each finger, while ReSkin offers a path to cover the entire hand (and arms or tools) with a continuous sensing layer. The choice between them depends on the use-case: if one needs robust, plug-in sensors for fine control (and budget allows), uSkin may be preferable; if one needs wide-area coverage, easy replacement, or has cost constraints, ReSkin is extremely attractive. Future developments may even hybridize these approaches โ€“ using structured arrays of ReSkin-like cells, or adding more intelligence to uSkinโ€™s data โ€“ to further enhance tactile sensing. What is clear from recent research is that both sensors greatly advance a robot handโ€™s ability to โ€œfeelโ€, bringing robotic manipulation closer to the dexterity of human touch by different means. Each has proven effective in various studies, and continued improvements (higher density uSkin, more stable ReSkin) are likely to expand their applications. In conclusion, uSkin and ReSkin represent two state-of-the-art solutions in tactile sensing, each with unique strengths, and both are instrumental in the ongoing development of tactile intelligence in robotic hands.

Copyright 2024, Jung Yeon Lee