Research ArticleSENSORS

A skin-inspired tactile sensor for smart prosthetics

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Science Robotics  19 Sep 2018:
Vol. 3, Issue 22, eaat0429
DOI: 10.1126/scirobotics.aat0429
  • Fig. 1 Schematic illustrations and photographs of the skin-inspired tactile sensor.

    (A) Schematic illustration of a human touch sensation. (B) Schematic illustration of the tactile sensor. (C) Schematic illustration of the sensing mechanism used for tactile sensing. (D) Scanning electron microscope (SEM) image of the surface of Co AW. Inset: SEM image of the fractured surface. (E) Photograph showing the current sensor. (F) Photograph of the sensor array. (G) Photograph showing the flexibility of the sensor array.

  • Fig. 2 Characterization and optimization of the device.

    (A) GMI ratio responses of the inductive sensing element to the magnetic field at different exciting frequencies. (B) Experimental impedance responses of the inductive sensing element to height changes. M is the remanent magnetization of the polymer magnet. Height is between the polymer magnet and the inductive sensing element. (C) The GMI ratio responses of the sensor to the displacements at different frequencies, that is, 75, 250, 750, and 1000 kHz. Displacement is the deformation of the polymer magnet under different loadings. (D) Relation of the factor of sensitivity κ of the inductive sensing element and frequency of driving current.

  • Fig. 3 Evaluation of sensing performance.

    (A) Relation between changes in impedance and applied pressures shows the sensitivity of the tactile sensor in the ultralow pressure range. (B) Response of the pressure sensor to water droplets, each with a volume of 1 μl. The corresponding pressure is calculated to be equal to 0.3 Pa. (C) Schematic illustration of the trail of a moving ant. (D) The responses of the tactile sensor to the moving ant.

  • Fig. 4 The biomimetic pressure sensing ability.

    (A) Schematic diagram showing the circuit that converts analog signals recorded from the sensor into digital-frequency signals. (B) The digital-frequency response of the device changed with applied pressure, a pressure range experienced by humans in their daily lives. (C) The digital frequency as a function of applied pressure in the range of 0 to ~1 kPa. (D) The digital frequency as a function of applied pressure in the range of 0 to ~7.5 Pa.

Supplementary Materials

  • robotics.sciencemag.org/cgi/content/full/3/22/eaat0429/DC1

    Additional methods

    Fig. S1. Schematic illustration of the operating mechanism of the device.

    Fig. S2. Characterization of Co AW.

    Fig. S3. Schematic illustration of the fabrication procedure of the tactile sensor.

    Fig. S4. Comparison of the magnetic gradient of the polymer magnet with the perpendicular and parallel magnetization.

    Fig. S5. Characterization of the polymer magnet.

    Fig. S6. GMI ratio of the inductive sensing element at different magnetic field values.

    Fig. S7. The GMI ratio of the inductive sensing element at different driving current values.

    Fig. S8. The first differential relations between the impedance of the inductive sensing element and the height obtained as a result of calculation from Fig. 2B.

    Fig. S9. The real-time response of the sensor to the subtle pressure.

    Fig. S10. The response of the sensor to the pressure in the range of 0 to 100 kPa.

    Fig. S11. The durability and stability of the current sensor.

    Fig. S12. The wearable pressure sensing performance of sensors.

    Fig. S13. The digital frequency as a function of applied pressure in the range of 10 to 180 kPa.

    Fig. S14. The logic circuit for the pulse waveform of the subtle pressure.

  • Supplementary Materials

    This PDF file includes:

    • Additional methods
    • Fig. S1. Schematic illustration of the operating mechanism of the device.
    • Fig. S2. Characterization of Co AW.
    • Fig. S3. Schematic illustration of the fabrication procedure of the tactile sensor.
    • Fig. S4. Comparison of the magnetic gradient of the polymer magnet with the perpendicular and parallel magnetization.
    • Fig. S5. Characterization of the polymer magnet.
    • Fig. S6. GMI ratio of the inductive sensing element at different magnetic field values.
    • Fig. S7. The GMI ratio of the inductive sensing element at different driving current values.
    • Fig. S8. The first differential relations between the impedance of the inductive sensing element and the height obtained as a result of calculation from Fig. 2B.
    • Fig. S9. The real-time response of the sensor to the subtle pressure.
    • Fig. S10. The response of the sensor to the pressure in the range of 0 to 100 kPa.
    • Fig. S11. The durability and stability of the current sensor.
    • Fig. S12. The wearable pressure sensing performance of sensors.
    • Fig. S13. The digital frequency as a function of applied pressure in the range of 10 to 180 kPa.
    • Fig. S14. The logic circuit for the pulse waveform of the subtle pressure.

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