Wise Skin for Tactile Prosthetics (WiseSkin) Hadrien Michaud, EPFL Partners, PI and co-PI’s CSEM: Dr. J. Farserotu (PI), Prof. Dr. C. Enz and Prof. Dr. J-D Decotignie EPFL: Prof. Dr. S. Lacour, Prof. Dr. O. Blanke M.D. (3rd party) The Bern University of Applied Sciences: Prof. Dr. V. Koch Advisory Board Member: S. Micera (EPFL)
Nano-Tera Annual meeting, Bern, May 4th 2015
Problem
[Tan et al., Sci.Transl. Med., 2014]
[Farina et al., Sci.Transl. Med., 2014]
[Fillauer LLC]
[Biddiss et al., Prosthet. Orthot. Int, 2007]
Restore of a natural sense of touch for persons using myoelectric prosthetic limbs, through an integrated sensing and stimulation system.
The WiseSkin solution
- A network of wireless pressure sensing nodes embedded in an elastomer skin. - Low power consumption through ad hoc radio, communication protocol, and waveguide. - Wearable haptic, non invasive stimulation system.
Sensing tactile stimuli: sensor technology
Elastomer membrane
ΔP
Silicon membrane Contact
0.1 0 0 -0.1 -0.2(V) Voltage
PCB
-0.3
Side (sensor height = 170 µm)
-0.4 -0.5
Implanted metal-PDMS composite 200 µm electrode Top
Time (a.u.) 500
1000
1500
2000
2500
Sensing tactile stimuli: sensor node integration
5 mm
E = 1.5 MPa
PDMS
Front side: sensor
Back side: electronics
TangoBlack
20 mm
E = 0.3 MPa
20 mm
Transmitting tactile information: waveguide
UHF antennas
VDD
Waveguide plane GND
Cross-section
Transmitting tactile information: radio
FM-Ultra Wide Band receiver: - Simulated power consumption 420 µW . - Estimated sensitivity is -80 dBm at 200 kb/s. - Consumes less power while providing similar performance and offering greater versatility (data rate, number of users, etc.) than the state of the art.
Core of the receiver occupies area of ~400×500 µm2
SPI interface for calibration and configuration
Test structures 65 nm technology
Transmitting tactile information: protocol •
Challenges: – Design a MAC and routing protocols to cope with the variability of the traffic.
•
Strategy:
3 S
5 6
1 2
4
– Adapt to changes in the traffic. – Under high traffic, communicate only the important tactile events with high reliability.
•
Currently: – Developing a proactive (Node Initiated) routing protocol with high reliability.
Omnet ++ simulation
Feedback to the prosthesis user
LRA
ERM ERM = Eccentric Rotating Mass
LRA = Linear Resonant Actuator
Vibro-tactile feedback devices
Sensory glove Mechano-tactile feedback devices
Testing with subjects
Feedback to the prosthesis user Functional prototype under construction
Sensor Data Actuator command Control unit
E
EMG Data
Haptic device and EMG electrodes
Robotic hand
Commercial force sensitive resistors
Conclusion
Pressure sensor
ULP receiver
Board
Haptic display
3 S 2 Elastomeric skin
Waveguide
1
5 6 4
Protocol
Next steps
Sensor characterization, transmitter, Âľ-controller interface
Skin electromechanical testing
Functional prototype
Hardware deployment
Sensor
Protocol
Thank you!
Skin technology Radio
Haptic feedback
References [Bidiss et al., 2007]E. a Biddiss and T. T. Chau, “Upper limb prosthesis use and abandonment: a survey of the last 25 years.,” Prosthet. Orthot. Int., vol. 31, no. 3, pp. 236–57, Sep. 2007. [Farina et al., Sci. Transl. Med., 2014] D. Farina and O. Aszmann, “Bionic Limbs : Clinical Reality and Academic Promises,” Sci. Transl. Med., vol. 6, no. 257, 2014. [Tan et al., Sci. Transl. Med., 2014] D. W. Tan, M. a. Schiefer, M. W. Keith, J. R. Anderson, J. Tyler, and D. J. Tyler, “A neural interface provides long-term stable natural touch perception,” Sci. Transl. Med., vol. 6, no. 257, pp. 257ra138–257ra138, Oct. 2014.