Bringing a sense of touch to robotic hands. Matthias Zenker

Transcription

1 Bringing a sense of touch to robotic hands Matthias Zenker Bielefeld University / CITEC Germany 1 Fachworkshop Mechatronic Integrated Devices (MID) Nuremberg, February 13, 2014

2 Cognitive Interaction Technology Center of Excellence (CITEC) Research institute in Bielefeld University Funded by the German Science Foundation (DFG) since 2007 >260 researchers involved Integrated graduate school with 80 PhD students Annual budget of ca. 6 Million 2

3 Key Functions of Cognitive Interactive Systems Motion Intelligence Attentive Systems 3 3 Memory and Learning Situated Communication

4 The importance of our human senses 4

5 Example: Grasping without a sense of touch Finger manipulation degradation due to anesthetized tactile receptors Experiment by Prof. Dr. Roland Johansson and colleagues (Umeå University, Sweden) 5

6 Robotic bimanual grasp lab setup at CITEC 6

7 Tactile sensor developement at CITEC 16 x 16 taxel modular high speed sensor 7

8 Construction and working principle of the resistive tactile sensor conductive foam digitalization PCB bus PCB 8

9 Tactile sensor with human fingertip size and shape Transfer sensor geometry to 3D surface Integrate circuits for data aquisition and data bus Design and bus compatible with Shadow hand 16 x 16 tactile sensor 9

10 Design process in 3D CAD construction software Constraints: No 3D PCB layout plugin Two sided PCB with vias Solderable by hand Simple single shot mold LCP specifications Wall thickness for vias Laser angle of incidence 10

11 Electronic component and wiring assembly Fingetip CAD rendering 11

12 Injection molding with Celanese Vectra 840i LDS Thin regions for vias Single shot mold for finger and thumb sized blanks 12

13 Laser-Direct-Structuring process 20 positions for two sided laser activation LPKF MicroLine 3D 13

14 Metallization process Front vias 14

15 Metallization process details Short circuit due to missalignement Area prone to unwanted metallization 15

16 Soldering methods and results Reflow soldering, glue and paste hand dispensed First prototype soldered by hand with soldering iron 16

17 Creating matching 3D shaped sensor material (conductive elastomer) Side for milling the outer shape Side for milling the inner cavity Finished sensor elastomer with glued on plastic mounting bracket High-speed elastomer CNC milling with vacuum clamping 17

18 Mounted on the robotic hand Easy replacement of sensor material 18 Shadow hand and mounted sensor

19 Mounted on the robotic hand Bimanual grasp lab setup 2014 with Kuka LBR Shadow hand and mounted sensor 19

20 Summary First true 3D shaped resistive tactile sensor - allows arbitrary shaped surfaces to be made sensitive to force/pressure/touch Very compact design embeds data acquisition and signal processing electronics High spatial resolution. Fingertip 5mm, less is possible High sensitivity - Fingertip has reliable detection of 0.03N/cm² High signal repeatability Relatively strong and robust design Versatile - usage in high number of fields possible 20

21 Some ideas for usage scenarios Tactile sensor inside prosthesis towards tactile feedback Toys with true graded force/pressure sensing 21

22 Acknowledgement The Team / Funding / Sponsors Matthias Zenker Risto Kõiva Carsten Schürmann Dr. Robert Haschke Prof. Dr. Helge Ritter 22

23 Thank you for your attention! 23