Development of a novel 6 DOF interaction force

Development of a novel 6 DOF interaction force sensor for micro-gripper applications. 18 -10 -2021 Jesse Bank Dept. of Precision and Microsystem Engineering Supervisors: Professor: Delft University of Technology Challenge the future M. Porta/P. Estevez U. Staufer

Content • Introduction to sensorized micro-handling • Conceptual design • Final Design • Fabrication • Conclusions & recommendations 18 -06 -2010 Development of a 6 DOF interaction force sensor. 2

Introduction Conceptual Design Sensorized micro-handling Fields of interest Final Design Sensorized microhandling Fabrication Conclusions & recommendations Micro-manipulation: Life science: • Assembly • Alignment • Cell manipulation • Tissue manipulation Surgery: • Minimal invasive Gas gyroscope http: //www. miamiroboticprostat ectomy. com F. Arai, et al - Micro manipulation based on micro physics-strategy based on attractive force reduction and stress measurement, 1995 G. Reinhart, et al. - Telepresence as a Solution to Manual Micro-Assembly http: //www. ritsumei. ac. jp/se/~sugiyama/Eng lish/research. htm 18 -06 -2010 http: //www. neurosurgery. ufl. edu Development of a 6 DOF interaction force sensor. 3

Introduction Conceptual Design Sensorized micro-handling Force sensing Final Design Fabrication Conclusions & recommendations • Grasping force • 1 degree of freedom • Force range: m. N • Force resolution: µN z • Interaction force x • 6 degrees of freedom • Force/torque range: m. N/m. Nmm y • Force/torque resolution: µN/µNmm 18 -06 -2010 Development of a 6 DOF interaction force sensor. 4

Introduction Conceptual Design Grasping force sensing Grippers already developed Final Design Fabrication Conclusions & recommendations • Grasping force approach: • Micro-grippers T. Chu Duc – Sensing microgripper for microparticle handling, 2007 18 -06 -2010 Development of a 6 DOF interaction force sensor. 5

Introduction Conceptual Design Interaction force sensing Interaction force sensor approach Final Design Fabrication Conclusions & recommendations • Interaction force approach: • Sensorized environment • Hybrid approach • Monolithic approach K. Kim, et al – Micronewton force-controlled manipulation of biomaterials using a monolithic MEMS micro-gripper with 2 axis force feedback, 2008 L. J. Love – Force reflecting tele-operation with force feedback, 2003 B. Kuebler, et al – Development of actuated and sensor integrated forceps for minimally invasive robotic surgery, 2005 18 -06 -2010 Development of a 6 DOF interaction force sensor. 6

Introduction Conceptual Design Goal of this thesis Focus: interaction force sensor Final Design Fabrication Conclusions & recommendations • Development of “smart and complete micro-gripper” Interaction force sensors Gripper support Gripper Actuators Grasping Position sensors Grasping force sensors Grasping surface 18 -06 -2010 Development of a 6 DOF interaction force sensor. 7

Introduction Conceptual Design Goal of this thesis Focus: interaction force sensor Final Design Fabrication Conclusions & recommendations • Development of an interaction force sensor to be easily integrated in a micro-gripper. • Including: • 6 DOF measurement • High resolution • Wide force range • Low crosstalk 18 -06 -2010 Development of a 6 DOF interaction force sensor. 8

Introduction Conceptual Design Conceptual design Final Design Fabrication Conclusions & recommendations 18 -06 -2010 Development of a 6 DOF interaction force sensor. 9

Introduction Conceptual Design Requirements Final Design Fabrication Conclusions & recommendations • Based on applications: • Silicon technology • Independent 6 DOF measurement (crosstalk <10%) • High resolution (10 µN and 2 µNmm) • Wide force range (10 m. N and 2 m. Nmm) • Stiffness > 50 N/m • Resonant frequency > 1000 Hz • As small as possible 18 -06 -2010 Development of a 6 DOF interaction force sensor. 10

Introduction Conceptual Design Concept generation Sensing principle Final Design Fabrication Conclusions & recommendations • Piezoresistive force sensing • Stress measurement • Advantages • Small • Flexible • Resolution/range • Fabrication process T. Chu Duc – Sensing microgripper for microparticle handling, 2007 18 -06 -2010 Development of a 6 DOF interaction force sensor. 11

Introduction Conceptual Design Final Design Fabrication Conclusions & recommendations Design process Electrical connection • Combine piezoresistors: • Signal to noise improvement • Facilitate signal analysis • Wheatstone-bridges: • Less temperature dependent • Measures only 1 force/torque • Other forces are cancelled 18 -06 -2010 Development of a 6 DOF interaction force sensor. 12

Introduction Conceptual Design Concept generation Important issues Final Design Fabrication Conclusions & recommendations • Concepts considerations: • Accessibility • Integration of a gripper • Resolution • 6 DOF measurement • • D. V. Dao, et al – Design of a multi-axis force/moment sensor, 2003 Symmetrical layout Fabrication issues • Piezoresistive coefficient 18 -06 -2010 Development of a 6 DOF interaction force sensor. 13

Introduction Concept generation Conceptual Design Concept A, B, C Final Design Fabrication z Concept A x Conclusions & recommendations Support y Sensing beams Piezoresistors Gripper location Concept C Concept B 18 -06 -2010 Development of a 6 DOF interaction force sensor. 14

Introduction Conceptual Design Final Design Fabrication Conclusions & recommendations Beam dimensions Design process Global process • 3 Concepts → 1 Final design Design improvement Concept A, B, C Boundary conditions Ok? no 18 -06 -2010 yes Performance comparison Electrical optimization - Resolution - Crosstalk - Sensitivity - Stiffness - Overall dimensions - Number of piezoresistors - Accessibility yes Best performance? no Development of a 6 DOF interaction force sensor. 15

Introduction Conceptual Design Final Design process Crosstalk minimization Fabrication Conclusions & recommendations For each force a different electrical connection is needed! • “Sensitivity matrix” [S] 18 -06 -2010 Development of a 6 DOF interaction force sensor. 16

Introduction Conceptual Design Final Design process Crosstalk minimization Fabrication Conclusions & recommendations For each force a different electrical connection is needed! • “Sensitivity matrix” [S] 18 -06 -2010 Development of a 6 DOF interaction force sensor. 17

Introduction Conceptual Design Final Design process Global process Fabrication Conclusions & recommendations Design improvement Concept A, B, C COMSOL Beam dimensions Boundary conditions Ok? no 18 -06 -2010 Performance comparison - Resolution - Crosstalk - Sensitivity - Stiffness - Overall dimensions - Number of piezoresistors - Accessibility MATLAB yes Electrical optimization yes Best performance? no Development of a 6 DOF interaction force sensor. 18

Introduction Conceptual Design Concept selection Final Design Fabrication Conclusions & recommendations • Comparison parameters: • Resolution • Crosstalk • Sensitivity Beam dimensions (µm) • Stiffness • Overall dimensions • Number of piezoresistors Resolution (µN / µNmm) • Accessibility Crosstalk (%) 18 -06 -2010 Concept A Concept B Concept C l 1400 1200 1300 w t 100 30 65 30 50 30 Fx 16 8. 0 16 6. 0 20 5. 5 Fy Fz 7. 5 2. 5 7. 5 1. 5 4. 5 3. 0 Mx 2. 5 1. 5 3. 0 My Mz Fx 3. 0 7. 0 16. 9 1. 5 11. 0 7. 6 4. 0 7. 5 4. 1 Fy Fz 4. 0 1. 3 10. 7 3. 4 1. 8 1. 9 Mx 14. 2 5. 4 1. 8 My Mz 0. 7 9. 8 1. 4 9. 3 0. 8 11. 8 Development of a 6 DOF interaction force sensor. 19

Introduction Conceptual Design Final design Mechanical structure Final Design Fabrication Conclusions & recommendations Parameter Stiffness (x-direction) Value 1930. 5 Unit N/m Stiffness (y-direction) Stiffness (z-direction) Mass (including test plate) 1 st resonant frequency (z-direction) 2419. 1 59. 6 76 4456. 5 N/m μg Hz 18 -06 -2010 Development of a 6 DOF interaction force sensor. 20

Introduction Conceptual Design Final design Electrical connections Final Design Fabrication R 1 R 2 R 3 R 4 R 9 R 10 R 11 R 12 R 17 R 18 R 19 R 20 R 21 R 22 R 23 R 24 Conclusions & recommendations 18 -06 -2010 Fx WBFx, 1 - WBFx, 2 - WBFx, 3 Fy - WBFy, 1 - WBFy, 2 WBFy, 3 - WBFy, 3 Wheatstone-bridges Fz Mx WBFz, 1 WBFz, 2 WBMx, 1 WBFz, 3 WBFz, 4 WBMx, 2 WBFz, 5 - WBMx, 3 - WBFz, 5 WBFz, 6 - WBMx, 4 - WBFz, 6 My WBMy, 1 - WBMy, 2 - WBMy, 1 WBMy, 2 - WBMy, 3 Development of a 6 DOF interaction force sensor. 21 Mz WBMz, 1 - WBMz, 1 WBMz, 2 - WBMz, 3 - WBMz, 2 WBMz, 3 - WBMz, 3

Introduction Conceptual Design Final design Performance Final Design Fabrication Conclusions & recommendations Resolution (µN and µNmm) Range (m. N and m. Nmm) Crosstalk (%) 18 -06 -2010 Fx Fy 4. 0 8. 5 14. 5 30. 5 3. 2 2. 7 Fz 1. 5 4. 0 1. 4 Mx 2. 5 4. 5 2. 8 My Mz 2. 0 10. 5 7. 0 37. 5 0. 9 4. 7 Development of a 6 DOF interaction force sensor. 22

Introduction Conceptual Design Gripper integration Performance influence Final Design Fabrication Conclusions & recommendations T. Chu Duc – Sensing microgripper for microparticle handling, 2007 18 -06 -2010 Development of a 6 DOF interaction force sensor. 23

Introduction Conceptual Design Gripper integration Gripper heating Final Design Fabrication Conclusions & recommendations • Gripper heating results in: • Deformations and stresses 18 -06 -2010 Development of a 6 DOF interaction force sensor. 24

Introduction Conceptual Design Final design Gripper influence Final Design Fabrication Conclusions & recommendations • Performance degradation with integrated gripper: Fx 17 130 Resolution (µN and µNmm) Crosstalk (%) Fy 800 451 Fz 44 607 Mx 275 367 My 0. 2 2. 9 Mz 14 99 • Reduction of the heating influence: • Gripper actuation principle • Heat sinks/fins • Thermal insulation • Reconfiguration of piezoresistors • Active compensation 18 -06 -2010 Development of a 6 DOF interaction force sensor. 25

Introduction Conceptual Design Fabrication Fabricated devices Final Design Fabrication Conclusions & recommendations 18 -06 -2010 Development of a 6 DOF interaction force sensor. 26

Introduction Conceptual Design Fabrication Fabricated devices Final Design Fabrication Conclusions & recommendations • Structure is defined by: • Frontside: Piezoresisitor processing • Backside: Wet etching (KOH etching) • Frontside: Deep Reactive Ion Etching (DRIE) 18 -06 -2010 Development of a 6 DOF interaction force sensor. 27

Introduction Conceptual Design Fabrication flowchart Final Design Fabrication Conclusions & recommendations (100) p-type silicon wafer, with p-type piezoresistors in a) the [110] direction b) Isolation of the piezoresistors c) Silicon Nitride deposition and aluminum sputtering d) Wet etching (KOH etching) e) Deep Reactive Ion Etching (DRIE) 18 -06 -2010 Development of a 6 DOF interaction force sensor. 28

Introduction Conceptual Design Fabrication Final Design Fabrication Conclusions & recommendations 18 -06 -2010 Development of a 6 DOF interaction force sensor. 29

Introduction Conceptual Design Conclusions & recommendations Final Design Fabrication Conclusions & recommendations • Conclusions: • An interaction force sensor is developed in which a micro-gripper can be easily integrated • High resolution (< 8. 5 μN & 10. 5 μNmm) • Large force range (up to 30 m. N & 37 m. Nmm) • Low crosstalk (< 5 %) • Sensitive to temperature variations • Recommendations: • Experimental validation • Temperature influence investigation 18 -06 -2010 Development of a 6 DOF interaction force sensor. 30

Questions? 18 -06 -2010 Development of a 6 DOF interaction force sensor. 31

Interaction-forces in literature Interaction-force sensor approach Advantages 1 Drawbacks 1 - Plug and play (easy to be - Hard to provide gripper used) with multiple DOF - No assembly needed - No calibration needed 2 - Flexible - Parallel development of gripper and sensor - Assembly of gripper and sensor is hard - Fabrication in two steps - Not simple to interchange grippers (no macro) - Calibration needed 3 - Parallel development of gripper and sensor - No plug play (time consuming) - Calibration needed 2 3 18 -06 -2010 Development of a 6 DOF interaction force sensor. 32

Fabrication issues 18 -06 -2010 Development of a 6 DOF interaction force sensor. 33

Introduction Concept generation Conceptual Design Piezoresistor position Final Design Concept B Fabrication Conclusions & recommendations Mx Fx My Fy z x Fz y Mz 18 -06 -2010 Development of a 6 DOF interaction force sensor. 34

Design process • Minimum dimensions • Piezoresistor number • Number of wires • Resolution (minimal detectable stress) • Range (yield stress and piezoresistor linearity) • Minimum stiffness • Resonant frequency Yes Dimensions of the beams (w, t, l) Stiffness Ok? Stress Ok? No No Yes Computed with FEM models Comparison on: • Resolution • Sensitivity • Crosstalk • Stiffness • Accessibility • Number of piezoresistors • Dimensions 18 -06 -2010 No Yes Computed with MATLAB® models Resolutio n Ok? • Wheatstone-bridge configuration Piezoresistor connections • Minimizing crosstalk Development of a 6 DOF interaction force sensor. 35

Wheatstone-bridge - + + + 18 -06 -2010 Development of a 6 DOF interaction force sensor. 36

Electrical connections 18 -06 -2010 Development of a 6 DOF interaction force sensor. 37

Wheatstone-bridges R 1 Fx WBFx, 1 Fy - WBFy, 1 R 2 - WBFx, 1 WBFy, 1 Wheatstone-bridges Fz Mx WBFz, 1 My WBMy, 1 Mz WBMy, 1 R 3 WBFz, 1 WBFz, 2 WBMx, 1 - WBMy, 2 WBMz, 1 R 4 WBFz, 2 WBMx, 1 WBMz, 1 R 9 R 10 - WBFx, 1 - WBFy, 1 WBFz, 3 - WBMy, 2 - WBMy, 1 WBFx, 1 WBFy, 1 WBFz, 3 - WBMy, 1 R 12 WBFz, 4 WBMx, 2 WBMy, 2 - WBMz, 1 WBFz, 4 WBMx, 2 WBMy, 2 WBMz, 1 R 17 - WBFy, 2 WBFz, 5 - WBMx, 3 WBMz, 2 R 18 WBFz, 5 - WBMx, 3 - WBFz, 5 - WBMz, 2 - WBMz, 3 - WBFx, 2 WBFy, 3 R 20 WBFx, 2 - WBFy, 3 - WBFz, 5 R 21 - WBFx, 3 - WBFy, 2 WBFz, 6 - WBMx, 4 - WBMz, 2 R 22 WBFx, 3 WBFy, 2 WBFz, 6 - WBMx, 4 WBMz, 2 R 23 WBFy, 3 - WBFz, 6 WBMy, 3 WBMz, 3 R 24 - WBFy, 3 - WBFz, 6 WBMy, 3 - WBMz, 3 R 19 - WBMy, 3 18 -06 -2010 WBMz, 3 R 1 R 2 R 3 R 4 R 9 R 10 R 11 R 12 R 17 R 18 R 19 R 20 R 21 R 22 R 23 R 24 Fx 1. 38 Fy - 0. 07 Stress (MPa) Fz Mx 5. 23 4. 47 - 1. 36 - 0. 42 - 1. 38 1. 35 0. 42 -0. 42 0. 13 -0. 11 -0. 27 -0. 13 0. 11 0. 27 --0. 27 0. 55 0. 49 - 0. 50 - 0. 07 0. 05 0. 49 - 0. 50 - 0. 66 - 0. 66 5. 20 0. 72 0. 71 5. 22 5. 21 0. 68 0. 67 0. 59 0. 62 -0. 58 -0. 62 0. 61 0. 62 -0. 55 - 0. 61 4. 46 2. 20 2. 26 4. 47 4. 46 2. 18 2. 24 - 1. 10 - 1. 09 1. 07 1. 08 - 1. 09 1. 08 Development of a 6 DOF interaction force sensor. My 3. 13 Mz - 0. 20 3. 13 - 0. 49 - 0. 53 - 3. 13 0. 50 0. 54 0. 36 - 0. 77 - 0. 81 - 0. 36 0. 77 0. 80 0. 16 0. 53 - 0. 55 0. 20 - 0. 16 - 0. 53 0. 55 0. 10 - 0. 08 - 0. 20 0. 21 - 0. 10 0. 08 0. 20 - 0. 21 38

Selection of concepts concept A Dimensions (µm) Number of piezoresistors Stiffness (N/m) 1400 100 set B 1 1000 65 concept B set B 2 1200 65 set B 3 1400 65 t 30 16 25 16 30 16 35 16 20 20 30 20 x y 2133 2425 1889 3160 1367 2288 1032 1722 1703 1275 1212 913 l w concept C set C 1 set C 2 1000 1300 50 50 Resolution (µN / µNmm) z Fx Fy 54 8. 0 7. 5 59 6. 5 7. 5 61 6. 0 7. 5 62 6. 0 7. 0 61 5. 0 4. 5 93 5. 5 4. 5 Sensitivity (N-1 / (Nmm)-1) Fz Mx My Mz Fx Fy 2. 5 3. 0 7. 0 0. 070 0. 233 1. 0 1. 5 10. 5 0. 370 0. 371 1. 5 11. 0 0. 368 0. 146 1. 5 2. 0 3. 0 12. 0 0. 189 0. 324 2. 5 2. 0 3. 0 5. 5 0. 371 0. 434 3. 0 4. 0 7. 5 0. 297 0. 470 Fz Mx My Mz Fx Fy 0. 834 0. 391 1. 275 0. 150 16. 895 3. 974 1. 582 0. 535 0. 334 0. 223 10. 191 5. 585 1. 364 0. 683 0. 672 0. 186 7. 597 10. 693 1. 175 0. 278 0. 867 0. 160 8. 797 12. 924 2. 100 2. 358 1. 409 0. 183 4. 5586 0. 8528 0. 623 1. 011 0. 777 0. 210 4. 1171 1. 8405 Fz Mx My Mz 1. 336 14. 267 0. 673 9. 809 1. 088 3. 428 1. 237 24. 916 3. 371 5. 439 1. 356 9. 288 2. 150 9. 475 1. 522 14. 989 1. 6007 1. 3815 0. 2522 8. 3457 1. 9457 1. 8061 0. 7930 11. 7723 Crosstalk (%) 18 -06 -2010 Development of a 6 DOF interaction force sensor. 39

Crosspoint Switch Array 18 -06 -2010 Development of a 6 DOF interaction force sensor. 40

Experimental setup Microscope Fine positioning stage Force probe Coarse positioning stage Interaction force sensor PCB Goniometer Vibration isolation table 18 -06 -2010 Development of a 6 DOF interaction force sensor. 41

Wheatstone-bridge: Fx 18 -06 -2010 Development of a 6 DOF interaction force sensor. 42

Wheatstone-bridge: Fy 18 -06 -2010 Development of a 6 DOF interaction force sensor. 43

Wheatstone-bridge: Fz 18 -06 -2010 Development of a 6 DOF interaction force sensor. 44

Wheatstone-bridge: Mx 18 -06 -2010 Development of a 6 DOF interaction force sensor. 45

Wheatstone-bridge: My 18 -06 -2010 Development of a 6 DOF interaction force sensor. 46

Wheatstone-bridge: Mz 18 -06 -2010 Development of a 6 DOF interaction force sensor. 47

Temperature influence Fx Fy Mx My 18 -06 -2010 Fz Mz Development of a 6 DOF interaction force sensor. 48