DCMM Design and analysis of a flexure based 3-DOF micro positioner MSc presentation · R.H.S. BruinenSupervisor · Prof. ir. R. H. Munnig Schmidt Daily supervisor · P. Estevez Castillo MSc

2 DCMM Content Introduction Conceptual design Stiffness analysis Results and conclusions

3 DCMM Introduction

4 DCMM Introduction / Application Sources: apple.com, shavers.co.uk, delfly.nl

5 DCMM Command Force & vision feedback User Haptic interface Micropositioner robot Introduction / Haptic teleoperation Gripper Sources: micropositioners.net, mekabot.com

6 DCMM Introduction / My project Specifications Workspace 20x20x20mm MIM (minimum incremental motion) 0,2µm Natural frequency > 100Hz Actuator forces < 1N Velocity 0.1 m/s Acceleration 1.5 m/s 2 … Allow 3D translations, constrain rotations Source: micropositioners.net Micropositioner robot

7 DCMM Conceptual design

8 DCMM Conceptual design / Serial or parallel SerialParallel Low moving mass High stiffness Small workspace Sources: xyz-stage.com, pi.com

9 DCMM Conceptual design / Parallel mechanisms Adept QuattroTripteron Sources: robot.gmc.ulaval.ca, motionsystemdesign.com

10 DCMM Conceptual design / Bearings or flexures No dry friction Short range BearingsFlexures Sources: rchellevoet.nl, flexpivots.com

11 DCMM Conceptual design / Architecture Mechanism Legs JointsBeams 1 DOF2 DOF3 DOF Sources: kxcad.net, hephaist.co.jp

12 DCMM Conceptual design / Architecture Design options from literature e.g. Jin and Zhao “New kinematic structures for 2-, 3-, 4-, and 5-DOF parallel manipulator designs” Examples: Modified DeltaCartesian mechanismU* design 1 DOF joints High stiffness Source: Jin and Zhao “New kinematic structures…”, Gosselin “Compact dynamic models…” Selected:

13 DCMM Conceptual design / Geometry Main design variables Upper leg angle Lower leg angle Line of actuation 90° in line with upper leg

14 DCMM Conceptual design / Joints Notch Flexure requirements Low pivot stiffness  Large workspace High off-axis stiffness  High resonances & precision 3-leaf Intersecting cross

15 DCMM Stiffness analysis

16 DCMM Stiffness analysis / Introduction Dimensioning Mechanism size Joint length, width and thickness Mechanism performance Workspace MIM Resonances Stiffness Case 1: Actuation force Case 2: Interaction force Stick-slip F

17 DCMM Stiffness analysis / Introduction Dimensioning Mechanism size Joint length, width and thickness Mechanism performance Workspace Resonances MIM Stiffness Howell and Midha “A Method for the Design of Compliant Mechanisms With Small-Length Flexural Pivots” - 1 DOF joint - No parallel mechanisms Pham and Chen “Stiffness modeling of flexure parallel mechanism” - Theoretical approach Existing literature

18 DCMM Stiffness analysis / Introduction Dimensioning Mechanism size Joint length, width and thickness Mechanism performance Workspace Resonances MIM Stiffness Stiffness analysis JointsLegsMechanism

19 DCMM Stiffness analysis / Joints LeafJoint Bending: Compression: Stiffness around pivot axis Stiffness around off-axis

20 DCMM Stiffness analysis / Legs Example: Translation, X direction θ = M·C p Δx = θ·l l C p = joint compliance around pivot axis = F·l l ·C p = F x ·l l 2 ·C p Case 1: Actuation forceCase 2: Interaction force

21 DCMM Stiffness analysis / Mechanism Case 2: Interaction forceCase 1: Actuation force

22 DCMM Stiffness analysis / Mechanism transformation Transform to horizontal-vertical coordinate system with Euler rotations

23 DCMM Dimensioning Mechanism size Joint length, width and thickness Mechanism size 16cm Joint length 8mm, width 10mm and thickness 0.15mm Stiffness analysis / Dimensioning Stiffness analysis JointsLegsMechanism Mechanism performance Workspace Resonances Stick-slip Stiffness 18x18x18 mm Hz 75 nm 20x20x20 mm Hz 200 nm - ++

24 DCMM Results and conclusions

25 DCMM Results Designed a flexure based 3 DOF micropositioner Developed stiffness analysis method for flexure parallel mechanisms ‘Second International Symposium on Compliant Mechanisms’ – Submitted a paper – Created 3D print – Presentation and demonstration

26 DCMM Conclusions The stiffness analysis – Addition to existing literature – Tool for the design of flexure parallel mechanisms – More insight into the mechanism The final design – High precision performance with a large workspace – Use in industry or research

DCMM Design and analysis of a flexure based 3-DOF micro positioner

28 DCMM Mechanism specifications

29 DCMM Conceptual design / Actuators and sensors Selected actuator: Lorentz motor No friction, no backlash No added stiffness in system Selected sensor: optical encoder Sufficient range and resolution Affordable

30 DCMM Stiffness analysis / Legs Example: Translation, X direction M=F x ·l l θ=M·C p Case I Δx 2 = θ 1 ·l l Δx 3 = F x ·l l 2 ·C p C xI = l l 2 ·C p

31 DCMM Stiffness analysis / Mechanism performance Resonances Stick-slip Workspace