HELLO! Divya Shah, Alberto Parmiggiani and Yong-Jae Kim IEEE/ASME AIM (Virtual), July 2020 I ve R obot I RI RI M nt eract i i cs & I ve M echani nnovat i sm Lab 1
CONSTANT LENGTH TENDON ROUTING MECHANISM THROUGH AXIAL JOINT IEEE/ASME AIM , Virtual, July 2020
I INTRODUCTION 3
HUMAN-ROBOT INTERACTION ⊡ Safe and Compatible ⊡ Light-weight ⊡ Backdrivability ⊡ Actuator relocation & Tendon transmission ⊡ Tendon Routings ?? BARETT TECHNOLOGIES WHOLE ARM MANIPULATOR (WAM) 4
TYPES OF TENDON ROUTING ROLLING CONTACT & PAIR OF SHEAVES PASSING AXIALLY OFFSET PIVOT RoboRay Hand ACT Hand UB Hand - IV KIM et.al. , ICRA 2014 DESHPANDE et.al. , T-MECH 2011 SCARCIA et.al. , ROBIO 2015 5
AXIAL JOINT ??? Tendon routing through axial joints is missing … 6
II DESIGN CONSIDERATIONS 7
LIMS ARM LIMS ROBOT ARM AND QUATERNION WRIST KIM et.al. , IROS 2018 8
DESIGN REQUIREMENTS HUMAN ARM DESIRED ROBOTIC ARM 2-DOF Wrist parallel wrist Ulnar deviation/ mechanism Radial deviation Wrist flexion/extension Tendon routing mechanism through an axial Forearm joint Pronation/ Supination Wrist tendon pair 1 Elbow rolling contact joint Wrist tendon pair 2 9
DESIGN CRITERIA ⊡ 1 DOF Rotational Axial Joint ⊡ Range of Motion: ±180° ⊡ Multiple tendon routing (4 for wrist) ⊡ Fulll decoupling 10
III SYSTEM DESIGN 11
CONCEPT IDEA – MOVING PULLEY SYSTEM Distal moving part Distal moving part A A B Rack 𝑦 B and Idling pinion C pulleys C D D Proximal fixed part 𝑦/2 𝑚 𝐵𝐶 = 𝑚 − 𝑦 𝐷𝐸 = 𝑚 + 𝑦 𝐵𝐶 = 𝐷𝐸 = 𝑚 2 2 The maximum range of motion would be: −2𝑚 + 2𝑒 𝑞 ≤ 𝑦 ≤ 2𝑚 − 2𝑒 𝑞 12
CONCEPT IDEA – MOVING PULLEY SYSTEM Distal moving part Distal moving part A ’ A ’ A A 𝜄 B B C C D D’ D ’ D 𝜄/2 Proximal fixed part 𝜚 𝑚 2𝜌 − 𝜚 𝑚 2𝜌 − 𝜚 𝑚 2𝜌 −2∅ 𝑚 + 2𝛽 𝑞 ≤ 𝜄 ≤ 2∅ 𝑚 − 2𝛽 𝑞 The maximum range of motion would be: −2𝜌 + 𝛽 𝑞 + 𝛾 𝑞 ≤ 𝜄 ≤ 2𝜌 − 𝛽 𝑞 − 𝛾 𝑞 13
MULTIPLE TENDONS Distal moving part Proximal fixed part 4 idling pulleys connected to the pinion gear 14
CAD MODEL - SECTIONAL VIEW Moving pulleys 15
CAD MODEL - TENDON LOOPS 16
IV PROTOTYPING AND VALIDATION 17
PROTOTYPE DEMO Rapid Prototyping using 3D Printers SCAN THE QR TO WATCH THE VIDEO ONLINE 18
VIDEO DEMONSTRATION Actuation using DC motors and timing belts SCAN THE QR TO WATCH THE VIDEO ONLINE 19
VALIDATION – COULOMB FRICTION TORQUE Average Torque Joint & [Standard Deviation] 128.68 m Nm Pronation-Supination [2.9 m Nm] 32.05 m Nm Wrist Actuation 1 [0.7 m Nm] 31.17 m Nm Wrist Actuation 2 [1.1 m Nm] 20
V CONCLUSIONS 21
CONCLUSIONS Novel tendon routing Provides simultaneous Exploits the concept of mechanism through routing for all 4 wrist moving pulley to axial joint , like the tendons . achieve full decoupling forearm pronation- between joint and Joint Range of Motion: supination. tendon motions. ±180° . General applicability Concept idea, design , The next steps would and can be exploited prototyping and focus on load testing , for any axial joint and validation are design optimization any number of tendon presented in this work. and integration within pairs. the arm. 22
THANK YOU!!! Any Questions ? divyashah.github.io divya.shah@iit.it 23
ACKNOWLEDGEMENT Special thanks to all the people from: ⊡ Interactive Robotics and Innovative Mechanism (IRIM) Lab at Korea University of Technology and Education (KOREATECH) & NAVER LABS ⊡ iCub Tech & Mechanical Workshop Facilities at Italian Istitute of Technology (IIT) I RI RI M I ve R obot nt eract i i cs & I ve M echani nnovat i sm Lab 24
“ FIN. 30
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