ExoFinger: Wearable

robotic hand for Finger

Rehabilitation

Hongliang REN

BN3101 Project Outline

• Clinical problem and needs• Anatomy of hand/finger

• Clinical Background

• Current Methods of treatment

• Unmet needs/gaps

• Robotic Exoskeleton Hands: review

• Project• Definition

• User Specifications

• IP Search

• ASTM standards

Clinical Needs:

Finger rehabilitation

Clinical problem and needs

Anatomy of hand/finger• Bones and joints

− 19 bones and 14 joints distal to the carpals;

− Thumb: 1 metacarpal and 2 phalanges; Others: 1 metacarpal

and 3 phalanges;

− Flexion : DIP ~ 90°; PIP ~ 110°; MCP ~ 90°;

− 20 degrees of freedom(DOFs) totally.

• Muscles

− 9 extrinsic muscles: contribute to finger flexion(3), the

extension of the fingers(5) and the abduction of the thumb(1).

− Intrinsic muscles: The dorsal interossei (DI) and the palmar

interossei (PI): flex the MCP joint and extend the PIP and

DIP joints.

• Tendons and Ligaments

− Extracapsular ligaments: TIML

− Capsular ligaments: MCP joint ligaments; the PIP and DIP

joint collateral ligaments.

Clinical problem and needs

Clinical Background

• Injuries of the hand or surgery

• In stroke survivors, hand function is often lost due to flexor and weakness in finger extensors;

• Spinal cord and other local injuries often lead to partial paralysis.

Clinical problem and needs

Current methods of treatment

• Currently only simple machines are available, prevent agglutination or adhesion of the involved tissue.

• The use of a functional electrical stimulation (FES)

system to stimulate muscles that are no longer

receiving signals from the central nervous system.

Clinical problem and needs

Unmet needs/gaps

• Simple Machines:

‐ Flexibility of these devices is limited;

‐ Not assist as needed

‐ Support only few independent DOFs

‐ Rare sensor feedback

‐ Time-consuming and labor-intensive, making the process expensive.

• FES:

‐ Fast fatigue;

‐ Not applicable to subjects with inflicted local trauma to the muscles.

Robotic Exoskeleton

Hands: A brief review

Classification:

‒ Actuator type

‒ Purpose

‒ Intention sensing method

‒ Power transmission

Robotic Exoskeleton Hands: review

Robotic Exoskeleton Hands: review

a) Direct matching of joint centers b) Linkage for remote center of rotation c) Redundant linkage structure

d) Tendon-driven mechanism e) C=Bending actuator attached to the joint f) Serial linkage attached to distal segment

Mechanisms

Actuator technologies

• Conventional exoskeleton actuators‐ Electric motor: easily available, reliable and easy to

control/larger volume and weight;

‐ Pneumatic actuator: flexibility, fast responsibility/bulky and noisy;

• Smart material actuators‐ Shape memory alloy(SMA): high power-to-weight

ratio/nonlinearity;

‐ Electroactive polymer(EAP): light weight, flexibility and low power consumption/Slow response and low actuation force;

Robotic Exoskeleton Hands: review

Intention sensing methods

• Force Sensing

• Motion Sensing

• Breath Switch

• Surface Electromyogrofhy (sEMG)

• Muscle Hardness

• Mechanomyography (MMG)

• Photoplethysmography (PPG) at Fingernail

• Finger-pad Deformation

• Pressure Pattern(Force Myography, FMG)

Robotic Exoskeleton Hands: review

Reference Force transmission DOFIntention sensing

methodNote

Rehabilitation exoskeleton driven by passive actuator

HandSOME (Brokaw et al.) Linkage 1Exert extension torque for compensating finger flexor

hypertonia

Rehabilitation exoskeletons driven by electric actuators

WaveFlex (Otto Bock) Linkage 1 CPM

Kinetec Maestra Portable Hand

CPM (Patterson Medical)Linkage 1 CPM

Mulas et al Cable 2 EMG Active control

Tong et al Linear actuator 5 EMG CPM / Active motion

HEXOSYS (Iqbal et al.) Linkage 2 Underactuated

HEXORR (Schabowsky et al.) Linkage 2 Torque sensor CPM / Active motion

HANDEXOS (Chiri et al.) Cable, crank-slider 5 Underactuated

Wege et al. Cable 20 EMG electrode Active motion

Ueki et al. Linkage 18Joint angles of healthy

handSelf-motion control

iHandRehab (Li et al.) Cable 8 Force sensor CPM / Active motion

Sarakglou et al. Cable 7 Virtual reality exerciser

AFX (Jones et al.) Cable, linkage 3

IntelliArm (Ren et al.) Linkage1 for

handPassive / assistive

Rehabilitation exoskeletons driven by pneumatic actuators

Hand Mentor (Kinetic Muscles) Linkage 1 Passive / assistive

HWARD (Takahashi et al.) Linkage 3 Assistive

Wu et al. Cable, linkage 2 Force sensor Assistive

Reference Force transmission DOFIntention sensing

methodNote

Assistive exoskeletons driven by electric actuators

Martinez et al. Cable 3 FSR Underactuated Passive extension

OHAE (Baker et al.) Cable 3 FSR Underactuated

Hasegawa et al. Cable 11 EMG Finger tracking for back-drivability

In et al. Cable attached to glove 1 EMG Underactuated Passive extension

In et al. Cable attached to glove 1 Underactuated Passive extension, Differential mechanism

Shields et al. Cable, linkage 3 Force sensors Passive extension

SkilMate (Yamada et

al.)Steel belt 3 Joint angle Equipped with tactile sensor at fingertip

Benjuya et al. Flexible shaft 1 EMG

Assistive exoskeletons driven by pneumatic actuators

DiCicco et al. Cable, linkage 2 EMG Passive extension

Sasaki et al. Directly attached to glove 6Expiration switch or

tactile sensorUnderactuated Passive extension

Kadowaki et al. Directly attached to glove 6 Flexion angle or EMG Underactuated

Tadano et al. Directly attached to glove 5 Force sensor Underactuated Passive extension

Takagi et al. Linkage 3 Bending sensor Passive extension

Toya et al. Directly attached to glove 4Estimate from

movement patternPassive extension

Moromugi et al. Linkage 1Muscle hardness

sensor

Assistive exoskeleton driven by shape memory alloy

Makaran et al. Linkage 1Sip-and-puff switch or

EMGPassive extension

1) Rehabilitation exoskeleton driven by

passive actuator

HandSOME

• Assisting stroke survivors with hypertonia to regain functional grasp ability;

• A 4 bar linkage mechanism was designed.;

• Following the normal kinematic trajectory of the hand;

• The torque profile can be adjusted.

2) Rehabilitation exoskeletons driven by

electric actuators

Wege et al.• focus on support of the rehabilitation

process after hand injuries or strokes

• 20 finger joints, four for each finger;

• Hall sensors, optical encoders, force

sensors, surface electromyograph sensors;

3) Rehabilitation exoskeletons driven by

pneumatic actuators

HWARD(Takahashi et al.)

• Exercises flexion and extension of the hand and wrist;

• Three double-acting cylinders are used(Two for the finger, one for the wrist);

• Force sensors and position sensors.

4) Assistive exoskeletons driven by electric

actuators

Hasegawa et al.

• A dual sensing system, supporting human hand and wrist activities by using user’s bioelectric potential;

• six DC motors are mounted on wearer’s backhand;

• A thumb is assisted by exoskeleton with two motors.

• A five-parallel-link mechanism is used to support six wrist joint motions in three degrees of freedom;

5) Assistive exoskeletons driven by pneumatic

actuators

Dicicco et al.

• An aluminum anchoring plate mounted to the back of the hand and three aluminum bands, one for each of the finger bones.

• They were pulled by a pneumatic cylinder acting in compression;

• Electromyography (EMG) signals are used to control the exoskeleton’s movement.

6) Assistive exoskeleton driven by shape

memory alloy

• Makaran et al.

• It provides a new grasping function for quadriplegic patients.

• Shape memory alloy(SMA) actuators are used.

Video demonstrations

Custom hinged finger orthoses < $100 per finger

Exoskeleton Robotic Finger Orthosis - Biorobotics Research LabReference: http://www.medgadget.com/2015/10/a-low-cost-3d-printed-finger-continuous-passive-motion-device-video.html

Exoskeleton Hand Robotic Training Devicehttps://www.youtube.com/watch?v=iGadOXHO624

3D Printed Powered Exoskeletonhttps://www.youtube.com/watch?v=eM2hydbs8d8

Robotic 'Wearable ExoSkeleton Hand'https://www.youtube.com/watch?v=Lgb1x7P3Anw

Hand Exoskeleton for Rehabilitation of Stroke Patienthttps://www.youtube.com/watch?v=Avt_3gJ8ddA

More videos online

You can also search a lot of them…

http://bioeng.nus.edu.sg/mm/bn3101/

Your Project

Project

General requirements

• Design a hand exoskeleton, with 3 fingers or more

• New mechanisms, sensors/actuators recommended

• You can refer but do beyond the exist robots

• Has grasping function for patients or teleoperation function as a wearable device

Hints FYI at starting point

• Literature review • Gaps between engineering SOA & unmet clinical needs

• Back-drivable?

• # of controllable DOFs?• bending + manipulation?

• Bending actuation mechanisms?• Soft, Ni-Ti elastic backbone, Tendon-driven, Shaft, or others?

• Materials• Soft silicon?

• Thermo-elastomer? 3D printable?

• Make it simple or complicated?

Expectations

1. Minimum / bottom-line

• Concept development and show it mechanically feasible

• Basic modeling, characterization

2. Bonus (only this if you are good enough for 1)

• Control electronics

• System

• bilateral-operation

• Advanced modeling

Concept! Concept! Concept!

Easy to fabricate

Facility supports from lab

• Vacuum

• Centrifuge

• 3D printer (rough prototyping)

• Components/consumables if any

Previous Lessons

• Over-ambitious

• Key: Proof-of-concept

• Simplicity is Beauty

Q & A

• Weekly Update/Tutorial• Mon 10AM: Brief written updates: work done, problems, plan

• Weekly QA hours• Fri afternoon: EA-05-30 (my office) or by appointment• 66012802 / 85788427

• Open for social networks, data sharing• LinkedIn, Facebook, dropbox/onedrive preferred• ID: hongliangren@msn.com

• In general reply in 24 hours and call me if not (I may miss messages from hundreds daily)

Lab tour

Dr. LI Changsheng

PhD student: GU Xiaoyi

Lab tour: Flexible robotic manipulators

in our research group

• Soft mechatronics for oral and nasal

• Tubular continuum manipulator

• Cable/tendon/shaft driven

• SMA Shape memory alloy based

Prototype demo

More from lab web:• http://bioeng.nus.edu.sg/mm/bn3101/