Conference Presentation BioRob2012
31
Directional vs Non-directional Modes of Vibrotactile Feedback for Arm Posture Replication Albert Causo, Le Dung Tran , Song Huat Yeo and I-Ming Chen School of Mechanical and Aerospace Engineering Nanyang Technological University, Singapore 25 th Jun 2012 1
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Transcript of Conference Presentation BioRob2012
Directional vs Non-directional Modes of Vibrotactile Feedback for Arm Posture Replication
Albert Causo, Le Dung Tran, Song Huat Yeo and I-Ming Chen
School of Mechanical and Aerospace Engineering
Nanyang Technological University, Singapore
25th
Jun 2012
1
Motivation & Objective http
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15m
67%
stroke patient
survive
Develop low-cost device
for rehabilitation
Best feedback strategy for
posture correction2
Presentation Outline
System Overview
Arm Posture Modeling & Measurement
Vibo-tactile for Posture Correction
3
Different ways of capturing motion
Inertial Motion Unit
MAGNETIC
MECHANICAL
SYSTEM
OPTIC
System Overview Modeling Vibro-tactile
4
Vibro-tactile Feedback
posture guidance
motor learning hand
rehabilitation
5
System Overview Modeling Vibro-tactile
IMU
IMU
Vibro-tactile Unit
System Overview
IMU
Vibro-tactile
Unit
6
System Overview Modeling Vibro-tactile
Software
Arm Posture Modeling
Wrist
Position
Elbow
Position
Forearm
Roll
7
System Overview Modeling Vibro-tactile
Shoulder
Wrist
Elbow
IMU 1
IMU 2
𝐿2
𝐿1
Arm Posture Kinematics
IMU 1 -
𝑟1 ,𝑝1 , 𝑦1
IMU 2 -
𝑟2 ,𝑝2 , 𝑦 2
Arm Lengths -
𝐿1,𝐿2
𝑓 (𝑟 1 ,𝑝1 , 𝑦 1 ,𝑟2 ,𝑝2 , 𝑦 2 ,𝐿1 ,𝐿2)𝑓 (𝑟 2 ,𝑝2 , 𝑦2 ,𝐿2)
wrist -
elbow -
forearm roll -
𝑟1
8
System Overview Modeling Vibro-tactile
Vibro-tactile feedback for arm posture correction
Vibro-tactile unit
Directional feedback
Non-directional feedback
9
System Overview Modeling Vibro-tactile
Directional Feedback Non-directional Feedback
Global
system at
shoulder 10
right hand right hand
System Overview Modeling Vibro-tactile
Local
system at
wrist
Experiments
1 2 3
4 5
11
System Overview Modeling Vibro-tactile
Calibration Step
12
System Overview Modeling Vibro-tactile
Using Vibro-tactile Feedback
Directional Feedback Non-directional Feedback
1m36s 25s13
System Overview Modeling Vibro-tactile
Results
Feedback Strategy Mapping Time (s)Directional Feedback 52.68 ± 17.98
Non-directional Feedback 36.82 ± 19.37
2 3
1 42 3 5
Average error of 7 subjects for 5 posturesAverage error of 7 subjects for 5 postures
14
The use of tactors as directional & non-directional feedback
Error Directional Feedback Non-directional Feedback
Wrist position (mm)
34.42 ± 22.46 26.61 ± 12.92
Elbow position (mm)
20.63 ± 9.53 19.61 ± 9.56
Forearm roll (deg) 6.81 ± 2.96 7.07 ± 3.05
System Overview Modeling Vibro-tactile
Conclusion
IMU
IMU
Vibro-tactile Unit
Integrated System
Arm Posture Modeling
& Measurement
Vibo-tactile for
Posture Correction
15
Future Work
• Combine active visual + audio + vibro-tactile feedback
• Compare direction & non-direction when adding vision
• Design rehab modules
16
APPENDICES
18
Design of GUI
Experiment tabTesting tabConfiguration tab 19
Software - System Overview
StartReceive
Master’s IMU
data
Determine
target
position
Receive
Student’s
IMU data
Determine
current
position
Handle
error
Send tactile
feedbackFinish
Student
adjusts
his/her arm
+-
Arm Replication Process
IMU Measurements
IMU packs 9 sensors (3 accelerometers, 3 angular rate
gyros, 3 magnetometers)
Given the angular value at (t − 1) and t, the numerical approximation becomes
Inertial Motion Unit
Kinematic Formulation (1)
Cartesian transformation
Kinematic Formulation (2)
Yaw - z axis
Pitch - y axis
Roll - x axis
Kinematic Formulation (3)
IMU Specification
Tactor Specification
Specifications of VPM2
VPM2 tactor
Dimensions of VPM2
Capture of Program
IMU device
Vibrotactile Unit
Average error of 7 subjects for 5 posturesAverage error of 7 subjects for 5 postures
Data
Directional and non-directional feedback indicators
Feedback Strategy Mapping Time (s)
Directional feedback 52.68 ± 17.98
Non-directional feedback 36.82 ± 19.37
Average mapping time of 7 subjects for 5 posturesAverage mapping time of 7 subjects for 5 postures
Error Directional feedback Non-directional feedback
Wrist position (mm)
34.42 ± 22.46 26.61 ± 12.92
Elbow position (mm)
20.63 ± 9.53 19.61 ± 9.56
Forearm roll (deg) 6.81 ± 2.96 7.07 ± 3.05
Threshold values
Directional and non-directional experiments
