1. Biomechanical Study of Gait Rehabilitation Robot
The 16th International Conference on Biomedical Engineering
Biomechanical Study of Gait Rehabilitation Robot
Hsiao-ju Cheng1, Pavithra Thangavel2, Gong Chen1, Vidhaya S2, Haoyong Yu1
1Department of Biomedical Engineering, NUS, Singapore
2Department of Biomedical Engineering, VIT University, Vellore, India
7th December 2016

2. Biomechanical Study of Gait Rehabilitation Robot
Introduction
Conventional Gait Rehabilitation
Robot-assisted Gait Rehabilitation
High demand on manpower
Physical demand for therapists
Inconsistency
Bulky and heavy
Expensive
Not suitable for home-based exercise
Introduction

3. Biomechanical Study of Gait Rehabilitation Robot
Robot Design
Human-robot interface controller
Intelligent control strategy
 Overground gait rehabilitation
[1] G. Chen, P. Qi, Z. Guo and H. Yu, “Gait-Event-Based Synchronization Method for Gait Rehabilitation Robots via a Bio-inspired Adaptive Oscillator,” IEEE Transactions on Biomedical Engineering, accepted on 25 August 2016.
[2] G. Chen, P. Qi, Z. Guo and H. Yu, "Mechanical Design and Evaluation of a Compact Portable Knee–ankle–foot Robot for Gait Rehabilitation", Mechanism and Machine Theory, vol. 103, pp , 2016.
[3] G. Chen, H. Yu, “A Portable Powered Knee-Ankle-Foot Orthosis,” ASME Transactions Journal of Medical Devices, 8(2): , 2014.
[4] H. Yu, S. Huang, Gong Chen, N. Thakor, “Control Design of a Novel Compliant Actuator for Rehabilitation Robots,” Mechatronics, 23(8): , 2013.
Introduction

4. Mechanical Design Modular design Bilateral structure
Compact and portable
Light weight (< 4Kg)
Compliant and backdrivable
Length adjustable (Height of subject: 158~186cm)
Introduction

5. Biomechanical Study of Gait Rehabilitation Robot
Novel SEA Design
Compact: 230 x 78 x 43 mm
Weight: 0.85 Kg
Power: 120 W
Low-force range: 0~240N
force resolution: N
High-force range: 240~1128 N
Force resolution: 5.6 N
Add one for gait phase detection
Introduction

6. Control Strategy
Gait-event-based synchronization method (based on hidden Markov model)
Introduction

7. Control Strategy (Cont.)
Adaptive Oscillator
Robot Assistive Method
SEA controller
Introduction

8. Biomechanical Study of Gait Rehabilitation Robot
Aim
To evaluate the performance and effectiveness of the exoskeleton by biomechanical analysis with assistive support
To determine the feasibility of the exoskeleton in healthy subjects
Introduction

9. Biomechanical Study of Gait Rehabilitation Robot
Experimental Setup
Task: 10 m overground walking
Conditions:
Free walking (FW)
Zero force (ZF)
Assistive condition (AS)
EMG  sEMG
Methods

10. Experimental Video
Methods

11. Biomechanical Study of Gait Rehabilitation Robot
Data Collection
Surface electromyography (sEMG)
Sampling rate: 1000 Hz
Tibialis Anterior (TA)
Gastrocnemius Lateralis (GL)
Rectus Femoris (RF)
Semitendinosus (SM)
Kinetics data: knee assistive torque
Kinematic data: knee joint angle
Gait phases and events by inertia measurement unit (IMU)
Elaborate function of muscles
Methods

12. Data Processing Processed by MATLAB (The MathWorks, Inc., US) sEMG:
Normalized by using the isometric maximal voluntary contraction (MVIC) method
percentage of the acquired MVC
Statistics analysis for three studied parameters
Repeated measures analysis of variance (ANOVA)
Least significant difference (LSD) method
α = 0.05
Methods

13. Participants 10 healthy male volunteers
Age: 25.3 ± 3.12 years
Weight: 71.3 ± 8.94 kg
Height :1.74 ±0.07 m
Signed the informed consent forms (granted by NUS-IRB)
Methods

14. Kinetics & Kinematics Analysis
Biomechanical Study of Gait Rehabilitation Robot
Kinetics & Kinematics Analysis
Mean knee torque
Mean knee angle
FW: Free Walking
ZF: Zero Force
AS: Assistive Condition
With assistive torque  knee joint angle is closer to normal walking
Results & Discussion

15. Biomechanical Study of Gait Rehabilitation Robot
sEMG Analysis
FW: Free Walking
ZF: Zero Force
AS: Assistive Condition
TA: Tibialis Anterior
GL: Gastrocnemius Lateralis
RF: Rectus Femoris
SM: Semitendinosus
*: P < 0.05
**: P < 0.01
After wearing the exoskeleton, the muscle activities increased
Providing assistive torque, the muscle activities significantly decreased
 Assistive torque does help subjects to lower the loading of the exoskeleton
Results & Discussion

16. Biomechanical Study of Gait Rehabilitation Robot
Conclusion
Experiments on the effect of the exoskeleton on lower limb kinematics and muscle activity during walking in healthy subjects
Significant reduction in muscle activity and improvement in the knee joint angle with assistive support
The exoskeleton is capable of providing assistance and the implemented control strategy is effective
 Suitable for future clinical trials
Conclusion

17. Acknowledgement Supervisor: Dr. Haoyong Yu Labmates:
Gong Chen
Pavithra Thangavel
Francisco Anaya Reyes
Ashwin Narayan
Gokhan Mert Yagli
Jen-Shuan Chang
Funding agency and collaborators: