PhD Research

RESEARCH INTERESTS

Soft Robotics, Rehabilitation, Biomechanics, Medical Device Design, Medical Robotics.

RESEARCH IMPACT

Google Scholar Records: 34, Citations: 2508, h-index: 19

PhD RESEARCH PROJECT

- Soft Robotic Glove for Hand Rehabilitation and Assistive Applications

Various robotic exoskeletons have been proposed to serve as assistive devices and provide assistance to the patients through rehabilitation exercises. However, traditional exoskeletons are comprised of rigid components that impede the natural movement of the joints, and thus reduce their wearability and cause discomfort to the wearers. In this project, we developed a wearable soft robotic glove for hand assistive and rehabilitation applications by using soft pneumatic actuators that are flexible and lightweight. The target users are the patients suffering from hand impairments due to neurodegenerative diseases (parkinson’s disease, amyotropic lateral sclerosis (ALS)), neuromuscular disorders (muscular dystrophies), neurovascular disorders/trauma (stroke and traumatic brain injuries) that require physical or occupational hand rehabilitation. Compared to existing devices, the soft robotic glove has the potential to increase user independence and allow at-home rehabilitation due to its portability and high customizability.

EsoGlove Fabric V2 (IEEE RAL 2017)

Fully Fabric-based Bidirectional Soft Robotic Glove (Folds-based Approach)

Publication: 

1. H.K. Yap, P.M. Khin, T.H. Koh, Y. Sun, X. Liang, J.H. Lim and C.H. Yeow, “A Fully Fabric-Based Bidirectional Soft Robotic Glove for Assistance and Rehabilitation of Hand Impaired Patients”, IEEE Robotics and Automation Letters. 2017.

Video:

EsoGlove Fabric V1 (ICORR 2017)

Fully Fabric-based Bidirectional Soft Robotic Glove (Zero Volume Actuation Concept)

Publication: 

1. H.K. Yap, F. Sebastian, C. Wiedeman, and C.H. Yeow, “Design and Characterization of Fabric-based Flat Pneumatic Actuators for Soft Assistive Glove Application”, in Proc. IEEE Int. Conf. Rehabilitation Robotics. (ICORR2017)

Video:

EsoGlove Elastomer V2 (ICRA 2016, IEEE TNSRE 2016)

Fabric-reinforced Soft Robotic Glove

Publications:

1. H.K. Yap, N. Kamaldin, F. Nasrallah, J.H. Lim, J.C.H. Goh, and C.H. Yeow, “A Magnetic Resonance Compatible Soft Wearable Robotic Glove for Hand Rehabilitation and Brain Imaging”, IEEE Transactions on Neural Systems and Rehabilitation Engineering. 2016.

2. H.K. Yap, B.W.K. Ang, J.H. Lim, J.C.H. Goh, and C.H. Yeow, “A Fabric-Regulated Soft Robotic Glove with User Intent Detection using EMG and RFID for Hand Assistive Application”, in Proc. IEEE Int. Conf. Robotics and Automation (ICRA 2016), Stockholm, Sweden, May 16-21, 2016, pp 3537-3542.

Video:

EsoGlove Elastomer V1 (ICRA 2015)

Soft Robotic Glove with Variable Stiffness Soft Actuators

Publication:

1. H.K. Yap, J.H. Lim, F. Nasrahllah, J.C.H. Goh, and C.H. Yeow, “A Soft Exoskeleton for Hand Assistive and Rehabilitation Application using Pneumatic Actuators with Variable Stiffness”, in Proc. IEEE Int. Conf. Robotics and Automation (ICRA 2015), Seattle, U.S., May 26-30, 2015, pp 4967-4972.

- Sensorized Actuators for Soft Wearable Robotic Applications

Despite the emergence of flexible and stretchable actuators, few possess sensing capabilities. Here, we present a facile method of integrating a flexible pneumatic actuator with stretchable strain sensor to form a soft sensorized actuator. The elastomeric actuator comprises a microchannel connected to a controlled air source to achieve bending. The strain sensor comprises a thin layer of screen-printed silver nanoparticles on an elastomeric substrate to achieve its stretchability and flexibility while maintaining excellent conductivity at ≈8 Ω sq–1. By printing a mesh network of conductive structures, our strain sensor is able to detect deformations beyond 20% with a high gauge factor beyond 50 000. The integration of a pneumatic soft actuator with our sensing element enables the measurement of the extent of actuator bending. To demonstrate its potential as a rehabilitation sensing actuator, we fit the sensorized actuator in a glove to further analyze finger kinematics. With this, we are able to detect irregular movement patterns in real time and assess finger stiffness or dexterity.

Publication:

1. J.C. Yeo, H.K. Yap, W.Xi, Z. Wang, C.H. Yeow, and C.T. Lim, “Flexible and Stretchable Strain Sensing Actuator for Wearable Soft Robotic Applications”, Advanced Materials Technologies. 2016

Video:

- Printable Pneumatics for Soft Robotic Robotic Applications

This work presents a novel technique for direct 3D printing of soft pneumatic actuators using 3D printers based on fused deposition modeling (FDM) technology. Existing fabrication techniques for soft pneumatic actuators with complex inner geometry are normally time-consuming and involve multistep processes. A low-cost opensource consumer 3D printer and a commercially available printing material were identified for printing soft pneumatic actuators with complex inner geometry and high degree of freedom. We investigated the material properties of the printing material, simulated the mechanical behavior of the printed actuators, characterized the performances of the actuators in terms of their bending capability, output forces, as well as durability, and demonstrated the potential soft robotic applications of the 3D printed actuators. Using the 3D printed actuators, we developed a soft gripper that was able to grasp and lift heavy objects with high pay–-to-weight ratio, which demonstrated that the actuators were able to apply high forces. To demonstrate the ability of the actuators to achieve complex movements, such as bidirectional bending movements, we also developed wearable hand and wrist exoskeletons that were able to assist finger flexion and wrist flexion–extension. The proposed technique is the first-in-class approach to directly 3D print airtight soft pneumatic actuators for soft robotic applications using FDM technology.

Publication:

1. H.K. Yap, H.Y. Ng, and C.H. Yeow, “High-Force Soft Printable Pneumatics for Soft Robotic Applications”, Soft Robotics. 2016.

Video:

PAST PROJECTS

- A Biomechanical Study of Arm Sling Design for People with Brachial Plexus Injury 

(Consultancy Project with a startup company, Avalanche Studio Pte Ltd)

Current commercial arm slings serve as a device that supports the weight of the forearm of the injured arm. However, commercial arm slings have several limitations. They do not provide adequate immobilization pertaining to the injured arm, which will then lead to excessive movement at the wrist joint as well as shoulder subluxation. A customized arm sling was designed to address the limitations. In this report, we examined the differences between a commercial arm sling and the customized arm sling in terms of stride characteristics such as speed, cadence and stride length as well as joint kinematics such as wrist angles, elbow angles, thorax angles and pelvis angles during walking and running trials. The preliminary results showed that the customized arm sling allowed the subject to adopt a more normal and efficient gait with less undesirable hand-wrist movement during ambulation.

For more details, please visit:

http://avalanche.com.sg/upload/research_Raye%20and%20HK%20-%20Sling%20Report%20finalized.pdf

- Biomechanics Study of Arm-Leg Synchronised Walking

Arm-Leg Synchronised Walking, in which the arm and the corresponding ipsilateral leg are moved at the same time, in contrast to normal walking, is believed to be more energy-efficient. However, limited studies exist regarding the motion analysis of Arm-Leg Synchronised Walking compared with that of normal walking. The purpose of this study was to investigate the biomechanical differences between Arm-Leg Synchronised Walking and normal walking in terms of kinematics, kinetics and energetics.

Publication: AN ENERGY-EFFICIENT LOCOMOTION: SAMURAI-INSPIRED NAMBA WALKING, ISBS 2014.

- Co-contraction profile of the lower limb musculature in chronic stroke patients with Genu Recurvatum

Genu Recurvatum (GR) is a common pathological knee condition characterised by increased hyperextension during the stance phase of gait. However the mechanisms of GR gait are poorly understood. Therefore, we aim to investigate the muscle activation pattern and co-contraction index (CCI) of the lower-limb musculature in stroke patients with GR.