Jamaluddin Mahmud

The development of finger rehabilitation device for stroke patients

Most stroke patients who have lost the ability to use their fingers do not recover the functions of the fingers in their activity of daily living (ADL). This paper presents a novel approach in finger rehabilitation for acute paralysed stroke survivors. Based on repetitive exercise concept, the device is designed to provide support for fingers to do flexion and extension movements according to the patients range of motion. A conceptual design of the device is proposed after considering the current mechanism and control from similar current devices published and commercialised. A comparison between 4 existing main working mechanisms: (1) Pneumatic Cylinders, (2) Artificial Rubber Muscles, (3) Linkage Mechanism, (4) Cable-Driven Mechanism is also provided in this paper. The key for designing the device is home-based practice, easy to use and affordable. Further investigation and experiments on the proposed: Cable Actuated Finger Exoskeleton (CAFEx) are currently still in progress.

Finite Element Implementations to Predict the Failure of Composite Laminates Under Uniaxial Tension

This paper aims to simulate the failure behaviour of composite laminates subjected to uniaxial loading using commercial software (ANSYS) and FE programme (Fortran). For the first time, the built-in failure criteria functions provided by ANSYS were explored extensively and successfully exploited to predict the failure curves of composite laminates. Finite element (FE) models are developed to replicate physical testing. A FE programme is developed using Fortan-90 to determine the lamina stresses based on High Order Shear Deformation Theory (HSDT). These stresses are then used to determine the strength of the plates using the Maximum Stress Failure Criteria. Then FE models are developed using ANSYS to replicate the procedure. Standard ANSYS formulation is utilised and laminate failure was predicted based on Maximum Stress and Tsai-Wu Failure Criteria. The failure curves for both approaches were plotted and found very close to the experiment results. The results show that the FE programme and ANSYS simulations produce an average error of 8% and 15% respectively. Nevertheless, simulations using ANSYS allows easier modification and manipulation. Therefore, it can be concluded the current study is useful and significant and contributes significant knowledge to the failure behaviour of composite laminate. Moreover, the simulations performed could eventually replace tedious and expensive physical testing.

Efficacy and Safety Testing of a New Biologically Based Design Ankle Foot Orthosis in Healthy Volunteer

The ankle-foot of human body is a multi-joint structure that accommodates complex foot motion. Abnormality to the ankle-foot due to injury or disease can result in abnormal gait motion. In such cases, physiotherapist has to assist hemiplegic patients (ankle dorsiflexor muscles with lack of dorsiflexion assist moment) in rehabilitation therapy by using gait training in parallel bars. Physiotherapist has to support hemiplegic patient to position foot and also supports their stand balance. This prolongs multiple task puts extra burden to physiotherapist which gives side effect such as muscular strain or bone fracture while doing the task. Consequently, the motion of the foot patients did not follow the normal gait pattern. Therefore, there is a need to develop an effective ankle foot orthosis (AFO) to solve the long issue-problem. This research was undertake to embark on the modeling and designing of new ankle foot orthosis (AFO) using active control system which later could be used to help patients with ankle dorsiflexor muscles problem. The work was carried out in four stages involving modeling and simulation of DC motor, algorithm development, design and fabrication of the orthosis and finally, evalaution of the product and its functions. The orthosis was tested on healthy volunteer and the results show that the objective to develop and fabricate a new type of robust ankle foot orthosis which can control movement has been achieved successfully.

Simulation and performance evaluation of a new type of powered Dynamic Ankle Foot Orthosis

Dynamic Ankle Foot Orthosis (DAFO) is a revolutionary of the Ankle Foot Orthosis, which is an equipment used to control the motion and position of ankles. It is designed to correct deformities for patients who require treatment of disorders related to muscles and nerves functional failure. Unfortunately, the current designs of DAFO are limited only for patients who can move ankles by their own. This drives for new researches with the aim to develop an innovative development of powered DAFO and currently many researches are still in progress. This paper proposes a new type of DAFO model, which was fabricated locally and assesses its design parameters and functions using computer simulation and numerical analyses. The proposed DAFO was modeled in 3-dimensional using SOLIDWORKS 2010 and several simulations and analyses were carried out to evaluate the current design. Finite element analysis was conducted to determine deformation and stress distribution for DAFO made of two types of materials, which are Acrylonitrile Butadiene Styrene (ABS) and Polypropylene (PP). The failure and factor of safety (FOS) of the proposed model were evaluated under specified boundary conditions and load applied for static and motion condition. Results from this study show that the model functions well and do not fail during testing. The results from the motion analysis show that the DAFO moves according to the design specification. This proves that the material used is the right choice and the current design is acceptable. The current study also proves that computational simulation could be a useful and practical tool in aiding product design. Moreover, it saves time and cost compared to laboratory and destructive testing. Therefore, it can be concluded that the current study has successfully utilized computational analysis and simulation tools in developing the proposed DAFO.

Force assisted hand and finger device for rehabilitation

To date, the development of robotic systems for hand assistance and rehabilitation purposes, particularly related to stroke patients has gained wide interest. Evidence shows that robotic treatment could positively influence hand recovery. Nevertheless, there is no single established treatment strategy or protocol. This paper for the first time attempts to design and assess a novel wearable multiphalanges device for hand and finger rehabilitation assisting acute paralysed stroke survivors. A prototype of a Pneumatic Actuated Finger Exoskeleton (PAFEx) has been developed. The design of the device is proposed after analysing four existing main working mechanisms, i.e. Pneumatic Cylinders, Artificial Rubber Muscles, Linkage Mechanism and Cable-Driven Mechanism. The main design considerations for the home-based device focus on the ease of use and affordability. The device focused on assist the MP joint and PIP joint of thumb and index finger. For that reason, the angular displacement relationship between MP joint and PIP joint is estimated. The current findings show that the device has great potential for individualised rehabilitation session for patients who require rehabilitation in the context of their own home. Nevertheless, further investigation and experiments involving the Pneumatic Actuated Finger Exoskeleton (PAFEx) are currently in progress and the results will be reported imminently.

An intelligent active force control algorithm to control an upper extremity exoskeleton for motor recovery

This paper presents the modelling and control of a two degree of freedom upper extremity exoskeleton by means of an intelligent active force control (AFC) mechanism. The Newton-Euler formulation was used in deriving the dynamic modelling of both the anthropometry based human upper extremity as well as the exoskeleton that consists of the upper arm and the forearm. A proportional-derivative (PD) architecture is employed in this study to investigate its efficacy performing joint-space control objectives. An intelligent AFC algorithm is also incorporated into the PD to investigate the effectiveness of this hybrid system in compensating disturbances. The Mamdani Fuzzy based rule is employed to approximate the estimated inertial properties of the system to ensure the AFC loop responds efficiently. It is found that the IAFC-PD performed well against the disturbances introduced into the system as compared to the conventional PD control architecture in performing the desired trajectory tracking.

The Mechanical Aspects of Martial Arts: Total Time of Execution and Kinematics of Kaedah A

The ability of Kaedah A as a technique to fend off an attack with bare hands is questionable since the estimated ordinary human minimal reaction time is 0.18 s while the offensive force can reach its target in less than 0.1 s. Therefore, this study aimed to analyze the effectiveness of Kaedah A based on its total execution time and to describe the kinematic characteristics of the hand movements during Kaedah A’s execution. The experiment was carried out using the motion capture method. The Kinect sensor detects the hand motion, while the Virtual Sensei Lite directly processes the motion capture through a digitizing procedure to prepare the coordinate data for further analysis. The execution of Kaedah A was repeated five times by four experienced Seni Silat Cekak Malaysia (SSCM) practitioners to investigate its accuracy and repeatability. The obtained data have provided the input for the trajectory mapping procedure for initial and end point identifications. Time difference, Δt, between these two points has demonstrated that the total time of execution for Kaedah A is less than 0.1 s. Further analysis involved smoothing out the obtained coordinate data in order to generate the polynomial equations of the motions of the hand during Kaedah A’s execution. Based on the velocity-time graph generated by the equation of motion, it can be concluded that the execution of Kaedah A has the features of a ballistic movement. The findings have provided useful data for reliability prediction as well as enhancement of Kaedah A’s execution.

Fibre Misalignment Measurement of Nanomodified-Unidirectional Carbon Fibre Laminates

This paper investigates the effect of nanosilica on the fibre waviness or misalignment angle distribution of carbon fibre reinforced polymer composite unidirectional laminates. The quality of the laminates was evaluated using image analyzer technique. The polished specimens were examined using Polyvar B-met optical microscope and analysed using KSRUN ZEISS software. The effect of 3, 7 and 13 vol.% nanosilica on the fibre misalignment angle distribution was determined. The results showed that, the fabricated laminates have average fibre volume fraction Vf of 42%, low fibre waviness distribution (average φo = 2.5o) and less than 1% void content. This implies that the fabrication technique, which was employed in the current work, successfully produced good quality laminates. The presence of nanosilica results in a narrow fibre angle distribution in the HTS40/828 laminate.

Evaluation of failure criteria for composite plates under tension

This paper aims to explore the built-in failure criteria functions provided by ANSYS to simulate the failure behaviour of composite plates under tension. The first ply failure (FPF) load is determined and the results are used for the time to assess the accuracy of the available built-in failure criteria. Finite element (FE) models are developed using standard ANSYS formulation to replicate physical uni-axial tensile tests. The built-in failure criteria functions are explored and the available criteria (Maximum Stress and Tsai-Wu Failure Criteria) are used to determine the FPF load for a composite laminate, with a layup of (θ4/04/- θ4)s. The angle, θ, is varied from 0° to 90°. The results are compared with a (FE) implementation using Fortran and available experiment data. The FPF curves for both ANSYS and Fortran were plotted and found very close to the experiment results. By comparing the curves, the results are used to assess and evaluate the accuracy of the failure criteria. The results show that the current ANSYS and Fortran simulations produce a maximum average error of 16%. Using ANSYS, the Maximum Stress and Tsai-Wu criteria produce an average error of 5.78%, and 13.19% respectively. Using Fortran programme, Maximum Stress produces an average error of 1.36%. Despite larger error, simulations using ANSYS allows easier modification and manipulation. Moreover, the procedure of simulations has the potential to replace tedious and expensive physical testing. Therefore, it can be concluded the current study has successfully explored the built-in failure criteria functions in ANSYS to replicate experiments. Apparently, the current study is novel, useful and contributes significant knowledge in conducting failure analysis of composite laminates.

THE DEVELOPMENT OF A LOW COST MOTION ANALYSIS SYSTEM: CEKAK VISUAL 3D V1.0

To date, there is lack of biomechanical characterisation on defensive technique (martial arts) due to the unavailability of appropriate motion tracking system that can be used to characterise the technique in quasi-training environment. Therefore, this paper presents the development of a novel low cost motion analysis system, Cekak Visual 3D v1.0 which is capable to track dual martial art practitioners skeleton motion in a single frame view using integration of Matlab GUIs and Microsoft Kinect. The accuracy and precision of the coordinate data recorded by the system was tested to ensure the quality of the system. The systems perform the tracking motion with a single Kinect which is a combination of various sensors (RGB and depth sensor) thus makes it capable in providing three dimensional coordinate data. The analysis reveals that Visual Cekak 3D v1.0 resulted lower percentage error with high internal consistency (Cronbach Alpha, α = 0.904). The proposed marker-less system is capable to track and store dual skeleton data in a single session tracking. This capability makes the systems suitable in providing quasi-training and natural setting environment for any martial arts biomechanics investigation. Therefore, we believe that the system provide new concept development for basic research in martial arts biomechanics.