Mohd Nor Azmi Ab Patar

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.

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.

Hand rehabilitation device system (HRDS) for therapeutic applications

The hand rehabilitation approach for people who are affected by cerebral apoplexy has been a long-standing issue with researchers worldwide. Currently, scientific research has discovered a way to recover the motor function. Moreover, the sensory function can be recovered by neuroplasticity. Previously, the conventional hand rehabilitation approach only focused on the motor function. Therefore, there is a need to develop an effective hand rehabilitation device to recover both the motor and sensory functions. This research embarked on the configuration setup and evaluation of new hand rehabilitation devices using a mechanical stimulation system. The system has directly led to the stimulation of tactile senses, which can later be used to help patients who lack motor and sensory functions. The work was carried out in four stages comprising the development of a programming algorithm, the design and fabrication of the device and finally, an evaluation of the product and its functions. The objective to develop and fabricate a new robust tactile grasping type stimulator for a hand rehabilitation device has been achieved successfully. The preliminary evaluation on a healthy volunteer was carried out to identify the safety factor in the implementation of hardware and software before targeted patients are used.

Testing standards assessment for silicone rubber

Skin biomechanics has become an emerging area in research as its interest covers a wide range of applications such as product design, surgery, animation and materials engineering. Based on literatures, silicone rubber is one of the best candidate materials that exhibit desirable skin characteristics, thus making it the right material for skin substitute. Nonetheless, there is no specific standard that has been used to measure the mechanical properties and deformation behaviour of synthetic skin. This paper for the first time aims to assess two standard testing methods for silicone rubber. The work is carried out in 2 stages involving uniaxial testing and quantifying the material constants using a Matlab programme. Mechanical tests are conducted on 2 types of materials (different grades of silicone rubber) using uniaxial tensile test with two different standards (ASTM D2209 and ASTM D412). The raw testing data (load-extension) are then input into an in-house developed Matlab programme to compute and plot stress-stretch value based on neo-Hookean model. Based on statistical analysis, the testing data is found valid, since the sample variance is found to be less than 1%. The neo-Hookean constants, C1, are found to be 0.7819 (ASTM D2209) and 1.3786 (ASTM D412) for Material 1; and 0.927 (ASTM D2209) and 1.4396 (ASTM D412) for Material 2 revealing a difference of 59.67% and 51.21% for Material 1 and Material 2 respectively. As a conclusion, the significant difference of the quantified Material constants suggests a dedicated testing standard must be used.

System integration and control of Dynamic Ankle Foot Orthosis for lower limb rehabilitation

Gait disorder is the inability of a person to assume upright position, maintain neither balance nor the aptitude to initiate and sustain rhythmic stepping. This form of disability may originate from cerebellar disease, stroke, spinal injury, cardiac disease or other general conditions that may bring about such disorder. Studies have shown that ones mobility may be improved with continuous locomotor activity. Traditional rehabilitation therapy is deemed labour as well as cost intensive. Rehabilitation robotics has been explored to address the drawbacks of conventional rehabilitation therapy and the increasing demand for gait rehabilitation. This paper presents a simple yet decent technique in the control and actuation of a new Dynamic Ankle-Foot Orthosis (DAFO) designed to rehabilitate the dorsiflexion and plantarflexion motion of the ankle. The DAFO is equipped with two force sensitive resistors (FSR), which act as a limit switch controlling the actuation of the DC motor to a certain dorsiflexion/plantarflexion motion according to the gait phases detected. The results show that the two FSR sensors are sufficient to detect gait phases and act as limit switches to control the actuation of the ankle DC motors, and thus proving the potential of the current system and design for future application.

Dynamics characterization of a high precision MM3A micro-manipulator system

This paper presents a study on control architecture improvement of a MM3A microrobotic system (MM3A) in terms of high precision capability using a hybrid control strategy viz. PD control scheme integrated with intelligent Active Force Control (AFC) and Fuzzy Logic (FL). The dynamic model of the MM3A is derived using Recursive Newton-Euler method. The simulation was carried out using MATLAB, Simulink. Three control schemes were utilized in this study namely, proportional-derivative (PD) controller, PD-AFC-Crude Approximation, and PD-AFC-Fuzzy Logic estimator in order to test the system performance and robustness. Based on the simulation results, it is proven that the proposed scheme has outstanding performance compared to the classical control scheme. Using AFC-FL strategy, the MM3A was able to achieve its desired performance excellently. Incorporating neural networks into the system tightens the errors and reduces the time taken for the robot to achieve its desired response.

Biomechanical analysis using Kinovea for sports application

This paper assesses the reliability of HD VideoCam–Kinovea as an alternative tool in conducting motion analysis and measuring knee relative angle of drop jump movement. The motion capture and analysis procedure were conducted in the Biomechanics Lab, Shibaura Institute of Technology, Omiya Campus, Japan. A healthy subject without any gait disorder (BMI of 28.60 ± 1.40) was recruited. The volunteered subject was asked to per the drop jump movement on preset platform and the motion was simultaneously recorded using an established infrared motion capture system (Hawk–Cortex) and a HD VideoCam in the sagittal plane only. The capture was repeated for 5 times. The outputs (video recordings) from the HD VideoCam were input into Kinovea (an open-source software) and the drop jump pattern was tracked and analysed. These data are compared with the drop jump pattern tracked and analysed earlier using the Hawk–Cortex system. In general, the results obtained (drop jump pattern) using the HD VideoCam–Kinovea are close to the results obtained using the established motion capture system. Basic statistical analyses show that most average variances are less than 10%, thus proving the repeatability of the protocol and the reliability of the results. It can be concluded that the integration of HD VideoCam–Kinovea has the potential to become a reliable motion capture–analysis system. Moreover, it is low cost, portable and easy to use. As a conclusion, the current study and its findings are found useful and has contributed to enhance significant knowledge pertaining to motion capture-analysis, drop jump movement and HD VideoCam–Kinovea integration.

Model Based Design of Finger Exoskeleton for Post Stroke Rehabilitation Using a Slotted Link Cam with Lead Screw Mechanism

Post stroke rehabilitation consumes a huge amount of health care resources in terms of costs related to hospital and home assistance. Recently, robot-assisted rehabilitation has been adapted to support physiotherapists in providing high-intensity and repetitive rehabilitation sessions. It has been observed that robotics offers an objective and reliable instrumented tool to monitor patient’s progress and accurately assess their motor function. Each finger is attached to an instrumented mechanism which allowing force control and a mostly linear displacement. This paper presents a novel finger rehabilitation approach for acute paralyzed stroke survivors using a wearable robotic interface for hand motor function recovery. The device designed based on biomechanics measurements, able to assist the subject in opening and closing movements. It capable to adapt with various hand shapes and finger sizes. Main features of the interface include a differential system, and a lead screw mechanism which allows independent movement of the five fingers with actuators. The device is safe, easily transportable, and offers multiple training possibilities. The prototype deployment was carried out to determine the requirements for a finger rehabilitation device, the design and characterization of the complete system. Offering ease of use and affordability, the device has great potential to be deployed for individualized rehabilitation session for patients who have to undergo therapy in their home.