Rifky Ismail

Numerical Study of Salat Movements for Total Hip Replacement Patient

Salat as a daily Muslim activitiy in praying contains several movements which are not suggested by orthopaedic doctor to be conducted by patient with total hip replacement (THR). Sujud and sitting are two movements in Salat which is recommended to be done above the chair for THR patients. There are lacks of scientific discussions about the consequences of the normal salat movement for Muslim THR patients. This paper observes the effect of these movements to the artificial hip joint in THR patient body. A three-dimensional finite element simulation is used to investigate the resisting moment, the contact pressure and the von Mises stress. An artificial hip joint model proposed by previous researcher is used in the simulations. The results show that sujud induces the impingement and plastic deformation whereas sitting is relatively safe to be conducted by THR patients. Some suggestions are also discussed with respect to the design of new artificial hip joint model which allows THR patients to conduct Salat in a normal way. The reduction of inset at the liner, the new profile at circumferential edge inner liner and the increase in the femoral head diameter can be considered as a guideline for new design of the artificial hip joint for Muslim.

The Effect of Repeated Impingement on UHMWPE Material in Artificial Hip Joint during Salat Activities

In Indonesia, a country with largest Muslim population in the world, the necessity to study the artificial hip joint which allows Muslim patients with total hip replacement to have normal Salat becomes important issues. This paper discusses the effect of impingement which occurs during one of the Salat movements. i.e. last tashahhud sitting motion. An artificial hip joint model, proposed by previous researcher from developed country, is simulated using finite element analysis to perform last tashahhud sitting motion. The result shows that impingement occurs and causes the plastic deformations and plastic strains in the acetabular liner component which is manufactured from UHMWPE material. The repetition of Salat movement induces repeated impingements and higher plastic deformation. It experiences dimensional change in the liner lip and has a potency to cause clinical failure of total hip replacement. A new design of the artificial hip joint is required to be proposed to avoid the repeated impingement and deformations.

Development of robotic hand integrated with SimMechanics 3D animation

In this study, a robotic hand is developed using low cost material to meet the demand for prosthetic hand in Indonesia. It has five actuators utilizing five micro servo motors. The robot consists of three joints for index, middle, ring and little respectively and two joints for the thumb. The robotic hand movement is triggered using electromyography (EMG) sensor. The sensors read the information of muscle activities and send them to the microcontroller to drive the robotic hand. By using the same signal for opening and closing fingers, the three pattern grip is embedded in the robotic grip pattern. The patterns are power grip, hook and OK sign. The 3D CAD model of robotic hand is exported into SimMechanics First Generation. The 3D animation in SimMechanics First Generation is augmented to visualize the 3D virtual hand. Based on the experimental result, the robotic hand successfully shows three patterns grip motion driven by EMG sensor. The present roboctic hand is the initial model of the prosthetic hand.

Development of a low cost anthropomorphic robotic hand driven by modified glove sensor and integrated with 3D animation

In this paper, a low cost anthropomorphic robotic hand is developed using low cost materials. The robotic hand has 6 joints and 6 actuators. User or operator gives the hand movement command by a modified glove sensor. The glove consists of six flex sensors placed on the fingers and wrist join that detect the bend of the fingers into a joint angle in each finger. 3D CAD model of robotic hand is exported into SimMechanics model using SimMechanics link to generate SimMechanics block diagram that can run in MATLAB/ Simulink environment. The model in SimMechanics is utilized as 3D animation hand. The relationship of the servo motor rotation angle among metacarpal phalangeal (MCP), proximal inter phalangeal (PIP) and distal inter phalangeal (DIP) joints will be presented. Finally, the performance of robotic hand is tested to grasp various objects and to perform specific motion augmented with 3D animation. The experiment results show the successful development of a low cost anthropomorphic robotic hand that can perform activities of daily living (ADLs).

New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil w...

A low cost anthropomorphic prosthetic hand using DC micro metal gear motor

This research focus on developing of low cost anthropomorphic prosthetic hand using DC micro metal gear motor. The DC metal gear motor is selected as actuator because it is easy to find, low cost, and light weight. The prosthetic hand is based on 3D printed material that enables it light weight, low cost, easy to manufacture and easy to maintain. The mechanism of the hand is based on the tendon spring mechanism. The prosthetic hand has five degree of freedom (DOF) and two joints in each finger. For performing the activities of daily living (ADLs), the hand is designed with seven grip patterns. Based on the experimental results in grasping test and writing test on the white board, the hand can be used as low cost prosthetic hand replacing the passive prosthetic hand that has been available on the market.

Induction Hardening of Carbon Steel Material: The Effect of Specimen Diameter

Induction hardening is well developed technology in many industrial applications, e.g. automotive, tool manufacturing, casting technology, sheet metal forming etc. The surface hardened medium carbon steels are widely used for critical automotive and machine components such as propulsion shafts, crankshafts and steering knuckles which require high fatigue resistance. However, some of small and medium sized enterprises, focused in metal manufacturing in Indonesia have not complete practical knowledge in employing induction hardening to harden the mechanical components. This paper present a technical report of induction hardening process for medium carbon steel material with considering the effect of specimen diameter. The results show that the increase of the specimen diameter increases the current input requirement which also increase the power requirement as a consequence. The induction frequency is automatically decrease when the specimen diameter is increase and resulted in the deeper hardening layer on the surface. The hardness layer of specimen A ranges from outer surface to 6 mm from the surface whereas specimen B ranges from outer surface to 10 mm from the surface from. The micro structure evolution from the surface to the center of the specimen for the both specimen is almost similar. It is mostly affected by the heating temperature and heat distribution from the surface to the center of specimen.

Modeling of Repeated Rolling Contact on Rough Surface: Surface Topographical Change

An finite element analysis (FEA) of a repeated rolling contact over an elastic-plastic deforming rough surface is performed. The surface topographical change is calculated to determine the running-in phase to the steady-state rolling contact situation. A rigid hemisphere is repeatedly rolled over a rough flat aluminum surface and the effect of the contact load and the number of overrollings is studied. It is found that the change in surface topography due to the repeated rolling contact results in smoothening of the rough surface due to the flattening of the highest asperities. The result shows that the running-in of the repeated rolling contact takes place within the first few overrollings.

Two‐Dimensional Finite Element Analysis on Running‐in of Elastic‐Plastic Rolling Contact

The running‐in of rolling contact between a rigid cylinder against a deformable rough surface is simulated by finite element method in this paper. Two‐dimensional model of rough surface is employed in the simulation by considering the elastic‐plastic material with strain hardening behavior. The topographical changes of the rough surface due to running‐in of rolling contact are observed for the applied load or interferences. A relatively high load is applied so that it operates in the elastic‐plastic deformation regime. The running‐in phase, indicated by the high asperity truncation, is found within the first two cycle of the rolling contact. After the third cycle, the steady state deformation occurs. A comparison between the running‐in of rolling contact and the repeated static contact for the same model and is also presented.

Speech control of robotic hand augmented with 3D animation using neural network

In this paper, speech control of robotic hand augmented with 3D animation system has been proposed and presented. Artificial neural network is employed for speech recognition method with tansig and softmax transfer function in hidden layer and output layer. Stream processing method is incorporated for processing the input signal in real time. Thirteen features in frequency domain and time domain that are commonly used in the EMG analysis are utilized in this system. To reduce the influence of noise, voice in noisy environment in the room is recorded as training data set. From the experimental results in offline speech recognition, ANN can recognize the voice command with very high accuracy. In the online real time speech recognition incorporating stream processing, the recognition accuracy decreased about 10%. The proposed speech control of robotic hand augmented with 3D animation is reliable enough with noisy environment.