M. Y. Abdullah

Experimental study of human hand-arm model response

This paper describes the development of a hand-arm model rig to represent the behavior of human postural tremor. The experimental rig is designed as an apparatus to induce vibration along the hand-arm model. In this study an Intra Vernacular (IV) Training arm is used as the hand-arm model. Two DC motors are used each driving an unbalancing mass to produce vibration along the arm model which is very similar to the human postural tremor behaviour. In this experimental work, three different frequencies are used for analysis. Displacement and acceleration dynamic responses of a selected point on the hand model are captured and recorded using a light-weight accelerometer mounted on a glove. The data can be used for further analysis of the human hand-arm tremor especially for Parkinsons disease (PD) patients. Results from the experiment are considered raw data which can later be used to assist in the design of appropriate instruments or devices that can suppress the hand tremor vibration.

Robust Active Force Controller for an Automotive Brake System

The paper presents a robust feedback control method to suppress the vibration and squeal noise phenomenon in disc brake model using an active force control (AFC) strategy. A two degree-of-freedom (2-DOF) Wagner model was considered in the study as the main dynamical element to be controlled. The system was tested for robustness and effectiveness in reducing the vibration and squeal, taking into account a number of disturbances acting on the system. Three control schemes were simulated and compared involving the classic proportional-integral-derivative (PID) controller, AFC with crude approximation (AFCCA) and AFC with fuzzy logic (AFCFL) schemes. The AFC-based schemes show superior performance compared to the PID only counterpart with the AFCFL method producing the best performance.

Development of experimental-rig for human postural tremor behaviour

The purpose of this study is to investigate the human hand tremor behaviour in postural condition considering experimental works performed on actual human hand and a developed rig which was specifically designed to induce vibration in an intra vernacular training (IVT) hand-arm model. Two DC motors were used to spin unbalanced masses as the source of excitation to the model. Thus, this produces vibration along the hand-arm model to emulate the behaviour of postural tremor phenomenon. The quantitative assessment of tremor of the hand-arm model was mainly measured and recorded using a light-weight accelerometer and a displacement laser sensor. The accelerometer converts the physical movement into acceleration signals while the laser displacement sensor was used for precise measurement due to their high sensitivity in motion. The latter transducer was directly targeted at the palm of the hand, adjacent to the location of the accelerometer. The displacement and acceleration signals were then examined in both time and frequency domains. The results from the experiment and simulation study can be used for further analysis of human hand-arm tremor (of typically a PD patient) and the development of anti-human arm tremor device that can eventually suppress the tremor.

Effect of transducer mass on thin plate vibration

Transducer attached to a structure during vibration testing is a direct addition of mass especially when the structure itself is relatively light. This paper present result from a study on the effect of transducer mass on thin plate vibration. A rectangular thin plate of mild steel was used as the test structure. The influence of the transducer mass on the natural frequencies and the mode shapes of the thin plate were investigated. Numerical analysis and experimental modal analysis were conducted on the test structure to obtain the natural frequencies and mode shapes for the first 3000 Hz. The numerical analysis was conducted using MSC Nastran finite element analysis software. Normal Modes Analysis and impact testing were conducted to obtain the natural frequencies and the corresponding mode shapes of the thin plate. The resulting natural frequencies were tabulated and mode shapes comparisons from the simulations are presented in contour plots.

Modeling of human motion through motion captured data

In this project, types of human motion studied in kinematics field are walking and running. The area of interest of the analyzing is lower part of human body segment. A video camera with medium resolution and frame rate is used as an image device to capture the human motion. The image is processed and analyzed to determine the location of every marker at each sequence of motion. Each marker represents a specific part of human body. The extracted data of location for specified limbs is used as a basic data. This basic data of coordinate is transformed into angle data to be the raw data in modeling the motion using non-linear identification. The parametric methods are used in modeling human motion. Finally, the identified models are validated using some model validation techniques.

Real-time machine controller verification and simulation using control signals emulation

The research study explores different types of controller simulation and verification methods and proposes a new method which employs the use of a control signals emulator. The research study has formulated a novel technique for emulating quadrature encoder signals to provide virtual closed loop control of servomotors. The deployment of a control signal emulator technique makes the system unique and removes its dependency on proprietary hardware or software. Enabling the real-time data from the signal emulation environment eases the task of realising a real-time machine simulator.

Development of hand-arm model rig for tremor excitation

This paper describes the development of a hand-arm model rig to simulate human tremor behaviour. The experimental rig is designed as an apparatus to induce vibration along a hand-arm model. An Intra Vernacular (IV) Training arm is used as the hand-arm model. Displacement and acceleration behaviour at three selected points along the hand-arm model were recorded by mean of piezoelectric accelerometer. The data from the experiment can be used for further analysis of the human hand-arm tremor especially for Parkinson’s disease (PD) patients. Results from the experiments are raw data which can later be used in designing an appropriate instrument that can suppress the hand tremor.