Asan Gani Abdul Muthalif

Novel design of a self powered and self sensing magneto-rheological damper

Magneto-rheological (MR) dampers are semi-active control devices and use MR fluids. Magneto-rheological dampers have successful applications in mechatronics engineering, civil engineering and numerous areas of engineering. At present, traditional MR damper systems, require a isolated power supply and dynamic sensor. This paper presents the achievability and accuracy of a self- powered and self-sensing magneto-rheological damper using harvested energy from the vibration and shock environment in which it is deployed and another important part of this paper is the increased yield stress of the Magneto rheological Fluids. Magneto rheological fluids using replacement of glass beads for Magnetic Particles to surge yield stress is implemented here. Clearly this shows better result on yield stress, viscosity, and settling rate. Also permanent magnet generator (PMG) is designed and attached to a MR damper. For evaluating the self-powered MR dampers vibration mitigating capacity, an Engine Mount System using the MR damper is simulated. The ideal stiffness of the PMG for the Engine Mount System (EMS) is calculated by numerical study. The vibration mitigating performance of the EMS employing the self-powered & self sensing MR damper is theoretically calculated and evaluated in the frequency domain.

H∞ robust controller for autonomous helicopter hovering control

Purpose – The purpose of this paper is to present the synthesis of a robust controller for autonomous small‐scale helicopter hovering control using extended H∞ loop shaping design techniques.Design/methodology/approach – This work presents the development of a robust controller for smooth hovering operation required for many autonomous helicopter operations using H∞ loop shaping technique incorporating the Vinnicombe‐gap (v‐gap) metric for validation of robustness to uncertainties due to parameter variation in the system model. Simulation study was conducted to evaluate the performance of the designed controller for robust stability to uncertainty, disturbance rejection, and time‐domain response in line with ADS‐33E level 1 requirements.Findings – The proposed techniques for a robust controller exhibit an effective performance for both nominal plant and 20 percent variation in the nominal parameters in terms of robustness to uncertainty, disturbance wind gust attenuation up to 95 percent, and transient pe...

Vibration based energy harvesting using piezoelectric material

Energy harvesting has been around for centuries in the form of windmills, watermills and passive solar power systems. It is not only restricted to the natural resources but it has widen the tapping source to utilise the vibration which happen all around us. In the last decade, beam with piezoceramic patches have been used as a method to harverst energy. An energy harvester system modelled in this paper consist of unimorph piezoelectic cantilever beam with a tip mass. It generates electric current or voltage from the piezoelectric strain effect due to base excitation. This paper is aimed at developing a mathematical model of unimorph cantilever beam with piezoelectric harvester by using Euler — Bernoulli beam theory. The step by step analytical solution and the simulation result are shown in the form of voltage around the natural frequencies.

ANT colony optimization for controller and sensor-actuator location in active vibration control

Developing light weight yet stronger and more flexible panels in aircraft structure to with stand from failure due to vibration has been the interest of many researchers nowadays. Piezoelectric material has been the popular choice to attenuate vibration actively and numerous techniques of optimal control and actuator placement have been proposed. This paper discusseson active vibration control of a simply supported thin plate excited and actuated by piezoelectric patches. Mathematical model of the simply supported plate with piezoelectric patches is derived using Euler-Bernoulli model. The main focus is to find the optimal location of the collocated sensor-actuatorand controller gains using a swarm intelligent algorithm called Ant Colony Optimization (ACO) which later verified with Genetic Algorithm (GA). A simply supported plate is taken as a benchmark model to perform simulation study.

Optimizing dynamic range of Magnetorheological fluid dampers: Modeling and simulation

The viscosity of Magnetorheological (MR) fluids changes dramatically in the presence of an electric or magnetic field, leading to their being referred to as ‘smart fluids’. These fluids have important applications in the field of damping systems. The MR damper parameters are different for different application and there always exist a trade-off. The optimal values of the parameters are important in the design of MR damper for a particular application. Dynamic range is one of the key parameters of the MR fluid damper. This study presents the mathematical derivation of optimal yield stress and shear force to determine the optimal dynamic range of an MR fluid damper.

Active dynamic vibration absorber for broadband control of a multi-mode system: Simulation and experimental verification

The control of broadband steady state vibration amplitude of a multi-mode system is presented. This objective is achieved using an Active Dynamic Vibration Absorber (ADVA). The stiffness property of the ADVA is adaptively tuned to attenuate the vibration of the multi-mode system at resonance. The ADVA detects the excitation frequency of the multi-mode system and calibrates its stiffness property to give the required stiffness for that mode. To implement the ADVA, a prototype model with low modal frequencies is designed. The equations of the steady state response of the multi-mode system with the attached ADVA are derived. The behavior of the prototype model when the ADVA is attached to different locations is used to determine the optimal location of the ADVA. The simulation result shows a reduction in the broadband of the multi-mode system. The result of the implementation of the ADVA reveals a 46%, 73% and 97% vibration amplitude reduction at first, second and third mode of the multi-mode system respectively.

Resonant coils analysis for inductively coupled wireless power transfer applications

This paper proposes Wireless Power Transfer (WPT) system, consisting of transmitter-receiver coils along with some conditioning and stabilizing circuits. The transmitter circuit is designed with a simple H bridge circuit to supply the pulses to source coil. The efficiency variation or performance with respect to the coil size has been demonstrated in this paper, which is not well demonstrated experimentally in the past. It is about an inductive link efficiency calculation as a function of the geometrical dimensions. The efficiency has been derived analytically, and analytical results are validated experimentally. From the results observed the effect of geometrical dimensions (area, distance, shape, and size) is explored. The performance analysis evaluated analytically against experimentally, infers that the inductive coupling with same sized coil has achieved maximum power transfer wirelessly, for a shorter distance with applied input voltage of 24 V at resonance frequency of 180 kHz. This proposed system is practically tested for applications such as charging of devices or providing wireless sensor networks with energy supplied. The results have got useful utility for Electric Vehicles automobile industry.

Enhancement of reflectance of densified vertically aligned carbon nanotube forests

Vertically aligned carbon nanotubes (VACNTs), also known as a carbon nanotube (CNT) forest, are a porous material that is well known for its exceptional optical absorbance property. The reflectance from a VACNT forest has been reported to be as low as 0.045% [1,2]. It is known as the darkest material on Earth. Because of its remarkable material properties, it has various other applications as gas sensors [3], pressure sensors [4], temperature sensors [5], and strain sensors [6]. Recently, various efforts have been made to mechanically manipulate the vertical structure of the nanotubes in the CNT forest and to conduct their optical characterization [7,8]. Optical reflection from bare VACNTs has also been investigated at different wavelengths by W?sik et al. [9]. Controlled densification by wetting of the CNT forest is another post processing technique that has been reported by other researchers [10]. A densification process is necessary to make the CNT forest useful as a future electronics interconnect [10]. However, no study has been done so far on the optical behavior of CNT forests densified by a wetting process. In this letter, for the first time, we investigate and explain the nature of the optical reflectance of densified VACNTs.

Hybrid DE-PEM algorithm for identification of UAV helicopter

Purpose – The purpose of this paper is to develop a hybrid algorithm using differential evolution (DE) and prediction error modeling (PEM) for identification of small-scale autonomous helicopter state-space model. Design/methodology/approach – In this study, flight data were collected and analyzed; MATLAB-based system identification algorithm was developed using DE and PEM; parameterized state-space model parameters were estimated using the developed algorithm and model dynamic analysis. Findings – The proposed hybrid algorithm improves the performance of the PEM algorithm in the identification of an autonomous helicopter model. It gives better results when compared with conventional PEM algorithm inside MATLAB toolboxes. Research limitations/implications – This study is applicable to only linearized state-space model. Practical implications – The identification algorithm is expected to facilitate the required model development for model-based control design for autonomous helicopter development. Original...

Evaluation of Different Control Policies of Semi-Active MR Fluid Damper of a Quarter-Car Model

Proportional Integral Derivative and clipped-optimal control strategy controllers are studied to control the response of Quarter-car suspension profile. A Semi-active device is used for this purpose because it carries valuable result which maintains the reliability of passive control methods and includes the advantage of the adjustable parameter characteristics of active systems. Semi-active devices like Magnetorheological fluids dampers are very effective to control vibration, which use MR fluids to produce controllable damping force and provide both the reliability of passive systems and the facility of active control systems with small power supply. The quarter car model is used here can be described as a nonlinear two degrees of freedom system which is subject to excitation from different road profile. For the best possible reduction of vibration in suspension systems, various Magnetorheological damper models are studied which Bouc-wen model, Neuro-fuzzy model and Bingham model. The performances of these models are evaluated to select a best model. The quarter-car model is executed using step input with two most common and effective control algorithm in vehicle suspension control which are linear quadratic regulator control, and Proportional Integral Derivative control algorithm. The main objective of this study is to evaluate performances of these control algorithms.