Papers by Keyword: Smart Material

Abstract: In Malaysia, every year approximately 40000 people suffer from stroke and many of them become immobilized as an after effect. Rehabilitation robotics to assist disabled people has drawn significant attention by the researchers recently. This project also aims to contribute to this field. This paper presents a Shape Memory Alloy (SMA) actuated wearable assistive robotic hand for grasping. The proposed design is compact and sufficiently light to be used as an assistive hand. It is a joint less structure, has the potential because the human skeleton and joint replace the robot’s conventional structure. This design has been implemented on index and thumb fingers to enable grasping. Shape memory alloy springs and bias force mechanism are used for purpose of hand’s flexion and extension. This paper describes the mechatronic design of the wearable hand, experimental study of actuation unit and sensory system. Open loop experiments are conducted to understand the hand characterization and grip force provided by index finger. Current, temperature, extension and contraction of shape memory alloy springs are reported. This mechanism requires approximately 2A current for the SMA to actuate which provides maximum of 1.6N of gripping force. Conducted experiments show promising results that encourage further developments.

Abstract: The aim of this paper is to present the results of laboratory research on Ionic Polymer-Metal Composite (IPMC), with measurements of electrical values (voltage and current) measured simultaneously with the displacement. The obtained values were used to investigate the possibility of parametric model building. The research is focused mainly on constant frequency sine wave voltage signals. Phase offsets between voltage, current and displacement for different frequencies are calculated. Envelope and mean values of the electrical values are also described.

Abstract: The aim of this paper is to study the potential application of magnetorhelogical (MR) fluid as a smart material used in semi-active damper of a vehicle suspension system. An MR damper was designed and fabricated and tested in the laboratory using damper test machine. The non-linear behaviour of the MR damper is modelled using third order polynomial model based on experimental data. Force tracking control is carried out in order to track the ability of the MR damper to produce force as close as possible with the desired force. Continuous state control is chosen for the inner loop controller of the MR damper. The performance of the proposed controller as a force-tracking controller is compared with the desired force produced by vehicle system. The results of the study shows that the proposed controller is able to track the desired force successfully.

Abstract: With the booming development of science and technology and the continuous progress of economy, the strategic focus of sustainable development is turning to ecological economy. The theory of people-oriented design becomes the mainstream, and green design, which is environmentally friendly and energy-saving, has become a trend in product design that attracting much attention. This article discusses at the height of humanization design that green material is necessary in future material application of product design, with the starting point of ecodevelopment; Under the theory of people-oriented design, smart material turns into the supporting material in future material selection of high-tech product; advanced composite is the leading trend in material application of future product design. This article will elaborate the future direction and the main trend of material research from the above three aspects.

Abstract: An Ionic Polymer-Metal Composite (abbr. IPMC) is a type of a smart materialconsisting of two layers of noble metal and an ion-conducting layer between them. Smart ma-terials are generally capable of actuating and sensing. Mechanical deformation of the IPMCbeam produces an electric potential di erence (in the order of mV) proportional to the tipdisplacement on the electrodes. In this paper, the sensing capabilities of IPMC samples will beinvestigated. The composites are manufactured in a form of a thin (0.3 mm) plate, which arecut into rectangular samples. Tests will be performed on separate samples and two electricallyconnected samples. Response to various frequencies will be tested for each sample and for twomechanically and electrically coupled samples, creating a simple sensor array.

Abstract: The paper presents an actuator based on a coil placed in the casing, with specially prepared connection rods. The construction allows installation of the fiber Bragg grating sensors inside the coil. It allows to measure deformation of the composite that is located in the core of the coil. Thanks to the signal generation with use of DASYLab software, it is possible to precisely control the frequency, value of amplitude excitation and to send the signal to the system with use of the measurement card. The main goal of the experiment is to keep constant value of deformation, by means of a feedback loop with use of PID control, and to change the initial conditions of the test by change of the external force. The system is designed to return to the initial settings by appropriate control of the intensity of magnetic field, and thus the deformation of the sample.

Abstract: This paper describes investigations of magnetorheological elastomers subjected to cyclic loading. The procedure comprised over 1 million of loading cycles per specimen. Mechanical properties of the manufactured composites have a tendency to stabilize in time. This leads to the conclusion that these MRE have a high application potential in the areas which are connected with energy dissipation, such as damping of vibrations.

Abstract: The technology monitoring the operating state of the architecture construction is always hot topics in civil engineering. In this paper, attempts using the NiTiSMA film/ferroelectric ceramics PZT composite materials with the function of force - electricity conversion are introduced to the design of structural safety monitoring system. The sensing materials based on the function of force - electricity conversion, directly perceive the stress changes of architectural structure under the vibration loads, monitoring the state changes of internal cracks in the architectural structure. The results show that the safety monitoring system of architectural beam structure,on the sense of NiTiSMA film / ferroelectric ceramics PZT composite materials, possesses reaction speed in milliseconds, response frequency at 0-1000 Hz. It is suitable for monitoring the damage status of cracks in the architecture construction.

Abstract: Ionic polymer metal composite actuators (IPMCs), a new kind of smart material, have taken much attention as suitable candidates for the next generation actuators, micro-electromechanical systems, medical devices and micro air vehicles. In this paper, a new kind of IPMCs was developed by incorporating sulfonated poly (styrene-co-maleic anhydride) (SSMA) into the Nafion structure to overcome some of the major drawbacks of traditional electro-active polymers. The results show that the ion exchange capacity and water uptake ratio of the SSMA-Nation membrane increased dramatically. Compared with general IPMCs, the maximum bending displacement and the maximum blocking force of the SSMA-reinforced IPMCs improved greatly: the 1 wt.% SSMA-IPMC exhibited the maximum bending displacement of 11 mm up to 1.4 times, while the 5 wt.% SSMA-IPMC exhibited the maximum blocking force of 26 mN up to 1.2 times.

Abstract: The corrosion of the steel structure not only causes the economic losses, but also poses a threat to the safety of the structure. The steel structure corrosion form is divided into uniform corrosion and local corrosion. Lead zirconate titanate (PZT) as a smart material was widely used in structural health monitoring (SHM) in recent years. For local corrosion damage in the form, a steel beam local corrosion monitoring experiments based on Electro-Mechanical Impedance (EMI) technique was designed. Marine environment was simulated and the steel beam local corrosion condition was designed firstly. Then the surface-mounted PZT transducer was used on the structure for long-term monitoring. The development process of corrosion and the admittance change was researched. The result shows that EMI technique is available to the beam local corrosion monitoring by analyzing the change rule of admittance signal and resonant frequency deviation ratio index with the steel beam corrosion.