Advanced Materials Research Vols. 931-932

Abstract: A magnetic linear actuator drop-on-demand printhead with interchangeable components is designed and fabricated. The manufacturing processes of all parts are carried out with simple techniques. A droplet generation relies on a linear motion from a piston inside a printhead chamber that causes a pressure wave to push an ink out from a nozzle-aperture. The motion is actuated by a voice coil liked actuator. The voltage applied across the actuator is significantly lower than the piezo actuator. The interchangeable components enable rapid configuration of a printhead to suit wide range of ink-materials. The prototype of our printhead was tested with inks prepared from glycerin-water solutions. The operability of the printhead was evaluated at actuated time ranging from 2 100 milliseconds. Our printhead was able to jet a single droplet of ink with viscosity up to 35 mPa.s. The drop size is comparable to other types of printheads.

Abstract: Maximum security is essential for a robotic device to achieve its optimum control. In this research, we present robotic motions, controlled by technological speech recognition techniques, using commands of Thai Speech Recognition (TSR). Examples of such speech words used are; Sai, Khwa, Na, Lang Khun, Long and Yood, which are the equivalent English language representations for; turn left, turn right, forwards, backwards, upwards, downwards, and stop, respectively. The speech commands are independent for any particular user and so, as a result, they are highly beneficial for general and practical use. The three main important parts of this paper comprise; Pre-processing, Discrete Fourier Transform (DFT), and Back Propagation Neural Network (BPN). The experimental results, when reviewed, exhibit results showing that the average accuracy percentages are equal to 71.00% for female commands, and 70.00% for male commands, respectively.

Abstract: This research presents the design, construct and performance evaluation of a 2-stage parabolic trough solar concentrator (2-stage PTC). The primary stage was constructed of polished stainless steel (SUS 400) to form the primary stage parabolic reflector (1.489 m ×1.489 m size), the second stage was constructed of multi piece mirror to form the hyperbolic shape reflector (0.13 m×1.489 m). Black painted copper pipe in the size of inside diameters (27.2 mm) covered with glass tube was used as receiver. One axis Sun tracking system has been installed to track 2-stage PTC according to the direction of beam propagation of solar radiation. By using water as a heat transfer fluid its capability to heat transfer and load high temperature (100°C). The storage tank is fabricated with stainless steel of size 40 L. The experimental tests have been carried out in Faculty of Industrial Technology, Vallaya Alongkorn Rajabhat University Pathum Thani, Thailand climatic conditions (14.134°N, 100.611°E) during 5 selected days of the months May 2013. The performance of a 2-stage PTC was evaluated using outdoor experimental measurements including the useful heat gain, the thermal instantaneous efficiency and the energy gained by the water. The experimental results shown the maximum thermal efficiency was 23.43%, the optical efficiency was 76%, and the total geometrical concentration was 27.08X.

Abstract: Programming control in industrial design is by its nature expert upon an example being Programmable Logic Controller (PLC). Such programmes are unsuitable for children or novices as they cannot understand how to use the programme. This research seeks to present tangible programming for a basic control system in new frameworks in engineering education for children. Such programmes could be for use in kindergartens, primary schools or general teaching where knowledge about basic control is required. Normally open-loop and closed-loop control system programming is taught at university and college level. This may be late as far as acquiring knowledge of basic control systems is concerned. Using tangible programming without a computer but instructions and interface, relay and motor could result in children in kindergartens and primary schools being able to programme open-looped control systems which mix chemicals or closed-loop control systems which control conveyor belts. However, the children would not be able to undertake programming using programmable control in a similar scenario.

Abstract: This study developed an onboard system to measure on road driving pattern for a motorcycle. The main components of the developed system consist of a magnetic wheel speed sensor for measuring speed of the motorcycle and a data logger. The developed data logger consists of a microcontroller, memory storage and data display panel for processing and recording the on road speed-time data. The developed system was validated to measure and correctly record speed per time interval. The developed onboard system will be applied by installing on driven motorcycles for recording a speed-time data that will be used to develop the motorcycle driving cycle.

Abstract: Tensile strength of some natural fibers such as hemp is higher than that of steel. To determine tensile properties of hemp fiber, a fiber or bundle is tensile tested with universal testing machine that is controlled by personal computer. This paper presents a small tensile testing equipment that is controlled by Raspberry Pi (RPi), a credit-card-sized single-board computer. General Purpose Input Output (GPIO) pins on RPi were used for controlling the machine crosshead and receiving the tensile load that apply to a hemp bundle. A stepper motor was used to drive the crosshead. Tensile load was measured by using a load measurement system included load-cell, instrument amplifier, and analog-to-digital converter. The applied load and extension were real-time displayed and continuously recorded throughout the test. Testing hemp-fiber bundles with the proposed equipment found that their tensile strength and Youngs modulus were 446.75±184.36 MPa and 18.23±8.26 GPa, respectively. These results were in good agreement with the properties founded in other publications. Test results also found that hemp-fiber bundle with smaller diameter showed higher tensile strength than that of larger one.

Abstract: This paper presents the development of wheelchair stair lift with an intelligent control system that aim to apply for helping the mobility of ageing, disabled and wheelchair people who are suffered from any inconvenience causes of building stair usages and also served for the fire stair evacuation path in the same time. The stair lift is controlled by PLC with the fuzzy proportional plus integral (F-PI) controller combined on their driver functions called as fuzzy ladder control which can generate an appropriate setting voltage and torque to maintain a target position and speed of stair lift when it move along the stair path with shorter time of accessing, travelling and dwelling process. To gain the precise value of target position and speed , the DC motor drive with smart steering gear box that are coupled on two stair guide rails is designed for acting easily as a linear moving control by F-PI controller. By several tests of the unknown characteristics of wheelchair users, the F-PI controller can solve this kind of problems with more efficiency because of the main advantage of fuzzy logic is that no mathematical model is required but can be achieved higher performance with the effective tuning parameters especially in an initial setting process. For more efficiency, the RFID detection method is applied to use for identifying and automatically accessing of wheelchair users who want to use this stair lift with some important data such as their name, age or weight as the prior knowledge data of the initial setting process. By applying the proposed system, performance has been improved by mathematical analysis, solid work simulation, matlab simulation and several tests at laboratory room and real building stair. The results are better than the conventional PI control with more accuracy, correctly, smoothly, stability and safety. Finally, the all system can work well as design concept and the future work will further improve the system performance both in mechanical and control part for more practical to use in any real stair usage.

Abstract: The aim of this paper is design a controller for force control of an Electro-Hydraulic System and selection of a PID gains are using genetic algorithm. The mathematical model is considered as the Newton second law and compressible fluid flow theory. This paper compares two kinds of tuning methods for PID controller. One is the controller design by the genetic algorithm, second is the controller design by the Ziegler and Nichols method. Each PID gains are tested with step input function, square signal, half-sine signal and half-saw signal. And results show performance index with rise time, settling time and Maximum %OS. It was found that the proposed PID gains tuning by the genetic algorithm is better than the Ziegler & Nichols method.

Abstract: This paper presents a design of a one-degree-of-freedom haptic interface system with an aim to investigate control of the system. The system comprised master devices, a system interacting with a user, and slave devices, a system interacting with environments. Both sets of devices were coupled with a gripper, which was designed in a shape of a cantilever beam, to measure force, and a DC motor was employed to drive precision ball screws, which were attached to the gripper, so as to create linear motion. In addition, an encoder was installed so as to investigate motion of the gripper, and the analysis results were employed for a design of a controller, based on the P, PI, PD, and PID type. The aim of this is to provide an operator with tactile sensing through control of the master devices while the slave devices were in contact with an object. The simulation results showed that the stiffness of an object affects stability of the system with a designed controller, causing, limitation of operation, that is, the system was stable when stiffness of the object was less than 43.3 kN/m, and the operator obtained a good response of positions and resistance while contacting with an object as though the operator has direct interaction with such an object.

Abstract: Recently, an integration of wireless sensor network with energy harvesters is getting more interested because it can extend the life time of battery in a sensor node, which is very important in many applications. This paper presents the concept of energy analysis in Zigbee based wireless sensor network, which is powered by a piezoelectric energy harvester to optimize the algorithms used in wireless sensor network. In this work, difference aspects related to piezoelectric energy harvester, characteristic of power consumption in Zigbee based wireless sensor node and concept of optimizing algorithms to balance input and output power in the integrated system are proposed. Keywords: energy harvesting, piezoelectric transducer, Zigbee based wireless sensor network