Advanced Materials Research Vols. 403-408

Abstract: In this paper, an appropriate mechanism for a hexapod spider-like mobile robot is introduced. Then regarding the motion of this kind of robot which is inspired from insects, direct kinematics of position and velocity of the centre of gravity (C.G.) of the body and noncontact legs are analysed. By planning and supposing a specific time variation for each joint variable, location and velocity of the C.G. of the robot platform and angular velocity of the body are obtained and the results are shown and analysed.

Abstract: In this article a proper mechanism for a hexapod spider-like mobile robot is presented. By using of geometrical method, inverse kinematic of the robot is analyzed. In further via differential kinematic, velocity of the joint variables is specified. Then inverse kinematic of the robot is solved for a specific motion and the related results are shown and analyzed.

Abstract: In this study, a design methodology is introduced that blends the neural and fuzzy logic controllers in an intelligent way developing a new intelligent hybrid controller. In this design methodology, the fuzzy logic controller works in parallel with the neural controller and adjusting the output of the neural controller. The performance of our proposed controller is demonstrated on a motorized robot arm with disturbances. The simulation results shows that the new hybrid neural -fuzzy controller provides better system response in terms of transient and steady-state performance when compared to neural or fuzzy logic controller applications. The development and implementation of the proposed controller is done using the MATLAB/Simulink toolbox to illustrate the efficiency of the proposed method.

Abstract: A simulation model of Steer-by-Wire(SBW) is built, including steering motor model, steering executive system model, vehicle model and Fiala tire model. Based on the Linear Active Disturbance Rejection Control(LADRC) technique, a kind of control algorithm on steer angle of vehicle SBW is designed. On the simulation system, the control algorithm is simulated and test. The results show that the LADRC controller can implement high precision and strong robust control effects on steer control of vehicle SBW system.

Abstract: For the nonliear and uncertainty parameters of the running driving component of Resonant cement-road breaking vehicle (RCRBV), the mathematic model of the speed Control is established, a adaptive backstepping control method based upon the dynamic recurrent fuzzy neural networks (DRFNN) is presented. The adaptive backstepping controlling arithmetic is designed firstly in transportational status without regard to the uncertain parameters. The convergence based on Lyapunov theory for the closed loop system is also analysised. secondly, the uncertain parameters of the Electro-hydraulic propotional system which affect the running speed controlling performances are defined as items to be estimated by DRFNN in breaking status to meet the high precision and stability requires, the parameter adjustment law is given based upon DRFNN. Finally, the results of the simulation show that the scheme is robust with respect to plant parameter variations and load disturbances.

Abstract: The prime reason for the accidents in the school zone is due to over speeding of the vehicles. The objective of the project is to design and implement a device that controls the speed of the vehicle in required areas. This is to be achieved using the Arduino processor board that is attached in the vehicle. The device consists of two main components, the transmitter and the receiver. The transmitter gets activated during the peak hours and sends the Radiofrequency .The receiver that is attached to the vehicle senses the Radio frequency. This enables the fuel control mechanism by automatically controlling the butterfly valve that is responsible for the amount of fuel pumped into the engine. Simultaneously the countdown timer starts. The speed is maintained till the timer reads zero, after that the vehicle resumes its original state.

Abstract: In this study, the physical, electrical, and structural parameter on radio frequency (RF) sputtered molybdenum thin film is investigated as a function of two deposition parameters: rf power, and argon (Ar) pressure. Films are sputtered onto the substrates nominally held in room temperature in a RF sputtering system at partial argon (Ar) pressure. A number of 10 films are deposited at 8 sccm of Ar pressure while varying the rf power from 90 to 360 watt. Besides, another set of 7 films are deposited at 240 watt RF power while varying the Ar pressure from 8 to 32 watts. All the films are characterized using FESEM, AFM, XRD, and four points probe. The analysis results substantiate that, to fabricate a low resistive thin layer of molybdenum (Mo) both sputtering power, and deposition time Ar pressure plays significant rules. It is found that, with the increase of the RF power (90 to 280 watt) the deposition rate increase from 1.2 A⁰/sec to 4.4 A⁰/sec. But at a RF power higher than 280 watt the deposition rate saturated and it does not increase as linear as before. Also resistivity continuously decreases as the RF power increases from 90 watt up to 270 watt, after that the resistivity remain almost same regardless the RF power increased. Besides, by varying the Ar pressure it is found that with the increase of the Ar pressure the deposition rate increase until 20 sccm (up to 2.4 A⁰/sec). With further increase of the Ar pressure deposition rate start reducing and reached 2.1 A⁰/sec at 32 sccm. Based on the above investigation and analysis optimized film is deposited and further analyzed. The surface roughness is analyzed using AFM characterization tool and found 27.4519 nm. The FESEM and XRD analysis along with the resistivity of the film is used to measure the strain of the deposited film and found a strain of less than 0.01% on the optimized film, which is essential for MEMS/NEMS device fabrication and energy harvesting applications.

Abstract: Microstructure of heterojunction usually has strong influence on its electrical characteristic. In order to study the effect of microstructure, the layers of copper phthalocyanine (CuPc) and tetracyanoquinodimethane (TCNQ) are deposited on indium tin oxide (ITO) coated glass substrate by thermal evaporation method. The modification of microstructure in the organic semiconductor layer with varied underneath layer is studied in the heterojunction between CuPc and TCNQ. Then the effect on its electrical characteristic is examined between ITO and aluminum (Al) electrodes in these alternative structures. By determining the microstructure by atomic force microscope (AFM), the CuPc and TCNQ thin films provide very tiny and large grain, respectively. These large grains in TCNQ thin film connect into line pattern probably due to the slow grain growth. Therefore the CuPc film is deposited on this TCNQ layer, the larger gain size of CuPc film can be achieved. However, the TCNQ layer grown on top of tiny grain of CuPc exhibits relatively small grain size. The variation of X-ray diffraction (XRD) peaks of these alternative structures support the microstructure extracted from AFM image very well. The optical absorption of these various structures exhibits the combination of absorption peaks from each layer. The electrical characteristics of these structures strongly depend on junction between ITO electrode and organic layer. The heterojunction structures of ITO/CuPc/Al and ITO/CuPc/TCNQ/Al show rectifier characteristics while the structures of ITO/TCNQ/Al and ITO/TCNQ/CuPc/Al exhibit similar IV characteristic for both polarities. However the effect of larger grain size in TCNQ layer leads to very much higher current than those other structures. By measuring current down to temperature of 50 K, it is found that the structures with rectifier junction indicate the current decreasing more than five orders of magnitude while the junctions with no rectifier characteristic exhibit only slightly current change even the measured temperature is reduced to very low temperature.

Abstract: The purpose of this study is to determine the optimal angle of wings which is attached to an oscillating body located in an incompressible flow. At present, there are some bridges with wings to prevent oscillation by the wind. The angle of the wing is very important so as to minimize the oscillation of bridge. In this study, the angle to minimize the oscillation is presented by optimal control theory. In order to minimize the oscillation, the performance function which is expressed by the displacement of body is introduced. The performance function should be minimized satisfying state equation. This problem can be transformed into the minimization problem by the Lagrange multiplier method. As a minimization technique, the weighted gradient method is applied. For the discretization, the arbitrary Lagrangan-Eulerian(ALE) finite element method is applied to solve the FSI problem. The optimal control of an oscillating bridge is shown as numerical study.

Abstract: Electronic Stability Program (ESP) has become the focus of the study in the field of automotive active safety and chassis control in recent years, which was developed from ABS and TCS. ESP mainly works through adjusting the size and the distribution of the longitudinal tire force. ESP can make vehicle produce effective yaw moment to restrain oversteering or understeering, However, ESP is a typical nonlinear, time-delay, time-varying parameter system and its mathematical model is very complex. It is difficult to design the control model by traditional control theory. Fuzzy control does not depend on a precise mathematical model. It is employed to handle complicated questions of nonlinear dynamics. First, in this paper, the7-DOF of vehicle dynamics model based on the H. B. Pacejka tyre model (magic formula) and vehicle reference model were established by using the MATLAB/SIMULINK. Then by using fuzzy control principle to direct at the nonlinear, time varying characteristics of the ESP system, a controller of yaw rate based on fuzzy control was designed. An analysis of the simulation results of J-turn and lane change on slippery road surface shows that the present stability control system based on the yaw rate is effective in maintaining the yaw rate and the sideslip angle within the optimal range, thus improving the vehicle stability.