International Journal of Advanced Design and Manufacturing Technology
Volume:8 Issue: 2, 2015 Jun

In this paper, multi-objective optimization based on Genetic Algorithm is used to find the desired values of three controllers of PID, fuzzy and Fuzzy-PID applying for a thrust vector control of CANSAT carrier system. Motion vector control is considered according to the dynamic governing equation of system and delivering payload into the specific height and flight path angle. The cost functions of the system are position error from the set point and deviation of the vector angle of carrier system with carrier body. These cost functions must be minimized simultaneously. Results show that Fuzzy-PID controller is superior to other controllers which are exerted in the thrust vector control of a CANSAT carrier system.

In recent years, manipulation process based on nano robotic system has become focus of attention. In this article a 3D model has been used to show the force-deformation relation. Furthermore, a state space model is used to find suitable feedback control for manipulation system. To verify force-deformation model a FEM simulation carried out which in detail showed constituency. With the recent development in using nano particles in MEMS and NEMS, proper understanding of cantilever’s response to force applied during process, has gained a great importance. Consequently, in this paper, a 3D control system for precise manipulation of nano particle has been proposed. Using the controller and proposed model improves capability of precise manipulation processes.

Stroke is one of the most common diseases among the elderly with high personal and societal costs. In recent years, robotic rehabilitation for stroke has become an active area of research for assistance, monitoring and qualifying the rehabilitation treatments. The key issue needed for improving rehabilitation system is that patient feedback should be taken into account by the robotic rehabilitation systems for providing rehabilitation treatment. Changes in the delivery of rehabilitation treatment are an important issue since the patient or specialist should be able to express their sense about doing things and apply the needed improvements in treatment. Therefore, in this dissertation, a three degree-of-freedom (3-DOF) exoskeleton design of a thumb has been provided. Then, a control structure is provided for greater security in which the patient feedback is evaluated in order to make necessary automatic changes in method of treatment (changing speed and force). In this design, a versatile framework with high performance is offered to simultaneously control thumb force and position regarding the patients’ feedback. This helps to keep the patient in the treatment process, reduce interventions and therapist caseload, effective automatic transmission of treatment and pain relief during the course of treatment. The results of the study suggest that the force and speed on the thumb can be changed during the rehabilitation period according to the patient's needs. This advantage can be considered as an essential step to improve and increase the efficiency of rehabilitation.

An attempt was made to investigate the thermal and residual stress distribution in a novel three layer (La2Zr2O7/ 8YSZ/ NiCrAlY) during a real-like heating regime which includes heating, service time and final cooling. For achieving maximum accuracy and consistency in calculation of thermal and mechanical properties of hybrid coating system, all related andrequired properties were introduced to the software in temperature- dependent mode. Element modification approaches like mass scaling leads to a considerable reduction in running time while satisfying and not violating accuracy and converging criteria and constrains. Applying adaptive hybrid meshing techniques which applies both mesh – part dependency and independency during numerical iterative solution avoids element distortion and diverging in coupled problem. Heat flux and nodal temperature contours indicated that, most of damaging and harmful thermal load and residual stress concentrate on ceramic top coats and this lead less harm and life time reduction in substarte.

The behavior of frequency response of the cantilever of the atomic force microscopy was different in the liquid environment in comparison with air environment. In this research, the dynamic analysis of atomic force microscopy in the air and liquid environments have been carried out with consideration of linear and non-linear interaction forces and also the effect of geometrical parameters such as length, width, height and angle between cantilever and sample's surface on the rectangular cantilever has been investigated. A rectangular beam based on the Timoshenko beam model has been simulated in ADAMS software environment and more accurate results has been received by considering the probe tip and the angle location of cantilever at simulation.At the end of the beam, a silicone tip has been considered that the applied forces on it have been approximated with two tangential and vertical springs and the vibrational simulation of cantilever at two states has been carried out with regard to linear and non-linear interaction forces.The amplitude and resonance frequency of the simulated beam based on Timoshenko model is different from obtained results of Euler beam model Due to the effect of shear deformation and rotary moment in Timoshenko beam.Therefore, the Timoshenko beam model has the better accuracy in comparison with Euler beam model.Many chemical and biological processes occurred so fast so using of short cantilever for increasing the speed of imaging at impact mode in liquid environment was very necessary. Eventually short beam that has been modeled based on Timoshenko model can produce more accurate results. This paper aimed to show that the amplitude and resonance frequency of vibration in the liquid environment were different from amplitude and frequency of vibration in the air environment due to the damping coeficient and added mass of liquid.

Mixed convection of Al2O3-water nanofluid in a square microcavity is investigated numerically. Governing equations are discretized and solved using the Finite Volume Method and SIMPLER algorithm. The Knudsen number is selected between 0.001 and 0.1 to consider slip velocity and the jump temperature boundary conditions. Results showed that Nusselt number is a function of Richardson number, Knudsen number and volume fraction of nanoparticles and could be enhanced up to 10.93% using nanoparticles in the base fluid.

This paper investigates the residual stress fields in the vicinity of weld bead in HSLA-65 steel weldments using a neural network. This study consists of two cases: (i) the experimental analysis was carried out the measurements of residual stresses by XRD technique. Many different specimens that were subjected to different conditions were studied. The values and distributions of residual stresses occurring in welding of HSLA-65 plate under various conditions were determined. (ii) The mathematical modeling analysis has been proposed the use of radial basis (RB) NN to determine the residual stresses based on welding conditions. The input of RBNN are welding current, welding voltage, welding heat input, travel speed of welding, wire feed speed and distance from weld. The best fitting training data set was obtained with 18 neurons in the hidden layer, which made it possible to predict residual stresses with accuracy at least as good as that of the experimental error, over the whole experimental range. After training, it was found the regression values (R2) are 0.999664 and 0.999322 for newrbe and newrb functions respectively. Similarly, these values for testing data are 0.999425 and 0.998505, respectively. Based on verification errors, it was shown that the radial basis function of neural network with newrbe function is superior in this particular case, and has the average errors of 7.70% in predicting of residual stresses in HSLA-65. This method is conceptually straightforward, and it is also applicable to other type of welding for practical purposes.

Artificial neural network is one of the most robust and reliable methods in online prediction of nonlinear incidents in machining. Tool flank wear as a tool life criterion is an important task which is needed to be predicted during machining processes to establish an online tool life estimation system.In this study, an artificial neural network model was developed to predict the tool wear and tool life in turning process. Cutting parameters and cutting forces were used as input and tool flank wear rates were regarded as target data for creating the online prediction system. SIMULINK and neural network tool boxes in MATLAB software were used for establishing a reliable online monitoring model. For generalizing the model, full factorial method was used to design the experiments. Predicted results were compared with the test results and a full confirmation of the model was reached.

The forging model for cold rolling is one of rolling models that is used in rolling calculations. In this model,the final rolling pressure is an average value and it is not an accurate model.Also by using this model,the firction hill curves are plotted due to the central point of the rolling bite length while frictional stresses intersect at the neutral point.In this study, a new model based on the forging model is presented to determine the rolling pressure during cold rolling process for using in a reversing tandem mill which is called “Improved forging model”. In the new model, the intersection of frictional forces is the neutral point.Finally the computing results from this model coincide well with the investigations done.

In this article, finite element method and ALE formulation were used to numerically simulate impact of low-velocity specific projectiles with water surface. For the simulation, Ls-Dyna finite element code was used. Material models which were used to express behavior of air and water included Null material model. For the projectile, plastic-kinematics material model was applied. Mie-Gruneisen equation of state was also attributed to air and water. First, the results were validated by analyzing the impact of metallic cylinder with water surface and then impact of a mine as a low-velocity projectile was simulated. Among major outputs were force and pressure applied to the projectile, velocity and acceleration variations upon entering water, stress-strain variations and variations of water surface in various steps of analysis. The results showed that impact of structure with fluid can be modeled using finite element model with high accuracy in terms of quality and quantity.