Advanced Materials Research Vols. 463-464

Abstract: An approach for cinematic analysis of mechanical assembled unit is presented. The equation for study of reciprocating movement of safety overflow valve is defined. We give the values of limiting technological parameters. Base these limiting conditions for pressure and rate of transported fluids developed a simulating model. Thus we are searching for collision, between components in composed assembled unit and are grounded the values for regulation of limiting conditions of flexible element in designed product. The results could be used for training of students of master degree and post-graduated students in this field of CAD design, as well as for creating animation models of assembled units in engineer design.

Abstract: Nowadays, robotics focused towards an interdisciplinary cooperation with other scientific fields, with the main goal of submitting solutions to improve the human life quality. This new orientation required the development of subsystems that differ from the common robotic components and match the new applications requisites. One of these preoccupations envisages the analysis and design of high performance actuators. The paper deals in this way with specific aspects characterizing the analysis and modelling of actuators with a serial elastic element.

Abstract: The paper showed the assisted research of one new model of digital dynamic neural network by using the LabVIEW proper virtual instrumentation and proper mathematical model. In the research were used some different way to optimize the convergence process, for example: using one time- delay of the first and second output from the neural layers; using the recursive link and time- delay; using the bipolar sigmoid hyperbolic tangent sensitive function replacing the sigmoid simple sensitive function. By on-line simulation of the neural network it is possible to know what will be the influences of all network parameters like the input data, weight, biases matrix, sensitive functions, closed loops and time- delay, to the gradient errors, in a convergence process. By on-line using the proper virtual LabVIEW instrumentation, were established some influences of the network parameters: number of input vector data, number of neurons in each layers, to the number of iterations before canceled the mean square error to the target. In the optimization research we used the minimization of the gradient error function between the output and the target.

Abstract: In the optimization of the trajectory or of the guidance of mobile robots one of the more important things is to assure one small difference between the output data of the system and the target. This paper show how on-line will be possible to establish one convergence way to the target without any influences of the input data or initial conditions of the weights or biases. The paper show the general components and the mathematical model of some more important neurons and one numerical simulation of the linear neural network. In the paper was used the least mean square (LMS) error algorithm for adjusting the weights and biases and incremental training by different training rate, finally to obtain one minimum error to the target.

Abstract: Modeling and Simulation is a discipline for developing a level of understanding of the interaction of the parts of a system, and of the system as a whole. The level of understanding which may be developed via this discipline is seldom achievable via any other discipline. A simulation is the manipulation of a model in such a way that it operates on time or space to compress it, thus enabling one to perceive the interactions that would not otherwise be apparent because of their separation in time or space. A model is a simplified representation of a system at some particular point in time or space intended to promote understanding of the real system.

Abstract: In an increasingly competitive global environment, more and more engineering designers are aware of the importance of facility layout on the entire manufacturing system. With the diversification of products, the proportion of multi-species and one-piece small batch production systems increase, this study focuses on small and medium enterprises as the main target, and researches its facility layout of manufacturing system and design of optimization model. In this paper, we discuss the layout of manufacturing system according to the characteristics of small and medium enterprises, and give a framework process for the layout design. Then learning from the existing planning model, we establish an optimization model for multi-objective non-linear programming to reflect the true environment of layout. By improving the original multi-objective non-linear programming model, we make this multi-objective non-linear programming model more consistent with requirements of facility layout

Abstract: This paperwork presents the results of the theoretical and experimental research that has had as object of study the hydraulic installations with hydro-pneumatic accumulators. It presents simulations for determining the performance of some hydraulic safety systems designed for actuating brakes, for ensuring bearings lubrication when the circuit incorporating the pump fails and for lifting loads in emergency situation. A hydraulic installation designed for a grinding machine is presented at the end.

Abstract: The purpose of this paper is to model and simulate a 6 DOF robotic system with revolute joints. This is in order to optimize the motion law which results in uniform coating deposited by spray pyrolysis. The structure and the complexity of the robotic system are determined by the necessary movements in the spray pyrolysis process. The nozzle (end-effector of the robot manipulator) has two translations, in longitudinal and transversal direction relative to the surface deposition. The mechanical model of the robot mechanism was developed by using the MBS (Multi Body Systems) environment ADAMS of MSC Software.

Abstract: Molybdenum disulphides (MoS2), which belong to the family of transition metal dichalcogenides, are well known for their solid lubricating behaviour. Thin films of MoS2 exhibit extremely low coefficient of friction in dry environments, and are typically applied by mixed in oil, grease or impregnated into porous matrix of powdered materials, sputter deposition, pulsed laser ablation, evaporation or chemical vapour deposition and, which are essentially either line-of-sight or high temperature processes. Solid lubricant coatings are attractive because they can reduce friction-generated heat. MoS2 is a common solid lubricant. However, the use of MoS2 can limited by excessive wear, as well as a friction coefficient. Several studies on solid lubricant coatings demonstrated success in lubricating dry sliding contacts over very long periods in tribometer tests or reciprocating sliding experiments.Several pellet-on-disk and pad-on-disk tribometer tests were conducted to study the lubrication characteristics of third-body particles of MoS2 powder. The tests consisted of simultaneous pellet-on-disk and pad-on-disk sliding contacts. Results from the tests show the self-repairing, self-replenishing, oil-free lubrication mechanism of MoS2. A theoretical control volume fractional coverage (CVFC) model was developed to predict: - (1) the friction coefficient at the pad-on-disk interface and - (2) the wear coefficient for the lubricated pellet-on-disk sliding contact. The fractional coverage varies with time and quantifies the amount of third-body film covering the disk asperities. Results from the model capture the tribological behaviour of the experimental sliding contacts reasonably well. The aim of this paper is modeling and experimentation of solid lubrification with MoS2 particles through self-repairing and self-replenishing and through the comparision between theoretical and experimental results obtained in the process of friction and wear by tribological tests.

Abstract: This paper presents a method of designing vibration compensators for linear mechatronic systems based on their inverse multimodal representation and a customized second order transfer function embedding the specified dynamic behavior. The linear non-compensated system is modeled by a parallel connection of independent second order transfer functions. There are four flavors of compensators described in this paper, each having a different choice of the reference model parameters. A brief numerical example is also provided.