IMECE2008-69005 A NEW LUGRE FRICTION MODEL FOR MR-9000 TYPE MR DAMPER

ABSTRACT This paper presents a new hysteresis model, based on the LuGre friction model, to analyze the dynamic behavior of large-scale Magneto-Rheological (MR) damper (MR-9000 type MR-damper [1]) accurately and efficiently. The gradient based optimization technique and the least square method will be utilized to identify the modal parameters. The dynamic behavior of MR-damper under different types of excitation and input current have been predicted using the proposed model and then compared with those predicted using modified BoucWen model to verify the validity of the proposed model. INTRODUCTION The Magneto-Rheological (MR) fluid dampers are one of the most promising devices to provide semi-actively controlled damper. Different Through comparing different numerical models for RD-1005 type , it can be found that although mos

IMECE2008-69001 SEISMIC RESPONSE CONTROLLED STRUCTURE WITH SEMI-ACTIVE MASS- DAMPER

ABSTRACT The structural vibration suppression using active and semi-active mass damper is investigated. The controller for full-active controlled mass dampers is designed using the H 2 /LQG method. Magneto-Rheological (MR) damper is used to design the semi-active controlled mass damper. The inverse MR-damper model is developed on the base of an improved LuGre friction model. It combined with the proposed H 2 /LQG controller to control the input current of the MR-damper to suppress the structural vibration efficiently. The illustrated examples are presented to compare the vibration suppression effectiveness of semi-active mass damper with MR-damper using the proposed controller with those reported in literatures in order to illustrate the validity of the proposed methodology

IMECE2008-66292 EXPERIMENTAL ANALYSIS OF VIBRATION OF MICROMACHINED RESONATORS

ABSTRACT Among many different mechanisms that are used for excitation and detection of vibration of micro-beam resonators, electrostatic comb-drives have the benefit of simplicity and large range of linear operation. The disadvantage of using comb-drives is the effect of added mass to the beam; however, the analytical model of the beam-mass system predicts that this shortcoming can be overcome by proper adjustment of the mass, rotary inertia, and location of the comb-drive. In addition, the analytical model can predict the effect of the axial force of the beam on the resonance frequencies. In this paper, the results of the experiments on two resonators are presented. These results are used to verify the validity of the analytical model and finding its parameters. Very close agreement between the theory and experiment is observed. The residual stress of the MEMS structural layer is measured using the calibrated analytical model parameters

Fabrication and Evaluation of Vacuumed metering drum Performance for row planting of Soybean with Grease Belt

In this study, a vacuumed metering drum was fabricated under special vacuum pressure for the cultivation of soybean seeds DPX and it was evaluated by grease belt machine. In order to evaluate this metering drum, the speed of planter was assessed with three levels of 0.5, 1 and 1.5 ms-1 and three levels of metering drum vacuum pressures of 980, 1180 and 1380 Pa with two seed-separating methods (mechanical and pneumatic) in three replications.  In this study, the effects of in-cylinder vacuum pressure and speed of planter’s forward movement on the filling percentage, multi-seed, non-planting, deviation from planting line, and uniform distribution of seed were assessed. The results of the test were examined in the form of a factorial experiment with a completely random design and comparison of means was performed by LSD test in SAS software. The results indicated that when the vacuum pressure was increased or the speed of planter was reduced, the filling percentage was increased. The filling percentage and multi- planting were increased with the increase of pressure and multi- planting was reduced with reduction of speed. The in-cylinder pressure and speed of planter have no effect on the rate of deviation from the planting line, and uniform distribution of seeds was done better in the lower pressure and speed. Moreover, the performance of this metering drum equipped with the pneumatic separator was better than mechanical separator in all parameters

AN OPTIMAL VEHICLE STABILITY ENHANCMENT STRATEGY FOR ARTICULATED VEHICLES

ABSTRACT Rollover and jack-knifing of articulated heavy trucks are serious threats for motorists. Active safety technologies have been demonstrated to have potential to reduce or prevent the occurrence of these types of accidents. The vehicle dynamic control (VDC) system utilizes differential braking to affect vehicle response and has been shown to be quite effective in controlling vehicle yaw response. A VDC system that improves the yaw and lateral motions of an articulated vehicle has been developed. For this purpose, an optimal yaw-moment control law has been designed and the optimal values of the controller gains have been determined. The results of the numerical computer simulation show that very good performance of the proposed control system could be achieved

Experimental investigation of active yaw moment control system using a momentum wheel

Active yaw moment control is one of the most effective methods to improve the lateral stability and safety of vehicle. In this method, the overall yaw moment of the vehicle is modified by applying the corrective yaw moment generated by the systems that are mostly dependent on the tyre and road interaction. A unique technique to generate the corrective yaw moment has been considered and experimentally analysed in this work. This system utilizes a momentum wheel to generate the corrective yaw moment, which is independent of the tyre/road interaction, and is not limited by the adhesion between the tyre and road. A prototype model has been designed and developed to conduct the experimental tests and also to analyse the vehicle dynamics responses and examine the effectiveness of the designed controller. A microcontroller along with the essential sensors has been employed in the prototype to execute the embedded control system, which consists of the control algorithms, states estimator and the Kalman filter. This system provides a better vehicle performance and improves the responses of vehicle on low-friction roads. Experimental results also confirmed that the momentum wheel performance is not limited by the tyre/road adhesion condition

Large Amplitude Free Vibration Analysis of Nanotubes using Variational and Homotopy Methods

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