Showing papers by "Quoc Hung Nguyen published in 2013"
TL;DR: This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF) and the configuration and working principle of the proposed MR mount is introduced.
Abstract: This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the 'lockup' problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.
51 citations
TL;DR: In this paper, a new configuration of a 3D haptic gripper for telemanipulation is proposed and optimally designed, where three magnetorheological fluid brakes (MRBs) reflect the rolling torque, the grasping force and the approach force from the slave manipulator to the master operator.
Abstract: In this research work, a new configuration of a 3D haptic gripper for telemanipulation is proposed and optimally designed. The proposed haptic gripper, featuring three magnetorheological fluid brakes (MRBs), reflects the rolling torque, the grasping force and the approach force from the slave manipulator to the master operator. After describing the operational principle of the haptic gripper, an optimal design of the MRBs for the gripper is performed. The purpose of the optimization problem is to find the most compact MRB that can provide a required braking torque/force to the master operator while the off-state torque/force is kept as small as possible. In the optimal design, different types of MRBs and different MR fluids (MRFs) are considered. In order to obtain the optimal solution of the MRBs, an optimization approach based on finite element analysis (FEA) integrated with an optimization tool is used. The optimal solutions of the MRBs are then obtained and the optimized MRBs for the haptic gripper are identified. In addition, discussions on the optimal solutions and performance of the optimized MRBs are given.
24 citations
TL;DR: In this paper, the performance characteristics of a new type of direct drive valve (DDV) system driven by a piezostack actuator are presented, in which the flexible beam mechanism is employed to amplify the output displacement from the actuator.
Abstract: This paper presents performance characteristics of a new type of direct drive valve (DDV) system driven by a piezostack actuator. The flexible beam mechanism is employed to amplify the output displacement from the piezostack actuator. After describing the operational principle of the proposed piezo DDV system, the governing equation of the whole piezo DDV system is then obtained by integrating the equations of the valve components. Based on the proposed model, significant structural components of the piezo DDV system are designed in order to achieve operational requirements (operating frequency: over 100 Hz; flow rate: 20 liter/Min.). An optimal design method is proposed for obtaining the geometry of the flexible beam mechanism by considering spool displacement, required operating frequency, and available space of the valve. After deciding the specific geometric dimensions of the piezo DDV system, a PID control algorithm is designed to enforce the spool position to the desired position trajectories by act...
15 citations
TL;DR: In this article, the authors proposed a magnetorheological fluid (MRF) based engine mount with both annular and radial flows to generate a high damping force, and the optimal design of the proposed MR mount is then considered.
Abstract: In this paper, novel configurations of a compact and high damping force engine mount featuring magnetorheological fluid (MRF) is proposed and analyzed. In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. Firstly, several configurations of the MR mount are proposed. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are then derived based on Bingham plastic behaviour of the MRF. Optimal design of the proposed MR mount is then considered. In the optimization, the objective is to find out the optimal structure of the MR mount that can generate a maximum damping force while the off-state force of the mount is constrained in such a manner that the force ratio of the mount is greater than a required value. Performance of the optimized MR mount is then evaluated based on finite element analysis and validated by experimental results.
14 citations
TL;DR: In this article, a new configuration of magnetorheological brakes (MRBs) is developed in order to improve the compactness, manufacturing accuracy and cost of conventional ones, where the nonmagnetic bobbin is eliminated and the coil is wound directly on a magnetic bobbin which is a part of the housing.
Abstract: In this work, a new configuration of magnetorheological brakes (MRBs) is developed in order to improve the compactness, manufacturing accuracy and cost of conventional ones. In the conventional configuration of MRBs, the coil is normally wound on a nonmagnetic bobbin which is placed on the stationary housing. This causes difficulties in manufacturing and the bottle-neck problem of the magnetic circuit of the MRBs. In the proposed configuration, the nonmagnetic bobbin is eliminated and the coil is wound directly on a magnetic bobbin which is a part of the housing. In this case, the magnetic bobbin part should be designed with a contractive cross-section in order to prevent magnetic flux going through and thus forcing the magnetic flux across the MR fluid (MRF) duct. After proposing the new configurations of MRBs, the modelling of the MRBs is performed based on the Bingham rheological model of the MRF. An optimal design of the proposed MRBs and conventional MRBs is then performed based on finite element analysis of the magnetic circuit of the MRBs. A comparative work between the optimal parameters of the proposed MRBs and the conventional MRBs is conducted and the advanced performance characteristics of the proposed MRBs are then investigated. In addition, experiments on both the conventional and the proposed MRBs are performed to validate the advanced performance characteristics of the proposed MRBs.
14 citations
TL;DR: In this article, the authors presented performance results of a novel jetting dispenser system actuated by dual piezostack actuators, lever mechanism, and needle part, which can provide a very small dispensing dot size of high viscous adhesive, 10,000cp at 100°C, at a high dispensing flow rate in semi-conductor packaging processes.
Abstract: This article presents performance results of a novel jetting dispenser system actuated dual piezostack actuators. The proposed piezo jetting dispenser system consists of a couple of piezostack actuators, lever mechanism, and needle part. The proposed dispenser can provide a very small dispensing dot size of high viscous adhesive, 10,000cp at 100°C, at a high dispensing flow rate in semi-conductor packaging processes. After describing the mechanism and operating principle of the proposed dispenser, a mathematical model of the system is obtained by considering behaviors of the piezostack, the return spring, the dispensing needle, and the adhesive fluid dynamics. For the computer simulation, the specific geometric dimensions of the proposed jetting dispenser are chosen in order to achieve operation requirements: needle motion amplitude: up to 0.15 mm; operating frequency: up to 500 Hz. With the high viscosity conditions, the dispensed amount of the adhesive and the maximum displacement of the piezo and the needle at 500Hz are evaluated in time domain.
5 citations
TL;DR: In this paper, an optimal design procedure of mount based on a magnetorheological fluid to isolate the vibration in heavy diesel engine system is presented, where frequency response and force-dis-position transmissibility methods are used to get required damping force that is necessary for effec- tive vibration isolation.
Abstract: This paper presents optimal design procedures of mount based on a magnetorheological(MR) fluid to isolate the vibration in heavy diesel engine system. At first, frequency response and force-dis- placement transmissibility methods are used to get required damping force that is necessary for effec- tive vibration isolation. From this result, a new type of high damping force engine mount is pro- posed and the governing equation of Bingham plastic behavior of MR fluid in flow path is mathe- matically derived under cylindrical coordinates. Finally, parametric design optimization featuring finite element is performed using ANSYS software to get the required damping force in MR mount system which can be used to reduce engine vibration. Damping force of the MR mount is then determined as an objective function in this analysis based on ANSYS. Furthermore, Magnetic analysis is then applied in this process.
3 citations
TL;DR: A new type of the DDV operated by piezostack actuator is proposed and the goal of the proposed DDV is to achieve an accurate control of the flow rate at high frequency.
Abstract: Electrohydraulic servo valves have been widely used in various automatic systems which need high precision of flow rate or pressure control to provide excellent static and dynamic control performance. The servo valves are generally classified into single-stage valve and two-stage valve. Direct drive servo valve (DDV) is a kind of single-stage valve in which the actuator is directly connected to the spool of the valve. In the conventional DDVs, the spool is generally actuated by electromagnetic actuator. Therefore, performance characteristics such as the accuracy and bandwidth of the DDVs are limited due to the inherent characteristics of the actuator. In this paper, a new type of the DDV operated by piezostack actuator is proposed and the goal of the proposed DDV is to achieve an accurate control of the flow rate at high frequency. The proposed DDV consists of a piezostack actuator, a lever mechanism to amplify displacement from the piezostack actuator and a spool part. A dynamic model of piezostack driven DDV system is derived by considering the flow force. After formulating the governing equation of the piezostack driven DDV system, a sliding mode control algorithm is designed to enforce the spool position to the desired position trajectories by activating the piezostack actuator. For the computer simulation, the specific geometric dimensions of the spool are chosen in order to achieve operation requirements: spool motion amplitude: over than 0.5mm; flow rate: over than 12liter/min; operating frequency: over than 200Hz. After confirming the maximum displacement of the spool and the flow rate of the valve at 200Hz, control performances are evaluated in time domain.
1 citations