ER Fluid Damper Research Articles

Novel technique of vibration minimization during hard machining

AbstractThis research paper explores the performance of electrorheological fluids, widely known as smart fluids, which are popular because they experience immediate changes in their characteristics when applied to exterior magnetic or electric field. On application of high voltage, the ER fluid alters its form to semisolid from viscous liquid within a few milliseconds, which is reversible. The reversible nature of ER fluid was employed to absorb vibrations during hard machining. In this research, the consequence of the application of electric field to the ER characteristics of numerous non‐Newtonian fluids with an accumulation of TiO2 and Al2O3 nano elements are investigated. The purpose of this research is to discover the ER sample, which has the highest viscosity, highest breakdown voltage, but less sedimentation. So the selected sample can be used in ER dampers for the purpose of shock absorption. The ER fluid behaves as a mainspring with nonlinear vibration features that are managed by an arrangement of ER fluid, the structure of plunger, and the constraints of applied electric field. In this research, we have employed steel metallic specimens made from EN24T of 302BHN and the machining experiments are conducted to attain the shape parameters that can reduce the tool vibration and help improve the process of cutting at the time of machining with minimum application of fluid utilizing hard metal inserts. In this work, cutting tool parameters were analyzed like cutting force, tool wear, tool vibration amplitude, and surface roughness. It was observed that ER damper has shown its better performance at 5KV. At 5KV, cutting force was the least, tool wear was the least, tool vibration amplitude was the least, and surface roughness was the least. The use of an ER fluid damper decreases tool vibrations and successfully enhances machining performance. The machining industry will be benefited with commercialization of this technique.

DIRECT-DRIVE MOTOR SYSTEM WITH PARTICLE-TYPE ER FLUID DAMPER

In most of robotic systems in industrial applications, vibratory problems occur at high-speed motion, because of elasticity of drive systems like reduction gear units and mechanical structures. Also friction and backlash in the drive systems cause serious problems. On the other hand, since direct-drive (DD) motor systems do not use reduction gears, those are effective for high-speed and high-precision control. In DD motor systems, however, low damping ratio, or large time delays of computers and amplifiers causes another type of problem at precise positioning phase. In this study, a particle type ER fluid damper was introduced to a DD motor system to compensate damping ratio mechanically. Because controlling viscosity of ER damper according to status of motion did not disturb advantage of the DD system that can move fast, the performance of the DD system was improved. The effectiveness of the proposed system was confirmed experimentally. The method of our study can contribute to expansion of usability of ER fluid dampers on industrial applications not limited to DD systems.

High-Voltage Power Supply for Semi-Active Suspension System With ER-Fluid Damper

Electrorheological (ER) fluid is a composite material sometimes applied to mechanical motion devices such as the semi-active suspension, high-speed clutch, and vibration isolator. ER fluid application needs a high-voltage power supply (HVPS) having special requirements such as sufficiently high and continuously controllable output voltage, fast dynamic performance, over-current-limiting capability, low cost, and compact size. This paper deals with the HVPS for the semi-active suspension using the ER-fluid damper. The electrical characteristics of the ER-fluid damper are analyzed and the design and implementation of the HVPS are presented. It is well demonstrated through experiments that the developed HVPS shows a satisfactory performance suitable for ER-fluid application.

Quasi-steady Bingham plastic analysis of an electrorheological flow mode bypassdamper with piston bleed

We present an improved experimental validation of our nonlinear quasi-steadyelectrorheological (ER) and magnetorheological damper analysis, using anidealized Bingham plastic shear flow mechanism, for the flow mode of damperoperation with leakage effect. To validate the model, a double-acting ER valve orbypass damper was designed and fabricated. Both the hydraulic cylinder and thebypass duct have cylindrical geometry, and damping forces are developed in theannular bypass via Poiseuille flow. The ER fluid damper contains a controlledamount of leakage around the piston head. The leakage allows ER fluid to flowfrom one side of the piston head to the opposite side without passing through theER bypass. For this flow mode damper, the damping coefficient, defined asthe ratio of equivalent viscous damping of the Bingham plastic material,Ceq, to the Newtonianviscous damping, C,is a function of the non-dimensional plug thickness only. The damper was testedfor varying conditions of applied electric field and frequency using a mechanicaldamper dynamometer. In this analysis, the leakage damping coefficient withincorporated leakage effects, predict the amount of energy dissipated for acomplete cycle of the piston rod. Measured force verses displacement cycles formultiple frequencies and electric fields validate the ability of the non-dimensionalgroups and the leakage damping coefficient to predict the damping levels for anER bypass damper with leakage. Based on the experimental validation of themodel using these data, the Bingham plastic analysis is shown to be an effectivetool for the analysis-based design of double-acting ER bypass dampers.

Study on High Gain Feedback Control of Direct-Drive Motor. (Application of Variable Damper Using Homogeneous ER Fluid).

Since a direct-drive(DD) motor system doesn't use the reduction gear, the structure of the servo system can be simple and stiff. On the other hand, in the DD system, the disturbance torque directly influences the accuracy of the control system. The high feedback gain is effective and important for reducing the influence of the disturbance. However, it easily makes the control system vibratory. Therefore, the servo gain has to be lowered for assuring stability, and this causes the influence of the disturbance large. In this study, we aim to realize the high gain feedback control and the DD motor system using an ER fluid damper is developed. By applying the ER damper to the DD motor system, it is possible to obtain the mechanical damping and to realize a high servo gain in the motion control. Finally, the effectiveness of the proposed system is confirmed experimentally.

Motion Control of Direct-Drive Motor by a Homogeneous ER Fluid

Since a direct-drive (DD) motor system doesn't have the reduction gear, the structure of the servo system can be simple and stiff. On the other hand, in the DD system, the disturbance torque directly influences the accuracy of the motor control. The high servo gain is effective and important for reducing the influence of the disturbance torque. However, the high servo control often makes the control system unstable or vibratory. Therefore, the servo gain must be lowered for assuring stability, and the influence of the disturbance becomes serious. In this study, the DD motor system using an ER fluid damper is discussed. By applying the ER damper to the DD motor system, it is possible to obtain the mechanical damping and to realize a high servo gain in the motion control. Finally, the effectiveness of the proposed system is confirmed experimentally.

High Performance Electro-Rheological Dampers

With the proprietary ER fluids available today it is not a viable proposition to develop a high force damper within the available space envelope. ER fluids are simply not strong enough and attempts to overcome this limitation by increasing the size of the damper result in excessive power demands. A bi-directional controllable damper has been developed that overcomes the limitations of available ER fluids and allows the development of exceptionally high forces with low control power. The forces generated by the damper are not directly linked to the performance of the ER fluid and both very low un-energised and very high energised forces can be developed. The nature of the design permits a wide range of controllable forces and force profiles. The main limitations of existing ER fluids, that of low excess shear stress, has been overcome with a novel and unique damper design. The performance of the damper is not limited by the performance of the ER fluid and controllable dampers can be developed that are able to generate almost unlimited forces. Two versions, for specific niche markets, have been fully developed to the preproduction stage.