SIMULATION AND EXPERIMENTAL STUDY OF A SEMI-ACTIVE SUSPENSION WITH AN ELECTRORHEOLOGICAL DAMPER

1994 ◽  
Vol 08 (20n21) ◽  
pp. 2987-3003 ◽  
Author(s):  
X. M. WU ◽  
J. Y. WONG ◽  
M. STURK ◽  
D. L. RUSSELL
Keyword(s):  
Field Strength ◽  
Ride Comfort ◽  
Control Strategies ◽  
Damping Ratio ◽  
Active Suspension ◽  
Test Facility ◽  
Experimental Investigations ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Wide Range

Various control strategies for a semi-active suspension system with an electrorheological (ER) damper were studied using computer simulation techniques, as well as experimentally using a quarter-car model test facility. The control strategies examined included those primarily designed for enhancing ride comfort and for improving road holding. It was found that the strategies designed for enhancing ride comfort do not necessarily provide improved road holding characteristics, and vice versa. Consequently, various composite control strategies for improving both ride comfort and road holding were investigated. Experimental investigations showed that the damping characteristics of an electrorheological damper depend not only on the electrical field strength but also on the frequency of excitation. For the electrorheological fluid used in the study, the equivalent damping ratio decreases significantly with the increase in the frequency of excitation. This is primarily due to the fact that the shear ratio of the fluid used, which is the ratio of the shear strength at a given electrical field strength to that without applied electrical field, decreases with the increase in the shear rate. This behavior must be taken into account in the development of electrorheological dampers. Furthermore, at high frequencies, the duration of the applied voltage with any of the control strategies examined is very short. As a result, there is little difference in the measured performance of the semi-active suspension with different control strategies examined over a wide range of frequency. To achieve the potential of an ER fluid damper, improvements in the mechanical behavior of ER fluids are a key factor.

Comprehensive Analysis for Influence of Controllable Damper Time Delay on Semi-Active Suspension Control Strategies

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yechen Qin ◽  
Feng Zhao ◽  
Zhenfeng Wang ◽  
Liang Gu ◽  
Mingming Dong
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Ride Comfort ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Active Suspension ◽  
Test System ◽  
Suspension Control ◽  
Simulation Results

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+τ to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results.

Gas Carry-Under in GLCC for Separated and Recombined Outlet Configurations

2018 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Volume Fraction ◽  
Swirling Flow ◽  
Control Strategies ◽  
Flow Behavior ◽  
Jet Impingement ◽  
Test Facility ◽  
Experimental Investigations ◽  
Level Control ◽  
Complex Flow ◽  
Control Configuration

Gas Carry-Under (GCU) is one of the undesirable phenomena that exists in the GLCC©1 even within the Operational Envelope (OPEN) for liquid carry-over. Few studies that are available on GLCC© GCU have been carried out when the GLCC© is operated in a metering loop configuration characterized by recombined outlets. In such configurations the gas and the liquid outlets of the GLCC are recombined downstream which acts as passive level control. However, studies have shown that the GLCC© OPEN increases significantly when active control strategies are employed. There has not been a systematic study aimed at analyzing the effect of control on the GCU in the GLCC. This study compares the previously published GLCC GCU swirling flow mechanism under recombination outlet configuration with data taken under the separated outlet configuration (control configuration). Experimental investigations for GCU are conducted in a state-of-the-art test facility for air-water and air-oil flow incorporating pressure and level control configurations. The experiments are carried out using a 3″ diameter GLCC© equipped with 3 sequential trap sections to measure simultaneously the Gas Volume Fraction (GVF) and gas evolution in the lower part of the GLCC. Also, gas trap sections are installed in the liquid leg of the GLCC© to measure simultaneously the overall GCU. The liquid level was controlled at 6″ below the GLCC© inlet for all experiments using various control strategies. Tangential wall jet impingement is the cause for entrainment of gas, thereby leading to GCU. 3 different flow mechanisms have been identified in the lower part of the GLCC and have significant effect on the GCU. Viscosity and surface tension are observed to affect the GCU. The extensive acquired data shed light on the complex flow behavior in the lower part of the GLCC© and its effect on the GCU of the GLCC©.

Electrohydrodynamic Printing via Spinneret with Conductive Probe

2013 ◽  
Vol 562-565 ◽  
pp. 1155-1160
Author(s):  
Yi Hong Lin ◽  
Guang Qi He ◽  
Hai Yan Liu ◽  
Jin Wei ◽  
Jian Yi Zheng ◽  
...  
Keyword(s):  
Field Strength ◽  
Applied Voltage ◽  
Industrial Application ◽  
Control Level ◽  
Direct Write ◽  
Electrical Field ◽  
Nano Structure ◽  
Electrical Field Strength ◽  
Electrohydrodynamic Printing ◽  
The Stability

Stability jet ejection and precision deposition are the two keys for industrial application of electrohydrodynamic printing. In this paper, inserted conductive probe is utilized to gain stability jet, which would increase the electrical field strength, reduce the back flow, onset and sustaining voltage. Lower applied voltage would enhance the stability of electrospun jet, in which fine jet can be used to direct-write orderly Micro/Nano-structure. With the guidance and constrain of inserted probe, the oscillating angle range of electrohydrodynamic jet is decreased to 3°from 15°, and the width of printed structures is 21μm in average that is much narrower than that printed from spinneret without probe (74μm in average). Spinneret with tip provides a good way to improve the control level of electrohydrodynamic printing, which would accelerate the industrial application of electrohydrodynamic printed Micro/Nano structure.

Saturated RISE Feedback Control for Uncertain Nonlinear MacPherson Active Suspension System to Improve Ride Comfort

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Huyen T. Dinh ◽  
Tuan-Duong Trinh ◽  
Van-Nhu Tran
Keyword(s):  
Ride Comfort ◽  
Control Strategies ◽  
Gain Control ◽  
Active Suspension ◽  
High Gain ◽  
Suspension System ◽  
Dynamics Simulation ◽  
Control Technique ◽  
Nonlinear Uncertainties ◽  
Bounded Disturbances

Abstract A continuous saturated controller using smooth saturation functions is established for MacPherson active suspension system which includes nonlinear uncertainties, unknown road excitations, and bounded disturbances. The developed controller exploits the properties of the hyperbolic functions to guarantee saturation limits are not exceeded, while stability analysis procedures of the robust integral of the sign of the error (RISE) control technique utilize the advantages of high gain control strategies in compensating for unknown uncertainties. The saturated controller guarantees asymptotic regulation of the sprung mass acceleration to improve the ride comfort despite model uncertainties and additive disturbances in the dynamics. Simulation results demonstrate the improvement in the ride comfort while tire deflection and the suspension deflection are within admissible range in comparison with three other suspensions.

Fully Developed Flow of Power-Law Fluid Through a Cylindrical Microfluidic Pipe: Pressure Drop and Electroviscous Effects

2008 ◽  
Author(s):  
Ram P. Bharti ◽  
Dalton J. E. Harvie ◽  
Malcolm R. Davidson
Keyword(s):  
Pressure Drop ◽  
Field Strength ◽  
Charge Density ◽  
Power Law ◽  
Maximum Velocity ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Fluid Behaviour

Pressure drop and electroviscous effects in the axisymmetric, steady, fully developed, pressure-driven flow of incompressible power-law fluids through a cylindrical microchannel at low Reynolds number (Re = 0.01) have been investigated. The Poisson-Boltzmann equation (describing the electrical potential) and the momentum equations in conjunction with electrical force and power-law fluid rheology have been solved numerically using the finite difference method. The pipe wall is considered to have uniform surface charge density (S = 4) and the liquid is assumed to be a symmetric electrolyte solution. In particular, the influence of the dimensionless inverse Debye length (K = 2, 20) and power-law flow behaviour index (n = 0.2, 1, 1.8) on the EDL potential, ion concentrations and charge density profiles, induced electrical field strength, velocity and viscosity profiles and pressure drop have been studied. As expected, the local EDL potential, local charge density and electrical field strength increases with decreasing K and/or increasing S. The velocity profiles cross-over away from the charged pipe wall with increasing K and/or decreasing n. The maximum velocity at the center of the pipe increases with increasing n and/or increasing S and/or decreasing K. The shear-thinning fluid viscosity is strongly dependent on K and S, whereas the shear-thickening viscosity is very weakly dependent on K and S. For fixed K, as the fluid behaviour changes from Newtonian (n = 1) to shear-thinning (n < 1), the induced electrical field strength increases and maximum velocity reduces. On the other hand, the change in fluid behaviour from Newtonian (n = 1) to shear-thickening (n > 1) decreases the electrical field strength and increases the maximum velocity. The non-Newtonian effects on maximum velocity and pressure drop are stronger in shear-thinning fluids at small K and large S, the shear-thickening fluids show opposite influence. Electroviscous effects enhance with decreasing K and/or increasing S. The electroviscous effects show complex dependence on the non-Newtonian tendency of the fluids. The shear-thickening (n > 1) fluids and/or smaller K show stronger influence on the pressure drop and thus, enhance the electroviscous effects than that in shear-thinning (n < 1) fluids and/or large K where EDL is very thin.

Comparative study on electro-microfiltration (EMF) of water containing different carbon nanotubes (CNTs)

2013 ◽  
Vol 67 (6) ◽  
pp. 1247-1253 ◽  
Author(s):  
Yu-Hsiang Weng ◽  
Hsin-Chieh Wu ◽  
Kung-Cheh Li
Keyword(s):  
Carbon Nanotubes ◽  
Field Strength ◽  
Removal Efficiency ◽  
Pure Water ◽  
Applied Pressure ◽  
Convective Transport ◽  
Single Wall Carbon Nanotubes ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
Electrical Voltage

Disposal and penetration of carbon nanotubes (CNTs) into the environment have raised increasing concerns over the years. In this study, a laboratory scale electro-microfiltration (EMF) was used to treat water containing single wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs). The goal was to examine and compare the performance during EMF of SWCNT and MWCNT. The results showed that the initial flux was increased as the applied electrical voltage increased. At an applied pressure of 49 kPa, the final flux was comparable to pure water flux when the applied electrical field strength was greater than the critical electrical field strength (Ecritical). In addition, dissolved organic carbon (DOC) removal efficiency increased as the electrical voltage increased. Due to high convective transport of organic matter toward the membrane at 98 kPa, a decrease in DOC removal efficiency with increasing electrical field strength was observed. Overall, the fluxes and DOC removal efficiencies for EMF of SWCNT and MWCNT were not significantly different with a 95% confidence.

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