1. Fluid Starch Concentration by Volume Conclusions/Future Work
Fabrication of Electrorheological Fluid and its Application in Haptic Feedback
Student Researchers: David Jacob and Alex Mazursky Faculty Advisor: Jeong-Hoi Koo, Ph.D.
Department of Mechanical and Manufacturing Engineering, Miami University, Oxford, Ohio, USA
Introduction
Design
Experimental Results
Fluid Fabrication
ER fluid samples have been fabricated using silicone oil as the electrically insulating fluid and varying concentrations by volume of amylum as the suspended particles.
Commercially available, GER fluid has been used to compare properties with that of the fabricated fluid.
Design and Construction of Haptic Device
Contains ER fluid and electrodes for an electric input to control fluid behavior
Surface of device features a nonconductive membrane, capable of being elastically indented by the user, similar to the stroke of a button.
The body of the device has been 3D printed, allowing for rapid prototyping.
Objective of the Study
Determine the ability of electrorheological (ER) fluid to provide haptic feedback to the user.
To create a device that manipulates ER fluid with applied electrical fields.
Measure the response of ER fluid to applied pressure while electric fields are applied.
Significance
Haptic feedback is the response of a user interface to touch. The information provided by the system is conveyed to the end user through physical feedback that can be touched.
Though many devices today incorporate vibrotactile feedback, most cannot be considered fully haptic, as they lack kinesthetic feedback.
This study addresses this by applying ER fluid’s ability to adjust its viscosity.
Research for electrorheological fluid is relatively new.
Integration of smart fluids and devices that provide haptic feedback can have simpler systems and manufacturing processes than purely mechanical solutions.
Electrorheological Fluid
Electrorheological fluid is a colloidal suspension of very fine ionic particles in an electrically insulating fluid.
When exposed to an external electric field, the suspended particles attract one another and rapidly arrange into fiber networks along the direction of the applied field.
These effects allow for the fluid’s viscosity to be tunable with the application of various electric field strengths.
The yield stress of ER fluid corresponds linearly to the strength of the applied electric field.
Giant electrorheological fluid (GER) is a specific category of ER fluid which features much higher yield strengths than conventional ER Fluid.
The particles are smaller and have a higher dielectric constant than conventional fluid.
Fluid Starch Concentration by Volume
Threshold (kV DC)
Full Effect (kV DC)
15%
3.3
3.5
30%
2.5
45%
2.0
3.0
Experimental Testing
Fluid Testing
Electrodes are dipped into fluid container and fluid is allowed to run down the electrodes back into its vessel.
The magnitude of the electric field influences the rate of runoff between the plates.
Conclusions/Future Work
Fluid Testing
The starch based fluid will be sufficient for testing the effectiveness of the ER effect.
Testing procedures should be improved to test yield stress and produce more quantifiable observations.
Haptic Device
The design of the haptic device should be reconsidered from the ground up for the ease of manufacture and testing.
More detailed 3-d printing can be used to manufacture a more consistent device.
Other materials can be explored.
Haptic testing
To measure the performance of the proposed device, dynamic mechanical analysis (DMA) will be conducted.
DMA measures the total resistive force with respect to indentation depth over the button’s stroke.
The performance will be evaluated under different conditions, such as input power and frequency and ER fluid composition.
‘The giant electrorheological effect in suspensions of nanoparticles’ Wen et al. | Nature Materials | Vol. 2| November 2003