Workshop: Mechanics and materials innovations to control fine touch
Compared to vision or sound, touch remains a difficult sense to recreate with the same richness and variety as found in everyday life. One reason fine touch is so challenging to recreate is that the finger is both a sensor and source of tactile stimuli. The way a person touches an object changes the tactile stimuli. To better understand and control the finger/object interface, increase tactile dimensionality, and increase information density, we will bring together experts in soft matter mechanics and material interfaces to devise new strategies for next generation haptic actuators.
A schedule is provided below.
|11:05-11:30||Prof. Matteo Bianchi (Virtual)||University of Pisa||PERSPECTIVES FOR TACTILE AUGMENTED REALITY: MOTION-PERCEPTION INTERPLAY AND FABRIC-BASED APPROACH|
|11:30-12||Mr. Zane Zook (O’Malley Lab)||Rice University||Dimensions of Wearable Haptics|
|12-12:30||Prof. Charles Dhong||University of Delaware||Controlling and studying touch perception through materials chemistry and soft matter phenomena|
|1:30-2||Prof. Roland Bennewitz||INM – Leibniz Institute for New Materials||Tactile perception of micro-structured surfaces: random roughness and fibril bending|
|2:30-3||Dr. Amir Firouzeh (Shea Lab)||EPFL||Rising out of the surface: Realizing physical controllers on any surface using popup buttons|
|3-3:30||Prof. Cynthia Hipwell (Virtual)||Texas A&M||Multiphysics in the Finger-Device Interface: Impact on Friction and Perception|
|3:30-3:35||Wrap up talks, begin poster session|
|3:40-5||Posters with refreshments|
PERSPECTIVES FOR TACTILE AUGMENTED REALITY: MOTION-PERCEPTION INTERPLAY AND FABRIC-BASED APPROACH
Dr. Matteo Bianchi
Besides providing information on elementary properties of objects, like texture, roughness, and softness, the sense of touch is also important in building a representation of object movement and the movement of our hands. Neural and behavioral studies shed light on the interplay between the geometrical and mechanical properties of the touched objects, such as shape and texture, for the control of movement of our hands. Interestingly, the interaction between motion and textures can generate perceptual illusions in touch. For example, the orientation and the spacing of the texture elements on a static surface induces the illusion of surface motion when we move our hand on it or can elicit the perception of a curved trajectory during sliding, straight hand movements. In this presentation, I will discuss the mechanisms underpinning the tactile representation of texture and motion and how these aspects can open interesting perspectives in augmented and mixed reality. Finally, I will present a fabric-based approach for the design of wearable haptic systems for an effective implementation of the feel trough paradigm in tactile augmented reality.
Dimensions of Wearable Haptics
Mr. Zane Zook (O’Malley Lab)
Wearable haptics refers to systems worn on the body or integrated into clothing that can provide haptic feedback to the wearer in a wide range of forms, such as vibrotactile, cutaneous, skin stretch, pressure, and kinesthetic feedback. These devices have become widely used to deliver information to users about the world around them. These devices come in many shapes and sizes but are limited by manufacturability and usability of current actuation solutions. Oftentimes, designers must balance constraints on the many dimensions of haptic device design. In this talk, I will present some of our wearable haptic systems, describe our target applications, and highlight the distinguishing features our hardware while identifying opportunities for improvement.
Controlling and studying touch perception through materials chemistry and soft matter phenomena
Prof. Charles Dhong
A key challenge for controlling and understanding touch is that the mechanical interface between the finger and an object is complex, yet these spatial and temporally varying mechanical forces ultimately give rise to tactile perception. Therefore, one lens for understanding or controlling touch is as an adhesion and interfaces problem, which is well-positioned for innovations from soft matter mechanics and materials. Here, we discuss our approach for controlling touch through materials chemistry, in contrast to approaches using physical topography or electrical stimulation. Through silane monolayers on surfaces smoother than discriminable by touch, we showed that humans are sensitive to single atom substitutions in the silane due to transitions in monolayer ordering. Through mechanical testing, we were able to predict which materials might generate enough differences in friction prior to human testing, thereby generating a library of potential tactile materials. These studies will show how materials chemistry may broaden the range of tools to control the sense of touch for haptic interfaces.
Tactile perception of micro-structured surfaces: random roughness and fibril bending
Prof. Roland Bennewitz
The tactile perception of similarity between surfaces with systematically varied microstructure will be discussed for two examples: randomly rough surfaces with different roughness amplitudes at small length scales  and elastomer samples with regular arrays of microfibrils .
 R. Sahli, A. Prot, A. Wang, M.H. Müser, M. Piovarči, P. Didyk, R. Bennewitz, Tactile perception of randomly rough surfaces, Scientific Reports, 10 (2020) 15800.
 A. Gedsun, R. Sahli, X. Meng, R. Hensel, R. Bennewitz, Bending as Key Mechanism in the Tactile Perception of Fibrillar Surfaces, Advanced Materials Interfaces, 9 (2022) 2101380.
Rising out of the surface: Realizing physical controllers on any surface using popup buttons
Dr. Amir Firouzeh (Shea Lab)
I will present our latest results in developing a pop-up tactile display. Any desired configurations of buttons in our submillimeter interface can rise out of the surface using a series of hydraulically amplified electro-static zipping actuators (that drive each button independently). With a 1.2 mm range of motion and a 1 N loading capacity, our pop-up buttons (9 mm in diameter) provide a realistic feeling of interacting with physical buttons. A series of PyzoFlex (R) sensors on our interface detect user proximity, touch, and key-press. This allows the interface to react to user movements and provide active tactile feedback.
Multiphysics in the Finger-Device Interface: Impact on Friction and Perception
Prof. Cynthia Hipwell
The finger-device interface is complex and variations with environment and person-to-person can impact device performance and human perception of it. Multiphysics modeling of interfacial phenomena can help predict friction under various conditions and enable purposeful design for consistent or enhanced performance. Examples of design for consistent performance with humidity, design for consumer preference, and consideration and use of temperature will be explored.