Fluid Elastomer Actuator
Fluidic Elastomer Actuators for Haptic Interactions in Virtual Reality
Virtual reality experiences via immersive optics and sound are becoming ubiquitous; there are several consumer systems (e.g., Oculus Rift and HTC Vive) now available with these capabilities. Other sensory experiences, such as that of touch remain elusive in this field. The most successful examples of haptic sensation (e.g., Nintendo 64’s Rumble Pack and its descendants) are vibrotactile, which do not afford for persistent, morphological shape experiences.
This project presents work on the development of a 12 DOF fluidically pressurized soft actuator for persistent and kinesthetic haptic sensations, a hardware controller for operating it, and software interface with NVIDIA’s game VR Funhouse.
Via increasing or decreasing internal pressure, FEAs allow for persistent shape changes for the reconstruction of objects and behaviors from the virtual environment. The force profile in a semicircular actuator, for example, is uniformly distributed along the wall when it is not disturbed. As described by pressure-vessel theory, when deformed, as in the presence of an impinging object (e.g., the press of a human finger), normal forces are concentrated in the normal direction of the points of contact and attempt to restore the object to a sphere.
We designed a haptic interface with 12, individually addressable, semicircular elastomeric actuators that formed an enveloping sleeve for an HTC Vive  controller. We designed the sleeve, which we call Omnipulse, to be lightweight and ergonomic, and arrayed the actuators in a 4x3 array configuration corresponding to the finger positions and possible variations of a human hand grip. We manufactured the Omnipulse using a combination of molding, 3D printing, and thermo-bonding methods. The sleeve consists of a 3mm layered system of plastic sheet chambers embedded between two layers of elastomer.
The haptic sleeve is controlled by 12 miniature solenoid pneumatic valves [Parker X-valve, 2-way NC 6V] that independently regulate the flow from the air source into every chamber of the sleeve. The valves are connected to an Arduino UNO controller through a TTL signal amplifier that includes a series of transistors and optocouplers. The valves, controller, electronics and power regulation unit were housed in an aluminum box for ease of handling
Cross section schematic of the device.
We tested the mechanical performance of the sleeve and performed a user study to assess how people interpret the motion from different classes of stimulus given by our haptic device.
Dynamic Response of FEA for a sequence of step functions.
The setup of the room is visualized in [a]. Participants were instructed to hold the controller as shown in [b].
This work was developed in collaboration with Bryan Peele (firstname.lastname@example.org) -original idea-, Houston Claure (email@example.com) and Omer Shapira (firstname.lastname@example.org), Josef Spjut (email@example.com), David Luebke (firstname.lastname@example.org) from NVIDIA Research under the supervision of Prof. Robert Shepherd and Prof. Malte Jung.
- Barreiros, Claure, Peele et. al., Fluidic Elastomer Actuators for Haptic Interactions in Virtual Reality, RA-L, 2018
- Shepherd, Peele, Mac Murray, Barreiros, Shapira, Spjut, Luebke, Stretchable Transducers for Kinesthetic Interactions in Virtual Reality, SIGGRAPH E-Tech, 2017