UC San Diego

The possibility of augmenting existing 3D-interaction devices for virtual reality with haptic feedback has generated wide interest in the field of human-computer Interaction. Designing interaction devices for haptic feedback is challenging due to the densely packed mechanoreceptors on the skin distributed over a large surface area. The widely used solution for the design of haptic interfaces rely on solid-state electronic components such as piezoelectric actuators, voice coils, vibrotactile actuators, or electromagnets that are built with rigid materials. Integrating these electronic components with textiles to match the spatial density of the mechanoreceptors on the skin can cause discomfort. Additionally, the rigid nature of these devices can limit them from conforming to the complex topological surfaces of the human body. The emerging field of soft robotics has the potential to address these challenges by replacing traditional actuators with unconventional materials that have mechanical properties close to those of human tissue. Various actuation strategies in soft robotics (including pneumatic, hydraulic, thermal, and electromechanical actuation) have been previously presented for applications in haptic devices. Fluidic systems have been widely explored in haptics due to their ability to enable actuators with ease of use. However, most fluidic systems control these actuators with individually addressable electromechanical valves, which make the system difficult to scale in number, to achieve the spatial density desired for haptic interfaces. Additionally, the nonlinear nature of elastomeric devices makes the stable, closed-loop control of such systems very complex. In this dissertation, I describe strategies to simplify the design and control of fluidically actuated systems to enable their application to wearable haptic interfaces and interactive media. First, I present the concept of "Fiber Jamming'', a mechanism to achieve variable stiffness by controlling the input pressure in an actuator. I demonstrate the application of fiber jamming using open-loop control in a variable-stiffness haptic glove and a reconfigurable truss structure. Next, I present a dot-matrix-inspired fluidic circuit to individually address actuators in a large array. I demonstrate the application of the fluidic circuit using 10 electromechanical valves to individually address a 2D-Shape Display with 25 actuators. Additionally, I also demonstrate the application of the fluidic circuit to actuate a haptic vest with an array of inflatable pouches. Finally, I present strategies for the design and evaluation of 3D designs to overcome the limitations of the existing 3D-input devices to facilitate tasks requiring precision. I present a tool for three interactions in three dimensions for the design and prototyping of structures in engineering applications. The first two techniques demonstrate how the design and control of fluidic systems can be simplified without compromising their rapid rates of actuation and ease of use. The 3D-interface design and evaluation strategies present techniques to design and evaluate VR applications to enable precision tasks. Overall, the results demonstrate strategies for realizing ubiquitous tangible interfaces for applications in wearable haptic interfaces and exoskeletons.