⌂ John Hilla

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KNIT HAPTICS

University of Michigan

Advances in computational design and digital fabrication have expanded the possibilities for creating adaptive material systems. These emerging technologies enable designers to move beyond static objects, supporting responsive, sensory-rich interactions and more open-ended forms of material exploration. As part of ongoing research initiatives at the University of Michigan, this project investigates how pneumatically actuated soft systems can be integrated with engineered knit structures to create tactile environments and wearable devices that actively engage the body through touch and movement.

The project focuses on knit-constrained inflatable systems, in which the behavior of a pneumatic actuator is shaped by both the geometry of the inflatable bladder and the mechanical properties of the surrounding knit textile. By controlling variables such as the wall thickness and cross-sectional profile of cast silicone tubes, a range of inflation behaviors can be achieved, from subtle rhythmic pulsing to more pronounced volumetric expansion. A low-durometer silicone was selected to produce balloon-like deformation, enhancing the softness, compliance, and expressive qualities of the resulting haptic interactions.

Knit surfaces were engineered to form sleeves that house the inflatable bladders, functioning simultaneously as structural constraints and as design tools that guide the motion of the actuators during pressurization. Their behavior can be tuned by varying yarn elasticity, stitch density, or knit pattern, allowing for precise control over how each actuator expands, bends, or deforms. These strategies can be applied across multiple scales, from wearable interfaces that provide localized tactile feedback to larger spatial environments.