CHING-YI TSAI

How can we combine grounded and ungrounded force feedback technologies to provide better VR experience?

Intro

Impact events, characterized by their short duration and high-force directional impacts, are common in VR games and real-world activities. Current ungrounded force feedback technologies like air jets and propellers, however, fall short in intensity and speed, being 5-100 times weaker and 10-500 times slower than real impacts. For example, they typically generate only 4N force over 50-500ms, as opposed to real-world impacts like baseball or tennis that produce 20-400N within 1-5ms. Addressing these gaps, we introduce AirCharge, an innovative haptic device that builds up air propulsion momentum to create immediate, directional impact forces. AirCharge employs compressed air jets on rotating swingarms, boosting the impact force by over 10 times and achieving realistic impulse durations of 3ms. To facilitate high-frequency impacts, we developed and tested various designs, ultimately creating a reciprocating dual-swingarm mechanism using a reversing bevel gearbox to counteract gyro effects. This allows for impact feedback up to 10Hz. Our user study (n = 16) demonstrated that AirCharge significantly improves realism and is preferred over traditional air jets, underscoring its effectiveness in enhancing user experience.