LeVR: A Dynamic Active Haptic Proxy to Render Weight in Virtual Reality

Abstract

Recent research suggests that haptic feedback—the use of physical stimuli to simulate tactile experiences—plays a crucial role in simulations in virtual reality (VR), as it can enhance immersion and facilitate motor learning. Unlike real-world objects, virtual objects lack the property of mass, necessitating its simulation through haptic devices to convey a realistic sense of weight. However, rendering weight remains a challenge, particularly for ungrounded haptic devices, which maintain a free range of motion but often face limitations such as high latency, side effects through noise, vibrations, and airflow, or the need for expensive equipment. In this work, we present LeVR, a low-cost, portable haptic proxy that simulates weight by rendering the vertical forces experienced when lifting objects—within the system’s constraints—by leveraging the force generated by an accelerated mass. The system comprises a linear rail and a capstan drive mechanism and ncorporates an impedance-based control scheme. We characterized the system’s response through step and frequency analyses. Results show that LeVR can produce a force output within a latency of 2.5 ms and render forces at frequencies ranging from 1 to 11 Hz. Furthermore, we conducted a pilot user study in which participants sorted five virtual objects by weight, ranging from 17 g to 227 g, solely based on the stimuli produced by our prototype. The results indicate that participants could generally distinguish between different stimuli, though limitations such as force instability, oscillations, and fatigue affected sorting accuracy. With our proposed system we aim to contribute to research on weight perception, to ultimately increase the effectiveness of skill acquisition and motor learning in VR.