An omnidirectional stroll-based virtual reality interface and its application on overhead crane training

Locomotion is a virtual reality interface that enables the user to walk inside the virtual environment in any direction over a long distance without actually leaving the physical device. In order to enable the user to freely navigate the virtual world and get fully immersed into the virtual environment accordingly, a locomotion device must fulfill the following two distinct requirements. First, it should allow the user to navigate an infinite distance within a limited area. Secondly, the user should not need to wear any tracking devices to detect his motion. The paper presents a locomotion mechanism called omni-directional ball-bearing disc platform (OBDP), which allows the user to walk naturally on it and thus to navigate the virtual environment. The gait sensing algorithm that simulates the userʹs posture based upon his footstep data collected from the OBDP is then elaborated. Followed with an omnidirectional stroll-based virtual reality system to integrate the OBDP with the gait sensing algorithm. Significantly, instead of using the three-dimensional (3-D) tracker, the OBDP adopts arrays of ball-bearing sensors on a disc to detect the pace. No other sensor, except the head tracker to detect the userʹs head rotation, is required on the userʹs body. Finally, a prototype of an overhead crane training simulator that fully explores the advantage of the OBDP is presented along with the verification of the effectiveness of the presented gait sensing algorithm.