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 user´s 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 user´s head rotation, is required on the user´s 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.