A Novel Locomotion Interface with Independent Planar and Footpad Devices for Virtual Walking

Abstract

This paper describes a novel locomotion interface that can generate infinite floor for various surfaces. This interface allows users to participate in a life-like walking experience within virtual environments, which include various terrains such as slopes and stairs. The interface is composed of two three-DOF (X, Y, Yaw) planar devices and two three-DOF (Pitch, Roll, and Z) footpads. The planar devices are driven by AC servomotor for generating fast motions, while the footpad devices are driven by pneumatic actuators for continuous support of human weight. For sensing system, a motion tracker is attached to the human foot in order to track the foot positions, and the combination of pla-nar forces from the planar device and the vertical forces of the footpad device gives the gravity reaction forces (GRF), which is important to recognize the walking condition. For control implementation, even though the human is walking continuously, the human body should be confined in certain area to walk on an infinite floor. Thus, the walking control algorithm is suggested to satisfy above conditions keeping the safety of the walker. For preliminary experimental evaluation of the interface device, the walking interface is proven for a general human to walk naturally without disturbing human body. This interface can be applied to various areas such as VR navigations, rehabilitation, vocational training, and military exercises.