Walking control of a dual-planar parallel robot for omni-directional locomotion interface

Abstract

This paper presents walking control of a novel omni-directional locomotion interface with a dual-planar parallel robot. The suggested interface can generate infinite floor on planar surfaces, allowing user's upright and turning walking motions. To provide continuous walking in a confined area, a walking control algorithm is suggested for planar surfaces. For continuous walking, each independent platform of the locomotion interface will follow a human foot during the swing phase, while the platforms will move back during single stance phase. For accurate foot tracking control, magnetic trackers are attached on each shoe with careful calibration and transition phases between the swing and the stance phases are detected by using switch system, which is composed of light steel plate, spring, and micro switch. For double limb support, two platforms will manipulate neutral positions to compensate the offset errors generated by velocity change. This algorithm can satisfy natural walking conditions for any directions of planar surfaces. From experimental results, a subject can walk naturally for upright motions without significant limitations, while limitations of maximum yaw angle of 20/spl deg/ are applied to each platform to prevent the collisions of two platforms during turning motions. By using the suggested interface, it is anticipated that a user can interact with virtual normal pathways by real walking including upright and turning motions.