| Volume 25 Issue 7 - Publication Date: 1 July 2006 |
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| A Novel Locomotion Interface
with Two 6-DOF Parallel Manipulators That Allows Human Walking on Various
Virtual Terrains |
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| Jungwon Yoon School
of Mechanical and Aerospace, Engineering and ReCAPT, Gyeongsang National
University, Jinju, Gyeongnam 660-701, Korea and Jeha Ryu Human-Machine-Computer
Interface, Department of Mechatronics, Gwangju Institute of Science and
Technology, Bukgu, Gwangju 500-712, Korea |
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| This paper proposes a novel
locomotion interface that can generate an infinite floor with various surfaces
and can provide a user with proprioceptive feedback about walking. The interface
allows users to experience life-like walking in virtual environments with
various terrains. The interface consists of two platforms, each consisting
of a three-degrees-of-freedom (3-DOF; x, y and yaw) planar device on which
a 3-DOF (pitch, roll and z) footpad is mounted. Alternating current servomotors
drive the planar devices to generate rapid motions, while pneumatic actuators
drive the footpad devices to generate the impedances required for various
virtual terrains, in addition to supporting the user's weight. To simulate
natural human walking, the locomotion interface design specifications are
based on gait analysis, and each mechanism is optimally designed and manufactured
to satisfy these requirements. The locomotion interface allows natural walking
(step, 0.8 m; height, 20 cm; load capability, 100 kg; slope, 55?) on various
terrains. |
| In addition, a new walking
control algorithm is proposed for generating continuous walking on an infinite
floor involving various terrains. In this algorithm, each independent platform
follows a human foot during the swing phase, while the other platform returns
to the home position during the single-limb stance phase. During the double-limb
stance phase, the two platforms assume neutral positions to compensate for
the offset errors generated by velocity changes. Therefore, this algorithm
can satisfy natural walking conditions in any direction. The transition
phase between the swing and stance phases is detected using a simple switch
sensor system, while human foot motions are sensed using a calibrated magnetic
motion tracker attached to the shoe. |
| Actual walking simulations
on level ground, slopes, and stairs show that the proposed locomotion interface
allows an average person to walk naturally on various virtual terrains in
safety, without marked disturbances. This interface has various applications,
such as in virtual reality (VR) navigation, rehabilitation, and gait analysis.
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| Multimedia Key |
= Video |
 = Data |
= Code |
= Image |
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Extension |
Type |
Description |
| 1 |
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Example
1: Passive turning motion of the planar device. (3.1 MB) |
| 2 |
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Example
2: Walking on level ground. (4.3 MB) |
| 3 |
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Example
3: Starting and stopping while walking using the neutral positioning
algorithm. (4.1 MB) |
| 4 |
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Example
4: Walking on stairs. (4.3 MB) |
| 5 |
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Example
5: Walking on a slope. (3.6 MB) |
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