Evaluation of Walking Motions with the Aid of Walkers Using Acceleration Sensors

Evaluation of Walking Motions with the Aid of Walkers Using Acceleration Sensors

Satoru Okamoto (Shimane University, Japan), Tetsuya Hirotomi (Shimane University, Japan), Keigo Aoki (Shimane Fujitsu Ltd, Japan) and Yasutomo Hosomi (Nabtesco, Japan)
DOI: 10.4018/978-1-4666-2113-8.ch036
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Abstract

Walkers are tools that are used to improve self-reliance when walking. In this study, the unstable motions of gait in subjects who use walkers were analyzed using tri-axial accelerometers and a motion capture system. Several markers were placed on the subjects’ backs and legs, and two high-speed video cameras were employed to record the motion of these markers. The subjects were asked to walk around a test course at a comfortable speed. The activities performed on the test course consisted of standing, normal walking, fast walking, walking over a barrier, and falling down. The authors’ results determined the characteristic rules of gait motion with walker use. They found that acceleration sensors are convenient for extracting characteristics from the gait motions. They believe that the methods employed with the acceleration sensors are suitable for the discovery of the average gait motions of elderly patients living in nursing homes and can be used to evaluate walking motion before and after rehabilitation.
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2. Experimental Apparatus And Methods

A full range of motion including walking was filmed in a three-dimensional (3D) image using the direct linear transform (DLT) method with two high-speed video cameras (NAC HSV-1000). The two high-speed video cameras were connected in advance using cables and were synchronized. To generate the 3D images, each camera recorded from a different angle. The filming was performed with Camera A from a diagonal direction and with Camera B from a lateral direction. The lighting equipment was also installed next to the cameras. To calibrate the two cameras, a triangular pyramid calibration unit with sides of 1000 mm in length and 1450 mm in height was used. The control points were fixed to prevent the high-speed video camera from slipping, which was accomplished by attaching the high-speed video camera to the body of the apparatus with hook-and-loop fasteners and using elbow and knee pads for the joints. A total of 20 control points were attached to the body and four-wheel walker (ETAC SL four-caster walker from Sharp Training Co.). A photograph of the experimental apparatus is shown in Figure 1. Preliminary experiments that analyzed the unstable movements while using a walker employed two high-speed video cameras and three tri-axial acceleration sensors.

Figure 1.

Experimental apparatus

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