| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
Keeping upright stance is important to other complex motions like locomotion and running for human being. How does brain manages to control the muscle-skeletal system in order to keep the body being balanced is still unknown. The aim of the present study is to use a simple PID control model to analyze the spontaneous body sway, and to investigate the influence of vision on balance control of upright stance. The healthy subjects (male 4, female 6, aged 37.7±7.21 years) took part in present study. An optical postural sway measuring system was used to measure the spontaneous body sway and proved that the upright body can be modeled as one link inversed pendulum model. By defining the model parameters according to subjects physical statue, the gain of PID control parameters (Kp, Kd, KI, Gains of proportion, derivative and integral respectively) could be quantified by least square method. Four kinds of visual stimulation patterns were designed (3 for central visual field stimulation, one in eyes closed). The results showed that the gain of Kd was decreased significantly in eyes closed (131.5±37.6 Nms/rad in eyes open and 90.4±26.0 Nms/rad in eyes closed, p<0.001) however,. Kp and Ki were unchanged. Simulation results also proved that when decreasing the gain of Kd locus of simulated was more like the measured spontaneous body sway in eyes closed. The results suggest a promising means to assess human balance keeping ability by using this PID model analysis.
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