• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.150-155
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• 2018

In Korea, the mechanization ratio of field farming is about 58.3%. Especially, mechanization ratio of harvest operation is 10% or less. So, it is required to improve the mechanization ratio of harvest operation to analyze the power requirement analysis of agricultural tractor. The purpose of this study is to analyze power requirement of the underground crop harvester attached on agricultural tractor for traction operation. First, a power measurement system was developed and installed in 45 kW agricultural tractor. Second, field experiments were conducted at two driving speed levels (1.41, 2.17 km/h), and axle torque and rotation speed were analyzed. At 1.41km/h driving speed, the average power requirement of driving axle is 3.13 kW, respectively, at 2.17km/h driving speed, the average power requirement of driving axle is each 4.20 kW. In addition, the field tests show that as the driving speed increases by 53%, the power requirement of the underground crop harvester attached on agricultural tractor increases by 34%. Therefore, it indicated that the power requirement of agricultural tractor was affected by the driving speed.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.69-80
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• 1998

This research was designed to investigate how the exercise program affects paraplegic standing and walking employing functional electrical stimulation(FES). Emphasis was also given to fatigue of major lower extremity muscles induced by different types of electrical stimulation. We applied continuous and intermittent rectangular pulse trains to quadriceps of 10 normal subjects and 4 complete paraplegic patients. The frequencies were 20Hz and 80Hz, and the knee angle was fixed at 90$^{\circ}$and 150$^{\circ}$to investigate how muscle fatigue is related to muscle length. The knee extensor torque was measured and monitored. We have been training quadriceps and gastrocnemius of a male paraplegic patient by means of electrical stimulation for the past two year. FES standing was initiated when the knee extensors became strong enough to support the body weight, and then the patient started FES walking utilizing parallel bars and a walker. We used an 8-channel constant-voltage stimulator and surface electrodes. The experimental results indicated that paralyzed muscles fatigued rapidly around the optimal length contrary to normal muscles and confirmed that low frequency and intermittent stimulation delayed fatigue. Our exercise program increased muscle force by approximately 10 folds and decreased the fatigue index to half of the initial value. In addition, the exercise enabled the patient to voluntarily lift each leg up to 10cm, which was of great help to the swing phase of FES walking. Both muscle force and resistance to fatigue were significantly enhanced right after the exercise was applied every day instead of 6 days a week. Up to date, the patient can walk for more than two and half minutes at 10m/min while controlling the on/off time of the stimulator by pushing the toggle switch attached to the walker handle.