Study on Tension Measurement of Rubber Crawler Focusing on Its Inner Structure

( Takashi Fukushima ),( Muneshi Mitsuoka ),( Eiji Inoue ),( Kunio Sato ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Agricultural crawler tractors that have adopted rubber crawlers are common because of the reduced effects of machine and road surface vibrations. This study targets the oscillating crawler unit that contains a special mechanism in which the unit oscillates around a hitch point that is set separately from the drive axis of the drive sprocket. Half-tracked tractors equipped with an oscillating crawler units have better stability on uneven ground than wheel type tractors, which respond directly to a concavo-convex surface. However, the crawler tension fluctuates according to the variation in the perimeter of the crawler unit when this unit travels on a concavo-convex surface because the hitch point of the oscillating frame is set separately from the drive axis of the drive sprocket. It is suggested that this fluctuation in the crawler tension influences driving performance. Moreover, driving performance factors (e.g., frame oscillation, traction, and drive torque) might be optimized by actively controlling the crawler tension. It is also generally known that some problems such as damage to and dropping of the rubber crawler have arisen during operation because of soil and stones sticking to the track rollers and the tension fluctuations of the crawler. These problems might be also obviated by actively controlling the crawler tension. We have proposed a driving simulation model for half-tracked tractors that has the ability to express the fluctuation in the crawler tension. However, this driving simulation is not verified, because it is very difficult to measure the crawler tension while driving, and little has been reported on the measurement of crawler tension. Therefore, this study aims to propose a measurement method for crawler tension fluctuation, which focuses on the inner structure of the rubber crawler. A fundamental experiment with a test piece cut out of a rubber crawler was carried out to evaluate the effectiveness of the proposed tension measurement, which uses steel cords arranged inner the rubber crawler. In conclusion, it has been demonstrated the possibility for stable measurement of crawler tension.

Investigation of Terrain Slope Information and Tractor Driving Simulation on Reconstructed Ground

( Soyoung Shin ),( Eiji Inoue ),( Muneshi Mitsuoka ),( Takashi Okaysu ),( Yasmaru Hirai ),( Masami Matsui ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Despite the efforts of many researchers to improve the safety of agricultural machinery, fatalities have been caused by agricultural machinery annually. In Japan, about 50% of casualties caused by agricultural machinery are occurred by tractor rollover. In particular, the rollover of agricultural machinery causes major fatalities on the farm road. Agricultural machinery is easily rollover due to its high center of gravity when compared to other vehicles. In addition, when the implements are attached, the center of gravity moves according to the position of the implements, thereby exposing it to a greater risk of rollover. ROPS has been developed in an effort to reduce fatalities caused by tractor rollover accidents. The ROPS keeps the operator's space in case the tractor is overturned, preventing the operator from laying down from the tractor. Since 1997, ROPS has been mandatory for all riding tractors in Japan. Despite these efforts, however, there are fatalities caused by tractor rollover, and safety devices such as ROPS and seatbelts can not prevent fundamental accidents. In this study, we reconstruct the terrain images in front of the tractor using the stereo camera and analyze the slope of the reconstructed ground to predict the rollover accident of the tractor sensitive to the slope. The high center of gravity provides an opportunity to rollover in response to unexpected obstacles or steep slope. A stereo camera was used to record the frontal ground, and the obtained images were processed into a three-dimensional space through image processing in Matlab. The slope of the road surface on which the tractor is to be driven was identified, and the tractor maneuvering was identified through simulation of the motion model.

Relationships between Mass and Porosity of Rough Rice Piled in a Combine Grain Tank

( Ryuichi Yoshizaki ),( Yasumaru Hirai ),( Muneshi Mitsuoka ),( Shio Inagaki ),( Eiji Inoue ),( Takashi Okayasu ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Percentage of ripened grains (PRG) is an important indicator to evaluate soil and crop management in rice production and is used to estimate weight of ripened brown rice by which economic returns are determined in Japan. This study focused on estimating PRG using bulk density of rough rice piled in the grain tank of a combine harvester. Our former study has showed that linear relationships between bulk density and particle density (an indicator of PRG) of rough rice piled in a vertical cylinder were dependent on the filling conditions of the rough rice. This finding required to clarify the filling conditions of the rough rice piled in a grain tank to estimate PRG using bulk density. Porosity is an indicator to evaluate the filling conditions. Thus, the objective of this study was to clarify factors affecting the porosity of rough rice piled in a grain tank. Relationships between mass and porosity of rough rice piled in a grain tank was measured through the field tests and the indoor experiments using a 6-row and a 4-row head feeding combine harvester, respectively. In addition, relationships between pressure at the bottom part in the grain tanks and porosity were compared between the field tests and the indoor experiments. The determination coefficients (R²) of regression lines between mass and porosity were high: 0.96 in the field tests and 0.88 in the indoor experiments. These relationships showed that mass is a major factor affecting porosity of rough rice piled in a grain tank. For the relationships between pressure at the bottom part of a grain tank and porosity, the field tests (moisture content: 23-29 %) showed 6 % larger porosity at around 2.5 kPa of pressure than the indoor experiments (moisture content: 15 %). Lowered fluidity of rough rice at higher moisture content is a possible cause of this larger porosity in the field tests. In addition, the magnitude of the slope of the regression line for relationships between the pressure and porosity was higher in the field tests (2.74) than in the indoor experiments (0.83). This result suggested that shaking of the combine during harvest, which involved only in the field tests, affected the porosity.

Early Disease Detection of Bacterial Leaf Blight on Rice Plant by using Hyperspectral Imaging

( M Naufal Rauf Ibrahim ),( Takashi Okayasu ),( Atsushi Yoshimura ),( Yoshiyuki Yamagata ),( Naruto Furuya ),( Eiji Inoue ),( Yasumaru Hirai ),( Muneshi Mitsuoka ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

In Southeast Asia, bacterial leaf blight (BLB) is one of the significant rice diseases that potentially causes productivity loss up to 50%. The early stage disease detection contributes to prevent the serious crop damage due to the disease outbreak. The hyperspectral imaging provides an extension of our vision by capturing the near infrared (NIR) region at 700-1000 nm which is the outside of visible light (VIS) region at 400-700 nm. In this study, the possibility of early stage disease detection method of BLB on rice plant was investigated in captured hyperspectral images with 40-50 cm from the top of rice plant. For early disease setting, the hyperspectral images for both the healthy and infected single leaf of the rice plants, both were taken from 2 days post-inoculation when the symptom had not been shown yet. The possible sensitive bands were explored from VIS to NIR and chosen by applying the principal component analysis (PCA) on reflectance value of the healthy and infected leaves using 400-850 nm. The PCA result provided that there several ranges of wavelength have high correlation with the disease development on early stage and found that the ratio of orange-red color (605-640 nm) and red edge (690-720 nm) has the highest possibility to detect the BLB.

Development of Monorail-type Mobile Robot for Field Environment and Plant Status Monitoring

( Takashi Okayasu ),( Daisaku Arita ),( Takashi Yoshinaga ),( Rin-ichiro Taniguchi Eiji Inoue ),( Yasumar Hirai ),( Muneshi Mitsuoka ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Field environmental and plant growth status monitoring is very important task to establish smart agriculture. Field monitoring device is usually installed only into the representative location in the field because of the management cost and complexity. Thus, their spatial distribution and time variation are not well grasped in actual cultivation. On the other hand, comprehensive analysis on the spatiotemporal field environmental and plant growth information is required in phenotyping researches. Various high-throughput plant phenotyping systems have been studied well and developed mainly in Europe and the US countries up to present. However, their systems are very expensive. Development of the low-price system is also required to create new cultivar and advanced agricultural production system. In this study, a monorail-type mobile robot for collecting field environment and plant status information was developed by using affordable devices such as a card-size microcomputer, sensors, and camera. Many of the robot frames were printed by 3D printer. The robot is driven by using two servo motors. The performance was verified by several conditions and then the spatiotemporal data measured was also evaluated.