The crab-steering vehicle with two tiller implements mounted at both ends was considered to provide automatic tillage method which does not require headland turns. When the automatic guidance on tilling operation is taken with the same mode steering, the center line of vehicle body is always parallel to a reference direction of travelling, so that positional relation of implement to sensor is simplified and able to be discussed in one dimension. In this paper, the characteristics of the automatic guidance system with this steering was discussed for application to automatic tillage with obtained results of developed trial vehicle tests and digital simulation.
1) The trial vehicle was composed of two front axle units of 4-wheel-drive tractor and frame on which engine and hydraulic devices for travelling and steering were arranged.
2) Automatic guidance tests were carried on asphalt road on which guide marker of painted white line was traced with the photoelectric detector. The tests data were provided to evaluation of simulation program, and it could be concluded that good over-all similarity between simulation and experimental paths of the guided vehicle was seen.
3) The frequency characteristics of the automatic guidance system was evaluated, and so its application to automatic tillage was considered as follows. To steer the vehicle to the tilled land, the maximum steering angle was taken larger, so that the boundary between tilled and untilled land which was detected as a guide marker was able to be traced for the land not to remain untilled. To steer the vehicle to the untilled land, the maximum steering angle was taken smaller, so that for the curved boundary with short wave length, the side part of the tiller implement overlapped with the tilled land and the amplitude ratio of vehicle path to the curved boundary line was able to be decreased. This was evaluated with the simulation about 10 and 5 degree in the maximum steering angles respectively to the tilled and untilled lands.

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To clarify the relation between the sinkage of combine harvester and soil moisture content, shape and pressure of ground contact surface, test was conducted using 1/5 scale models of track of combine harvester.
The outline of experimental results are as follows.
1) Nine models shown in Fig. 2 were used. Factors which influenced upon the sinkage are the width and contact area of track and soil moisture content when the ground contact pressure is under 0.2kgf/cm² (19.6kPa). The influence of tread length is not significant in this test.
2) When the ground contact pressure is lower than 0.2kgf/cm² (19.6kPa), the sinkage of smaller track is less than that of larger one under the same ground contact pressure. This means that the sinkage of the track depend on the weight of combine. When the tracks have the same contact area, the sinkage of the track having narrower width is less than that of wider one. This means that shorter track is easier to sink than longer one.
3) Soil moisture content is the main factor which affects to the sinkage of track. Even if the ground contact pressure is lower than 0.2kgf/cm² (19.6kPa), the sinkage of track increases rapidly as the soil moisture content increases. The sinkage is remarkable when the soil moisture is near the liquid limit. The sinkage is more when the soil is kneaded in the same moisture content. These results indicate that the soil moisture content and the soil structure are the important factors for the sinkage of track. Under high soil moisture content, the influence of the shape of track is not recognized.
4) The effect of the tread length of tracks is not clear.
5) Assuming that sinkage behaviours of combine harvester exhibit a similar tendency to the model experiments we have done, it can be said that the elements for designing combine harvester are: the weight of combine should be as light as possible, the length of track should be long enough within the limit of giving no serious effect on turning operation and the tread of tracks should be arranged so that they do not run on the same trace. However, it must be born in mind that the sinkage behaviour is more heavily affected by the soil moisture content than the shape of track.

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In the previous paper the essential cutting force data such as to predict the power requirements for a chain saw engine over a large portion of its operating range at forest operation was absent with respest to hard woods which belong to higher density wood species. Therefore, cutting experiments were carried out to accomplish these parts. The results were as follows:
1) Four types of cutter tooth which had been investigated in part 2 were re-examined using 3 kinds of wood species such as katsura, Japanese elm and white oak which can be seen in Hokkaido, northern parts of Japan. The obtained characteristics of cutting forces in the radial-tangential plane with 12 combinations showed fairly good approximation to the cutting of spruce and could be represented by hyperboloid regression equations with respect to the speed ratio λ. Thereupon, mathematical models for the analytical determination of cutting horsepower were proposed in table 2.
2) As the result of reexamining specific cutting resistance forces f_H and f_V the ranking of 4 types of cutter tooth got at the cutting of spruce were found not to be applied to these hard woods. The difference will come from the characteristics of wood structure of particular species and types of cutter tooth tested.
3) In the grooving by saw-chain cutter tooth, the side wall of a kerf was cut by the side plate edge and the bottom of that was cut by the top plate edge. Therefore, the magnitude of cutting forces due to the bottom of the kerf seems to dominate the differences of total cutting forces against with the same depth of cut.
4) From this viewpoint, the adaptability of 4 types of cutter tooth to the different kinds of wood species were reexamined. As a result, chipper type saw-chain (51CP) which has a large curved side plate was suitable for the wood species having a gradual transition from early to late wood. Chisel type saw-chain (72LP & 76LP) which have squareshaped junction of both plate edge was suitable for the wood species having clear annual rings such as spruce which belonged to soft woods. Semi chisel type saw-chain (72DP) which have a small radious junction of both plate edge was suitable for cutting either soft and hard woods.

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The noise abatement quantity due to trees and shrubs was experimented on the condition that the sound pressure level at the noise source was changed. On the other hand, the capacity of noise abatement due to a tree were measured, and compared with the above noise abatement quantity. Furthermore, we studied the capacity of noise abatement due to trees under the changing sound pressure level at the each spectrum from the play back noise source of some farm machines. The experimental results may be summarized as follows.
1) The capacities of noise abatement of the test grove of Magnolia grandiflora at every frequencies were down by same dB for the distance in spite of the differences of the sound pressure level at the noise source.
2) When the play back noises of a tractor, a forage harvester and a combine in operation were passed through a tree, we found the same abatement tendency on the spectrum distribution.
3) There were some differences in the capacity of noise abatement between the actual test vegetation and the ideal one which was planted densely. The difference of the maidenhair tree was 2.6dB(A), the Japanese ceder 3.4dB(A), the mulberry tree 10dB(A) and Irex rotunda THUNB 0.3dB(A).
The mass of Irex rotunda THUNB was the most superior in these plants on the noise abatement.
4) The variation of the sound pressure level by the tracor was largest at frequencies over 1kHz in the three tested farm machines.
The noise which had smaller variation of sound pressure level was advantageous on the noise abatement due to trees.

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1. The experimental method of the compressive dehydration was developed for animal waste. The characteristics of the compressive dehydration was investigated from the many experimental results for pig and cattle waste.
The experiments were performed for the combinations of five initial layer thicknesses which represented waste weight per the effective area A (=52.30cm²), five initial moisture contents, five pressures, five compression velocities and three conditions of filtration-assistants.
The number of experiments amounted to 134 for pig waste and 75 for cattle waste, hence the total number of experiments amounted to 209. Changes of moisture contents were researched concerning with operating time θ.
2. The authors determined the regression equation (1) as fitting to the experimental results. Parameter Me in the equation was fixed by the least square method. The fitness of the equation to the experiments was investigated and it was confirmed that parameter n and value ln k could explain clearly the characteristics of the compressive dehydration.
3. Parameter n and value ln k in the equation (1) were obtained from the many experimental results for animal waste. The mean values of parameter n formed a line as shown in Fig. 3-6. The deviation values were ranged from 0.1 to 0.3 for the pig waste and from 0.2 to 0.4 for the cattle waste.
4. The consolidation experiments had been performed for clay which was regarded as an elastic corpuscular. When the results were applied to equation (1), it was found that the value of parameter n approximated 0.5 and that the clay was regarded as the incompressible cake at the initial stages of consolidation. And it was also found that the smaller than 0.5 the values of parameter n was, the more compressible the waste became.
As the value of parameter n was small, animal waste could be regarded as an incompressible cake. The pig waste was more compressible than the cattle waste.

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The effects of unbalanced weights and the static displacements of rubber springs on the separating capacities were studied using a shaking separator.
The ratio of unbalanced weights was the ratio of the inertia force of attached unbalanced weights to that of separating decks in the direction of vibration. The ratio of unbalanced weights used was in the range of 0 to 1.5 and the static displacement of rubber springs used was in the range of 0 to 7mm. The separating capacities were represented by recoveries, Newton's efficiencies and tangential angles of the brown rice recovery curve.
The main results were as follows:
1) When the unbalanced weights were attached at the position of 180 degrees, the recoveries of brown rices, tangential angles of brown rice recovery curve and Newton's efficiencies gradually increased with the increase of the ratio of unbalanced weights.
In general, there is a tendency that the increase of the ratio of unbalanced weights gives the increase of inertia force acting on brown rices, which are resulted in the movement of brown rices toward the upper part of the discharge end. Consequently, the distribution of grains in the discharge end was the higher in the upper part and the lower in the lower part.
2) The recoveries of brown rice and Newton's efficiencies when the unbalanced weight was attached at 90 and 180 degrees was larger than those in the case of 0 and 270 degrees.
3) It is clear that the static displacements of rubber springs has very little effect on the separating capacities when the displacements are less than 3mm or thereabout.
4) The ratio of the unbalanced weight, the attached position and the static displacement of rubber springs might have considerable effects on separating capacity.
5) It is clear that the available conditions of the unbalanced weight and the static displacement of rubber springs are: about 0.6 to 1.0 in the ratio unbalanced weight, about 180 degrees in the attached position and within about 3mm in the static displacement of rubber springs.

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The curve of quickest descent was applied to improve the efficiency of the transport of agricultural products (grains). The course was produced with vinyl pipe. The theory and the speed characteristics in free transport and forced transport by ventilating method were studied. The results were as follows:
(1) When the sphere moves in the course by only potential energy and slides with roll (tan φ>3.5μ), the equation of motion is shown by the equation (14). If it rolls without slide (tan φ<3.5μ), the equation of motion can be shown by the equation (18). If the coefficient of friction is small, the equation of motion of the whole course can be approximately expressed with the equation (14). The results of analysis of this equation by Milne's method are shown in Fig. 3.
(2) The relation between the arrival ratio and the coefficient of profile is almost linear as shown in Fig. 6. The distribution of speed (Fig. 7) agreed with the theoretical results in the case of sphere.
(3) The insufficient energy caused from frictional and air resistance in the course was compensated by blower. The distribution of speeds were as showen in Fig. 8. It is recognized that the transport speeds correlated with the coefficient of profile and the coefficient of static friction.
(4) The efficiency of transport energy, defined by the equation (20), was compared in the case of curve of quickest descent and straight pipe. If the coefficient of profile is high (above ζ=0.8), the curve of quickest descent is advantageous to the straight pipe.

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DLE characteristics of Apples were investigated by new type of DLE measurement apparatus to obtain the basic data for automatical evaluation of quality during the sorting procedure, and the following results were obtained.
1. Relation between dark period and DLE intensity was investigated. Maximum DLE intensity was obtained under the dark period beyond 10min (Fig. 4).
2. The highest DLE intensity was obtained with an exciting illumination of 4000lx for 4 to 5sec (Fig. 5).
3. The DLE intensity were saturated with exciting illumination of 2000lx, 1000lx and 500lx for decay period of 0.4 to 0.5sec, 0.7sec and 1.0sec respectively (Fig. 6).
4. DLE intensity of apple was affected by fruit temperature. DLE intensity had peak value at higher temperature under the shorter decay period (Fig. 7).
The exciting conditions for obtaining high and stable DLE intensity were established as follows; Dark period; 10min, Illumination intensity; 4000lx, Exciting time; 5sec, Decay period; 0.5sec.
5. DLE intensity of Apples changed remarkably according to the harvesting maturity. The optimum harvesting time can be determined by measuring DLE (Table 1).
6. Saturation of peel color had a high correlation with DLE intensity of Apples. Evaluation of peel color and maturity of Apples is possible by means of DLE (Fig. 8).
7. Chlorophyll content of Apple peel had a high linearity with the intensity of DLE (Fig. 9).

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In order to investigate the internal stresses of a rice kernel, the moisture movement in the kernel was studied during the drying process. The results obtained were summarized as follows:
(1) It could be considered that the moisture content reached an equilibrium value on the surface of the kernel with the drying condition.
(2) It could be assumed that the mechanism of moisture movement was given by a diffusion model based on the gradient of the moisture content in the kernel.
(3) The effective diffusivity of the kernel could be estimated by observing the drying curve and measuring the dimensions (length, width and thickness) of the kernel, and an equivalent radius of the kernel could be also determined by the above experimental results.
(4) It was found that the temperature of the rice kernel would reach that of the air in a few minutes after drying at the air velocity above 0.5m/sec.

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The drying system (Fig. 1) with heat pump using atmospheric heat and exhaust heat as heat source is used in experiment of rice drying; the changes of states of flow, air, rough rice and refrigerant, the energy flow and efficiency are clearly determined.
1. The experimental conditions and the main results are presented in Tab. 1. With 600kg of rough rice, the evaporating rate is 6.36kg/h, the drying rate is 1.33%d.b./h (0.92%w.b./h) and the energy consumption per 1kg of removed water is 300kcal/kg·H₂O. The energy consumption is well improved and becomes about 1/4 of a common heated air rice drier.
2. The operating condition of heat pump using exhaust air as heat source is approximately fitted with the design value, the heat rejected at condenser is 7070kcal/h, the heat recovered by evaporator is 5280kcal/h and the consumed electric power is 2.2kW.
The influence of the change of temperature of exhaust on the heat rejected at condenser decreases due to the refrigerant flow control characteristic of expansion valve. Accordingly, the degree of superheat is high in comparison with the general refrigerating cycle except for the starting period. The coefficient of performance during drying period is 3.95, the ratio of rejected heat by consumed electric power is 3.72 and the satisfactory results are obtained due to the utilization of high enthalpy exhaust air as a heat source.
3. The change of state of flow air is shown in Fig. 3. The inlet air (1) is heated to the desired temperature of 48°C by using only heat pump (atmospheric temperature+27°C), the temperature of heated air (2) (3) is stable due to the self-regulations of the heat pump and the system. The exhaust air (4) which passes through the layer of rough rice is humidified and cooled, is blown into the condenser, cooled to the temperature which is lower than the inlet air by 5°C and then discharged. Subsequently, the inlet flow of sensible heat of atmospheric air is larger than the outlet flow of sensible heat of exhaust air by 1300kcal/h. In case of common heated air drier, this relation is inversely different.
4. The change of state of rough rice is illustrated on the enthalpy-concentration diagram(Fig. 7). With the progress of drying, the moist grain increases its enthalpy and approaches the state of equilibrium with heated air marked by _??_.
5. The energy flow of this drying system is expressed in Fig. 10. Among the heat flow 7070kcal/h to heat the fresh air by the heat pump, the recovered heat occupies 75% and the power of compressor is 25%. On the other hand, among the heat flow into rough rice from heated air, sensible heat is 1000kcal/h in total and the latent heat of grain moisture evaporation including the moisture concentration energy is about 4000kcal/h. The enthalpy increment of rough rice before and after drying is about 540kcal/h, among this, the moisture concentration energy which is accumulated in rough rice due to the removal of moisture is 244kcal/h. Accordingly, the conversion efficiency of the air heat quantity to moisture concentration energy is 3.5%. Moreover, the conversion efficiency of the supplied energy (electric power consumption of compressor) to moisture concentration energy is 13% which is about 4 times of ordinary combustion heating.

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In this study, automatic detecting and sorting were attemped for the shape of agricultural products by using an opto-electronic system that consists of an opto-electronic line sensor and minicomputer. Because of using the line sensor for detecting, this system is simple and less expensive as compared with the system that made up of ITV camera or image sensor.
Basing on the shape index which was calculated from Walsh-transform, the properties of shape were derived from the detected shape.
In experiment, the satsuma oranges, tomatoes and apples were tested and calculated for the shape index. Additionally, the satsuma oranges were attemped to sort into two groups A and B basing on the shape index. This method seems to be valid as compared with the results that were obtained from manual sorting in the fruits sorting plant.

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