Experiments to measure the side-slip angle of an articulated vehicle were conducted using a wheel loader equipped with displacement, global positioning system (GPS), and fibre-optic gyro (FOG) sensors. In addition, a constant circular turn of the articulated vehicle in a horizontal plane was simulated using equations of motion for a vehicle with no tractive force. The cornering stiffness between tire and unpaved ground was determined by comparing the experimental and simulation results.
Small boat with no screw or rudder has been used for showering the canopies of orchards in Thailand. During the showering operation, the boat moves forward by a reaction force of two flat nozzles used for showering. This study discusses the drag coefficient of the boat and the feasibility of using fluidics as a driving and steering unit of the boat in place of conventional flat nozzles. A one-fifth scale model of the boat and a fluidics were built to determine its drag coefficient, the thrust imparted by the fluidics and boat traveling speed. The drag coefficient of the model was found to be inversely proportional to the Froude number and effective in predicting the traveling speed of a boat.
The contact stresses between a tire and sand were measured with a tri-axial force sensor embedded on the tread surface of the tire. The results showed that the sensor could detect normal and tangential contact reactions with sufficient accuracy. Moreover, we observed a forward shift of the rotational angle for which both normal and longitudinal tangential stresses are maximum. There were three points of measurement on the lateral direction of tire tread, and the tractive performance of a tire in terms of gross tractive effort, drawbar pull, and running resistance could be obtained through integration using the detected contact forces.
An end-effector was developed for a tomato cluster harvesting robot. This end-effector can harvest not individual fruits but a whole fruit cluster to improve the robot's harvest efficiency. Experiments for harvesting tomato clusters were conducted in a high-density plant training system. According to a harvesting algorithm, the end-effector was able to perform well, even when target peduncle orientations were not given. Although the success rate of harvesting tomato clusters was 50 %, it is considered that this rate would improve if an end-effector is used for the high-wire tomato plant training systems in Dutch systems where the node lengths of plants are long enough to loosely hold the main stems.
This study investigated the use of machine vision for monitoring water content in Sunagoke moss. The main goal is to predict water content by utilizing machine vision as non-destructive sensing and Neural-Genetic Algorithm as feature selection techniques. Features extracted consisted of 13 colour features, 90 textural features and three morphological features. The specificities of this study was that we were not looking for single feature but several associations of features that may be involved in determining water content of Sunagoke moss. The genetic algorithms successfully managed to select relevant features and the artificial neural network was able to predict water content according to the selected features. We propose neural network based precision irrigation system utilizing this technique for Sunagoke moss production.
Difference in vegetation growth, taste properties, and grain yield between liquid fertilizer (LF) and chemical fertilizer (CF) applied fields were identified and analyzed to promote the use of the methane fermentation digested sludge as LF using precision agriculture technology. Vegetation growth and these ratios of LF to CF were different at panicle initiation and heading stages but no significant difference in nitrogen content was at the heading stage. Dry mass is greater in CF fields and nitrogen concentration is higher in LF fields is confirmed. In spite of no topdressing in 2006, differences in vegetation growth ratios were decreased because of the organic nitrogen in LF. Difference in GreenNDVI was decreased at the heading stage but the pattern was not changed. Differences in taste properties were significant in 2006 but not in 2005. When grain yield would be decreased 25% by hulls, brown rice yield of LF fields in 2005 was 93% of the average amount in the region (510 kg/10a) and 84% of that (505 kg/10a) in 2006.