The authors previously proposed an Unmanned Ground Vehicle (UGV) in an orchard as a base platform for autonomous robot systems for performing tasks such as monitoring, pesticide spraying, and harvesting. To control a UGV in a semi-natural environment, accurate self-localization and a control law that is robust under large disturbances from rough terrain are the first priorities. In this paper, a selflocalization algorithm consisting of a 2D laser range finder and the particle filter is proposed. A robust nonlinear control law and a path regeneration algorithm that the authors proposed for underactuated mobile robots are combined with the localization method and applied to a drive-by-wire experimental vehicle. Excellent experimental results were obtained for traveling through a real orchard. The standard deviation of the control error in the lateral direction was less than 15cm.
We present a novel practical design optimization for the primary core in an induction heating roll, which significantly affects the heating performance. To optimize the 3D eddy current field problem within an acceptable CPU time, we effectively combine 2D magnetostatic optimization and 3D coupled magnetic-thermal FEM. For the 2D optimization, we adopt the level-set method, which has an advantage of being able to derive a feasible shape. However, the disadvantage is that its result occasionally falls into a local optimal solution. To overcome this disadvantage, we propose conducting the initial conceptual design with the linear level-set method before using the nonlinear level-set method to expand the search domain. Furthermore, we incorporate the parallelized move-limit strategy into the level-set method to prevent the configuration from undergoing excess deformation by the operation for the area constraint. Finally, the 2D optimal shape obtained using our new level-set method is converted into a straight line cross-sectional configuration to improve manufacturability, and the final 3D design is created with slits. The final 3D design obtained as a result of the 3D FEM successfully improves both the heating speed and temperature uniformity on the surface of the heating part under the same conditions of input AC current and material volume.
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