In the field of robotics and automation, path planning holds significant potential for optimizing field operations. These operations must cover the work area comprehensively and efficiently with minimal movement. To achieve these goals, coverage path planning (CPP) utilizing the Boustrophedon method is essential. However, in an experimental environment, CPP often results in missed work areas due to cumulative sensor errors and structural inconsistencies. This paper aimed to improve CPP by employing the Douglas-Peucker algorithm to simplify the work path and minimizing missed areas. Additionally, Edge Zone Path method was used to generate edge paths, enhancing safety of the trajectory. For experimental purposes, data were acquired from an actual barn. The work area was divided using three segmentation algorithms. Among these, the Voronoi Segmentation, which demonstrated superior performance, was used to extract the data. Experimental results indicated that the proposed optimized CPP improved path safety by maintaining a safe distance from obstacles during frequent turns. Additionally, the Coverage Ratio increased the coverage area of the autonomous robot by an average of 17% compared to the original CPP. These findings suggest that the proposed method can generate more efficient and safe work paths.

In this study, we present the multilayered symmetrical droplet splitting microfluidic system for preparation of microspheres. The microfluidic device was fabricated by conventional photolithography and PDMS casting. Multiple layers of microfluidic channels for symmetrical droplet splitting were stacked and integrated into a device. Each layer was designed to obtain 16 microdroplets from one droplet by droplet splitting. The droplet size was controlled with flow rate of dispersed phase (DI-water) and continuous phase (Mineral Oil with 3 wt.% SPAN80) by using a syringe pump. The droplet splitting behavior and production rate were analyzed by high-speed camera and inverted microscope in one layer of the microfluidic device. Additionally, the droplet size and size distribution were observed in each layer of the microfluidic device. The droplet size could be controlled by flow control of two phase flows with high uniformity of droplet size less than 5% coefficient of variation.

The planetary geartrain can be reduced in size and weight, and has excellent durability since the input torque is divided by the number of planet gears when the power is transmitted. In order to improve its durability, the load sharing among planet gears must be even. However, of the various manufacturing errors possible, the carrier pinhole position error has the greatest influence on load sharing. This study compared and analyzed the load sharing and the gear safety of planetary gears, according to the phase of the carrier pinhole position error. We confirmed that load sharing among the planet gears varied, depending on the phase of the carrier pinhole position error. The mesh load factor is inversely related to the gear safety factor for bending and contact, and affects the durability of the planetary geartrain. Also, in the design of the planetary geartrain, the load sharing among planet gears is directly affected by the carrier pinhole position error and its phase. Therefore, the geometric tolerance must be managed efficiently, which needs to be reflected in the production drawings.

Finite element analysis was performed for a split-type CFRP bicycle frame, which was designed to apply a compression molding process with carbon fiber prepreg for a conventional bicycle. An epoxy adhesive material for joining the frames was selected by the extent of stress at joint interfaces. The split-type bicycle frame was then formed and its weak parts examined by the boundary conditions according to reliability tests. The results verified the reliability of the bicycle frame after modification of these weak parts. The finished product was manufactured by using this developed split-type bicycle frame.