This paper addresses exhaustive coverage path planning of a mining robot based on cellular decomposition in minable area. For this work, the followings are done. First, the map of minable area is decomposed into cells by exact cell decomposition. Second, the coverage path is generated using back-and-forth motion. Third, direction of coverage path and generating graph path using proposed special spanning tree is considered to get minimum distance of moving path. The exhaustive coverage path is obtained by combining coverage path and moving path. Fourth, a controller is designed for a two-wheeled robot to track the exhaustive coverage path generated by path planning method. Finally, simulation and experimental results can prove efficiency of the proposed exhaustive coverage path planning method.
In this paper, a differential sliding mode tracking controller (DSMC) using voltage input is designed for trajectory tracking of the three-wheeled omnidirectional mobile platform (OMP) based on its dynamic modeling with disturbances. First, a tracking error vector is defined, and then a differential sliding surface vector is chosen. A control law is obtained by using Lyapunov direct method with backstepping technique. The control law stabilizes the sliding surface vector and makes the tracking error vector go to zero asymptotically. To implement the designed controllers, a control system is developed based on PIC microcontroller. A camera sensor and encoders are used. The simulation and experiment results are presented to illustrate effectiveness of the proposed controller.
This study examines the possibility of implementing the technology financing for export-import based small and medium sized enterprises. Our sample consists of 2,753 small and medium sized enterprises, receiving financial support from the Export-Import Bank of Korea for the period of 2011-2013. We find that only 400(200) firms reserve IPs(patents) annually. Given that IPs are likely to concentrate on manufacturer industries such as electronic components, computers, video, sound and communication equipment manufacturing(KSIC 26), other machinery and equipment manufacturing(KSIC 29), manufacture of motor vehicles and trailers(KSIC 31). We also find that the total assets, sales and R&D expenses of IP holding companies greatly exceeds those of companies without IPs. In addition, IP holding companies' liquidity seems slight edge and the leverage ratio is somewhat lower. However, profitability ratios of IP holding companies are rather than harsh or similar level. 20~30% of IP holding firms show very week credit scores, implying that banks' default risk is expected to be significant.
This paper describes development results of a 2 wheeled welding mobile robot with seam tracking sensor touched on welding line. The motion control is realized in the view of keeping constant welding velocity and precise seam line even though the target welding line is on straight or curved one. The body position and direction are controlled by using signal errors between two potentiometer type of touched sensors attached on torch slider and body side. In tuming motion, the body and torch slider are controlled by using the kinematic mathematical model related with two motions of body tuming and torch sliding. The straight locomotion is controlled according to 11 control pattems obtained from displacements between seam tracking sensor and body positioning sensor. The effectiveness is proven through the experimental results for arc welding machine.
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