• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.159-164
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• 2016

This paper reports the load factor logic design for a fly-by-wire helicopter flight envelope protection. As a helicopter is very complex system with a rotor, fuselage, engine, etc., there are many constraints on the flight region. Because of these constraints, pilots should consider them carefully and have a heavy workload, which causes controllability degradation. In this respect, automatic logic is needed to free the pilot from these considerations. As one of these logics, the flight envelope protection logic for the load factor of a FBW helicopter was designed. The flight to exceed the load factor is caused by an abrupt pitch cyclic stick change. In this scheme, the load factor limit logic was added between the pilot stick command block and pitch attitude command block. From the current load value, the available attitude range was calculated dynamically and simulated on the helicopter simulator model to verify the performance. A comparison of the simulation results at the hovering and forward speed region with and without applying the load limiting logic showed that the load factor limit was exceeded more than 20% when the logic was not applied, whereas with the load factor limit logic the load factor was within the limit. In conclusion, a dynamically allocated limitation logic to helicopter FBW controller was verified by simulation.

• Journal of the Mineralogical Society of Korea
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• v.18 no.1
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• pp.19-31
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• 2005

A study on the beneficiation of illite occurring in Youngdong province is performed with applying selective grinding and air classification techniques. Quartz and illite are occurred as major components, and sulfide minerals such as pyrite, chalcopyrite are associated as minor components. The result of sieving test shows that contents of Al₂O₃, K₂O and ignition loss are increased, whereas SiO₂ is decreased with particle size decrease. Fe₂O₃ content is almost same in all the particle size range but slightly lower at coarse particles. The yield of fine particles is increased with increasing rotor speed in both grinding stage and air classification stage. When the selective grinding and air classification are carried out at optimal condition, yield of the concentrate is 76.16 wt.%. The chemical compositions of the concentrate are SiO₂70.13%, Al₂O₃ 19.40%, Fe₂O₃ 1.62%, K₂O 5.20%, and ignition loss 2.77%. The beneficiation process developed in the current study is very effective method which purification and particle size control can be achieved simultaneously.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.463-466
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• 2017

The purpose of this paper is to develop a module capable of all-directional driving different from conventional wheeled robots, and to solve the problems of the conventional mobile robot with side driving performance degradation, It is possible to overcome the disadvantages such as an increase in the time required for the unnecessary driving. The all - direction spherical wheel drive module for driving a ball - balancing robot is required to develop a power transfer mechanism and a driving algorithm for driving the robot in all directions using three rotor casters. 3DoF (Axis) A driver with built-in forward motion algorithm is embedded in the module and a driving motor module with 3DoF (axis) for driving direction and speed is installed. The movement mechanism depends on the sum of the rotation vectors of the respective driving wheels. It is possible to create various movement directions depending on the rotation and the vector sum of two or three drive wheels. It is possible to move in different directions according to the rotation vector field of each driving wheel. When a more innovative all-round spherical wheel drive module for forward movement is developed, it can be used in the driving part of the mobile robot to improve the performance of the robot more technically, and through the forward-direction robot platform with the drive module Conventional wheeled robots can overcome the disadvantage that the continuous straightening performance is lowered due to resistance to various environments. Therefore, it is necessary to use a full-direction driving function as well as a cleaning robot and a mobile robot applicable in the Americas and Europe It will be an essential technology for guide robots, boarding robots, mobile means, etc., and will contribute to the expansion of the intelligent service robot market and future automobile market.