With the recent development of autonomous driving technology, many researchers have studied autonomous mobile robots. Accordingly, they are developing diverse mobile robot actuators. However, most actuators mainly use reducers made of chains, belts, multi-stage gears, etc. So the volume and size of the actuators increase, and power transmission efficiency tends to be relatively low. Therefore, this study has proposed the reducer of the mobile robot actuator using a complex planetary gear train with small volume and high power transmission efficiency, and has confirmed the stability of the proposed reducer through finite element analysis.

There are many risks in using grass cutter because of the pebble in grass and high speed rpm when the cutter hits the hard objects in grass. In this study, the existing patents are surveyed and classified for the new mechanism about the bottom safety cover. The new mechanism was modelled and the planetary gear are designed. The power source (engine or motor) will rotate the sun gear and the carrier of planetary gear is fixed into handle frame. The ring gear will drive the final cutter. The carrier fixed the bottom safety cover through the planetary gear hole at the handle bar. In this paper, we develop a new mechanism and analyze the idea for safe grass cutter and investigate the possibility of having patent through patent search.

본 연구에서는 무단변속시에 사용되며, 세 개의 유성기어로 구성된 복합유성기어가 기어의 회진시 비선형적인 기어의 강성과 감쇠를 고려하여 모델링 되었고, 복합유성기어의 운동 방정식이 유도되었다. 소음과 진동의 원인인 선기어의 중심궤적이 구하여진 상태방정식에 4차 룬게-쿠타 수치해석 방법을 수행함으로써 구하였다.

Control of a robot manipulator in contact with the environment is usually conducted by the direct feedback control using a force-torque sensor or the indirect impedance control. In these methods, however, the control algorithms become complicated and the performance of position and force control cannot be improved because of the mechanical properties of the passive components. To cope with such problems, redundant actuation has been used to enhance the performance of position control and force control. In this research, a Double Actuator Unit (DAU) is proposed, with which the force control algorithm can be simplified and can make the robot ensure the safety during the external collision. The DAU is composed of two actuators; one controls the position and the other modulates the joint stiffness. Using this unit, it is possible to independently control the position and stiffness. The DAU based on the planetary gears is investigated in this paper. Performance using the DAU is also verified by various experiments. It is shown that the manipulator using this mechanism provides better safety during the impact with the environment by reducing the joint stiffness appropriately on detecting the collision of a manipulator.