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Cross Hole Type 비 연삭 밀링 인서트의 가공특성에 관한 연구
김택수,이상민,박휘근,채승수,이충석,손일복,김학규,이종찬 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-
This paper reports some experimental results on the machining performance of non-ground cross hole type milling inserts. Six kinds of milling inserts were manufactured without using grinding process. Machining experiments were carried out to compare the machining performance of non-ground inserts with that of ground ones. The experimental results indicate that the cutting forces and surface roughnesses of machined surface of both ground and non-ground inserts are comparable.
Design of safety mechanism for an industrial manipulator based on passive compliance
Hwi-Su Kim,박정준,송재복,경진호 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.11
In recent years, collision safety between humans and robots has drawn much attention since human-robot cooperation is increasingly needed in various fields. Since positioning accuracy and collision safety are both important, an industrial manipulator should maintain very high stiffness for positioning accuracy in a normal situation, but exhibit very low stiffness when subjected to a collision force greater than the tolerance for human injury. To satisfy these requirements, we proposed in our previous research a safety mechanism composed of a linear spring and a double-slider mechanism for a service robot with a small payload. We modified this device to meet more stringent requirements for an industrial manipulator which usually has a payload higher than a service robot. Several experiments on static and dynamic collisions showed high stiffness of the safety mechanism in response to an external torque that was less than a predetermined threshold torque, but low stiffness that enabled absorption of the collision force when the external torque exceeded the threshold. Thus, positioning accuracy and collision safety were improved using the proposed design. Furthermore, a new safety criterion is suggested to verify the collision safety of a manipulator that uses the proposed safety mechanism.
Hwi-Su Kim,Jae-Kyung Min,Jae-Bok Song IEEE 2016 IEEE transactions on robotics Vol.32 No.1
<P>Low-cost but high-performance robot arms are required for robot arms to come into widespread use. To provide sufficient torques to support the robot mass and payload, most arms use expensive motors and speed reducers, which are the main reasons for their high price. As a solution to these problems, a multiple-degree-of-freedom (DOF) counterbalance mechanism and robot arm were developed in our previous study, which can compensate for the gravitational torque due to the robot mass. However, there are durability and reliability problems associated with wire-based mechanisms. To solve these, in this study, we proposed a new counterbalance mechanism based on a spring and slider-crank mechanism, along with a double-parallelogram mechanism composed of bevel gear units. Moreover, a 6-DOF counterbalance robot arm was built to verify the performance of the proposed mechanism. Simulation and experimental results showed that the proposed mechanism effectively decreased the torque required to support the robot mass, thus allowing the prospective use of low-cost motors and speed reducers for high-performance robots.</P>
Multi-DOF Counterbalance Mechanism for a Service Robot Arm
Hwi-Su Kim,Jae-Bok Song IEEE 2014 IEEE/ASME transactions on mechatronics Vol.19 No.6
<P>Low-cost but high-performance robot arms are required for widespread use of service robots. Most robot arms use expensive motors and speed reducers to provide torques sufficient to support the robot mass and payload. If the gravitational torques due to the robot mass, which is usually much greater than the payload, can be compensated for by some means; the robot would need much smaller torques, which can be delivered by cheap actuator modules. To this end, we propose a novel counterbalance mechanism which can completely counterbalance the gravitational torques due to the robot mass. Since most 6-DOF robots have three pitch joints, which are subject to gravitational torques, we propose a 3-DOF counterbalance mechanism based on the double parallelogram mechanism, in which reference planes are provided to each joint for proper counterbalancing. A 5-DOF counterbalance robot arm was built to demonstrate the performance of the proposed mechanism. Simulation and experimental results showed that the proposed mechanism had effectively decreased the torque required to support the robot mass, thus allowing the prospective use of low-cost motors and speed reducers for high-performance robot arms.</P>
김휘수(Hwi-Su Kim),박정준(Jung-Jun Park),송재복(Jae-Bok Song) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
In recent years, collision safety between humans and robots has drawn much attention since cooperation between humans and robots is increasingly needed in various fields. Since both positioning accuracy and collision safety are important, an industrial manipulator should maintain very high stiffness for positioning accuracy in the normal situation, but exhibit very low stiffness when subjected to a collision force greater than the injury tolerance. In order to achieve these requirements of an industrial manipulator, a safety mechanism composed of a linear spring and a double-slider mechanism was proposed in the previous research. To satisfy the operational requirements of an industrial manipulator, the spring stiffness of this safety mechanism was designed by conducting various dynamic analyses. Several experiments on static collisions show high stiffness of the safety mechanism against an external torque less than the pre-determined threshold torque, but the absorption of collision force when the external torque exceeds this threshold torque, thereby guaranteeing positioning accuracy and collision safety.