• Tribology and Lubricants
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• v.12 no.4
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• pp.13-17
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• 1996

립실의 중요 설계 변수인 접촉력의 측정에는 스플릿트축장치가 흔히 사용된다. 축과 립실의 간섭량은 두 개 스플릿트축의 간격으로서 조절된다. 두 축을 초기 위치로부터 측정하고자 하는 임의 위치로 이동시킬 때 정확한 원을 이루지 못해 측정되는 접촉력은 오차를 포함되게 된다. 본 연구에서는 작은 간섭량 범위 내에서 접촉력을 이론적으로 예측할 수 있는 수식을 유도하고 측정 오차 값을 예측하였다. 측정된 립실의 접촉력은 측정 간섭량이 초기간섭량과 일치하는 경우 외에는 항상 오차를 포함하고 있음을 밝혔다. 이 오차는 작은 간섭량 범위 내에서 립실의 재료 특성이나 형상에 무관하며, 10% 이내의 측정 오차 유지를 위해서는 측정 간섭량이 초기 간섭량의 68%에서 187% 범위 내에 들어야 함을 확인하였다.

• Korean Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.19-27
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• 1997

This paper presents rough cut tool path planning for the fewer-axis machine consisting of a three-axis CNC machine and a rotary indexing table. In the problem dealt with in this paper, the tool orientation is "intermediately" changed, distinguished from the conventional problem where the tool orientation is assumed to be fixed. The developed rough cut path planning algorithm tries to minimize the number of tool orientation (setup) changes together with tool changes and the machining time for the rough cut by the four procedures: a) decomposition of the machining area based on the possibility of tool interference (via convex hull operation), b) determination of the optimal tool size and orientation (via network graph theory and branch-and bound algorithm), c) generation of tool path for the tool and orientation (based on zig-zag pattern), and d) feedrate adjustment to maintain the cutting force at an operation level (based on average cutting force). The developed algorithms are validated via computer simulations, and can be also used in pure fiveaxis machining environment without modification.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.3
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• pp.21-26
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• 2011

Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seals in high speed pneumatic cylinders is analyzed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the squeeze type piston seal are simulated with variation of the seal radial installed interference, the operating pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the squeeze type piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.25-31
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• 2003

A computer simulation model for investigating a two-dimensional (2-D) rounding mechanism in a centerless grinding process is described. This model includes the interference phenomena and the concept of machining elasticity. Since initial contact points are used as a reference, the result of this simulation is not affected by the location of the reference circle center and the radius of the reference circle. Also, details of the machining factor are studied by using process variables (grinding wheel speed, wheel specification, workpiece speed, dressing condition, etc.). The effect of the threshold grinding force on the size of ground workpiece is investigated. For the verification of this method, simulation results are compared with the experimental work.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.102-107
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• 2012

In this study, the design procedure of hybrid active mount by an electro-magnetic actuator is proposed to reduce the transmitted force from naval shipboard equipment to ship hull structure. The hybrid type mount which is composed of a passive rubber element and an electro-magnetic actuator is introduced and, through the vibration measurement for the objective pump system, the required force of the actuator is computed and discussed in detail. The initial designs were supposed for three types, one is moving coil type actuator and the others are moving permanent magnet type actuators. Based on the initial design concept, the final designs considering shock resistance and interference with mover and stator are proposed and examined.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.99-104
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• 2010

Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seal in high speed pneumatic cylinders is analysed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the piston seal are simulated with variation of interference fits, supply pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.753-761
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• 2012

This paper describes development of a hand and finger fixing system for the rehabilitation exercise of patient's fingers. In order to exercise the finger rehabilitation using a finger rehabilitation robot, a patient's hand or fingers are fixed safely. In this paper, The hand and fingers fixing system can safely fix stroke patient's hand and fingers by pressing with force control system. The characteristic test of the system was carried out. It is thought that the system could be used for fixing their fingers in stroke patient's finger rehabilitation exercise.

• Korean Journal of Computational Design and Engineering
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• v.17 no.5
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• pp.324-332
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• 2012

In this paper, a method for calculating the contact force and the frictional force caused by contacts between the wire rope and the rigid body is introduced based on multibody dynamics. And the method is applied to a simulation of contacts between the wire rope and the shell plate of a block that can occur during shipbuilding. The wire rope is composed of a number of lumped masses and the wire rope segments that connect the masses. After calculating the position of interference, we inserted a contact node into the wire rope. We then derived the equations of motion of the wire rope and the rigid body using augmented formulation based on multibody dynamics taking into account the constraints between the contact node and the rigid body. Using the equations, we were able to obtain the constraint force between the contact node and the rigid body, and calculate the contact force and the frictional force, based on which the position of the contact node was corrected. Finally, we applied our results to perform simulation of contacts between the wire rope and the shell plate of a block in order to verify the efficacy of the method proposed in this paper.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.90-97
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• 2007

This paper describes the development of 6-axis force/moment sensor considered adult weight far an intelligent foot of humanoid robot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself and control the foot using the forces and moments. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to the foot, which is composed of Fx sensor, Fy sensor, Fz sensor, Mx sensor, My sensor and Mz sensor in a body. Each sensor should get the deferent rated load, because the applied forces and moments to foot in walking are deferent. Therefore, one of the important things in the sensor is to design each sensor with the deferent rated load and the same rated output. In this paper, a 6-axis force/moment sensor (rated load of Fx and Fy are 500Nm and Fz sensor is 1000N, and those of Mx and My are 18Nm, Mz sensor is 8Nm) for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using by ANSYS software (FEM (Finite Element Method) program). Then, a 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.14-20
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• 2001

The mass-spring system with four arms for the force-balance servo accelerometer was designed and fabricated. The response characteristics of a mass-spring system was calculated with the change of arms thickness and seismic mass by the finite element method (FEM). Furthermore, the response characteristics of accelerometer was measured using the change of interference pattern and response voltage value by Michelson interferometer. The response characteristics with changing length and thickness of arm was changed drastically, and changing seismic mass was minor effect for the response characteristics of mass-spring system. The measured resonant frequencies have good agreement with that of numerical analysis within 5％ range.