• 전기학회논문지
• /
• 제67권7호
• /
• pp.884-891
• /
• 2018

In this paper, we propose an automatic earthquake P-wave detection algorithm based on the variations of the impact momentum derived from the seismic acceleration signals. The amount of change in the impact momentum induced by the acceleration refers to the influence of buildings or facilities on the earthquake, The proposed algorithm can effectively detect the seismic P-wave by simultaneously considering the amplitude and the frequency change of the seismic wave when the earthquake occurs. Computer simulations using the observed seismic signals were performed to evaluate the validity of the induced impact momentum variation and the superiority of the proposed algorithm.

• 대한기계학회논문집A
• /
• 제28권1호
• /
• pp.31-39
• /
• 2004

This paper presents design solutions for cam type transfer unit in which feeding, lifting, and clamping motions are generated by cams. In order to achieve faster transfer motion, each designed cam must satisfy the given specifications such as velocity, acceleration, jerk, pressure angle, cam thickness, and torque. To reduce absolute torque magnitude and torque variation, a conjugate cam and a torque reduction cam are used respectively. The conjugate cam eliminates the redundant pre-load by using complementary cam to avoid jumping between a cam and a follower. The torque reduction cam reduces the torque variation by applying opposite torque to a cam shaft. The experimental result shows the reductions of the absolute torque value and torque variation. The improvement of working speed and life span of cam type transfer unit can be expected.

• 전기학회논문지
• /
• 제56권10호
• /
• pp.1757-1762
• /
• 2007

Recently, the demand for the low cost power conversion equipment is rapidly increased. To develop this three phase voltage source inverter, optimum power conversion equipment to system is designed. The optimum operation method to minimize the power loss also satisfy the life time of the power electronics that is request in the present industry. In this paper, the efficient operating method to change of the acceleration, jerk, and switching frequency in the interval of acceleration is selected to optimize the power loss and life time of the power electronics by using the elevator model. So, we proposed the method that 50[A] rating power electronics is adopted in 9[kW] load.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2008년도 하계학술대회 논문집
• /
• pp.595-597
• /
• 2008

자동반송 장비의 주행축에 적용되는 횡자속 선형전동기는 위치제어를 목적으로 한다. 위치제어는 자동 반송 장비가 최소구동시간에 최대의 생산을 할 수 있도록 성능이 우수한 구동프로파일을 사용하게 되는데, 어떤 종류의 구동 프로파일을 적용하느냐에 따라 시스템 전체의 응답 속도는 물론이고 진동과 소음을 최소화하여 전체 시스템의 성능을 좌우하게 된다. 일반적으로 사용되는 사다리꼴 속도 프로파일은 변화가 일정한 가감속 전류를 필요로 하고, 전체 구동시간이 짧아 간단한 시스템에 널리 사용되고 있지만, 가속의 끝점과 감속 구간의 시작점에서 급격한 속도 변화에 따른 져크(Jerk)가 발생하여 기구부에 충격이 가해지며, 이로 인한 진동과 소음을 유발해 순간적으로 큰 동적 에러를 발생시킨다. 따라서, 본 연구에서는 부드러운 속도 프로파일을 가지며 운동의 시작점과 끝점에서 '0'의 가속과 져크를 가지는 고차원의 구동 프로파일을 제시하고 횡자속 선형전동기에 적용하여 소음 특성을 분석하였다.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권10호
• /
• pp.1259-1263
• /
• 1999

In this paper, a method to guarantee system continuity is developed, which can be applied to discontinuity problem in the time domain of restructurable control system. This method can be summarized as input alternation using weight change considering convergence speed of system mode. Input is changed from 'system continuity guarantee input,' which is defined as a input that minimizes the change of state variables, to 'alternative controller input,' which is selected by Neil's PI/EAM[3]. AIDC aircraft model is used for simulation. By showing the waveform of system input and state variable, we can sure that this method is effective for depression of system shock like jerk.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.25.3-25
• /
• 2001

This paper describes a control method of a robot cooperating with a human. A task in which a robot and a human move an object cooperatively is considered. To develop the force controller of the robot, the characteristics of human arm are investigated. The arm is forced to move along a trajectory in the experiment and the exerted force and the displacement are analyzed, It is found the force characteristics of the human arm is regarded as an optimal damper with minimizing a cost function. Then, the model is implemented to a robot and the cooperation of the robot and a human operator is examined. The effectiveness of the derived model is investigated and the experimental results show that the human moves the object supported by the robot with a minimum jerk trajectory.

• 제어로봇시스템학회지
• /
• 제1권1호
• /
• pp.16-16
• /
• 1995

Like the usual systems, the industrial robot manipulator has some constraints for motion. Usually we hope that the manipulators move fast to accomplish the given task. The problem can be formulated as the time-optimal control problem under the constraints such as the limits of velocity, acceleration and jerk. But it is very difficult to obtain the exact solution of the time-optimal control problem. This paper solves this problem in two steps. In the first step, we find the minimum time trajectories by optimizing cubic polynomial joint trajectories under the physical constraints using the modified evolution strategy. In the second step, the controller is optimized for robot manipulator to track precisely the optimized trajectory found in the previous step. Experimental results for SCARA type manipulator show that the proposed method is very useful.

• Transactions on Control, Automation and Systems Engineering
• /
• 제1권1호
• /
• pp.16-20
• /
• 1999

Like the usual systems, the industrial robot manipulator has some constraints for motion. Usually we hope that the manipulators move fast to accomplish the given task. The problem can be formulated as the time-optimal control problem under the constraints such as the limits of velocity, acceleration and jerk. But it is very difficult to obtain the exact solution of the time-optimal control problem. This paper solves this problem in two steps. In the first step, we find the minimum time trajectories by optimizing cubic polynomial joint trajectories under the physical constraints using the modified evolution strategy. In the second step, the controller is optimized for robot manipulator to track precisely the optimized trajectory found in the previous step. Experimental results for SCARA type manipulator show that the proposed method is very useful.

• 대한기계학회논문집
• /
• 제19권5호
• /
• pp.1168-1175
• /
• 1995

The application of cubic spline is presented for basic curve (DRD motion) of cam motion. The purpose of this paper is to achieve better dynamic characteristics than general cam curves. A cubic spline is a piecewise function that is continuous in displacement, velocity and acceleration. The best cam curve is obtained by changing the weights of the object function. So the method can be used to any machine system case by case. For the proposed object function, the result has improved all characteristics such as velocity, acceleration and jerk compared with that of the modified sine curve.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.844-847
• /
• 2003

This thesis suggests design considerations and solutions for cam type transfer unit in which feed, lift, and clamp motions are occurred by cams. For fast transferring and avoiding cam breakage, each designed cam must satisfy the given specifications such like velocity, acceleration, jerk, pressure angle, ram thickness, and torque. To reduce absolute torque magnitude, conjugate cam is suggested. Conjugate cam eliminates the redundant pre-load by using complementary cam and follower to avoid jumping between them. The result from the prototype shows the reductions of the absolute torque value, and it indicates that conjugate cam could enhance the working speed of cam type transfer unit and extend of the life span of cam type transfer unit.