• 제어로봇시스템학회논문지
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• 제19권3호
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• pp.190-194
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• 2013

This paper presents experimental results of the attitude control for a two-rotor system with 3-DOF(degree-of-freedom). Two DC motors are equipped at the two ends of a rectangular beam to generate lift force and the relation between motor voltage and lift force is found experimentally. And inertial sensors are mounted at the center of the beam to measure the roll angle and a complementary filter is designed to get the angle during DC motors driving. A controller with nonlinear compensation, integrator and state feedback to achieve asymptotic tracking for a step input and reject input disturbance is designed and experimented.

• Tribology and Lubricants
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• 제26권2호
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• pp.136-141
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• 2010

In an oil hydraulic vane pump for an automobile, it is very important that the vane doesn't separate from the camring inner race during the operation of the vane pump. The vane generally has not only the oil hydraulic force acting on the bottom face to contact to camring inner race but there is also an inertial force and viscous force. Because the oil hydraulic force is much larger than the other forces, the contact state between the vane tip and the camring inner race is sufficient. However, the contact state between the vane tip and the camring inner race is only affected by the inertial and viscous forces during the delivery of the vane pump, because the oil hydraulic force acting on the vane is in equilibrium. If the inertial force is larger than the viscous force, which happens when the vane is separated from the camring inner race, the delivery of the vane pump can become unstable or the volume efficiency can become decrease rapidly. Therefore, in this paper, the state of the contact between the vane and the camring is considered. The results show that the rotating speed of the shaft, the operating temperature of the oil, the clearance between the vane and the rotor, and the mass of the vane exert a great influence on the state of the contact between the vane and the camring.

• Journal of Magnetics
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• 제16권3호
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• pp.263-267
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• 2011

The present paper proposes a novel cableless magnetic actuator with a new propulsion module that exhibits a very high thrusting force. This actuator contains an electrical inverter that directly transforms DC from button batteries into AC. The electrical DC-AC inverter incorporates a mass-spring system, a reed switch, and a curved permanent magnet that switches under an electromagnetic force. The actuator is moved by the inertial force of the mass-spring system due to mechanical resonance energy. The experimental results show that the actuator is able to move upward at a speed of 33 mm/s when using 10 button batteries when pulling a 10 g load mass. This cableless magnetic actuator has several possible applications, including narrow-pipe inspection and maintenance.

• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.81-88
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• 2007

This paper presents the development of a new inchworm actuation system using the shearing deformation of the piezoelectric actuators. In this new actuation system, piezoelectric shearing/expanding actuators, an inertial mass and an advanced preload system are configured innovatively to generate the motion of an inertial mass. There are two modes in the new actuation system: (1) stick mode, and (2) clamp mode. In stick mode, the deformation of the piezoelectric shearing actuators drives an inertial mass by means of the friction force at their contact interface. On the other hand, in clamp mode, the piezoelectric expanding actuators provide the gripping force to an inertial mass and, as a result, eliminate its backward motion following the rapid backward deformation of the piezoelectric shearing actuators. To investigate the feasibility of the proposed new actuation system, the experimental system is built up, and the static performance evaluation and dynamic analysis are conducted. The open-loop performance of the linear motion of the proposed new actuation system is evaluated. In dynamic analysis, the mathematical model for the contact interface is established based on the LuGre friction model and the equivalent parameters are identified.

• 한국대기환경학회지
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• 제16권2호
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• pp.165-178
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• 2000

In this study the effects of block distance have been investigated on the particle deposition efficiency in the collecting cell of two-stage electrostatic precipitator by numerical analysis. Particle trajectories have been changed by the electrostatic and inertial force of particle with the inlet velocity electrostatic number and particle diameter. The total deposition efficiency has a minimum value by the interaction between the effect of particle inertial force and electrostatic force in the collecting cell. The increase of block distance makes the total deposition efficiency decrease under the range of the particle size which has the minimum deposition efficiency. However beyond the range of particle size which has minimum deposition efficiency total deposition efficiency has no trend with the variation of block distance.

• Physical Therapy Rehabilitation Science
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• 제11권3호
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• pp.311-320
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• 2022

Objective: To investigate the reliability and validity of static balance measurements using an acceleration sensor and a gyroscope sensor in smart phone inertial sensors. Design: Equivalent control group pretest-posttest. Methods: Subjects were forty five healthy adults aged twenty to fifty-years-old who had no disease that could affect the experiment. After pre-test, all participants wore a waist band with smart phone, and conducted six static balance measurements on the force plate twice for 35 seconds each. To investigate the test-retest reliability of both smart phone inertial sensors, we compared the intra-correlation coefficient (ICC 3, 1) between primary and secondary measurements with the calculated root mean scale-total data. To determine the validity of the two sensors, it was measured simultaneously with force plate, and the comparision was done by Pearson's correlation. Results: The test-retest reliability showed excellent correlation for acceleration sensor, and it also showed excellent to good correlation for gyroscope sensor(p<0.05). The concurrent validity of smartphone inertial sensors showed a mostly poor to fair correlation for tandem-stance and one-leg-stance (p<0.05) and unacceptable correlation for the other postures (p>0.05). The gyroscope sensor showed a fair correlation for most of the RMS-Total data, and the other data also showed poor to fair correlation (p<0.05). Conclusions: The result indicates that both acceleration sensor and gyroscope sensor has good reliability, and that compared to force plate, acceleration sensor has unacceptable or poor correlation, and gyroscope sensor has mostly fair correlation.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 추계학술대회
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• pp.270-270
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• 2019

관성측정장치(Inertial Measurement Unit)는 선박, 잠수함, 항공기 등 여러 응용분야에서 적용되어 자세 측정 영역에 주로 사용되고 있지만, 이런 장비는 고가의 장비이기 때문에 특수 분야에서만 한정적으로 이용되어 왔다. 본 연구에서는 저가의 관성측정장치(Inertial Measurement Unit)를 이용하여 실시간으로 선박의 속도와 방향, 중력, 가속도를 측정함으로써 선박의 감항성을 확인하며, 더 나아가 실선 선박의 저항 및 조종성능 추정을 위한 유체력 미계수 추정을 위한 연구방법을 고안하였다. 이에 본 연구는 실제 해상에서 선체 운동요소를 계측하고, 계측된 데이터의 처리 및 해석을 통하여 선박의 종합적인 안전성 평가 및 실선의 저항 및 조종성능 추정을 행하였다.

• 드라이브 ㆍ 컨트롤
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• 제10권4호
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• pp.14-21
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• 2013

The numerical analysis of the automatic ship mooring system which was equipped in the ship for trying to berth at the pier was performed in this study. The automatic ship mooring using hydraulic winch was a new method that had not need to change the existing devices and to help a pilot ship of outside. The numerical results of the proposed mooring system including ship motion were that the speed and rolling phenomenon of ship was affected by changing in the ship weight and affected the slope maintenance and yaw degree of ship if there has a trim of stern. Also, a static force of ship at the initial movement was important to calculate the mooring power. The moving force and inertial force of ship on the vertical direction was confirmed for the mooring stability. Therefore, the power and velocity of hydraulic mooring winch should be determined by considering the significant characteristics such as weight, velocity, inertial force and moving force of ship.

• 한국지반공학회논문집
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• 제29권4호
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• pp.33-44
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• 2013

Mononobe-Okabe (M-O) 이론은 현재 국내외에서 가장 일반적으로 사용되는 지진 시 옹벽에 작용하는 동적토압 산정 방법이다. M-O방법은 강체거동(Rigid Behavior)을 갖는 중력식 옹벽의 사질토 뒤채움 지반에 대하여 제안된 방식이지만 현재 여러 지반 조건 및 캔틸레버 형태의 옹벽에도 널리 적용되고 있다. M-O 방법은 지진 시 발생하는 뒤채움 지반의 관성력만을 고려하기 때문에 벽체의 관성력이 동적 토압에 미치는 영향을 고려하지 못하는 단점이 있다. 본 논문에서는 M-O 방법을 포함하여 지진 시 옹벽에 작용하는 동적토압을 산정하는 기존에 제안된 방법들의 이론적 배경 및 현재까지의 연구동향을 분석하였으며, 이를 통하여 지진 시 토압산정의 중요한 요소인 동적토압의 분포 및 작용점에 대한 합리적인 재평가가 필요함을 도출하였다. 역 T형 옹벽을 대상으로 동적원심모형실험을 수행하여 지진 시 옹벽에 작용하는 동적 토압을 M-O 이론과 모형 모델 거동과의 비교를 통하여 차이점을 평가하였다. 실험 결과, 지진 시 옹벽의 실제 거동은 M-O 방법의 가정과 달리 벽체의 관성력과 동적토압 사이에 위상차가 발생함을 알 수 있었다. 또한 벽체에서 주동방향으로 최대 휨 모멘트 발생 시 계측된 토압은 정적토압보다 감소하는 결과를 보였으며 이는 벽체 관성력이 원인인 것으로 판단된다.

• 한국군사과학기술학회지
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• 제25권1호
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• pp.9-22
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• 2022

A fighter performing a reconnaissance mission is equipped with a pod that drives optical/infrared sensors for acquiring and identifying target information on the lower part of the fuselage. Due to the nature of the reconnaissance mission, the fighter performs high speed evasive maneuvers, and the resulting load should be considered importantly for the development of the pod. This paper concerns a numerical investigation into the inertial and aerodynamic loads of the airborne pod of high performance aircrafts. For the aerodynamic load analysis, the pylon and pod shapes are added to the fighter 3D model, and the commercial software was used for static and dynamic analysis. Considering the practical mission conditions, the common/extreme conditions were established respectively in the static and dynamic situations of pods and the driving torque could be tripled under dynamic conditions. In the analysis of inertia load, a 3-DOF model considering roll and turning maneuvers was derived by the Lagrangian method, and then the numerical integration method was applied to the analysis. As a results, it was conformed that the inertia load was generally induced at a low level compared to the aerodynamic load, but depending on the unbalance mass condition of the pod, the inertia load cannot be negligible.