• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.667-673
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• 2010

This paper proposes a control method based on a pseudo-impedance model to control the motion of biped robots walking on an uneven surface. The pseudo-impedance model simulates the action of the ankle of a foot landing on the ground when a human walks. When the foot is in contact with the ground, the human ankle goes through two different phases. In the first phase, the human exerts little or no effort and applies no torque on the ankle so that the orientation of the foot is effortlessly and passively adjusted with respect to the ground. In the second phase of landing, the ankle generates a significant amount of torque in order to rotate and move the main part of the human body forward and to support the weight of the human; this phase is called the weight acceptance phase. Computer simulations of a 12-DOF biped robot with a 6-DOF environment model were performed to determine the effectiveness of the proposed pseudo-impedance control. The simulation results show that stable locomotion can be achieved on an irregular surface by using the proposed model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.910-919
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• 2015

A weapon control algorithm equipped on a fighter is closely related to the mission accomplishment and fighter survivability during the engagement. In the case of a air-to-surface missile, the weapon control algorithm typically provides a pilot the target shoot-down possible region known as launch acceptability region(LAR) in the multi function display(MFD). LAR is produced by the range table(RT) through computation of an engagement range. In this paper, the operation system of AGM-84 and AGM-88 air-to-surface missiles is introduced. And the engagement range computation and LAR algorithm based on the real-time pseudo 6-DOF simulation are proposed. In order to verify the performance of the algorithm, numerical engagement simulations of air-to-surface missiles to produce LAR have been done.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.762-772
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• 2014

A weapon control algorithm equipped on a fighter is closely related to the mission accomplishment and fighter survivability during engagement. The weapon control algorithm typically provides a pilot the dynamic launch zone(DLZ), the target shoot-down range of air-to-air missiles, in the head-up display(HUD). DLZ is produced by an engagement range computation algorithm. In this paper, the components of DLZ for AIM-9 and AIM-120 air-to-air missiles are introduced. The real-time computation algorithm for DLZ based on the pseudo 6-DOF program is then addressed The operational aspects of DLZ algorithm for the air-to-air missiles to various engagement scenarios is investigated vis simulations.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.405-412
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• 2017

In the present study, two phase flows around a projectile vertically launched from an underwater platform have been numerically investigated by using a three dimensional multi-phase RANS flow solver based on pseudo-compressibility and a homogeneous mixture model on unstructured meshes. The relative motion between the platform and projectile was described by six degrees of freedom(6DOF) equations of motion with Euler angles and a chimera technique. The propulsive power of the projectile was modeled as the fluid force acting on the lower surface of the body by the compressed air emitted from the platform. Qualitative analysis was conducted for the time history of vapor volume fraction distributions. Uncorking pressure around the projectile and platform was analyzed to predict impact force acting on the surfaces. The results of 6DOF analysis presented similar tendency with the surficial pressure distributions.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.50.6-50
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• 2001

This paper deals with a design of nonlinear glide slope capture logic using dynamic model inversion in singular perturbation, which is applicable to the autolanding in ILS. Aircraft dynamics are separated into the fast time-scale variables, related with the inner-loop design, and the slow time-scale variables, related with the outer-loop design. It is assumed that the aircraft starts landing at 1000ft of altitude, -2.5deg of flight path angle, and 250ft/sec of velocity. In the outer-loop design, commands of altitude and velocity are selected and thereby the pseudo-controls of power level and pitch rate are determined. Also the elevator input to the aircraft is determined in the inner-loop design. The final design is evaluated in 6 DOF simulation model of the associated aircraft, in which the actuator models are not included. The results show the satisfactory autolanding ...

• International Journal of Aeronautical and Space Sciences
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• v.17 no.2
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• pp.204-213
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• 2016

A differential game theory based approach is used to develop an automated maneuver generation algorithm for Within Visual Range (WVR) air-to-air combat of unmanned combat aerial vehicles (UCAVs). The algorithm follows hierarchical decisionmaking structure and performs scoring function matrix calculation based on differential game theory to find the optimal maneuvers against dynamic and challenging combat situation. The score, implying how much air superiority the UCAV has, is computed from the predicted relative geometry, relative distance and velocity of two aircrafts. Security strategy is applied at the decision-making step. Additionally, a barrier function is implemented to keep the airplanes above the altitude lower bound. To shorten the simulation time to make the algorithm more real-time, a moving horizon method is implemented. An F-16 pseudo 6-DOF model is used for realistic simulation. The combat maneuver generation algorithm is verified through three dimensional simulations.

• Wind and Structures
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• v.14 no.5
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• pp.413-434
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• 2011

Without output covariance estimation, one reference-based Stochastic Subspace Technique (SST) for extracting modal parameters and flutter derivatives of bridge deck is developed and programmed. Compared with the covariance-driven SST and the oscillation signals incurred by oncoming or signature turbulence that adopted by previous investigators, the newly-presented identification scheme is less time-consuming in computation and a more desired accuracy should be contributed to high-quality free oscillated signals excited by specific initial displacement. The reliability and identification precision of this technique are confirmed by a numerical example. For the 3-DOF sectional models of Sutong Bridge deck (streamlined) and Suramadu Bridge deck (bluff) in wind tunnel tests, with different wind velocities, the lateral bending, vertical bending, torsional frequencies and damping ratios as well as 18 flutter derivatives are extracted by using SST. The flutter derivatives of two kinds of typical decks are compared with the pseudo-steady theoretical values, and the performance of $H_1{^*}$, $H_3{^*}$, $A_1{^*}$, $A_3{^*}$ is very stable and well-matched with each other, respectively. The lateral direct flutter derivatives $P_5{^*}$, $P_6{^*}$ are comparatively more accurate than other relevant lateral components. Experimental procedure seems to be more critical than identification technique for refining the estimation precision.