• 로봇학회논문지
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• 제18권3호
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• pp.241-250
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• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• Transactions on Control, Automation and Systems Engineering
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• 제3권3호
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• pp.176-180
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• 2001

In this papers, we derive a simple kinematic and dynamic formulation of an unmanned electric bicycle. We also check the controllability of the stabilization problem of bicycle. We propose a new control algorithm for the self stabilization of unmanned bicycle with bounded wheel speed and steering angle by using nonlinear control based on the sliding patch and stuck phenomena which was introduced by W. Ham. We also propose a sort of optimal control strategy for steering angle and driving wheel speed that make the length of bicycle\`s path be the shortest. From the computer simulation results, we prove the validity of the proposed control algorithm.

• 한국정밀공학회지
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• 제25권7호
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• pp.72-78
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• 2008

The line-of-sight(LOS) stabilization system is a precision electro-mechanical gimbals assembly for suppressing vibration due to its environment and tracking the target in a desired direction. This paper describes the design of gimbals system to reject the disturbance and to improve stabilization. The controller consists of a DSP with transducer and actuator interfaces. Unknown parameters of the gimbals are estimated by the signal compression method. The cross-correlation coefficient between the impulse response from the assumed model and the one from model of the gimbals is used to obtain the better estimation. The quasi-impulse response through linear element included in the gimbals could be obtained by the signal compression method. The unknown parameter of the linear element could be estimated as comparing the bode plots for impulse response from gimbals with them from model's response.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3177-3195
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• 2014

In many moving object detection problems of an aerial video, accurate and robust stabilization is of critical importance. In this paper, a novel accurate image alignment algorithm for aerial electronic image stabilization (EIS) is described. The feature points are first selected using optimal derivative filters based Harris detector, which can improve differentiation accuracy and obtain the precise coordinates of feature points. Then we choose the Delaunay Triangulation edges to find the matching pairs between feature points in overlapping images. The most "useful" matching points that belong to the background are used to find the global transformation parameters using the projective invariant. Finally, intentional motion of the camera is accumulated for correction by Sage-Husa adaptive filtering. Experiment results illustrate that the proposed algorithm is applied to the aerial captured video sequences with various dynamic scenes for performance demonstrations.

• 한국항공우주학회지
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• 제32권3호
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• pp.95-101
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• 2004

액체 로켓엔진 개발과정에서 수행되는 여러 가지 시험 중 연소 안정성 평가 시험을 통해, KSR-III 로켓엔진의 연소 안정성을 평가하였다. 안정성 평가시험에서, 엔진이 외부 교란에 의한 압력 진동을 감쇠시켜 본래의 안정한 연소를 회복하는 경우, 그 엔진은 연소 안정 화 능력을 가지고 있다고 판정할 수 있다. 로켓엔진은, 교란의 크기를 예측하기 어려운 외부 섭동에 노출될 수 있으므로, 연소 안정화 가능 여부를 확인하는 것과 더불어 엔진이 갖고 있는 연소 안정화 성능을 정량화하여 파악하는 작업이 필요하다. 이를 위해 몇 가지 주요 인자를 도입하였고, 이를 평가하는 방법을 검토하였다. 성공적으로 완료된 KSR-III 로켓 개발과정에서 로켓엔진의 안정성 확보를 위해 6회의 안정성 평가 시험이 수행되었다. 이를 토대로, 연소 안정화 성능의 정량화 방법을 KSR-III 엔진에 적용하여 엔진의 안정화 성능을 분석하였다.

• International Journal of Contents
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• 제9권4호
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• pp.72-77
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• 2013

The purpose of this study was to examine the effects of general sling-bridge exercise (GSE) and sling-bridge exercise with rhythmic stabilization technique (SER) on trunk muscle endurance and flexibility in adolescents with low back pain (LBP). 30 adolescents who had complaints of LBP were randomly assigned to one of the two groups: the GSE group (n=15) and SER group (n=15). Subjects performed each exercise programs for 4 weeks with the aim of improving trunk muscle stability; GSE group trained general bridge exercise with sling, SER group trained rhythmic stabilization bridge exercise with sling. The static and dynamic trunk muscle endurance and flexibility were measured before and at the end of the exercise program. The static and dynamic trunk muscle endurance were significantly improved in both groups (p<.05) and the SER group showed significant difference from the GSE group after the exercise (p<.05). The trunk muscle flexibility was significantly improved in both groups (p<.05) and the SER group were significantly different from GSE group post-exercise (p<.05). The results of this study showed that sling bridge exercise with rhythmic stabilization technique may be appropriate for improving trunk muscle stability in adolescents with LBP.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.538-538
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• 2000

This paper presents a learning controller for repetitive gate control of biped robot. The learning control scheme consists of a feedforward learning rule and linear feedback control input for stabilization of learning system. The feasibility of teaming control to biped robotic motion is shown via dynamic simulation with 12 dof biped robot.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.79-81
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• 2009

In this paper, we design a dynamic state feedback smooth stabilizer for a nonlinear system whose Jacobian linearization may have uncontrollable because its eigenvalues are on the right half-plane. After designing an augmented system, a dynamic exponent scaling and backstepping enable one to explicitly design a smooth stabilizer and a continuously differentiable Lyapunov function which is positive definite and proper.

• 전자공학회논문지SC
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• 제46권2호
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• pp.7-14
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• 2009

본 논문에서는 불확실성을 가지는 비선형 시스템에 대한 강인 유한 시간 안정화 문제를 고려한다. 불확실성은 시변 외란 혹은 이미 알고 있는 옹골 집합에 포함된 파라미터들이다. 제안된 설계기법은 역진기법(backstepping)과 추가된 다이나믹스를 이용한 다이나믹 지수 보정법(dynamic exponent scaling)에 기반을 두고 있으며, 이로부터 다이나믹 스무스 궤환 제어기(dynamic smooth feedback controller)가 유도된다. 페루프 시스템의 유한 시간 안정과 제어기의 유한함은 각각 유한 시간 안정에 관한 리아푸노프 안정 이론과 새로운 개념인 '차수 지표자(degree indicator)'를 이용하여 증명된다.

• 정보처리학회논문지A
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• 제10A권6호
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• pp.677-684
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• 2003

VOD 서비스의 대부분 정책들은 주로 서버 시스템에 대해 연구되고 있고, 단절감 없는 재생과 재생질 보증의 근간이 되는 클라이언트의 버퍼 안정화 문제에 대해서는 언급되지 않고 있다. 본 논문에서는 클라이언트의 버퍼 상태가 스타베이션 또는 오버런인 경우 서버에 동적인 제어신호를 발하고, 서버에서는 수신된 제어 요구 신호에 따라 프레임을 생략하여 전송하는 정책을 제안한다. 그리고 시뮬레이션을 통하여 제안 정책이 클라이언트의 버퍼 상태 악화로 인한 프레임의 미수신 및 손실을 방지하여 클라이언트의 버퍼를 안정화시켜 재생질 보증에 더 효율적임을 보인다.