• 대한기계학회논문집A
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• 제41권8호
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• pp.783-789
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• 2017

9축 IMMU기반의 3차원 자세추정에 있어 대표적인 정확성 저하요인은 가속도계 신호를 교란시키는 외부가속도와 지자기센서 신호와 관련된 자기교란이라는 두 가지 교란성분이다. 교란성분에 의한 영향을 최소화하기 위해 모델링기반 기법과 스위칭 기법이 제안되어 왔고, 이를 비교한 연구도 진행된 바 있다. 그러나 모델링기반 기법에서 모델링의 차이가 자세추정 성능에 미치는 영향에 대한 연구는 현재까지 발표된 바 없다. 본 논문은 교란성분 모델링이 IMMU기반 자세추정 정확성에 미치는 영향을 확인하기 위해, 모델링에 차이가 있는 최근 발표된 두 알고리즘을 다양한 시험조건에서 비교하였다. 이를 통해 교란성분 모델링의 차이는 진행잡음 공분산 행렬에 차이를 발생시키며, 이로 인해 자세추정 성능에 영향을 끼칠 수 있음을 확인할 수 있었다. 시험결과 두 알고리즘은 평균제곱근오차에서 롤 피치 요평균 $1.35^{\circ}$ 및 요성분 $3.63^{\circ}$의 차이를 발생시켰다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1998년도 추계학술대회논문집:21세기에 대비한 지능형 통합항만관리
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• pp.175-180
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• 1998

In container crane system, the variation of cargo weight have effect on the travelling and sway control of load. For precise travelling and/or anti-sway control of crane system, the cargo weight should be measured and considered with control algorithm. But, and added attachment for measuring the cargo weight put restraint upon the control freedom for travelling and anti-sway. In this paper, we propose an estimation method for cargo weight in container crane system by using observation technique. First of all, we model the container crane system as a bilinear system and transform this model into linear system with external disturbance model. Second, we propose a generalized type - disturbance estimation observer and set a disturbance model, where, the cargo weight is related with the sway of load, and the sway is represented as a periodic external disturbance. Lastly, by using simulation we verify that the proposed algorithm of disturbance estimation observer is effective to estimate the cargo weight, and it will be used with anti-sway control algorithm.

• 제어로봇시스템학회논문지
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• 제10권1호
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• pp.15-21
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• 2004

This paper deals with asymptotic stabilization problems for linear systems with time-varying input disturbances. In order to eliminate the influence of a disturbance on the system, a disturbance observer is designed and the time-varying disturbance can be rejected using its estimated value. Since the disturbance observer is kind of low-pass filter, it has inevitably estimation errors. To eliminate the inflences on the performance due to these errors, the additional control is designed based on these estimation errors using a well-known min-max control method. It is shown that the asymptotic stability of the closed-loop system is guaranteed. In general, the min-max control method requires the switching of control inputs and the switching magnitude of the control input is determined by the disturbance estimation error bounds. As the error bounds can be made arbitrarily small by choosing the high gain for the disturbance observer, the control method suggested in this paper can reduce the chattering phenomena as small as possible. Therefore, it has superior performance to the existing ones.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1166-1171
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• 2001

The method for output disturbance estimation is proposed. In this method, output disturbance is estimated from the closed loop system dynamics using the output and control input signals. In the closed-loop output-disturbance estimator, precise system identification is required to reduce estimation error. The realization of estimator was done by the DSP board (DSPl103), and disturbance estimation in various environments was performed： change of rotation speed, media feature and spindle motor with (or without) auto-ball balancing system (ABS). From these experiments, the disturbance characteristics of ODD under various conditions are analyzed, and the desirable servo loop configuration based these results is proposed.

• 반도체디스플레이기술학회지
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• 제11권3호
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• pp.13-18
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• 2012

This paper presents a velocity disturbance estimation system for the stable fine seek control using a genetic algorithm. To estimate accurately the velocity disturbance in spite of the uncertainties of fine actuator, the system utilizes an objective function to minimize the differences of the frequency characteristics between the nominal velocity control loop and the extremal velocity control loops. The objective function is considered by applying a genetic algorithm and the velocity disturbance is estimated by the measurable velocity, the adjusted velocity controller, and the fine actuator model. The proposed velocity disturbance estimation system is applied to the fine seek control system of a DVD recording device and is evaluated through the experimental results.

• 조명전기설비학회논문지
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• 제27권4호
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• pp.62-72
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• 2013

To operate an automatic picking system in distribution center with high precision and high dynamics, this paper presents a robust control scheme of a linear induction motor (LIM) using the mass estimation and disturbance force observer. The force disturbance which gives a direct influence on the control performance of LIM is estimated in real-time through the disturbance observer and compensated by a feedforward manner. To get a satisfactory performance even under the mass variation by reducing the disturbance force due to the mismatched mass during the speed transient such as the acceleration and deceleration periods, a mass estimation algorithm is proposed. A Simulink model for LIM is developed and the validity of the proposed scheme is verified through the comparative simulation studies using Matlab - Simulink.

• 센서학회지
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• 제26권4호
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• pp.286-291
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• 2017

With regards to heading estimation using gyroscope and magnetometer signals, magnetic disturbance added in the magnetometer signals is a main degradation factor in the estimation accuracy. Although there are a number of existing mechanisms that may properly compensate for the magnetic disturbances, they are designed to react only to the magnetic disturbances, but not to the time derivative of disturbances. Note that the sensors may experience abrupt changes in the magnetic disturbances, particularly for ambulatory applications. This paper proposes a magnetic disturbance model-embedded heading estimation filter for time-varying magnetic environments. The proposed magnetic disturbance model is based on a first-order Markov chain with a conditional switching technique depending on the time derivative of disturbances. Once a high amount of derivative is detected, the corrupted magnetometer signals are discarded to protect the filter from them. In our experimental results, the averaged heading error of tests was $1.46^{\circ}$, while that of the original approach without switching was $5.75^{\circ}$.

• 대한전기학회논문지:전력기술부문A
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• 제48권9호
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• pp.1140-1146
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• 1999

In this paper, a force estimation method is proposed for force control without force sensor. For this , a disturbance observer is applied to each joint of an {{{{ { n}_{ } }}}} degrees of freedom manipulator to obtain a simple equivalent robot dynamics(SERD) being represented as an n independent double integrator system. To estimate the output of disturbance observer due to internal torque, the disturbance observer output estimator(DOOE) is designed, where uncertain parameters of the robot manipulator are adjusted by the gradient method to minimize the performance index which is defined as the quadratic form of the error signal between the output of disturbance observer and that of DOOE. when the external force is exerted, the external force is estimated by the difference between the output of disturbance observer and DOOE, since output of disturbance observer includes the external torque signal as well as the internal torque estimated by the output of DOOE. And then, a force controller is designed for force feedback control employing the estimated force signal. To verify the effectiveness of the proposed force estimation method, several numerical examples and experimental results are illustrated for the 2-axis direct drive robot manipulator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.319.1-319
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• 2002

A frequency-domain PES estimation and its prediction method are proposed for the tightly-coupled servo/mechanical design of high-TPI HDD system above 100kTPI. The major two disturbance energies which are related with mechanical vibrations inside of HDD are used to predict the drive-level PES, while considering closed-loop servo dynamics. One is the torque disturbance which mainly comes from aerodynamic excitation of HSA system and the other is the displacement disturbance from disk-spindle dynamics. (omitted)

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.48.5-48
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• 2001

The resulting stabilizing controller in this paper consists of the disturbance estimator and the gain scheduled controller. The disturbance estimator tracks the unknown external disturbance and its derivative information in the closed-loop control system using fuzzy logic based adaptation law. Moreover, the gains of the stabilizing controller are appropriately scheduled according to the estimated values. Furthermore, since the estimation law is combined with the stabilizing controller in the closed control loop, it asymptotically minimizes the estimation error. In order to conrm the usefulness of the proposed control scheme, it is applied to the magnetic suspension systems.