• 전기학회논문지
• /
• 제65권4호
• /
• pp.652-658
• /
• 2016

In practical control systems differences between nominal and real systems arise from internal uncertainties and/or external disturbances. This paper presents a model-based low-order disturbance observer for a sinusoidal disturbance with unknown constant offset. By using the disturbance model of a biased harmonic signal, the proposed method can successfully estimate the biased sinusoidal disturbance with unknown amplitude and phase but known frequency. At the first stage of the observer design, a model-based disturbance observer is designed when all the system states are measurable. Next, a sufficient condition is presented for the proposed observer to estimate the sinusoidal disturbance with a minimal-order additional dynamics using only output measurement. Comparative computer simulations are performed to test the performance of the proposed method. The simulation results show the enhanced performance of the proposed disturbance observer.

• 제어로봇시스템학회논문지
• /
• 제20권12호
• /
• pp.1231-1237
• /
• 2014

본 논문에서는 축소 차수 외란 관측기를 이용하여 외란이 있는 이종 다개체 시스템을 위한 협조 추종 제어기를 제안하였다. 이를 위해 우선 주어진 제어 문제가 외란과 모델 불확실성을 가지는 시스템을 위한 강인 제어 문제로 변환 될 수 있음을 보이고 변환된 문제에 외란 관측기 기반의 동적 협조 추종 제어기를 설계하였다. 모의 실험을 통해서 제안하는 이종 다개체 시스템의 협조 추종을 성공적으로 달성함을 보였다.

• 한국전자통신학회논문지
• /
• 제16권3호
• /
• pp.511-518
• /
• 2021

전동기의 좋은 추종 성능을 얻기 위해서는 외란 관측기가 포함되어 외란에 대응할 수 있는 제어기를 설계하는 것이 필요하다. 전동기의 외란 관측기는 1차 저역통과 필터를 기반으로 부하 토크과 역기전압을 추정하도록 설계하였다. 외란 관측기와 제어기의 상호관계를 비교하고, 개선된 제어 성능을 얻기 위하여 PI 제어기와 IP 제어기를 설계하였다. 설계된 관측기와 제어기의 성능을 확인하고자 120 [W]급의 BLDC 전동기에 적용하였다. 그 결과 오버슈트가 줄어들며, 정상상태 오차가 영으로 수렴하는 것을 확인할 수 있다.

• 전기학회논문지
• /
• 제67권11호
• /
• pp.1423-1433
• /
• 2018

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

• 한국해양공학회지
• /
• 제15권1호
• /
• pp.67-72
• /
• 2001

In this study, a methodology of synchronous control which can be applied to position synchronization of a two-axes driving system has been developed. The synchronous error is caused by model uncertainties and torque disturbance of each axis. To overcome these problems, the proposed synchronous control system has been composed of two speed controllers, disturbance observers, and one synchronous controller. The speed controllers, based on the PID control law are aimed at the following to speed reference. And the parameters of speed controllers have been designed in order for the speed response fo the second axis to correspond with the one of the first axis. The disturbance observer has been designed to restrain the torque disturbance. The synchronous controller eliminates the synchronous error by controlling the speed of the second axis. The effectiveness of the proposed method has been verified through simulation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제51권3호
• /
• pp.116-124
• /
• 2002

Design and analysis of disturbance observer-based deadbeat control fur single-phase inverter applications are comprehensively presented in this paper. Load current can be estimated by disturbance observer, which is basically structured with the first order equation in this case and is regarded as a relatively simple method in comparison with conventional full-order Luenberger observer. Also, an inherent one-step delay problem appeared in the deadbeat control method is overcome by a simple prediction technique proposed. Output voltage dip is reduced by the feedforward control with the change rate of the estimated load current involved in the deadbeat current control loop. The proposed algorithms are verified by the respective simulation and experiment results.

• 전자공학회논문지B
• /
• 제31B권9호
• /
• pp.36-46
• /
• 1994

A analog disturbance observer, which is suitable for servo motor drive, was employed to suppressi control of the impact drop disturbance. The main advantage of the observer is that a fast response disturbance estimation is obtained using the detected motor cuttent and speed. And the new M/T method for motor speed detection is proposed. The method should be able to reduce the detection dead time compared with the Ohmae's M/T method. Also, the low speed control of a servo motor using instantaneous speed detection method is described. To estimate the instantaneous speed from the average speed, the speed estimator of the first order is proposed. Actually we confirmed that these methods improve the speed control performance of the servo system with experiments.

• Journal of Electrical Engineering and Technology
• /
• 제12권1호
• /
• pp.272-283
• /
• 2017

In this paper, an improved predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) control system is proposed, on account of the standard PFC method cannot provides a satisfying disturbance rejection performance in the case of strong disturbances. The PFC-based method is first introduced in the control design of speed loop, since the good tracking and robustness properties of the PFC heavily depend on the accuracy of the internal model of the plant. However, in orthodox design of prediction model based control method, disturbances are not considered in the prediction model as well as the control design. A minimum-order observer (MOO) is introduced to estimate the disturbances, which structure is simple and can be realized at a low computational load. This paper adopted the MOO to observe the load torque, and the observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC strategy with torque compensation, called the PFC+MOO method, is presented. The validity of the proposed method was tested via simulation and experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.

• 전기학회논문지
• /
• 제57권9호
• /
• pp.1612-1617
• /
• 2008

Since most disturbance observer (DOB) approaches have been limited to minimum-phase systems (or systems having no zero dynamics), we propose a new DOB structure that can be applied to non-minimum phase systems. The new structure features an additional system, which is called as V-filter, whose role is to yield a minimum phase system when connected with the plant in parallel. In order to design the V-filter systematically we first consider a class of linear systems that can be stabilized via PID controller. By inverting the controller's transfer function, we can simply construct the filter. A convenient way of designing V-filter is presented by using an iterative linear matrix inequality (LMI) algorithm. With an illustrative example the simulation result shows that substantial improvement in the performance has been achieved compared with the control system without the DOB.

• Smart Structures and Systems
• /
• 제25권1호
• /
• pp.37-45
• /
• 2020

This paper aims at enlightening the properties, computational and implementation issues related to Kalman filter based state estimation algorithms and sliding mode observers, by applying them for estimating the states of a smart structure system. The Kalman based estimators considered in this work are Kalman filter and information filter and, the sliding mode observers considered are Utkin observer and higher order sliding mode observer. A fourth order linear time invariant model of a piezo actuated beam is used in this work. This structure is embedded with four number of piezo patches, of which two act as sensors, one as disturbance actuator and the other as control actuator. The performance of the state estimation algorithms is evaluated through simulation, for the first two vibrating modes of the piezo actuated structure, when the structure is maintained at first mode and second mode resonance.