• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.251-260
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• 1998

A DSP-based robust nonlinear speed control of a permanent magnet synchronous motor(PMSM) which is robust to unknown parameter variations and speed measurement error is presented. The model reference adaptive system(MRAS) based adaptation mechanisms for the estimation of slowly varying parameters are derived using the Lyapunov stability theory. For the disturbances or quickly varying parameters. a quasi-linearized and decoupled model including the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode controller to improve the robustness and performance of the nonlinear speed control of a PMSM is designed and compared with the conventional controller. To show the validity of the proposed control scheme, simulations and experimental works are carried out and compared with the conventional control scheme.

• Journal of Power Electronics
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• 제11권5호
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• pp.655-661
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• 2011

This paper presents two topologies for single-stage single-phase double-buck type PFC converters, designed to operate at high power factor, near sinusoidal input currents and adjustable output voltage. Unlike the known buck type PFC topologies, in which the output voltage is always lower than the maximum input voltage, the proposed converters can operate at output voltages higher than the ac input peak voltage. A reduced number of switches on the main path of the current are another characteristic of the two proposed topologies. To shape the input line currents, a fast and robust controller based on a sliding mode approach is proposed. This active non-linear control strategy, applied to these converters allows high quality input currents. A Proportional Integral (PI) controller is adopted to regulate the output voltage of the converters. This external voltage controller modulates the amplitude of the sinusoidal input current references. The performances of the presented rectifiers are verified with experimental results.

• 한국생산제조학회지
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• 제20권2호
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• pp.121-128
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• 2011

As high precision industries such as semiconductor, TFT-LCD manufacturing and MEMS continue to grow, the demand for higher DOF precision stages has been increasing. In general, the stages should accommodate a prescribed range of payloads in order to position various precision manufacturing/inspection instruments. Therefore a nonlinear controller using sliding motion is developed, which bears mass perturbation and makes the upper plate of the stage move in 6 DOF. For the application of the nonlinear control, an observer is also developed based on expected noise covariance. To eliminate the steady state error of step response, integral terms are inserted into the state-space model. The linear term of the controller is designed using optimization scheme in which parameters can be weighted according to their physical significance, whereas the nonlinear term of the controller is designed using trial and error method. A comprehensive simulation study proves that the designed controller is robust against mass perturbation and completely eliminates steady state errors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.936-941
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• 2004

An Optimal Feedforward Integral Variable Structure or FIVSC approach for an electrohydraulic position servo control system is presented in this paper. The FIVSC algorithm combines feedforward strategy and integral in the conventional Variable Structure Control (VSC) and calculating the control function to guarantee the existence of a sliding mode. Furthermore, the chattering in the control signal is suppressed by replacing the sign function in the control function with a smoothing function. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances when compared with some existing control methods, like the IVSC and MIVSC strategies. Simulation results illustrate that the purposed approach can achieve a zero steady state error for ramp input and has an optimal motion with respect to a quadratic performance index. Moreover, Its can achieve accurate servo tracking in the presence of plant parameter variation and external load disturbances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1337-1338
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• 2015

In this paper, a new control technique using WIPDC(Weighted Integral Parallel Distributed Compensation) and ISMC(Integral Sliding Mode Control) is proposed for high performance and robust trajectory tracking control of a wheeled mobile robot. The WIPDC reduces the steady-state error by adding a weighted integral controller to the PDC. So, the trajectory tracking control using the WIPDC can obtain more accurate control performance than the PDC. And the ISMC based control input gives the mobile robot to preserve the system dynamics controlled by the WIPDC control input in spite of external disturbances. Therefore, the proposed control method shows a robust and precise trajectory tracking performance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.442-445
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• 1991

In the physical system, if we can precisely control an acceleration and force, we can improve the performance of their integral values, velocity and position. From this point of view, in this paper we try to use an obverser which is constructed by using Variable Structure System for estimating the acceleration in the system with the bounded unknown disturbance and the parameter mismatching. To obtain the robust control performance, the VSS with sliding mode is adopted in the design of the servo controller.

• 대한기계학회논문집
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• 제17권2호
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• pp.385-392
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• 1993

This paper presents a new stable composite control law for the flexible joint robot manipulators, which incorporate an additional stabilizing control law with the sliding property. The singularly perturbated models in this paper include inertia moments which are functions or the deformations of actuators as well as link positions. The values of renewedly defined fast controller variables are computer from the corrected reduced-order model without additional computational loads. Proposed schemes are compared with the conventional one. The simulations for 2 DOF flexible joint manipulator show that the proposed schemes are more stable than the conventional scheme, and especially effective for the manipulator with high joint-flexibilities.

• 한국정보통신학회논문지
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• 제19권7호
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• pp.1660-1670
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• 2015

불확실성에 강인한 제어기에 대한 연구는 활발하지만 대부분의 연구들은 제어 이론의 효용성을 검증하기 위한 실험 수준에 머무르거나 특정한 전용시스템에만 구현되고 있어 범용성을 가지는 상용화된 제품에는 적용되지 못하고 있다. 따라서 본 논문에서는 슬라이딩모드제어기와 외란관측기를 이용한 보다 실용적인 강인한 제어기를 제안하였다. 도달시간을 제거하고 정상상태오차를 최소화하기 위해 적분슬라이딩모드를 이용하였고, 외란관측기를 적용하여 스위칭 입력의 채터링을 감소시켰다. 또한 아직까지 남아있는 채터링은 데드존 함수를 이용함으로써 완전히 제거하였다. 제안된 제어기는 PID제어기에 비해 개선된 정상상태 오차와 강인성을 보인다.

• 한국정보통신학회논문지
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• 제21권6호
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• pp.1203-1211
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• 2017

본 논문은 유연관절로봇의 추종성능과 정합과 비정합 외란 모두에 대한 강인성을 향상시키기 위한 강인한 제어기를 제안한다. 제안된 제어기는 백스테핑 외란관측기(DOB), 수동성기반 제어기(PBC)와 적분슬라이딩모드 제어기(ISMC)가 백스테핑기법 형태로 구성되어 있다. 백스테핑 DOB는 링크측의 비정합 외란을 고려하는데 사용되며 모터측의 기준입력을 제공하는 역할을 한다. IDA-PBC는 모터측의 추종제어를 수행하며 적분슬라이딩모드제어와 결합될 때 공칭제어기의 역할을 하며 전체 공칭제어시스템의 안정도를 보장받도록 한다. 반면에 적분슬라이딩모드제어는 정합조건을 만족시키는 모터측의 외란의 영향을 제거하는데 사용된다. 링크측의 제어기를 설계하는데 있어서는 PD타입의 임피던스제어기와 DOB가 결합됨으로써 강인한 제어특성과 함께 모터측의 기준입력에 적합한 연속적인 입력의 제공이 가능하도록 하였다.

• 한국정보통신학회논문지
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• 제21권1호
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• pp.173-179
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• 2017

본 논문은 고자유도의 로봇에 대한 강인한 임피던스제어를 제안한다. 자유도가 높은 로봇에 대해서 동특성기반으로 제어하기 위해서는 해석적인 로봇의 동특성확보가 거의 불가능하기 때문에 수치해석적인 모델을 사용하게 된다. 이에 근본적으로 모델링오차가 존재하고 작업공간에서 임피던스제어기를 설계하는 경우에 많은 개수의 관절의 움직임의 영향을 받기 때문에 강인제어의 필요성이 더욱 절실하다. 이에 모델링 불확실성과 외란의 존재와 상관없이 원하는 임피던스를 유지하기 위해서는 공칭계통의 동특성에 슬라이딩모드의 강인성을 추가할 수 있는 적분슬라이딩모드제어를 도입하였고 입력외란의 영향을 제거할 수 있는 외란 관측기를 동시에 적용한 강인한 임피던스제어기를 제안하였다. 외란과 모델 불확실성이 존재함에도 불구하고 공칭계통을 기반으로 한 임피던스제어기의 특성을 그대로 유지할 수 있는 제어기가 설계되었다.