• Wind and Structures
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• v.21 no.4
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• pp.443-460
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• 2015

In this paper, an integrator based method to estimate the effective wind speed in wind turbine systems is proposed. First, the aerodynamic torque was accurately estimated through a proportional gain based observer where the generator speed is the measured output of the system. The torque signal contains not only useful frequencies of the wind, but also high frequencies and the ones due to structural vibration. The useful information of the wind signal is low frequency. A spectral analysis permitted the determination of the useful frequencies. The high frequencies were then filtered before introducing the torque signal in the wind speed observer. The desired effective wind speed was extracted through an integrator based observer using the previously estimated aerodynamic torque. The strength of the method is to avoid numerical solutions used in literature of the wind speed estimation. The effectiveness of the proposed wind speed estimator and its use to control the generator speed has been tested under turbulent situations using the FAST software (Fatigue, Aerodynamics, Structures, and Turbulence), for large scale Megawatt turbine.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1751-1756
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• 2007

This paper presents a high performance pressure control scheme for SR(Switched Reluctance) type hydraulic oil pump using DITC(Direct Instantaneous Torque Control). SR drive has a good feature for pump applications due to a high efficiency, high speed and high torque characteristics. But, SR drive has high torque ripple in commutation region. So, the pump pressure variation is high in the region. In order to reduce the pressure variation, DITC combined with pressure control scheme is presented in this paper. A simple PI controller with flow and pressure limit, generates a reference torque to keep the constant actual pump pressure. The direct torque controller of SR drive generates inverter switching signals according to a control rule and a torque estimator. Computer simulation and experiemtal results show the validation of the proposed control scheme.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.64-72
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• 1991

This paper deals with the state estimator and controller. All state variables' feedback in the system were used to improve electro hydraulic servo sysem were used to improve electro hydraulic servo system's responese charact- eristics. Many gains of the state variables'and estimator's are produced by the algebraic Riccati equation, and every state variables'optimal gain and estimator gain is selected by trial and error method. For the designed estimator performance's examination, this paper simulate the time response for the step input, the reduced velocity output in subjected to load torque, and the time response for the step input in changing the inertiamoment.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.16-18
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• 2007

In this paper, an advanced DTC(Direct Torque Control) scheme for PMSM(Permanent Magnet Synchronous Motor) is presented. The proposed DTC method uses a conventional torque estimator and torque error. But the switching signal is generated by PWM method according to the switching rules and torque error. A simple calculation of PMW without any complex determination of space vector can assure the constant switching frequency with an excellent control performance. The proposed torque control scheme for PMSM is verified by computer simulation.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.576-578
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• 1994

In this. paper, a new technique to estimate both the instantaneous speed and disturbance load torque using a low precision shaft encoder in very low speed range is proposed. To detect the instantaneous speed and disturbance load torque, the Kalman filter which is an optimal full order estimator is used. Experimental results conform the validity of the proposed estimation technique. The effects of parameter variations are discussed, and it is verified that the system is robust to the modeling error.

• Journal of Auto-vehicle Safety Association
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• v.12 no.3
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• pp.13-19
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• 2020

This paper presents steering controller for unintended lane departure avoidance under crosswind using vehicle lateral disturbance estimation. Vehicles exposed to crosswind are more likely to deviate from lane, which can lead to accidents. To prevent this, a lateral disturbance estimator and steering controller for compensating disturbance have been proposed. The disturbance affecting lateral motion of the vehicle is estimated using Kalman filter, which is on the basis of the 2-DOF bicycle model and Electric Power Steering (EPS) module. A sliding mode controller is designed to avoid unintended the lane departure using the estimated disturbance. The controller is based on the 2-DOF bicycle model and the vision-based error dynamic model. A torque controller is used to provide appropriate assist torque to driver. The performance of proposed estimator and controller is evaluated via computer simulation using Matlab/Simulink.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.10
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• pp.555-561
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• 1999

This paper proposes a new compensation algorithm for stator resistance that is crucial for improving the direct vector control performance of an induction motor. This algorithm is based on the flux estimator that is derived from the stator voltage equation. Since a flux estimator is dependent on the stator resistance, a flux error originates from the variation of the stator resistance. This parameter mismatch in the estimator thereafter affects the flux and torque response. Accordingly, a new compensator has been designed to offset this degradation in the responses. The proposed compensator is very simple to implement and does not require any modifications to the motor model or any special interruptions of the controller. The value of the stator resistance is attained in real time through measuring the terminal voltage and current. The effectiveness of the proposed scheme has been confirmed through both simulation and experimentation.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.899-905
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• 2014

In this paper, we propose a method that can be used to back-stepping controller design for speed control of Brushless Direct Current (BLDC) motor. First, back-stepping controller is designed with load torque estimator. The estimator is included to adapt to the variation of load torque in real time. Finally, the proposed controller is tested through experiment with a 120W BLDC motor for the angular velocity reference tracking performance and load torque volatility estimation. The simulation result verifies the performance of the proposed controller.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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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.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.133-138
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• 1993

This paper presents neural network based position estimation method in slippery environment as an approach to solve one of problems which are engaged in dead reckoning method. Position estimator is composed of slip detector and linear velocity estimator. Both of them are based on the fact that dynamic characteristic of mobile robot in slippery environment is different from the case without slip. To find out the dynamic relation among driving torque, angular acceleration of driving wheel and linear acceleration of mobile robot, accelerometer is used for measuring acceleration of mobile robot and neural network is used for dynamic system identifier in slippery environment.