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This article presents an advanced parameter-free velocity observer-based nonlinear decentralized tension control scheme for roll-to-roll systems governed by nonlinear dynamics. The system parameter uncertainties and nonlinear dynamics yield the second-order perturbed nominal open-loop systems, which are used for devising the web velocity and tension control law for each station. The features of this result are summarized as follows: (a) the tension-derivative observers including the disturbance observer mechanism as a subsystem, (b) the observer-based active-damping pole–zero cancellation velocity error stabilizer for each tension loop, and (c) the closed-form nonlinear feedback gain boosters and exponential surface stabilizers to secure the improved transient performance and robustness for web velocity and each tension loop. The various simulation results based on MATLAB/Simulink show both the qualitative and quantitative advantages of the proposed technique.
Seok-Kyoon Kim; Choon Ki Ahn. Observer-based decentralized pole–zero cancellation tension control with gain booster and surface stabilizer for roll-to-roll systems. Nonlinear Dynamics 2021, 105, 2313 -2326.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Observer-based decentralized pole–zero cancellation tension control with gain booster and surface stabilizer for roll-to-roll systems. Nonlinear Dynamics. 2021; 105 (3):2313-2326.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2021. "Observer-based decentralized pole–zero cancellation tension control with gain booster and surface stabilizer for roll-to-roll systems." Nonlinear Dynamics 105, no. 3: 2313-2326.
This paper presents a novel output voltage regulator in the cascade structure under the consideration of both the parameter and load uncertainties. It leads to the first-order closed-loop inner and outer loop dynamics in the low-pass filter form by the pole-zero cancellation through the active damping injection, which is the main contribution of this study. Moreover, it is proved that the active damping injection level determines the disturbance rejection capability of the closed-loop system. A 3-kW DC/DC boost converter confirms the actual advantages from these two contributions.
Sung You; Koo Bonn; Dong Kim; Seok-Kyoon Kim. Cascade-Type Pole-Zero Cancellation Output Voltage Regulator for DC/DC Boost Converters. Energies 2021, 14, 3824 .
AMA StyleSung You, Koo Bonn, Dong Kim, Seok-Kyoon Kim. Cascade-Type Pole-Zero Cancellation Output Voltage Regulator for DC/DC Boost Converters. Energies. 2021; 14 (13):3824.
Chicago/Turabian StyleSung You; Koo Bonn; Dong Kim; Seok-Kyoon Kim. 2021. "Cascade-Type Pole-Zero Cancellation Output Voltage Regulator for DC/DC Boost Converters." Energies 14, no. 13: 3824.
This study aims to accomplish the output voltage tracking task for buck converters without current feedback, diminishing the performance degradation from model-plant mismatches and load variations. The following contributions overcome these difficulties: a) the combination of Luenberger and disturbance observer (DOB) techniques for a parameter-independent voltage-derivative observer, b) the pole-zero cancellation control incorporating the DOB and active-damping injection techniques, and c) the exponential convergence guarantee to the target tracking system subject to the variable convergence rate mechanism. Convincing experimental evidence confirms the effectiveness of proposed tracking control using a prototype 3-kW buck converter control system.
Seok-Kyoon Kim; Ki-Chan Kim; Choon Ki Ahn. Output-voltage-tracking Control for Buck Converters using Variable Convergence Rate Mechanism without Current Feedback. IEEE Transactions on Industrial Electronics 2021, PP, 1 -1.
AMA StyleSeok-Kyoon Kim, Ki-Chan Kim, Choon Ki Ahn. Output-voltage-tracking Control for Buck Converters using Variable Convergence Rate Mechanism without Current Feedback. IEEE Transactions on Industrial Electronics. 2021; PP (99):1-1.
Chicago/Turabian StyleSeok-Kyoon Kim; Ki-Chan Kim; Choon Ki Ahn. 2021. "Output-voltage-tracking Control for Buck Converters using Variable Convergence Rate Mechanism without Current Feedback." IEEE Transactions on Industrial Electronics PP, no. 99: 1-1.
This study suggests an intelligent position-tracking control algorithm for rover vehicles considering actuator (DC motor) dynamics. The parameter and load uncertainties in the vehicle and DC motor dynamics are explicitly handled by modifying the original open-loop system dynamics. The proposed controller forms the conventional multi-loop structure including disturbance observers (DOBs) for each loop. The features of this study fall into three parts: first, the learning part from the real-time feedback gain mechanism (named the self-tuner) in the closed-form for outer loop; second, the adaptation part from the online wheel radius estimation securing the outer-loop control accuracy; and third, the parameter-independent angular acceleration observer-based pole-zero cancellation DC motor speed controller without current feedback considering the inner- and outer-loop vehicle control algorithms. Experimental evidence is also provided to demonstrate the practical merits of the proposed technique with the use of the TETRIX, myRIO-1900, and LabVIEW.
Seok-Kyoon Kim; Jae Kyung Park; Choon Ki Ahn. Learning and Adaptation-based Position-tracking Controller for Rover Vehicle Applications Considering Actuator Dynamics. IEEE Transactions on Industrial Electronics 2021, PP, 1 -1.
AMA StyleSeok-Kyoon Kim, Jae Kyung Park, Choon Ki Ahn. Learning and Adaptation-based Position-tracking Controller for Rover Vehicle Applications Considering Actuator Dynamics. IEEE Transactions on Industrial Electronics. 2021; PP (99):1-1.
Chicago/Turabian StyleSeok-Kyoon Kim; Jae Kyung Park; Choon Ki Ahn. 2021. "Learning and Adaptation-based Position-tracking Controller for Rover Vehicle Applications Considering Actuator Dynamics." IEEE Transactions on Industrial Electronics PP, no. 99: 1-1.
The proposed observer-based control mechanism solves the trajectory tracking problem in the presence of external disturbances with the reduction in sensor numbers. This systematically considers the quadcopter nonlinear dynamics and parameter and load variations by adopting the standard controller design approach based on a disturbance observer (DOB). The first feature is designing first-order observers for estimating the velocity and angular velocity error, with their parameter independence obtained from the DOB design technique. As the second feature, the resultant velocity observer-based control action including active damping and DOBs secures first-order tracking behavior for the position and attitude (angle) loops through pole zero cancellation, thereby forming a proportional–derivative control structure. Closed-loop analysis results reveal the performance recovery and steady-state error removal properties in the absence of tracking error integrators. The numerical verification confirms the effectiveness of the proposed mechanism using MATLAB/Simulink.
Seok-Kyoon Kim; Choon Ki Ahn. Velocity-sensorless proportional–derivative trajectory tracking control with active damping for quadcopters. Nonlinear Dynamics 2021, 103, 1681 -1692.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Velocity-sensorless proportional–derivative trajectory tracking control with active damping for quadcopters. Nonlinear Dynamics. 2021; 103 (2):1681-1692.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2021. "Velocity-sensorless proportional–derivative trajectory tracking control with active damping for quadcopters." Nonlinear Dynamics 103, no. 2: 1681-1692.
This study presents a novel energy-shaping technique-based speed controller for permanent-magnet synchronous motors (PMSMs) considering machine nonlinearities and load and parameter changes. There are three features: The time-varying damping term is injected into the speed loop, which is automatically updated by the proposed self-tuner. The disturbance observers are designed for both the speed and current loops to achieve better disturbance rejection performance with removal of offset errors without the use of tracking error integral actions. Furthermore, the closed-loop analysis result is provided to demonstrate its beneficial closed-loop properties. The practical advantages are experimentally verified in several convincing scenarios with a prototype 500-W PMSM driven by a three-phase inverter.
Seok-Kyoon Kim; Yonghun Kim; Choon Ki Ahn. Energy-Shaping Speed Controller With Time-Varying Damping Injection for Permanent-Magnet Synchronous Motors. IEEE Transactions on Circuits and Systems II: Express Briefs 2021, 68, 381 -385.
AMA StyleSeok-Kyoon Kim, Yonghun Kim, Choon Ki Ahn. Energy-Shaping Speed Controller With Time-Varying Damping Injection for Permanent-Magnet Synchronous Motors. IEEE Transactions on Circuits and Systems II: Express Briefs. 2021; 68 (1):381-385.
Chicago/Turabian StyleSeok-Kyoon Kim; Yonghun Kim; Choon Ki Ahn. 2021. "Energy-Shaping Speed Controller With Time-Varying Damping Injection for Permanent-Magnet Synchronous Motors." IEEE Transactions on Circuits and Systems II: Express Briefs 68, no. 1: 381-385.
This article devises a novel signal-filtering technique subject to the feedback structure without the exact source signal dynamics information. The main idea of this result is comprised of two parts: first, the combination of the Luenberger and disturbance observer design techniques to improve the disturbance rejection capability in the feedback structure; second, the closed-form filtering gain-boosting mechanism updating the gain into the direction of the filtering error reduction. It is experimentally confirmed that the proposed filter contributes to lowering the current regulation performance degradation level from the filtering performance improvement using a 500-W permanent-magnet synchronous motor driven by the three-phase inverter.
Seok-Kyoon Kim; Ki-Chan Kim; Choon Ki Ahn. Nonlinear Signal-Filtering Technique With Real-Time Gain Booster for Feedback System Applications. IEEE Signal Processing Letters 2020, 27, 2183 -2187.
AMA StyleSeok-Kyoon Kim, Ki-Chan Kim, Choon Ki Ahn. Nonlinear Signal-Filtering Technique With Real-Time Gain Booster for Feedback System Applications. IEEE Signal Processing Letters. 2020; 27 (99):2183-2187.
Chicago/Turabian StyleSeok-Kyoon Kim; Ki-Chan Kim; Choon Ki Ahn. 2020. "Nonlinear Signal-Filtering Technique With Real-Time Gain Booster for Feedback System Applications." IEEE Signal Processing Letters 27, no. 99: 2183-2187.
This paper develops an observer-based positioning scheme for ball-beam systems considering actuator dynamics. The practical constraints are handled systematically, including the mechanical dynamical nonlinearities, mismatched load disturbances, and parameter uncertainties. This result provides contributions as follows. First, parameter-independent observers exponentially estimate the ball velocity, motor speed, and its acceleration to remove the velocity, motor speed, and current feedback. Second, the auto-tuner automatically adjusts the desired closed-loop input-output behaviors to update its cut-off frequency in the transient operations. Third, observer-based active damping injection reduces the closed-loop ball position and actuator speed dynamics to 1 by pole-zero cancellation. Finally, disturbance observers act as a dynamic compensator by estimating the disturbances from model-plant mismatches such as dynamic nonlinearities, mismatched load disturbances, and parameter variations. The experimental study verifies the applicability of the proposed technique using the Quanser Ball-Beam hardware driven by an SRV02 servomotor.
Yonghun Kim; Seok-Kyoon Kim; Choon Ki Ahn. Variable Cut-Off Frequency Observer-Based Positioning for Ball-Beam Systems Without Velocity and Current Feedback Considering Actuator Dynamics. IEEE Transactions on Circuits and Systems I: Regular Papers 2020, 68, 396 -405.
AMA StyleYonghun Kim, Seok-Kyoon Kim, Choon Ki Ahn. Variable Cut-Off Frequency Observer-Based Positioning for Ball-Beam Systems Without Velocity and Current Feedback Considering Actuator Dynamics. IEEE Transactions on Circuits and Systems I: Regular Papers. 2020; 68 (1):396-405.
Chicago/Turabian StyleYonghun Kim; Seok-Kyoon Kim; Choon Ki Ahn. 2020. "Variable Cut-Off Frequency Observer-Based Positioning for Ball-Beam Systems Without Velocity and Current Feedback Considering Actuator Dynamics." IEEE Transactions on Circuits and Systems I: Regular Papers 68, no. 1: 396-405.
This article presents a decentralized tension controller for large-scale roll-to-roll machines under the consideration of inherent nonlinearity and parameter variations. First, active-damping injection with specific proportional-integral gain is adopted to render the first-order dynamics for the closed-loop system via stable pole– zero cancelation. Second, the nonlinear disturbance observers for each loop intensify the high-frequency disturbance attenuation capability with a combination of regulation error integral actions. Moreover, the closed-loop analysis results include the proof of performance recovery from the first and second features. Various simulation results validate the effectiveness of the proposed technique from a combination of active-damping and DOBs using MATLAB/Simulink.
Seok-Kyoon Kim; Choon Ki Ahn. Decentralized Tension Control With Active-Damping Injection for Large-Scale Roll-to-Roll Systems. IEEE Systems Journal 2020, PP, 1 -10.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Decentralized Tension Control With Active-Damping Injection for Large-Scale Roll-to-Roll Systems. IEEE Systems Journal. 2020; PP (99):1-10.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2020. "Decentralized Tension Control With Active-Damping Injection for Large-Scale Roll-to-Roll Systems." IEEE Systems Journal PP, no. 99: 1-10.
This study devises a variable-performance control law for rover vehicles servoing the velocity and pitch angle commands. This considers both vehicle and actuator dynamics as well as load and parameter variations. The main merits are summarized as follows. First, the proposed auto-tuning law magnifies the feedback gain for desired systems to achieve transient performance improvement with the guarantee of the convergence property. Second, the collaboration of pole-zero cancellation controller and disturbance observers eliminates over/undershoots through closed-loop order reduction by a special form of feedback gain. Beneficial closed-loop properties are also derived from the closed-loop analysis. The prototype rover vehicle built with TETRIX and MyRIO-1900 experimentally validates the closed-loop performance and robustness improvement.
Seok-Kyoon Kim; Choon Ki Ahn. Variable-Performance Servo System Design Without Actuator Current and Angle Measurement for Rover Vehicles. IEEE Transactions on Vehicular Technology 2020, 69, 12725 -12733.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Variable-Performance Servo System Design Without Actuator Current and Angle Measurement for Rover Vehicles. IEEE Transactions on Vehicular Technology. 2020; 69 (11):12725-12733.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2020. "Variable-Performance Servo System Design Without Actuator Current and Angle Measurement for Rover Vehicles." IEEE Transactions on Vehicular Technology 69, no. 11: 12725-12733.
This paper presents an offset-free global tracking control algorithm for the input-constrained plants modeled as controllable and open-loop strictly stable linear time invariant (LTI) systems. The contribution of this study is two-fold: First, a global tracking control law is devised in such a way that it not only leads to offset-free reference tracking but also handles the input constraints using the invariance property of a projection operator embedded in the proposed disturbance observer (DOB). Second, the offset-free tracking property is guaranteed against uncertainties caused by plant-model mismatch using the DOB’s integral action for the state estimation error. Simulation results are given in order to demonstrate the effectiveness of the proposed method by applying it to a DC/DC buck converter.
Kyunghwan Choi; Dong Soo Kim; Seok-Kyoon Kim. Disturbance Observer-Based Offset-Free Global Tracking Control for Input-Constrained LTI Systems with DC/DC Buck Converter Applications. Energies 2020, 13, 4079 .
AMA StyleKyunghwan Choi, Dong Soo Kim, Seok-Kyoon Kim. Disturbance Observer-Based Offset-Free Global Tracking Control for Input-Constrained LTI Systems with DC/DC Buck Converter Applications. Energies. 2020; 13 (16):4079.
Chicago/Turabian StyleKyunghwan Choi; Dong Soo Kim; Seok-Kyoon Kim. 2020. "Disturbance Observer-Based Offset-Free Global Tracking Control for Input-Constrained LTI Systems with DC/DC Buck Converter Applications." Energies 13, no. 16: 4079.
This study presents a real-time optimal torque control scheme for interior permanent magnet synchronous motors (IPMSMs). The proposed scheme enables computation of optimal current reference for a torque reference under all operating regions, including the maximum torque per ampere (MTPA), flux weakening (FW), maximum current (MC), and maximum torque per voltage (MTPV), using numerical optimization techniques to simplify the problems and obtain the corresponding solutions with reduced computation burden. Linearizing the torque equation of IPMSM is utilized to derive solutions for the MTPA and FW. These solutions are proved to converge to their optimum with the aid of the reference smoother. Numerical solutions for the MC and MTPV are derived based on the assumption that the resistive voltage drop is small enough but not zero. These solutions differ from the existing solutions that ignore the resistive voltage drop. The effectiveness of the proposed method is numerically and experimentally verified using a 7.5-kW IPMSM with a considerable reduction in computational time of approximately 90% in the simulation compared with the analytic solution.
Kyunghwan Choi; Yonghun Kim; Kyung-Soo Kim; Seok-Kyoon Kim. Real-Time Optimal Torque Control of Interior Permanent Magnet Synchronous Motors Based on a Numerical Optimization Technique. IEEE Transactions on Control Systems Technology 2020, 29, 1815 -1822.
AMA StyleKyunghwan Choi, Yonghun Kim, Kyung-Soo Kim, Seok-Kyoon Kim. Real-Time Optimal Torque Control of Interior Permanent Magnet Synchronous Motors Based on a Numerical Optimization Technique. IEEE Transactions on Control Systems Technology. 2020; 29 (4):1815-1822.
Chicago/Turabian StyleKyunghwan Choi; Yonghun Kim; Kyung-Soo Kim; Seok-Kyoon Kim. 2020. "Real-Time Optimal Torque Control of Interior Permanent Magnet Synchronous Motors Based on a Numerical Optimization Technique." IEEE Transactions on Control Systems Technology 29, no. 4: 1815-1822.
This paper presents an advanced proportional-derivative (PD) voltage control mechanism for DC/DC boost converters suffering from the parameter and load variations. The proposed controller eliminates the requirement for current feedback by designing the first-order observer estimating the voltage derivative without the use of converter parameters, which corresponds to the first contribution. As another contribution, a specific feedback gain structure for PD-loop and the active damping component guarantees the first-order closed-loop transfer function from the reference to the output voltage by the stable pole-zero cancellation. A prototype bi-directional 3-kW boost converter experimentally validates the closed-loop performance of the proposed technique.
Seok-Kyoon Kim; Choon Ki Ahn. Proportional-Derivative Voltage Control With Active Damping for DC/DC Boost Converters via Current Sensorless Approach. IEEE Transactions on Circuits and Systems II: Express Briefs 2020, 68, 737 -741.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Proportional-Derivative Voltage Control With Active Damping for DC/DC Boost Converters via Current Sensorless Approach. IEEE Transactions on Circuits and Systems II: Express Briefs. 2020; 68 (2):737-741.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2020. "Proportional-Derivative Voltage Control With Active Damping for DC/DC Boost Converters via Current Sensorless Approach." IEEE Transactions on Circuits and Systems II: Express Briefs 68, no. 2: 737-741.
This brief proposes a proportional-type angle filter with the variable feedback gain mechanism for motor drives using the encoder for angle feedback. In this case, the angle measurement suffers from discontinuity that has to be made continuous through low-pass filters and observers. There are three features. The first designs a real-time feedback gain update rule to improve the closed-loop filtering performance by magnifying the feedback gain in transient periods. The second introduces the disturbance observer (DOB) in the resultant proportional-type feedback filter for enhanced disturbance attenuation against the speed variations. The third proves the useful properties of the filtering error convergence and performance recovery by investigating the filtering error dynamics. A prototype 500-W permanent-magnet synchronous motor (PMSM) drive system validates the practical advantages of the proposed technique.
Younghun Kim; Seok-Kyoon Kim; Choon Ki Ahn. Variable-Performance Proportional-Type Angle-Filtering System for Motor Drives. IEEE Transactions on Circuits and Systems II: Express Briefs 2020, 68, 511 -515.
AMA StyleYounghun Kim, Seok-Kyoon Kim, Choon Ki Ahn. Variable-Performance Proportional-Type Angle-Filtering System for Motor Drives. IEEE Transactions on Circuits and Systems II: Express Briefs. 2020; 68 (1):511-515.
Chicago/Turabian StyleYounghun Kim; Seok-Kyoon Kim; Choon Ki Ahn. 2020. "Variable-Performance Proportional-Type Angle-Filtering System for Motor Drives." IEEE Transactions on Circuits and Systems II: Express Briefs 68, no. 1: 511-515.
This study presents an advanced algorithm for controlling the web longitude and tension of nonlinear roll-to-roll systems in the form of a cascade structure. Parameter variation and disturbance attenuation problems are addressed systematically. The features of this article are divided into two parts. First, active damping terms are injected to stabilize the system nonlinear dynamics so that the first-order closed-loop transfer functions are obtained for each loop via pole-zero cancelation. Second, disturbance observers are introduced to ensure the performance recovery property by attenuating the disturbances from the model-plant mismatches. The closed-loop system is numerically emulated using MATLAB/Simulink to show the effectiveness of the proposed technique.
Seok-Kyoon Kim; Choon Ki Ahn. Active damping injection controller for web longitude and tensions of nonlinear roll-to-roll systems. Nonlinear Dynamics 2020, 100, 3367 -3379.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Active damping injection controller for web longitude and tensions of nonlinear roll-to-roll systems. Nonlinear Dynamics. 2020; 100 (4):3367-3379.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2020. "Active damping injection controller for web longitude and tensions of nonlinear roll-to-roll systems." Nonlinear Dynamics 100, no. 4: 3367-3379.
This paper presents a velocity-sensorless decentralized tension control scheme without true machine parameter dependence for roll-to-roll printing machines. Both the nonlinear nature and parameter uncertainties are taken into account the development task. As the first merit, the proposed observer eliminates the requirement of velocity feedback without any plant information even the nominal parameters. The introduction of the active-damping with the estimated state reduces the closed-loop system order to 1 by the pole-zero cancellation using the specified feedback gains. Finally, the disturbance observer (DOB) replaces the regulation error integrators with the closed-loop robustness improvement against the high-frequency disturbances. The MATLAB/Simulink-based simulations validate the effectiveness of the proposed decentralized scheme.
Yonghun Kim; Kyung-Soo Kim; Seok-Kyoon Kim. Velocity-Sensorless Decentralized Tension Control for Roll-to-Roll Printing Machines. IEEE Access 2020, 8, 93682 -93691.
AMA StyleYonghun Kim, Kyung-Soo Kim, Seok-Kyoon Kim. Velocity-Sensorless Decentralized Tension Control for Roll-to-Roll Printing Machines. IEEE Access. 2020; 8 (99):93682-93691.
Chicago/Turabian StyleYonghun Kim; Kyung-Soo Kim; Seok-Kyoon Kim. 2020. "Velocity-Sensorless Decentralized Tension Control for Roll-to-Roll Printing Machines." IEEE Access 8, no. 99: 93682-93691.
Kyunghwan Choi; Yonghun Kim; Seok-Kyoon Kim; Kyung-Soo Kim. Current and Position Sensor Fault Diagnosis Algorithm for PMSM Drives Based on Robust State Observer. IEEE Transactions on Industrial Electronics 2020, 68, 5227 -5236.
AMA StyleKyunghwan Choi, Yonghun Kim, Seok-Kyoon Kim, Kyung-Soo Kim. Current and Position Sensor Fault Diagnosis Algorithm for PMSM Drives Based on Robust State Observer. IEEE Transactions on Industrial Electronics. 2020; 68 (6):5227-5236.
Chicago/Turabian StyleKyunghwan Choi; Yonghun Kim; Seok-Kyoon Kim; Kyung-Soo Kim. 2020. "Current and Position Sensor Fault Diagnosis Algorithm for PMSM Drives Based on Robust State Observer." IEEE Transactions on Industrial Electronics 68, no. 6: 5227-5236.
Seok-Kyoon Kim; Choon Ki Ahn. Position Regulator With Variable Cut-Off Frequency Mechanism for Hybrid-Type Stepper Motors. IEEE Transactions on Circuits and Systems I: Regular Papers 2020, 67, 3533 -3540.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Position Regulator With Variable Cut-Off Frequency Mechanism for Hybrid-Type Stepper Motors. IEEE Transactions on Circuits and Systems I: Regular Papers. 2020; 67 (10):3533-3540.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2020. "Position Regulator With Variable Cut-Off Frequency Mechanism for Hybrid-Type Stepper Motors." IEEE Transactions on Circuits and Systems I: Regular Papers 67, no. 10: 3533-3540.
This study proposes intelligent nonlinear web tension and velocity controllers for roll-to-roll printing systems. The introduction of the perturbed machine model makes it easy to handle machine nonlinearities and parameter variations, simultaneously, with the simple static and first-order dynamic compensator. The feedback gains of web tension and velocity are automatically updated by the proposed self-tuner, which corresponds with the first feature of this study. As the second feature, the introduction of disturbance observers in place of the regulation error integrators provides an improved disturbance rejection performance and offset-free property, which is rigorously analyzed based on the Lyapunov stability criterion. The closed-loop performance improvement is numerically demonstrated under various scenarios using MATLAB/Simulink.
Seok-Kyoon Kim; Choon Ki Ahn. Self-Tuning Nonlinear Control System Design for Roll-to-Roll Printing Systems. IEEE/ASME Transactions on Mechatronics 2020, 25, 2667 -2676.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Self-Tuning Nonlinear Control System Design for Roll-to-Roll Printing Systems. IEEE/ASME Transactions on Mechatronics. 2020; 25 (6):2667-2676.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2020. "Self-Tuning Nonlinear Control System Design for Roll-to-Roll Printing Systems." IEEE/ASME Transactions on Mechatronics 25, no. 6: 2667-2676.
In this article, the position-tracking problem for magnetic levitation (MAGLEV) systems is addressed by handling the model nonlinearities and uncertainties of parameters and loads. The first feature is devising a variable cut-off frequency algorithm enhancing the transient tracking performance by updating the feedback gain accordingly. The second is introducing the disturbance observer (DOB) improving the disturbance attenuation performance with the offset-free property, which corresponds to the replacement of tracking error integrators. The simulation results numerically demonstrate the effectiveness of the proposed technique considering model-plant mismatches and load variations.
Seok-Kyoon Kim; Choon Ki Ahn. Variable Cut-Off Frequency Algorithm-Based Nonlinear Position Controller for Magnetic Levitation System Applications. IEEE Transactions on Systems, Man, and Cybernetics: Systems 2019, 51, 4599 -4605.
AMA StyleSeok-Kyoon Kim, Choon Ki Ahn. Variable Cut-Off Frequency Algorithm-Based Nonlinear Position Controller for Magnetic Levitation System Applications. IEEE Transactions on Systems, Man, and Cybernetics: Systems. 2019; 51 (7):4599-4605.
Chicago/Turabian StyleSeok-Kyoon Kim; Choon Ki Ahn. 2019. "Variable Cut-Off Frequency Algorithm-Based Nonlinear Position Controller for Magnetic Levitation System Applications." IEEE Transactions on Systems, Man, and Cybernetics: Systems 51, no. 7: 4599-4605.