• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1251-1258
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• 2003

This paper presents a nonlinear robust approach to the slip control problem for a torque converter bypass clutch in a passenger car. The proposed nonlinear robust controller builds upon only the measurements avail-able from inexpensive sensors that are already installed in passenger cars for control. The issue of torque estimation problems for the implementation of the proposed controller is addressed. The stability of the internal dynamics is investigated, upon which a nonlinear robust controller is designed using input-output feedback linearization and Lyapunov redesign technique. The performance of the designed controller is validated by simulation studies.

• Korean Management Science Review
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• v.24 no.2
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• pp.73-80
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• 2007

Robust Design(RD) is a cost-effective methodology to determine the optimal settings of control factors that make a product performance insensitive to the influence of noise factors. To better facilitate the robust design optimization, a dual response surface approach, which models both the process mean and standard deviation as separate response surfaces, has been successfully accepted by researchers and practitioners. However, the construction of response surface approximations has been limited to problems with only a few variables, mainly due to an excessive number of experimental runs necessary to fit sufficiently accurate models. In this regard, an innovative response surface approach has been proposed to investigate robust design optimization problems with larger number of variables. Response surfaces for process mean and standard deviation are partitioned and estimated based on the multi-level approximation method, which may reduce the number of experimental runs necessary for fitting response surface models to a great extent. The applicability and usefulness of proposed approach have been demonstrated through an illustrative example.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2125-2133
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• 2018

To achieve high performance speed regulation, a robust adaptive speed controller is proposed for the permanent magnet synchronous motor (PMSM) subject to parameter uncertainties and input saturations in this paper. A nonlinear adaptive control is introduced to compensate the PMSM speed tracking errors due to uncertainties, disturbances and control input saturation constraints. By combining the adaptive control and the nonlinear robust control based on the interconnection and damping assignment (IDA) strategy, a new robust adaptive control is designed for speed regulation of PMSM. Stability and robustness of the closed-loop control system involved with the constrained control inputs rather than unconstrained control inputs are validated. Simulations for PMSM control in the presence of uncertainties and saturations nonlinearities show that the proposed approach is effective to regulate speed, and the average tracking error using the proposed approach is at least 32% smaller than the compared methods.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.282-284
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• 1995

A robust nonlinear control technique for brushless DC(BLDC) motors is presented using a feedback linearizing technique. The nonlinear model of the BLDC motor is first linearized far the exactly known system by an input-output linearizing method. Then, the robust control is designed for the unknown parts of the system using the Lypunov second method. By employing the proposed control scheme, the a robust control performance against the parameter uncertainties is obtained and therefore a robust feedback linerizing control of the BLDC motor is realized. The effectiveness of the proposed control scheme is well demonstrated through the comparative simulations.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.446-449
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• 2003

The conventional GSC is inappropriate in real situation when the target signal is present. The steering vector error cancels the target signal and the target signal misadjusts the weight of the adaptive filter. To prevent the target signal cancellation, the robust GSC using the constrained adaptive filters was already proposed. However, the adaptive weight misadjustment is not settled in robust GSC. This Paper proposes a revised robust sidelobe canceller with adaptive compensator. To compensate the influence of target signal, the adaptive compensator is used in cascade. In computer simulation, we show the performance improvement by comparing the robust GSC with the proposed GSC.

• Advances in aircraft and spacecraft science
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• v.6 no.5
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• pp.371-389
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• 2019

The implementation of a robust $H_{\infty}$ Control, which is numerically efficient for uncertain nonlinear dynamics, on longitudinal and lateral autopilots is realised for a quarter scale Piper J3-Cub model accepted as an unmanned aerial vehicle (UAV) under the condition of sensor noise and disturbance effects. The stability and control coefficients of the UAV are evaluated through XFLR5 software, which utilises a vortex lattice method at a predefined flight condition. After that, the longitudinal trim point is computed, and the linearization process is performed at this trim point. The "${\mu}$-Synthesis"-based robust $H_{\infty}$ control algorithm for roll, pitch and yaw displacement autopilots are developed for both longitudinal and lateral linearised nonlinear dynamics. Controller performances, closed-loop frequency responses, nominal and perturbed system responses are obtained under the conditions of disturbance and sensor noise. The simulation results indicate that the proposed control scheme achieves robust performance and guarantees stability under exogenous disturbance and measurement noise effects and model uncertainty.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.21-24
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• 2001

This paper presents a loop shaping procedure for tuning optimal and robust PID controller by selecting the appropriate weighting factors Q and R in order to satisfy such the performance requirements.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.731-737
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• 2013

In this paper, we propose an image-based output feedback robust controller of robot manipulators which have bounded parametric uncertainty. The proposed controller contains an integral action and high-gain observer in order to improve steady state error of joint position and performance deterioration due to measurement errors of joint velocity. The stability of the closed-loop system is proved by Lyapunov approach. The performance of the proposed method is demonstrated by simulations on a 5-link robot manipulators with two degrees of freedom.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.434-437
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• 1997

In this paper, we present an $H^{\infty}$ controller design of RTP system satisfying robust stability and performance using weighted mixed sensitivity minimization. In industrial fields, RTP system is widely used for improving the oxidation and the annealing in semiconductor manufacturing process. The main control factors are temperature control of wafer and uniformity in the wafer. The control of temperature and uniformity has been solved by PI control method. We improve robust stability and performance of RTP system by the design of $H^{\infty}$ controller using the weighted mixed sensivity function. An example is proposed to show the validity of proposed method.d.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1249-1253
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• 2004

A robust input modification approach to the control of flexible joint robot is presented. In our previous study, we developed an observer based state feedback control for the suppression of residual vibration of a robot. The control was very effective in suppressing the inherent vibration of a flexible joint robot. However it did not meet high performance requirements under high speed motion and model uncertainties. As a solution of the problem, we present an input modification method with robustness against parametric uncertainties. The main idea of the proposed input modification method is to generate a modified reference position command for fast and accurate motion of the robot. Using this proposed method we can reduce the servo delay and settling time by about 60% and substantially improve the path accuracy.