• ETRI Journal
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• v.6 no.2
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• pp.3-9
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• 1984

This paper proposes an optimal control scheme for shaft position control using microcomputer-based state-variable feedback. In this scheme a performance index was set up in order to ruduce the overshoot and improve the steady- state response speed, and the time-variant system parameters were identified in real time for optimal control. As a result of experiment, the over-shoot was not occured and the response speed was improved 2. 9 times about proportional control. This scheme improves the performance against the variation of load and sampling time, and adding the integral control in this scheme can reduce the steady-state error without any change in response time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1752-1767
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• 2015

As a special type of mobile ad-hoc network, Vehicular Ad-hoc Network (VANET) is considered as an attractive topic by many researchers. In VANETs, vehicles act as routers and clients, which are connected with each other through unreliable wireless links. Due to the dynamic nature of vehicles, developing communication protocols for VANETs is a challenging task. In this paper, we tackle the problem of real-world VANET operations and propose a new dual-level communication scheme through the combination of power and rate control algorithms. Based on the game theoretic approach, the proposed scheme effectively formulates the interactive situation among several vehicles. With a simulation study, it is confirmed that the proposed scheme can achieve better performance than other existing schemes under widely diverse VANET environments.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.39.2-39
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• 2001

This paper describes the design of an output-feedback controller based on an adaptive fuzzy observer for uncertain single-input single-output nonlinear dynamical systems. Especially, we have focused on the realization of minimal dynamic order of the adaptive fuzzy observer. For the purpose, we propose a new method in which no strictly positive real(SPR) condition is needed and combine dynamic rule activation scheme with on-line estimation of fuzzy parameters. By using proposed scheme, we can reduce computation time, storage space, and dynamic order of the adaptive fuzzy observer ...

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.458-467
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• 1994

It has been well known that the assumption of full state availability is one of the most important restrictions to the practical realization of VSCS. And several attempts to alleviate the assumption had been made. however, it is not easy to find a positive scheme among them. Recently, an output feedback variable structure control system(OFVSCS) was proposed and the effectiveness of the scheme was validated for the disturbance free systems. The purpose of this study is to propose a robust OFVSCS that have the robust properties against process parameter variations and external disturbances by extending the basic OFVSCS and to evaluate its control performances. The ROFVSES is composed of dynamic switching function and output feedback switching control inputs that are constructed by the use of the unknown vector modeling technique. With the proposed schems, existence of sliding mode is guaranteed and any nonzero bias can be suppressed in the face of disturbances and process parameter variations as far as well-known matching condition is satisfied. Due to the fact that the ROFVSCS is driven by small number of measured informations, the practical application of VSCS for the systems with unmeasurable states and for high order systems, the conventional schemes cannot be applied, is possible with the proposed scheme. It is noticeable that the implementation cast of VSCS can be considerably reduced without sacrifice of control performances by adopting ROFVSCS since there is no need to measure the states with high measurement cost.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.71-79
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• 2008

In the manufacture of flat panel display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic suspension device far glass panels where the glass panel is supported by electrostatic forces without any mechanical contact is proposed. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Using this scheme, a $100{\times}100mm^2$ glass panel was levitated stably with airgap variation decreasing down to $1\;{\mu}m$ at an airgap of $100\;{\mu}m$.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.45-49
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• 1988

This paper presents a centralized adaptive control scheme based on perturbation equations in the vicinity of a desired trajectory,which are used to design a feedback control about the desired trajectory. This adaptive control scheme reduces the manipulator control problem from a nonlinear control to controlling a linear control system about a desried trajectory. Computer simulation studies of a two-joint manipulator are performed on a IBM-PC to illustrate the performance of this adaptive control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1537-1541
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• 2003

In this paper, presented is a feedback control performance of vibratory gyroscope at various vacuum levels. Micro gyroscope, whose operation is based on the vibrating motion at the vacuum conditions, is highly influenced by the vacuum level of the operating circumstances. In general, we apply the feedback control scheme to the gyroscope in order to improve the performances of the sensor. And control performances of the gyroscope are related to those vacuum levels. So we need investigate the performances of the closed loop control at various vacuum conditions comparing with those of the open loop. The experimental results show that the sensitivity of the closed loop is less than that of the open loop especially in low vacuum conditions. Therefore, there should be trade-off between sensitivity and other sensor performances such as linearity, bandwidth when we apply feedback control to the gyroscope.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.32-35
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• 1987

An adaptive control scheme has been recognized as an effective approach for a robot manipulator to track a desired trajectory in spite of the presence of nonlinearties and parameter uncertainties in robot dynamic models. In this paper, an adaptive control scheme for a robot manipulator is proposed to design the self-tuning controller which combines the pole placement with the extended linearized perturbation model. And this control scheme has two components: a feadforward control and a feedback compensation control. Based on this, the controller is demonstrated by the simulation about position control of a three-link manipulator with payload and parameter uncertainty.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.344-345
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• 2018

In order to alleviate the negative impacts of harmonically distorted grid condition on grid-connect inverters, an optimal control design-based gain selection scheme of an LCL-filtered grid-connected inverter and its ability to compensate selective harmonics are presented in this paper. By incorporating resonant terms into the control structure in the state-space to provide infinity gain at selected frequencies, the proposed control offers an excellent steady-state response even under distorted grid voltage. The proposed control scheme is achieved by using a state feedback controller for stabilization purpose and by augmenting the resonant terms as well as intergral term into a control structure for reference tracking and harmonic compensation. Furthermore, the optimal linear quadratic control approach is adopted for choosing an optimal feedback gain to ensure an asymptotic stability of the whole system. A discrete-time full state observer is also introduced into the proposed control scheme for the purpose of reducing a total number of sensors used in the inverter system. The simulation results are given to prove the effectiveness and validity of the proposed control scheme.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.154-160
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. The limitation of this control scheme is that the feedback signal does not account for additional dynamics of the tool post and the material removal process. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surfice. However, as the accuracy requirement gets tighter and desired surface cnotours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated dapth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in additn to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamoneter. Based on the parameter estimation of cutting dynamics and the admitance model-based nanodynamic control scheme, simulation results are shown.