• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.526-533
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• 1990

The dynamic stability of a single cam drive mechanism is investigated by an analytical approach. The nonlinear differential equation describing the motion of a single cam drive mechanism is linearized with respect to the imput power angle, and results a linear parametric differential equation. The instability region is examined by applying the harmonic balance method to linearized parametric equation having periodicity. Through the dynamic stability analysis of a single cam drive mechanism, it is observed that the parametric resonances exist and the instability regions tend to become wide as increasing the drive speed and follower mass.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.6
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• pp.402-408
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• 2004

This paper proposes the novel V/f control method to improve the stability of a V/f controlled induction motor drive system. The conventional V/f control method used in the proposed V/f control method is a vector-based method that is slightly different from the existing conventional V/f control method. The proposed control method uses a dynamic current compensator to improve the stability of a V/f controlled induction motor drive system. This proposed method is easy to implement and completely eliminates the motor oscillation phenomenon causing the instability of a V/f controlled induction motor drive system, especially when the system is driven near the resonant frequency in steady-state with light load. Additionally, this paper analyzes theoretically the instability of a V/f controlled induction motor drive system and shows the validity of the Proposed V/f control method through simulation and experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2028-2038
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• 2003

High-speed feed drive systems have been widely used in the manufacturing and semiconductor industries. Specifications for high-speed systems require more advanced capabilities than conventional feed drive systems. It is necessary to devise special design concepts to achieve the level of performance for high-speed feed drive systems. In this paper, an integrated design method is proposed for high-speed feed drive systems in which the interactions between mechanical and electrical subsystems ought to be considered simultaneously during the design process. Based on the integrated design method, a nonlinear optimal design procedure of mechanical subsystems considering the Abbe and radius errors is accomplished through the design process of electrical subsystems satisfying the control stability and the saturation condition of actuators as well as the relative stability. Both mechanical and electrical parameters are considered as design variables. Simulations and numerical case studies show that the integrated design method of high-speed feed drive systems creates results satisfying the desired performances of mechatronic systems.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.131-138
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• 1996

This paper suggests a servo control algorithm to reduce the repeatable tracking error which is not explicitly taken into account in the design of a conventional PID controller of a computer hard disk drive. The robust stability of the repetitive control system with multiplicative modelling error is analyzed, and the controller was implemented using a fixed point DSP(Digital Signal Processor). Experimental results show that the repetitive errors are suppressed effectively by the proposed controller.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.1
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• pp.39-46
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• 1999

Disturbances acting on the track-following servo system of an optical disk drive inherently contain significant periodic components that cause tracking errors of a periodic nature. Such disturbances can be effectively rejected by employing a repetitive controller, which must be implemented carefully in consideration of system stability. Plant uncertainty makes it difficult to design a repetitive controller that will improve tracking performance yet preserve system stability. In this paper, we examine the problem of designing a repetitive controller for an optical disk drive track-following servo system with uncertain plant coefficients. We propose a graphical design technique based on the frequency domain analysis of linear interval systems. This design method results in a repetitive controller that will maintain system stability against all admissible plant uncertainties. We show simulation and experimental results to verify the validity of the proposed design method.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.675-677
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• 2004

This paper presents a nonlinear controller design for optical disk drive systems to improve anti-shock performance. The nonlinear anti-shock controller is added parallel to the original linear servo control loop. In the previous work, dead-zone nonlinear element is used for nonlinear controller and PID control method is used for linear controller. Although this strategy improves anti-shock performance, it has a narrow stability bound. In this paper, we propose dead-zone with saturation nonlinear element for the nonlinear controller. Since this nonlinear element improves stability margin, we can use higher gain of dead-zone than the controller with dead-zone only. In the linear controller design, we show that lead-lag control has improved stability margin over PID control. Numerical simulation results show that the proposed method can get better performance to the external shock than previously proposed method.

• Journal of KSNVE
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• v.9 no.2
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• pp.355-362
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• 1999

Vibration reduction of an optical disk drive is achieved by an automatic ball balancer and dynamic behaviors of the drive are studied by theoretical approaches. Using Lagrange's equation, we derive nonlinear equations of motion for a non-autonomous system with respect to the rectangular coordinate. To investigate the dynamic stability of the system in the neighborhood of equilibrium positions, the Floquet theory is applied to the perturbed equations. On the other hand, time responses are computed by an explicit time integration method. We also investigate the effects of mass center and the position of the ABB on the dynamic behaviors of the system.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.17-22
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• 2013

Design of braking system is one of the most critical subjects in vehicle stability. In this paper, optimal scheme for brake force proportioning of all-wheel-drive vehicle is proposed to guarantee the vehicle dynamic stability under plausible drive circumstances. A brake force distribution of generic $8{\times}4$ vehicle is calculated according to proposed scheme and braking stability of this vehicle is verified by using a commercial vehicle software, Trucksim.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.265-270
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• 1998

In this paper we introduce a modeling of wheeled mobile robot with a differential drive derived by R.M. DeSantis and using the dynamics model-ing with some disturbance term we control the wheeled mobile robot using fuzzy sliding mode control(FSMC) method. In a fuzzy control approach it is very difficult to prove the stability of the fuzzy controller. Therefore, to overcome that difficult proof of the stability in a fuzzy control method, we first propose a sliding mode controller and prove the stability of the proposed controller. Next, transforming the proposed sliding mode controller into a fuzzy sliding mode controller without changing the basic structure of the sliding mode con-troller, we easily obtain a fuzzy sliding mode con-troller(FSMC) whose stability is guaranteed with-out difficult stability proof procedure of the proposed FSMC.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.393-398
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• 2006

This paper classifies driving technologies for AMOLEDs by the driving TFT conditions in pixels. A saturation region operation type driving TFT circuit provides good stability of OLED because of constant current drive. However, complicated compensation circuits are necessary to avoid effect of the TFT characteristics deviation. On the other hand, a linear region operation type driving TFT circuit provides better uniformity of the display image and lower power consumption. However, the stability of OLED is critical because of constant voltage drive.