• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.17-18
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• 2009

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1211-1214
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• 1992

AC servo motor drives, Fara DS series, proposed in this paper can be effectively used in robots, CNC machine tools, and FA system with AC servo motors as actuators. The inverter of the AC servo drive consists of IGBT (Insulated Gate Bipolar Transistor) which have high switching frequency. Noises and vibrations generated in variable speed control of AC servo motors can be greatly reduced due to their high switching frequencies. In the developed servo drive, maximum torque is always generated in the whole speed range by compensating phase shift, which results from the nonlinearies of the AC servo motor during abrupt acceleration and deceleration. Abundant protection functions are provided to prevent abnormal state of the servo motor, and furthermore diverse user options are considered provided for the effective application. The proposed AC servo motor drive is designed to minimize velocity variation with respect to external load, supply voltage, environmental temperature, and humidity, so can be widely used in the fields of factory automation including robots and CNC msachine tools.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.400-402
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• 1996

The paper describes the control strategy and hardware design for forced commutation cycloconverter which was developed for ac servo motor drive application of vector control. 12-pulse cycloconverter is used to investigate experimentally the performance of an induction motor drive system. The cycloconverter has the facility for continuous control of both the frequency and magnitude of the output voltage to keep a constant flux in the induction motors.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.96-103
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• 2006

An MRAC-based adaptive current control scheme of an AC servo motor is presented for the performance improvement of a servo drive. Although the predictive current control is known to give ideal transient and steady-state responses, its steady-state response my be degraded under motor parameter variations. To overcome such a limitation, the disturbances caused by the parameter variations will be estimated by using an MRAC technique and compensated by a feedforward control. The proposed scheme does not require the measurement of the phase voltage unlike the conventional disturbance estimation scheme using observer. The asymptotic stability is proved. The proposed scheme is implemented using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.12
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• pp.616-623
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• 2003

Conventional P/PI speed controller of today's servo drives should be manually tuned the controller switching set-point by trial-and-errors, which may translate the drive system down-time and loss of productivity. The adjustable drive performance is heavily dependent on the quality of the expert knowledge and becomes inadequate in applications where the operating conditions change in a wide range, i.e., tracking command, acceleration/deceleration time, and load disturbances. In this paper, the demands on simple controls/setup are discussed for industry servo drives. Analyzing the frequency content of motor torque command, P/PI control mode switching is automatically performed with some prior knowledge of the mechanical dynamics. The dynamic performance of the proposed scheme assures a desired tracking response curve with minimal oscillation and settling time over the whole operating conditions. For comprehensive comparison of traditional P/PI control scheme, extensive test is carried out on actual servo system.

• Journal of Power Electronics
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• v.4 no.1
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• pp.28-38
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• 2004

In this paper, the position control of a detuned indirect field oriented control (IFOC) induction motor drive is studied. A proposed Simple-Neuro-Controllers (SNCs) are designed and analyzed to achieve high-dynamic performance both in the position command tracking and load regulation characteristics for robotic applications. The proposed SNCs are trained on-line based on the back propagation algorithm with a modified error function. Four SNCs are developed for position, speed and ｄ-ｑ axes stator currents respectively. Also, a synchronous proportional plus integral-derivative (PI-D) two-degree-of-freedom (2DOF) position controller and PI-D speed controller are designed for an ideal IFOC induction motor drive with the desired dynamic response. The performance of the proposed SNCs and synchronous PI-D 2DOF position controllers for detuned field oriented induction motor servo drive is investigated. Simulation results show that the proposed SNCs controllers provide high-performance dynamic characteristics which are robust with regard to motor parameter variations and external load disturbance. Furthermore, comparing the SNC position controller with the synchronous PI-D 2DOF position controller demonstrates the superiority of the proposed SNCs controllers due to attain a robust control performance for IFOC induction motor servo drive system.

• 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 KIPE Conference
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• 2004.07b
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• pp.839-841
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• 2004

This paper presents a SPMSM servo motor drive system using high performance TMS320 F281T DSP for the industrial application. This high performance DSP contains some special peripheral circuits such as PWM (Pulse Width Modulation) waveform generation circuit, Quadrature Encoder Pulse (QEP) generation circuit and Analog to Digital Converter (ADC) circuit. In this paper, a servo drive control system is constructed using high performance DPS for the overall system cost reduction and the size minimization.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.418-421
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• 1988

A disturbance and parameter variations cause a steady and/or transient error in the conventional de servo motor drive system. In this paper robust control system for dc servo motor drive taking disturbance and parameter variations into account is proposed. The proposed control system compensates rapidly the state error caused by disturbance and parameter variations. Simulation results show that the proposed method is robust for the steady and transient response in the presence of both disturance and parameter variations.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.136-136
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• 2000

The direct drive servo valve(DDV) is composed of a DC rotor, link, valve spool and displacement sensor(LVDT) where the spool is directly coupled to the DC motor through the link. Since the DDV is a kind of one-stage valve, the robust controller is required to overcome the flow force effect on the spool motion. The mathematical equations are derived and the stability, accuracy and response speed of a DDV are investigated analytically using a linearized system block diagram. Proportional control, PID control. Time-Delay control, Sliding Mode control, and Proportional control using the load pressure are applied to DDV to find which one shows the best control performance. The digital computer simulation results show that the proportional control using the load pressure satisfies the design requirement of response speed and steady state error regardless of the variation of load pressure,