• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.154-161
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• 1999

This paper presents a new approach to the design of adaptive control system using DSPs(TMS320C30) for robotic manipulators to achieve trajectory tracking by the joint angles. Digital signal processors are used in implementing real time adaptive control algorithms to provide an enhanced motion control for robotic manipulators. In the proposed control scheme, adaptation laws are derived from the improved Lyapunov second stability analysis method based on the adaptive model reference control theory. The adaptive controller consists of an adaptive feedforward controller, feedback controller, and PID type time-varying auxillary control elements. The proposed adaptive control scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Moreover, this scheme does not require an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a SCARA robot.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.508-517
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• 2000

For shift quality improvement, torque sensors are currently too expensive to be used on production vehicles. To achieve smooth acceleration shift, the reference trajectory of the clutch slip speed for accomplishing the shift process within a designated shift completion time and its relationship with the clutch actuating torque were suggested by Jeong and Lee (1999). In order to facilitate the proposed algorithm, nonlinear estimators for necessary information such as the axle shaft torque, clutch friction and turbine torque were designed using only speed sensors. Accounting for the modeling error, a control law for this indirect smooth shift was proposed based on the above mentioned suggestions. Simulation results of the proposed estimators and shift controller were presented and further considerations for practical applications are discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.8
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• pp.708-714
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• 1990

This paper has proposed a self-tuning controller for tracking reference trajectory by measuring End-point of arm on robot manipulator whose link is light and flexibls, and proved the perforformance of the algorithm proposed through the computer simulation. As an object of control, a flexible robot manipulator with two-links was selected. As for structure of model, it utilized an assume mode shape method with include travity force and derived a dynaics equation by adapting two kinds of vibration mode of each.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.7
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• pp.1241-1246
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• 2008

The dynamics of mobile robot is nonlinear. To cope with this nonlinearity, many advanced control schemes have been proposed recently. Generally, the advanced control schemes are complicated and not good for the practical real-time control when they are implemented as control programs. So, in this paper, a relatively simple PI controller is proposed and applied to the position control of mobile robot with the adoption of reference trajectory calculation method used for the AUV(Autonomous Underwater Vehicle) control. The proposed PI controller is programmed using LabVIEW which is popular for its graphical programming characteristics. The simulation and experimental results show the feasibility and effectiveness of the proposed PI controller.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.4-4
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• 2000

In this paper, the backstepping control method that is useful for cascade systems is applied to the slew maneuver of the spacecraft. The quaternion is used for representing the attitude of the spacecraft, because the reference trajectory of angular velocity has simple mathematical form. The conventional backstepping control has severa] problems such as slow convergence, trivial cancelling of nonlinear terms, and excessive control input. To overcome these problems, the modified backstepping control method which is redesign of Lyapunov function is proposed. To design a tracking function for angular velocity, it is necessary to estimate the process of maximum angular velocity, and therefore the estimation procedure using Bellman-Gronwall inequality is developed. To verify the effectiveness of the proposed control law, numerical simulation is performed and the results are compared with the exiting control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.428-428
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• 2000

A robust intelligent algorithm for AGV navigation control is presented here based on both magnetic and gyro sensors to track a reference trajectory. Since the proposed system uses an intermittent array of short magnetic tape strips, it lends itself to a very easy installation and maintenance compared to other types of positioning references such as electric wire, magnets, RF and laser beacons. The neural network is to predict the lateral deviation of the AGV in the intervals where no magnetic tape references are available. Further, the use of intelligent control ensures a robust and flexible control performance. Computer simulation of AGV control demonstrates its adequate tracking performances even where the sensor information is not available. Real experiments using Samsung AGV are also on the way for real verification

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.94-101
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• 2005

This work proposes a new method for describing the hysteresis non-linearity of a piezoelectric actuator. The hysteresis behaviour of piezoelectric actuators, including the minor loop trajectory, are modeled by geometrical relationship between a reference major loop and its minor loops. This hysteresis model is transformed into inverse hysteresis model in order to output compensated voltage with regard to the given input displacement. A feedforward neural network, which is trained by a feedback PID control module, is incorporated to the inverse hysteresis model to compensate unknown dynamics of the piezoelectric system. To show the feasibility of the proposed feedforward-feedback controller, some experiments have been carried out and the tracking performance was compared to that of simple PTD controller.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.2
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• pp.44-49
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• 2008

This paper describes the problem of ultraprecision positioning with a ball screw mechanism in the microdynamic range, along with its solution. We compared the characteristics of two ball screw mechanisms with different table masses. The experimental results showed that the vibration resulting from the low stiffness of the ball screw degraded the positioning performance in the microdynamic range for the heavyweight mechanism. The proposed nominal characteristic trajectory following (NCTF) controller was designed for ultra precision positioning of the ball screw mechanism. The basic NCTF control system achieved ultra precision positioning performance with the lightweight mechanism, but not with the heavyweight mechanism. A conditional notch filter was added to the NCTF controller to overcome this problem. Despite the differences in payload and friction, both mechanisms then showed similar positioning performance, demonstrating the high robustness and effectiveness of the improved NCTF controller with the conditional notch filter. The experimental results demonstrated that the improved NCTF control system with the conditional notch filter achieved ultra precision positioning with a positioning accuracy of better than 10 nm, independent of the reference step input height.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.83-89
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• 2000

This paper presents a dynamic modeling and a sliding mode controller for the high-speed / high-accuracy position control system. Selected target system is the wire bonder head assembly which is used in semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as a actuator and transducer horn as a bonding tool. For the modeling elements, the system is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled by using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.129-136
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• 2006

A new guidance synthesis for anti-ship missiles to control impact angle and impact time is proposed in this paper. The flight vehicle is assumed as a 1st order lag system to consider more practical system. The proposed guidance synthesis enhances the survivability of anti-ship missiles because multiple anti-ship missiles with the proposed synthesis can hit the target simultaneously. The control input to satisfy constraints of zero miss distance and impact angle, and the feedforward bias control input to control impact time constitute the guidance law. The former is from trajectory shaping guidance, the latter is from neural network. And particle swarm optimization method is introduced to furnish reference input and output for learning in neural network. The performance of the proposed synthesis in the accuracy of impact time and angle is validated by numerical examples.