• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.4
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• pp.26-31
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• 2008

This paper deals with the issue of position tracking control of a clamp-cylinder for injection moulding machine with electric-hydrostatic drives. A fixed displacement pump is utilized in combination with AC motor in order to directly control a clamp-cylinder. A clamp-cylinder may be required to operate under a variety of operating conditions. Therefore, robust control performance is important in position tracking control applications. In order to accommodate mismatches between the real plant and the model used for controller design, discrete-time sliding mode control is developed by combining a velocity feedforward loop. From tracking control experiments, it is shown that significant reduction in position tracking error is achieved through the use of sliding mode control.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1309-1313
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• 2010

In this paper, we propose a novel guidance law for controlling an UAV(Unmanned Air-Vehicle) to follow a reference line in vertical plane. A kinematics model representing the relative motion of the UAV to the reference line is derived. And then LQR(Linear Quadratic Regulator) theory is applied to the model to derive the VLFG(Vertical Line Following Guidance) law. The resultant guidance law forms a gain-scheduling controller scheduled by a simple parameter $\sigma$ which is a function of the UAV's velocity, axial acceleration, gravity, and the slope of the reference line. Also derived is a stability condition for the $\sigma$ variation based on Lyapunov theory. Simulation results show that the proposed guidance law can be applied effectively to UAV guidance algorithm design.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2871-2873
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• 2000

Lots of automation equipments and robots have been developed and been used. But most control systems have been developed as dedicated systems rather than general-purpose systems. Thus, users cannot modify or improve their software including GUI. In this paper, an open architecture GUI is proposed in order to make it easy to modify some functions of GUI or to add some functions of GUI. The format of all menu is similar as in previous systems, but some menu can be deleted and be added. Also some menu can be defined by users.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3078-3080
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• 2000

In this paper. we designed a high precision Linear DC Motor(LDM) Driver with $120^{\circ}$ commutation method. It was composed of three parts which were divided into Power and Inverter Circuit. Analog Circuit with PWM Generation and Fault Protections. and Logic Circuit. We selected PMAC Controller by Delta Tau Co. for testifying a high accuracy of a designed driver. A high precision driver enhanced a response to changes of velocity and acceleration in motion and improved the accuracy.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.435-437
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• 1998

In this productive system, it needs to control the each axis motion harmoniously to perform accurately for the manufacturing, transporting and printing. Independent Axis Control usually used for this objection. However, if Independent Axis Control mismatched the parameter of each axis system or in the case of free curve tracking or the case of high speed control, there would be big contour error so that cannot achieve control objection. As a result, there is Contour Control method suggested to supply for this defect. This paper carried modeling of biaxial system and implemented Independent Axis Control & Contouring Control on straight line, circular, and coner path by simulation and experiment. If feedrate increased, contour error growed. In consequence, according to this factor, we introduced contouring controller, so we could find the fact that contour error was reduced more than that of independent axis control about each path.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.828-833
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• 2004

The performance of a mixed $H_{\infty}/H_2$ design with pole placement constraints based on robust vibration control for a piezo/beam system is investigated. The governing equation of motion for the piezo/beam system is derived by Hamilton's principle. The assumed mode method is used to discretize the governing equation into a set of ordinary differential equation. A robust controller is designed by $H_{\infty}/H_2$ feedback control law that satisfies additional constraints on the closed-loop pole location in the face of model uncertainties, which are derived for a general class of convex regions of the complex plane. These constraints are expressed in terms of linear matrix inequalities (LMIs) approach for the multiobjective synthesis. The validity and applicability of this approach for vibration suppressions of SMART structural systems are discussed by damping out the multiple vibrational modes of the piezo/beam system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.47-52
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• 1996

The interpolator is very important in CNC machines. This study proposed a parametric curve interpolator(PCI) which can be used for machining any sculptured surface represented in a parametric form and generates commands for tool motion between CAD data points according to given accuracy demands. The proposed interpolator is superior to the existing linear interpolator in accuracy, feed rate and acceleration continuity. Moreover in comparison to the recently developed cubic spline interpolator, the PCI has the capability of handling higher order parametric curves and also ensures precise tracking in the velocity domain. Results from real time simulations and experiments on open architecture CNC machines equipped with the proposed interpolator are presented to show its practical capagility. It is believed that the combination of the proposed interpolator and the open architecture machine controller further advances the area of command generation which is an important aspect of CAD/CAM.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.114-118
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• 1996

This paper proposes a new technique to the design of adaptive control system using DSPs(TMS320C50) for Digital signal processors are used in implementing real time adaptive control algorithms to provide motion for robotic manipulators. In the proposed scheme, adaptation laws are derived from the improved second stability analysis based on the indirect adaptive control theory. The proposed control scheme is simple in structure, fast in computation. an suitable for implementation of real-time control. Moreover, this scheme does not requre an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by exeperimental reults for a SCARA robot.

• Journal of Ship and Ocean Technology
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• v.11 no.1
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• pp.1-10
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• 2007

This study introduces the development of robot fish ROFI 1.1. Today, robot fish is one of strong candidates for next-generation UUV. The present paper describes the design, manufacturing, and operation tests of the robot fish developed at Seoul National University. The very first robot fish in Korea, ROFI 1.1 is operated by a wireless remote controller. Its overall length is 680mm, and weight is 8.8kg. The fore body contains main mechanical and electrical systems and is covered by a FRP skin. The aft body has a mechanical bone system that mimics fish bones, and its skin is made of flexible silicon sponge to allow elastic motion for propulsion. It is found that this mechanical system creates effective and realistic fish-like swimming mode. It is observed that the normal and maximum advancing speeds of ROFI 1.1 are about 1 and 2 m/sec, and the turning radius is between $0.7{\sim}2.5m$, depending on the turning mechanism.

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.7-12
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• 2000

This paper presents a non-regressor based adaptive control scheme for the trajectory tracking of underwater vehicle-mounted manipulator systems(UVMS). The adaptive control system includes a class of unmodeled effects is applied to the trajectory control of an UVMS. The only information required to implement this scheme ios the upper bound and lowe bound of the system parameter matrices the upper bound of unmodeled effects the number of joints the position and attitude of the vehicle and trajectory commands. The adaptive control law estimates control gains defined by the combinations of the bounded constants of system parameter matrices and of a filtered error equation. To evaluate the performance of the non-regressor based adaptive controller computer simulation was performed with a two-link planar robot model mounted on an underwater vehicle. The hydrodynamic effects acting on the manipulator are included. It is assumed that the vehicle's motion is slow and can be predicted with a proper compensator.