• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1664-1672
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• 2002

Gantry mechanisms have been widely used for precision manufacturing and material handling in electronics, nuclear, and automotive industries. Dual-drive servo mechanism is a way to increase control bandwidth, in which two primary axes aligned in parallel are synchronously driven by identical servo motors. With this mechanism, a flexible coupling (compliance mechanism) is often introduced in order to avoid the damage by the servo mismatch between the primary drives located at each side of gantry. This paper describes the design guidelines of the dual-drive servo mechanism with focus on its dynamic characteristics and control ramifications. That is, the effect on the system bandwidth which is critical on the system performance, the errors and torques exerted on guide ways in case of servo mismatch, the vibration characteristics concerned with dynamic error and settling time, and the driving force required at each axis for control are thoroughly investigated.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.134-139
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• 2001

Laser scanners are widely used for reverse engineering and inspection of freeform parts in industry such as motors, electronic products, dies and molds. Due to the lack of measuring software and positioning device, the laser scanning processes have been erroneous and inconsistent. In order to automate measuring processes, an automated scan plan generation software and a proprietary hardware are developed. In this paper, an automated laser scanning system using a 3-axis motorized stage is proposed. In the scan planning step, scan directions, paths, and the number of scans are generated considering optical and mechanical parameters. In the scanning step, the generated scan plan is downloaded into the laser scanner and the motorized stage and the points on the surface are captured automatically. Finally, the point data set is analyzed to evaluate the performance of the system.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.6
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• pp.906-915
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• 2004

In this paper, we address the development of magnetic levitation positioning system. This planar magnetic levitator employs four permanent magnet liner motors. Each motor generates vertical force for suspension against gravity, as well as horizontal force for driving levitation object called a platen. This stage can generate six degrees of freedom motion by the vertical and horizontal force. We derived the mechanical dynamics equation using Lagrangian method and used coenergy to express an electromagnetic force. We proposed a control algorithm for the position and posture control from its initial value to its desired value using sliding mode control. Some simulation results are provided to verify the effectiveness of the proposed control scheme.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.1-7
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• 2016

The cutting processes used for monitoring engineering includes analysis and feedback about strange conditions, tools collision and tools wear in real time, for improving the working ratio of equipment and productivity. In this study, we proposed monitoring using profibus to increase the reliability as the most important factor for cutting monitoring. The profibus can increase the reliability of cutting monitoring for cutting torque of a main spindle motor and a feed motors through PLC-based interface.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.199-205
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• 2002

This application study presents a solution to control a Permanent Magnet Synchronous Motor without sensors. The use of this system yields enhanced operations, fewer system components, lower system cost , energy efficient control system design and increased efficiency. The control method presented is field oriented control (FOC). The sinusoidal voltage waveforms are generated by the power module using the space vector modulation technique. A practical solution is described and results are given in this application Study. The performance of a Sensorless architecture allows an intelligent approach to reduce the complete system costs of digital motion control applications using cheaper electrical motors without sensors. This paper deals with an overview of sensorless solutions in digital motor control applications whereby the focus will be the new Controller without sensors and its applications.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.5
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• pp.54-62
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• 1999

This paper describes the design and implementation of a PC(personal computer) based open architecture machine tool controller. The hardware of open architecture CNC has generally a motion control board on a PC for controlling a servo motor. But this paper describes open architecture hardware that consists of a PC, a counter board a DAC board and a DIO board only. This makes it easy to generate CNC software module in a hardware-independent way. The proposed open architecture CNC software runs on the MS-Windows NT. The paper describes a method of con-trolling servo motors using a real-time timer of MS-Windows NT and a commercial real-time operating system on the MS-Windows. NT. An open and reconfigurable software module is made up of an object and an API(application programming interface). Using the object and the API a new CNC system can be quickly configured to control dif-ferent machine tools. The proposed open architecture CNC system is applied to 4-axis lettering center.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.347-353
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• 2004

Due to various advantages over the conventional linear motion device such as ball-screw, linear motors have been used in wide variety of industrial applications for years. Driven by increased demand for precision machine tools, the importance of high positioning accuracy, high stiffness and high thrust are greatly increasing. The merits of linear motor are high speed high acceleration and good positioning accuracy. In addiction, Linear motor for high qualify machine tool call for high thrust, high stiffness. In this paper, thrust ripple, detent force and thermal behavior are considered for the development of high performance linear motor whose thrust is up to 1,900N. This paper presents a comprehensive study for an iron core type linear motor characteristics that include the influence of PM position on thrust ripple by detent force and motor dynamics as well.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.445-448
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• 2004

Linear motor is very rapidly substituted for rotary motor and ball screw for precision positioning applications because of its characteristics such as high speed, no backlash and simplicities. A precision positioning system which is composed of linear motion(LM) guide and linear motor is widely used since it has easy controllable property but this system has low accuracy problem caused by friction of the LM guide. In this study, a scanning type XY stage is manufactured and some experiments is performed to improve the accuracy of the stage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.3
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• pp.266-272
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• 2014

This study proposes a closed-loop shaping control method with $H_{\infty}$ optimization for optical image stabilization (OIS) in mobile phone cameras. The image stabilizer is composed of a horizontal stage constrained by ball bearings and actuated by the magnetic force from voice coil motors. The displacement of the stage is measured by Hall effect sensors. From the OIS frequency response experiment, the transfer function models of the stage and Hall effect sensor were identified. The weight functions were determined considering the tracking performance, noise attenuation, and stability with considerable margins. The $H_{\infty}$ optimal controller was executed using closed-loop shaping and limiting the controller order, which should be less than 6 for real-time implementation. The control algorithm was verified experimentally and proved to operate as designed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.84-91
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• 2002

Thrust vector characteristics of jet vanes installed in a shroud are very unique and much more complicated than those of the jet vane acting without any shroud by the fact of additional physical phenomena. The fluid dynamic interferences induced by jet vanes and shroud as well as jet vane's aerodynamic performance are investigated to characterize thrust vector control by semi-empirical model, three dimensional numerical analysis including real complex geometry, and ground firing test of real motors.