• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.530-536
• /
• 2004

In this paper a servo-system is developed to improve straightness of linear motor stages. When a linear motor stage is used for high-precision linear motion systems, high precision straightness accuracy is necessary to meet the required position accuracy. In such cases, machining and assembling cost increases to improve the straightness accuracy. An electro-magnetic actuator which is relatively cost effective than any other conventional servo-systems is suggested to compensate the fixed straightness error. To overcome the compensation error due to the friction, a sliding mode control is applied. The effectiveness of the suggested mechanism and the control performance are illustrated along with some experimental results.

• Tribology and Lubricants
• /
• v.27 no.2
• /
• pp.65-70
• /
• 2011

The power servo cylinder for driving accurately turbine stop valve of an atomic power plant is necessary to do turn-over owing to a leakage of oil and a structure problem, especially, it of a power plant be in demand a high quality standard depends entirely on import. There are much problem that the AlBC be to used as a material of piston head in cylinder are caused by wear. Therefore, it is necessary to examine friction characteristics of it. In this study, wear test experiments was carried out with AlBC and SCM440, using reciprocating friction tester of pin on disk. This result was shown that the wear mechanism of AlBC on working condition is adhesive wear and the maximum temperature of infra redray thermal image of frictional surface show over 2 mm from contact surface of pin and disk.

• 제어로봇시스템학회:학술대회논문집
• /
• 1999.10a
• /
• pp.302-305
• /
• 1999

Twin-servo mechanism is used to increase the payload capacity and speed of high precision motion control system. In this paper, we propose a robust synchronizing motion control algorithm to cancel out the skew motion of twin-servo system caused by different dynamic characteristics of two driving systems and the vibration generated by high accelerating and decelerating motions. This proposed control algorithm consists of separate feedback motion control algorithm of each driving system and skew motion compensation algorithm between two systems. Robust model reference tracking controller is proposed as a separate motion controller and its disturbance attenuation property is shown. For the synchronizing motion, skew motion compensation algorithm is designed, and the stability of whole Closed loop system is proved based on passivity theory.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.135-139
• /
• 1990

In general, the control of robot arms falls into two board categories (position control and force control). The joint interpolated trajectory schemes generally interpolate the desired joint path by a class of polynomial functions and generate a sequence of time based control set points for the control of a manipulator from a initial location to its destination. A digital position controller was designed and adapted to the industrial balancing manipulator. And also, the joint interpolated trajectory using 3rd order polynomial was generated in this study. The IBM PC used as the main controller and the trajectory planner had enough run-time capabilities. The 8097BH microcontroller is an integral pan of the joint controller which directly controls an axis of motion. The PI servo control system to treat each joint of the robot arm as a independent joint servo mechanism had satisfying performance, and a sequence of time-based intermediate configurations of the manipulator hand showed good continuity and smoothness on position and velocity of the manipulator's joint coordinates along the trajectory.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.2
• /
• pp.13-19
• /
• 2012

Ultra Precision Machining Techniques, such as manufacturing Micro Lens Array(MLA), off-axis mirror, $F-{\theta}$ lens for laser printer, are achieved, based on technologies in consequence of development of modern high-precision machining mechanism. Above all, FTS(Fast Tool Servo) and STS(Slow Tool Servo) are more innovative technologies for reducing time and development costs. In this paper, it is described that MLA machining technique by FTS, off-axis mirror machining technique by STS, optics for observing space, and development of infrared aspheric lens for a thermal imaging microscope.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.721-724
• /
• 2002

This study deals with a dynamic behavior analysis of pump control regulator varied the swash plate tilting angle with the positive and negative direction. To accomplish it's purpose, modeling and displacement response analysis about principal parts (spool, servo piston, feedback lever, sleeve) of pump control regulator was performed. We have been able to verifying the propriety of servo mechanism and design parameters of pump control regulator by research results. So, it respect to utilized with useful research data at variable displacement control valve development of variable displacement piston pump.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.3
• /
• pp.263-272
• /
• 2008

We implemented a real-time servo system for a manipulator based on Laser Range Finder (LRF). and established algorithms for grasping a moving cylinder. We devised a manipulator mechanism and driving hardware based on a system board equipped with Xscale Processor with real-time operating system RTAI on Linux. The manipulator motor driver is connected to the system board via CAN communication link, and LRF is connected via RS-232C. We implemented real-time software including CAN device driver, RS-232C device driver, manipulator trajectory generator, and LRF control software. A typical application experiment for grasping a cylinder with circle motion demonstrated our system's real-time performance.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2461-2463
• /
• 2000

This paper presents a scheme for designing a fuzzy observer for servo control system with nonlinear element, i.e., backlash. It is found that backlash occurs when the feed direction is reversed. Due to the imperfect transient response of the driving mechanism, not only the static backlash error but also the dynamic backlash error is generated on the contouring profile. And also, we utilized two inertia modeling in order to deals with coupled system accurately. The overall control system consists of two parts - a servo controller and an Fuzzy obsever. It is a Takagi-sugeno type fuzzy model whose consequent part is of the state space form is obtained. A simulation is carried out to demonstrate the effectiveness of the proposed scheme.

• Journal of Aerospace System Engineering
• /
• v.12 no.3
• /
• pp.9-17
• /
• 2018

For Earth observation, a small satellite camera has relatively weak structural stability compared to medium-sized satellite, resulting in misalignment of optical components due to severe launching and space environments. These alignment errors can deteriorate the optical performance of satellite cameras. In this study, we proposed a 3-axis focus mechanism to compensate misalignment in a small satellite camera. This mechanism consists of three piezo-electric actuators to perform x-axis and y-axis tilt with de-space compensation. Design requirements for the focus mechanism were derived from the design of the Schmidt-Cassegrain target optical system. To compensate the misalignment of the secondary mirror (M2), the focus mechanism was installed just behind the M2 to control the 3-axis movement of M2. In this case, flexure design with Box-Behnken test plan was used to minimize optical degradation due to wave front error. The wave front error was analyzed using ANSYS. The fabricated focus mechanism demonstrated excellent servo performance in experiments with PID servo control.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.45-46
• /
• 2006

In this paper, a dual stage servo mechanism has been developed for image tracking system to improve transient control performances such as small rise time, small overshoot, small settling time, etc. A secondary stage, a platform, actuated by a pair of electro-magnets is mounted on a conventional elevation gimbal. In this mechanism, the gimbal provides large range but slow motion and the platform provides small range but fast positioning. A sliding mode control is applied to the platform positioning to attain robust performances and stability in the presence of the disturbance related to dynamic coupling of the gimbal and the platform. Results from experiments illustrate that the suggested dual stage mechanism controlled by the sliding mode control is effective in improving transient responses and attenuating the disturbance related with dynamic coupling.