• Journal of the Korean Society for Precision Engineering
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• v.12 no.8
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• pp.140-146
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• 1995

In case the uncertainty existing in a system is assumed to satisfy the matching condition and to be come-bounded. Y. H. Chen proposed an adaptive robust control algorithm which introduced adaptive sheme for a design parameter into robust deterministic controls. In this paper, the adaptive robust control algorithm is applied to the position tracking control of direct drive robots, and simulation and experimental studies are conducted to evaluate control performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.77-78
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• 2009

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.5
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• pp.90-96
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• 2001

This paper proposes the hybrid fuzzy control system for fast response time and precision control of auto-equipment which exist disturbance, parameter alteration of system, uncertainty. The purposed system, which provides the improvement in terms of the control region in high speed and precision control, first used the fuzzy control method for fast response time and when the error reaches the preset value, used the frequency-locked method for precision control. The theoretical and experimental studies have been carried out. The presented results from the above investigation show considerably improved performance in the position control of auto-equipment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.647-652
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• 2000

This paper presents a study on the position tracking control of robot system on the uncertain elastic base. The elastic base is modeled as a virtual robot which has passive joints and the control strategy is using approximate Jacobian operators. Jacobian operators represent the overall robot system including base movement. However, because we don't know the base movement we can't estimate the jacobian operators directly. The control algorithm is proposed which uses only Jacobian operators of a real robot as approximate Jacobian operators. The measured errors from external sensor are compensated by approximate Jacobian operators. The simulation results of a single-axis robot system show that the control strategy can be used for position tracking.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.456-460
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• 1996

A nonlinear control scheme for preventing limit cycle due to the nonlinearity of themulti-step bang-bang actuator in mechanical position control systems is proposed. A linearized model, SIDF, fora multi-step bang-bang actuator is introduced to compensate the nonlinearity of the multi-step bang-bang actuator. Using that model, a $H_{\infty}$robust controller for position control systms with a bang-bang actuator is proposed by loop shaping tecniques with normalized coprime factorization stabilization to address the robustness. The proposed scheme needs a smaller deadband as a result of compensating the nonlinearity of the bang-bang actuator. A single-axis servo system is served in order to verify the proposed control scheme experimentally. Experimental results show that the controller can satisfy the special intersts, silent contact switching of the actuator.r.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.03a
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• pp.40-62
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• 1995

A micro positioning system using piezoelectric actuators have very wide application region such as ultra-precision machine tool optical device measurement system. In order to keep a high precision displacement resolution it to useful to take a position sensor and feedback of the error. From the practical point of view high-resolution displacement sensor systems are very expensive and it is difficult to make such a sensitive sensor work properly in a poor operational environment of industry. In this study a piezo-electric micro-depth control system which does not require position sensor but piezoelectric voltage feedback has been developed. It is driven by hysteresis-considering reference input voltage calculated in advance and actuator/sensor characteristics of piezoelectric materials. From the result of experiments a fast and stable response of micro-depth control system has been achieved and an efficient technique to control the piezoelectric actuator suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.190-194
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• 2001

Because, Piezo-electric transducer(PZT) transform electric energy into mechanical energy, it is a adequate material for positioning control and force control, take excellent properties as actuator with high speed and high performance. Recently, researches of ultra precision positioning using this PZT are advanced in. In this paper, we use a actuator of PZT, design a positioning apparatus with ultra precision position apparatus as hinge structure. Because of this purpose, before, we were confirmed in control properties of ultra precision stage by FEM method.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.6
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• pp.66-71
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• 2007

Development of a locomotive mechanism for the capsule type endoscopes will largely enhance their ability to diagnose disease of digestive organs. As a part of it, there should be provided a detection device of their position in human organs for the purpose of observation and motion control. In this paper, a permanent magnet outside human body was employed to project magnetic field on a capsule type endoscope, while its position dependent flux density was measured by three hall-effect sensors which were orthogonally installed inside the capsule. In order to detect the 2-D position data of the capsule with three hall-effect sensors including the roll, pitch and yaw angle, the permanent magnet was extra translated during the measurement. In this way, the 2-D coordinates and three rotation angles of a capsule endoscope on the same motion plane with the permanent magnet could be detected. The working principle and performance test results of the capsule position detection device were introduced in this paper showing that they could be also applied to 6-DOF position detection.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.339-344
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• 1993

A study for a lathe to machine workpieces with noncircular corss-sections is presented. The noncircular cutting is accomplished by controlling the radial tool position synchronized with the revolution angle of spindle. A learning control algorithm is suggested for the toll positioning, of which the control performances are analyzed and simulated on a numerical computer that the effectiveness of the control is convinced. The learning control is tested on a NC-lathe which shows successful results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.383-387
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• 1996

This paper presents a steering control strategy applicable to vehicle path following problems. This control strategy is based on realistic nonlinear equations of motion of multibody systems described in terms of relative joint coordinates. The acceleration of the steering angle is selected as a control input of the system. This input is obtained by considering position and slope errors at current and at advance times. This steering control strategy is tested in circular and lane change maneuvers with a nonlinear vehicle model.