• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.464-467
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• 1997

In this paper, a high precision track following control algorithm is proposed for micro electrostatic actuator considering of the application for hard disk drive. The micro electrostatic actuator proposed has nonlinear voltage-displacement characteristic in a working range of 0.8.mu.m and has uni-directional movement. Mid range reference and open-loop bias are proposed for the revision of negative position error, and inverse model for linearization.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.9-15
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• 1999

A piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, the piezoelectric actuator lacks in repeatability because of its inherently high hysteresis characteristic between voltage and displacement. In this paper, a controller is proposed to compensate the hysteresis nonlinearity. The controller is composed of a PID and a neural network part in parallel manner. The output of the PID controller is used to teach the neural network controller by the unsupervised learning method. In addition, the PID controller stabilizes the piezoelectric actuator in the beginning of the learning process, when the neural network controller is not learned. However, after the learning process the piezoelectric actuator is mainly controlled by the neural netwok controller. In this paper, the excellent tracking performance of the proposed controller was verified by experiments and was compared with the classical PID controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.460-465
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• 1994

A high precision position control techinque of Brushless DC(BLDC) motor system with time varying parameters is expressed using the self tuning control method. The time varying parameters is estimated on real time by detecting voltage references from controller and mechanical motor speeds from tacho-generator. The effectiveness of the method is evaluated through the positon control experimental results of a BLDC motor system for reference change and arbitrary disturbance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.590-593
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• 2001

In this paper we describe the 6-axes robot's position determination using a stereo vision and an image based control method. When use a stereo vision, it need a additional time to compare with mono vision system. So to reduce the time required, we use the stereo vision not image Jacobian matrix estimation but depth estimation. Image based control is not needed the high-precision of camera calibration by using a image Jacobian. The experiment is executed as devide by two part. The first is depth estimation by stereo vision and the second is robot manipulator's positioning.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.159-165
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• 1999

Based on the cable-extension transducers, a new technique for two dimensional position measurement is developed in this paper. This new technique includes the use of two such transducers and the planar position is determined through triangulation. This paper also presents uncertainty analysis results for establishing sensor design specifications. An actual prototyped sensor system is built and its accuracy is verified through h\both experiments with coordinate measurement machines and its application to the real-time control of a high load wheeled mobile robot. This new type of position sensor can be easily used in a wide variety of automation applications in industry for two dimensional position measurements with high accuracy over a relatively large range, and it is both cast effective and robust against hostile environments.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.931-938
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• 2016

Application of vector control scheme for consumer products is enlarging to improve control performance. For the field-oriented control, accurate position detection is essential and generally requires expensive sensors. On the other hand, cost-reduction is important in home appliances, so that binary-type Hall-effect sensors are commonly used rather than using an expensive sensor such as an encoder. The control performance is directly influenced by the accuracy of the position information, and there exist non-uniformities related to Hall sensors in electrical and mechanical aspects, which result in distorted position information. Therefore, to get high-precision position information from low-resolution Hall sensors, this paper proposes a new position estimator consisting of a Kalman filter and feedforward compensation scheme, which generates a linearly changing position signal. The efficacy of the proposed scheme is verified by simulation and experimental results carried out with a 48-pole permanent magnet motor.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.2
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• pp.28-33
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• 2001

The subject of this study is to improve the position performance of the linear motion for hybrid type Linear Pulse Motor (HLPM). Generally, there are two applicable methods to ensure precise position control ; a good processing method. This paper is suggested an electrical 125 microstep driving method so as to achieves the excellent control performance, besides the small mechanical manufacture of teeth pitch. The compensation method of digital PI control is apply to step response of stable position control, step error, vibration suppression and the approach to high stability, and the Ziegler-Nichols tuning method is applied to the proper design of control parameter. The proposed control method has been verified by simulation results of the suitable gain and phase margin of bode plot, and from experiment result of step response.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.553-557
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• 1994

We propose a design method that uses H$_{\infty}$ optimization method to suppress oscillation of a shaft between motor and load for high precision (0.001 % of reference input) position controls. PI speed control loop was introduced as a minor loop. Standard problem is used for the modeling of the system and Glover-Doyle's algorithm is used for the optimization in the H$_{\infty}$ space. Friction is considered to be an important factor that makes it difficult for the system to reach steady state in short time. In this paper, we propose a hybrid controller that includes PI speed feedback loop, which is expected to have a role to reject torque disturbance like friction.n.n.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1450-1452
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• 2005

AC Servo system has been implemented to semiconductor equipments system for their requirements of the high resolution control. This paper is based on the newly produced DSP TMS320F2812 which has the performance of fast processing speed, 150 MIPS, and rich peripheral interface. The implemented system has been developed for the position control that also has speed and current control as inner loops. The controller implemented a high precision position control system with SVPWM and digital PI control and using high resolution rotary encoder.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.629-632
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• 2003

Piezo actuators are mainly used in precision position control system because of their high position resolution. Although there have been many approaches in open loop control of this, those method turn out to be not effective in precision control due to hysteresis and creep. To overcome the problems, closed loop PI control method is used in commercial products. However, it is very difficult to obtain fast response with conventional PI control although piezo actuator has fast response. In this paper, we propose a fuzzy PI control method with the proposed fuzzy PI controller, we obtains faster settling response over the conventional PI controller. We verify the effectiveness of the proposed method with experimental results.