• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.839-840
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• 2006

Our paper proposes a novel moving object tracking scheme for biped robot using a single camera. For walking control of a biped robot we analyze the dynamics of a three-dimensional inverted pendulum model. This analysis leads us a simple linear dynamics. And, the control parameter of the biped robot is derived from the feedback signal which converges the position of a image feature to the feature position of a desired image and the feedforward signal which compensates the motion component due to the moving object.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.420-422
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• 1998

In this paper, we propose a position-speed control of servo system with a state estimator. And also we utilized two mass modelling in order to deals with real system accurately. The overall control system consists of two parts: the position-speed controller and state estimator. The Kalman filter applied as state - feedback controller is an optimal state estimator applied to a dynamic system that involves random perturbations and gives a linear,unbiased and minimun error variance recursive algorithm to estimate the unknown state optimally. Therefore we consider the error problem about the servo system modelling, the measurement noise at low-speed ranges a stochastic system, and implement a optimal state observer. Performance of the proposed state estimator are demonstrated by computer simulations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.411-416
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• 2002

In a high speed spindle system, it is very important to monitor the state of rotating rotor. Particularly in active control spindle system, the position sensor must provide feedback to the control system on the exact position of the rotor. In order to monitor the state of a high speed spindle exactly, high accuracy and wide frequency bandwidth of sensors are important. The focus in this paper is to make a fiber optic sensor for monitoring rotor of magnetic bearing, to design the circuit for detecting optical signal, and to evaluation static and dynamic characteristics of fiber optic sensor.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2240-2242
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• 2001

A rotary double inverted pendulum, the nonlinear system has a regulation problem. In this paper, we linearize the nonlinear system at the upright equilibrium position. The linearized system can be expressed in state space. To maintain the upright position, we design a feedback controller using LQR(Linear Quadratic Regulator) algorithm. Then we simulate the system with third-order Adams Bashforth Moulton Method. The simulated result shows that the applied algorithm is effective for the regulation problem.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.42-48
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• 1999

A control method for a robot hand grasping a object in a partially unknown environment will be proposed, where a proximate sensor detecting the distance between the fingertip and object was used. Particularly, the finger joints were driven servo-pneumatically in this study. Based on the proximate sensor signal the finger motion controller could plan the grasping process divided in three phases ; fast aproach, slow transitional contact and contact force control. That is, the fingertip approached to the object with full speed, until the output signal of the proximate sensor began to change. Within the perating range of the proximate sensor, the finger joint was moved by a state-variable feedback position controller in order to obtain a smooth contact with the object. The contact force of fingertip was then controlled using the blocked-line pressure sensitivity of the flow control servovalve for finger joint control. In this way, the grasping impact could be reduced without reducing the object approaching speed. The performance of the proposed grasping method was experimentally compared with that of a open loop-controlled one.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.15-17
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• 1996

In this paper, a modified microstep drive of PM step motor is presented. The open-loop drive of a step motor is attractive and widely accepted in applications of speed and position controls. However, the performance of the step motor is limited under the open-loop drive. The closed-loop control is advantages over the open-loop control not only in that step failure never occurs but that the motion is much quicker and smoother. However, a high resolution sensor is needed for detecting position and speed. The modified microstep drive is constructed as a microstep drive with speed feedback. The advantages of the proposed method is that the controller can be designed by a low resolution sensor and is simpler than other closed-loop controller. A concept of vector control is used for verifying the proposed scheme. Simulations show the performance of the proposed method and a comparison with a classic drive method.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.3
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• pp.181-187
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• 1996

A frictionless positioning device using cone-shaped active magnetic bearings(AMBs) is developed, which is driven by a brushless DC motor equipped with resolver. The cone-shaped AMB feature that the structure is simple and yet the five d.o.f. rotor motion is controlled by four magnet pairs. A linearized dynamic model, which accounts for the relationship between input voltage and output current in the cone-shaped magnet, is developed and the azimuth motion of the frictionless positioning device is modeled as the second order system. The feedback controller is designed by using linear quadratic regulator with integral action optimal control law so that the cone-shaped AMB system is stabilized and the frictionless positioning device gets the zero steady state. It is observed that the linearized dynamic model is adequate and the frictionless positioning device can achieve the tracking accuracy within the sensor resolution.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.244-247
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• 2003

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. A minimum order state observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor. A minimum order state observer is implemented to compute the speed and Position feedback signal. The validity of the proposed sensorless scheme is confirmed by various response characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1038-1041
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• 2003

The magnetic suspension system is used in many areas, because it has great advantages. such as no friction, no noise, no lubrication and so on, but it is a unstable system in natural. It must have a feedback control with the position is measured for a stable levitation. There are an eddy-current sensor, a capacitive sensor, an inductive sensor, and an optical sensor with a laser as the sensor which measures displacements without contact. Among them, an inductive sensor is made with lower price than others. And it has a good linearity. In this paper, a magnetic circuit leads a linear equation between an input as a displacement and an output as a voltage. Experiments establish that voltage change according to displacement is linear. This paper presents the preliminary study of an inductive position sensing for self-sensing magnetic suspension system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.1
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• pp.1-12
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• 1991

In this paper the design and construction of discrete model following servo dontroller on the position control system is proposed. The operational time delay of the plant in the controller which is proposed, is considered and the system which is added by the integral compensation in first order difference equation is constructed. By applying the optimal regulator method to the system, the method which find the optimal state feedback gain is developed theoretically. The output of a model which is correspond to a DC Servo motor follow quickly the speed response of a DC Servo motor and the velocity error in ansteady-state is reduced in zero and the position response is controlled correctly, the performance of the controller is contoller is confirmed by Computer Simulation.