• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.1
• /
• pp.71-78
• /
• 2011

In this paper, the effect of parameter errors to the estimation of the rotor angle in sensorless operation of a permanent magnet synchronous motor is analyzed. The angle error information which is utilized to estimate the rotor position can be classified into two factors, namely, the sign factor and the gain factor. This paper particularly focuses on parameter errors reflected in the sign factor of the angle error information which causes a deviation in the angle estimation. In this paper, mathematical expressions describing the deviation of the angle estimation due to the inductance error and the resistance error in the sensorless control are derived. The validity of the expression is verified by the computer simulations and the experimental results.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.3
• /
• pp.60-67
• /
• 2011

Visible light communication system transmits data by controlling light emission of LED and receives data through photo detecter, which is considered as one of strong candidates of next generation wireless communication systems. The transmission capacity of visible light communication system depends on light intensity emitted from LED, sensitivity of PD, distance between transmitter and receiver, angle of incidence at the receiver. In particular, the receiver's vertical and horizontal movement changes distance between transmitter and receiver and angle of incidence, which may degrades transmission capacity of system. In this paper, we propose an estimation algorithm of receiver's position and angle based on tracking of received light intensity for indoor visible light communication systems. The performance evaluation of proposed algorithm confirms that the estimation algorithm of receiver's position and angle is quite important for visible light communication system to improve its transmission capacity.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.1
• /
• pp.51-57
• /
• 2011

Information of the lateral velocity and the sideslip angle in a vehicle is very useful in many active vehicle safety applications such as yaw stability control and rollover prevention. Because cost-effective sensors to measure the lateral velocity and the sideslip angle are not available, reliable algorithms to estimation them are necessary. In this paper, a sliding mode observer is designed to estimate the lateral velocity. The side slip angle is estimated using the recursive least square with the disturbance observer and the pseudo integral. The estimated parameters from the combined estimation method are updated recursively to minimize the discrepancy between the model and the physical plant, and any possible effects caused by disturbances. The performance of the proposed monitoring system is evaluated through simulations and experiments.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.476-476
• /
• 2000

This paper deals with an estimation method far sideslip angle by using an unknown input observation technique in 4WS passenger car systems. Firstly, a 4WS vehicle model with 3DOP is derived under the constant velocity and same tyre's properties. The induced model is transformed into the linear state space model with considering the external disturbance. Secondly, an unknown input observer is introduced and its property which estimating the states of system without any disturbance information is shown. Lastly, the estimated sideslip angle of the 4WS system is verified through numerical simulation.

• Current Optics and Photonics
• /
• v.8 no.3
• /
• pp.300-306
• /
• 2024

To solve the nozzle swing angle non-contact measurement problem, we present a nozzle pose estimation algorithm involving weighted measurement uncertainty based on rotation parameters. Firstly, the instantaneous axis of the rocket nozzle is constructed and used to model the pivot point and the nozzle coordinate system. Then, the rotation matrix and translation vector are parameterized by Cayley-Gibbs-Rodriguez parameters, and the novel object space collinearity error equation involving weighted measurement uncertainty of feature points is constructed. The nozzle pose is obtained at this step by the Gröbner basis method. Finally, the swing angle is calculated based on the conversion relationship between the nozzle static coordinate system and the nozzle dynamic coordinate system. Experimental results prove the high accuracy and robustness of the proposed method. In the space of 1.5 m × 1.5 m × 1.5 m, the maximum angle error of nozzle swing is 0.103°.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.3
• /
• pp.605-613
• /
• 2009

In this paper, we studied for the real-time azimuthal measurement of HMD (Head Mounted Display) to control the tele-operated vision system on the mobile robot. In the preexistence tele-operated vision system, a joystick was used to control the pan-tilt unit of the remote camera system. To give the sense of presence to the tele-operator, we used a HMD to display the remote scene, measured the rotation angle of the HMD on a real time basis, and transmitted the measured rotation angles to the mobile robot controller to synchronize the pan-tilt angles of remote camera with the HMD. In this paper, we suggest an algorithm for the real-time estimation of the HMD rotation angles using feature points extraction from pc-camera image. The simple experiment is conducted to demonstrate the feasibility.

• Proceedings of the IEEK Conference
• /
• 2009.05a
• /
• pp.360-362
• /
• 2009

In this paper, we studied for the real-time azimuthal measurement of HMD(Head Mounted Display) using the feature points detection to control the tele-operated vision system on the mobile robot. To give the sense of presence to the tele-operator, we used a HMD to display the remote scene, measured the rotation angle of the HMD on a real time basis, and transmitted the measured rotation angles to the mobile robot controller to synchronize the pan-tilt angles of remote camera with the HMD. In this paper, we suggest an algorithm for the real-time estimation of the HMD rotation angles using feature points extraction from pc-camera image.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.11
• /
• pp.1053-1059
• /
• 2010

This paper treats the DIS (Digital Image Stabilization) problem subject to base motions such as translation, rotation and zoom. For the local motion estimation from a raw image, the Harris corner detection algorithm is exploited to extract feature points, and comparing those of consecutive images, the zoom ratio (scale factor) is computed. For the global motion estimation, an equivalent model is derived to account for a 3-dimensional composite motion from which the center point and Euler angle can be determined. Finally, the motion compensation follows. To show the effectiveness of the present DIS scheme, experimental results for synthetic images are illustrated.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.5C
• /
• pp.472-478
• /
• 2010

In the environment of wireless communication system of IEEE 802.15.3a UWB standard, the angle of arrival(AOA) estimation technique for the indoor wireless positioning algorithms, based on the AOA parameter estimation which fits well for the wireless communication channel and shows high estimation accuracy, is proposed. After the UWB signal model, based on the IEEE 802.1.3a standard, is constructed, the average weighted MUSIC technique is proposed, which shows better estimation accuracy than those of conventional estimation technique. Through the simulation studies, the environment of the indoor wireless positioning system including the IEEE 802.15.3a channel is configured and we demonstrate better estimation results by the proposed AOA estimation technique than those from the conventional method.

• Journal of Korea Multimedia Society
• /
• v.7 no.12
• /
• pp.1745-1753
• /
• 2004

A method of estimating the pose of a three-dimensional object from a set of two-dimensioal images based on parametric eigenspace method is proposed. A Gaussian blurred edge image is used as an input image instead of the original image itself as has been used previously. The set of input images is compressed using K-L transformation. By comparing the estimation errors for the original, blurred original, edge, and blurred edge images, we show that blurring with the Gaussian function and the use of edge images enhance the data compression ratio and decrease the resulting from smoothing the trajectory in the parametric eigenspace, thereby allowing better pose estimation to be achieved than that obtainable using the original images as it is. The proposed method is shown to have improved efficiency, especially in cases with occlusion, position shift, and illumination variation. The results of the pose angle estimation show that the blurred edge image has the mean absolute errors of the pose angle in the measure of 4.09 degrees less for occlusion and 3.827 degrees less for position shift than that of the original image.