• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1998년도 춘계학술대회 논문집
• /
• pp.143-147
• /
• 1998

As the accuracy of manufactured goods needed high-accuracy processing has made the efficiency of NC and measurment technology develop, the innovation of machine tools has influence the development of the semi-conductor and optical technology. We can mention that a traction role of the acceleration for the development like that depends on the development of the measurement technics - Stylus instrument method, STM, SEM, Laser interferometer method - which are used for measuring the movement accuracy of machine tools. The movement error factors in movement accuracy are expressed as yaw, roll, and pitch etc. Machining center has 21 movement error factors including of 3 axies joint errors because that has 3 axies and has been measured as the standard of the unloaded condition until now inspite of getting static, dynamic, and servo-gain errors in the case of expending the error range. Therefore, this study tries to measure position accuracy according to loading on the X-Y table of the machining center.

• 자동차안전학회지
• /
• 제12권3호
• /
• pp.34-42
• /
• 2020

ADAS (Advanced Driver Assistance Systems) uses sensors such as camera, radar, lidar and GPS (Global Positioning System). Among these sensors, the camera has many advantages compared with other sensors. The reason is that it is cheap, easy to use and can identify objects. In this paper, therefore, a theoretical formula was proposed to obtain the distance from the vehicle's front wheel to the lane using a monocular camera. And the validity of the theoretical formula was verified through the actual vehicle test. The results of the actual vehicle test in scenario 4 resulted in a maximum error of 0.21 m. The reason is that it is difficult to detect the lane in the curved road, and it is judged that errors occurred due to the occurrence of significant yaw rates. The maximum error occurred in curve road condition, but the error decreased after lane return. Therefore, the proposed theoretical formula makes it possible to assess the safety of the LKA system.

• International Journal of Precision Engineering and Manufacturing
• /
• 제9권4호
• /
• pp.26-31
• /
• 2008

A precision four-degree-of-freedom measurement system has been developed for simultaneous measurement of four motion errors of a linear stage, which include straightness and angular errors, The system employs a retro-reflector to detect the straightness errors and a plane mirror to detect the angular errors. A common-path compensation method for laser beam drift is put forward, and the experimental results show that the influences of beam drift on four motion errors can be reduced simultaneously. In comparison with the API 5D laser measuring system, the accuracy for straightness measurement is about ${\pm}1.5{\mu}m$ within the measuring range of ${\pm}650{\mu}m$, and the accuracy for pitch and yaw measurements is about ${\pm}1.5$ arc-seconds within the range of ${\pm}600$ arc-seconds.

• 전자공학회논문지
• /
• 제52권5호
• /
• pp.190-196
• /
• 2015

본 논문은 항법장치 위치보정을 위해 칼만필터를 적용한 GPS/INS융합의 다중보정방법을 제안한다. 연구에서는 관성항법장치를 구현하기 위해 9축 항법장치로 보정알고리즘을 적용하여 위치오차를 감소시킨 방법을 적용했다. 일반적으로 GPS/INS는 위치정보를 얻어낼 수 있지만 위치정보를 구하는 과정에서 오차 또한 더불어 커지게 되기에 이를 보정하기 위한 강인한 오차 보정 알고리즘이 필요하다. 본 논문에서는 9축 관성센서(mpu-9150)의 외란에 대한 강인성 향상을 위해 가속도계 보정 알고리즘을 사용하여 tilt보정을 수행했으며, 제어 대상체의 정확한 방위를 파악할 수 있도록 Yaw각 재정의 알고리즘을 적용하였다. 최종적으로 GPS/INS와 칼만 필터를 함께 결합한 통합시스템을 구현하였다.

• 반도체디스플레이기술학회지
• /
• 제21권4호
• /
• pp.132-137
• /
• 2022

In this paper, we have studied the quadrature error reduction for the single drive 3-axis MEMS Gyroscope. There was a limitation of the previous study which is the z-axis quadrature error was large. To reduce this value, design methodologies were presented. And the methodologies included a different mesh application, z-rate spring structure change, and mass compensation for balancing of the structure. We conducted the modal analysis, drive mode analysis and sense mode analysis using COMSOL Multiphysics. As a result, a drive resonant frequency was 26003 Hz, with the x-sense, y-sense, z-sense being 26749 Hz, 26858 Hz, 26920 Hz, respectively. And the Mechanical sensitivity was computed at 2000 degrees per second(dps) input angular rate while the sensitivity for roll, pitch, and yaw was computed 0.011, 0.012, and 0.011 nm/dps respectively. And z-axis quadrature error was successfully improved, 2.78 nm to 0.95 nm, which the improvement rate was about 66 %.

• 한국항행학회논문지
• /
• 제18권3호
• /
• pp.215-222
• /
• 2014

본 논문은 패러포일 투하 시스템을 설계하고 분석하는데 있다. 패러포일 시스템의 6-자유도(6-DOF) 모델을 새우고, 비선형 모델 예측 제어와 PID 제어 방법이 펄럭 편 요각을 제어하기 위해 각각 적용되었다. 펄럭 편 요각의 오버슈트 시간 및 세팅 시간의 결과를 비교하면서 PID제어 방법을 사용하는 것으로부터 펄럭 편 요각이 좀 더 안정화 되는 것을 확인하였다. 그런 다음 MATLAB에 의해 수행된 궤적 추종 효과의 시뮬레이션 결과에 의해 궤적 추종 제어기가 설계되었다. 패러포일 궤적의 측 방향 오차가 그것의 측 방향 편차 제어 방법에 의해 제거 될 수 있었다. 참고로 측 방향 편차는 현재 경로계획의 보간법에 의해 얻어졌다. 그리고 설계된 궤적을 사용하면서, 풍 외란을 추가하는 것으로부터 궤적 추종 시스템이 시뮬레이션 되었다. 시뮬레이션 결과는 풍외란이 PID로 제어되는 펄럭 편 요각 변화에 의해 제거됨으로써 설계된 궤적에 아주 만족하였다.

• 한국자동차공학회논문집
• /
• 제24권2호
• /
• pp.198-204
• /
• 2016

In this study, a wind tunnel test was conducted to measure the aerodynamic characteristics of a streamline-designed high-speed bus with the change of wind direction and speed and the result is compared with the aerodynamic performance of a commercialized high-speed bus model (Model-0) manufactured by Zyle Daewoo Bus Corp. Aerodynamic performance of the existing rear-spoiler was tested to prove its aerodynamic effect on the test model bus. From the study, it was found that 24.6 % of the total drag of the original bus model (Model-0) was reduced on the streamline-designed model bus(model-1) without the rear-spoiler but only 14.3 % of the total drag was reduced with the spoiler on the streamlined model bus. It means that the rear spoiler does not work properly with the streamlined model bus (model-1) and should be noted that an optimum design of a rear-spoiler of a vehicle is important to reduce the induced pressure drag and increase the driving stability of a vehicle against yaw motion. The experimental outcome was also compared to the previous numerical research result to evaluate the reliability of the numerical algorithm of the aerodynamic performance analysis of a vehicle. The error rate (%) of the numerical result to the experimental output is about 5.4 % and it is due to the simplified body configuration of the numerical model bus. The drag increases at the higher yaw angle because the transparent frontal area of the model vehicle increases and the downward force increases with the yaw angle as well. It has a positive effect to the driving stability of the vehicle but the moderated downward force should be kept for the fuel economy of a vehicle.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
• /
• pp.324-327
• /
• 1996

This paper describes the robust controller design methods applied to the problem of an automatic system for tow-vehicle/trailer combinations. This study followed an inverse Linear Quadratic Regulator(LQR) approach which combines pole assignment methods with conventional LOR methods. It overcomes two concerns associated with these separate methods. It overcomes the robustness problems associated with pole placement methods and trial and error required in the application of the LQR problem. Moreover, a Kalman filter is used as the observer, but is modified by using the loop transfer recovery (LTR) technique with modified transmission zero assignment. The proposed inverse LQG,/LTR controllers enhances the forward motion stability and maneuverability of the combination vehicles. At high speeds, where the inherent yaw damping of the vehicle system decreases, the controller operates to maintain an adequate level of yaw damping. At backward moton, both 4WS (2WS tow-vehicle, 2WS trailer) and 6WS (4WS tow-vehicle, 2WS trailer) control laws are proposed by using inverse LQG/LTR method. To evaluate the stability and robustness of the proposed controllers, simulations for both forward and backward motion were conducted using a detailed nonlinear model. The proposed controllers are significantly more robust than the previous controllers and continues to operate effectively in spite of parameter perturbations that would cause previous controllers to enters limit cycles or to loose stability.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.1102-1105
• /
• 2004

In this paper, the problem of a viewer's head tracking in a desktop-based interactive stereoscopic display system is considered. A fast and low-cost approach to the problem is important for such a computing environment. The system under consideration utilizes a shuttle glass for stereoscopic display. The proposed method makes use of an image taken from a single low-cost video camera. By using a simple feature extraction algorithm, the obtained points corresponding to the image of the user-worn shuttle glass are used to estimate the glass center, its local 'yaw' angle, as measured with respect to the glass center, and its global 'yaw' angle as measured with respect to the camera location. With these estimations, the stereoscopic image synthetic program utilizes those values to interactively adjust the two-view stereoscopic image pair as displayed on a computer screen. The adjustment is carried out such that the so-obtained stereoscopic picture, when viewed from a current user position, provides a close-to-real perspective and depth perception. However, because the algorithm and device used are designed for fast computation, the estimation is typically not precise enough to provide a flicker-free interactive viewing. An error concealment method is thus proposed to alleviate the problem. This concealment method should be sufficient for applications that do not require a high degree of visual realism and interaction.

• The Journal of the Acoustical Society of Korea
• /
• 제24권1E호
• /
• pp.7-15
• /
• 2005

This paper addresses issues encountered in measuring the general, 6-degree-of-freedom motion of a human head, A complete mathematical description for measuring the head motion using the six-accelerometer configured bite-bar is suggested, The description shows that the six-axis vibration cannot be completely obtained without the roll, pitch and yaw angular velocity components, A new method of estimating the three orthogonal (roll, pitch and yaw) angular velocities from the six acceleration measurements is introduced. The estimated angular velocities are shown to enable further quantitative error analysis in measuring the translational and angular accelerations at the head. To make this point clear, experimental results are also illustrated in this paper. They show that when the effects of angular velocities are neglected in the head vibration measurement the maximum percentage errors were observed to be more than $3 \%$ for the angular acceleration of the head and to be close to $5 \%$ for its translational acceleration, respectively. It means that the inclusion of all the angular velocity dependent acceleration components gives more accurate measurement of the head vibration.