• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제43권7호
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• pp.648-656
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• 2015

Active SAR satellite's main maneuver is roll axis maneuver to change SAR antenna direction. In addition, yaw steering is required to minimize the doppler centroid variation. Thus, it is resonable to assign the torque/momentum capacity mostly to roll axis and then yaw axis. In this case, the pitch axis shows low agility performance. However, due to orbit maintenance, large angle maneuver about pitch axis is sometimes required. In this paper, we study the pitch axis maneuver time reduction through sequential rotation about roll and yaw axis. Since these two axes have high agility performance than pitch axis, maneuver time reduction is possible when large angle rotation about pitch axis is required.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제21권5호
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• pp.637-649
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• 1997

Effects of cone angle, pressure-hole orientation and Reynolds number on the five-hole probe calibration have been investigated for eight large-scale conical five-hole probes, which have either perpendicular pressure holes or forward-facing pressure holes for the cone angles of 45 deg, 60 deg, 75 deg and 90.deg. Pitch and yaw angles are changed from -40 deg to +40 deg with an interval of 5 deg, respectively, when the probe Reynolds numbers are 1.77*10$^{4}$, 3.53*10$^{4}$ and 7.06*10$^{4}$. The result shows that larger cone angle results in more sensitive changes in the calibration coefficients. In the case that the cone angle is 45 deg, the pitch-angle and yaw-angle coefficients of the five-hole probe with the perpendicular pressure holes show a very different trend compared with those of the five-hole probe with the forward-facing pressure holes. On the other hand, when the cone angle is more than 60 deg, each calibration coefficient is nearly independent of the pressure-hole orientation. Additionally, the effects of the Reynolds number on the calibration coefficients are also reported in detail.

• Journal of Advanced Navigation Technology
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• 제18권3호
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• pp.215-222
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• 2014

In this paper, parafoil airdrop system has been designed and analyzed. 6-degrees of freedom (6-DOF) model of the parafoil system is set up. Nonlinear model predictive control (NMPC) and Proportion integration differentiation (PID) methods were separately applied to adjust the flap yaw angle. Compared the results of setting time and overshoot time of yaw angle, it is found that the of yaw angle is more stable by using PID method. Then, trajectory following controller was designed based on the simulation results of trajectory following effects, which was carried out by using MATLAB. The lateral offset error of parafoil trajectory can be eliminated by its lateral deviation control. The later offset deviation reference was obtained by the interpolation of the current planning path. Moreover, using the designed trajectory, the trajectory following system was simulated by adding the wind disturbances. It is found that the simulation result is highly agreed with the designed trajectory, which means that wind disturbances have been eliminated with the change of yaw angle controlled by PID method.

• Korean Journal of Applied Biomechanics
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• 제22권2호
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• pp.131-140
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• 2012

This study was to investigate the relationship between the distance and projection factors, angle factors of javelin in women's javelin throwing. The data were collected in the 2011 National Sports Festivals for 11 players. Three-Dimensional motion analysis using a system of 4 video cameras at a sampling frequency of 60 fields/s was performed for this study. The factors of release conditions calculated using Matlab 2009a program. The statical analysis on the records(n=42) included mean and standard deviation of the mean(SD), Pearson's product moment correlation coefficient(SPSS Version 16.0 for Windows). There was a statistically significant positive relationship between the records and release velocity(r=.866, p<.01), height(r=.433, p<.01) and height rate(r=.340, p<.05). The attitude angle, release angle, and attack angle showed not a statistically significant relationship between the records. The medial-lateral tilt angle of javelin showed not a statistically significant relationship between the records, but the yaw angle of javelin(r=.549, p<.01) showed a statistically significant positive relationship between the records.

• Journal of Institute of Control, Robotics and Systems
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• 제19권1호
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• pp.45-55
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• 2013

With the recent advancement of control method and battery technology, the electric vehicle have been researched to replace the conventional vehicle with electric vehicle with the view point of the environmental concerns and energy conservation. An electric vehicle which is equipped with the independent front steering system and in-wheel motors has advantage in terms of control. For example, the different torque which generated by left and right wheels directly can make yaw moment and the independent steering using outer wheel control is able to reduce the sideslip angle. Using of independent steering and driving system, the 4 wheel electric vehicle can improve a performance better than conventional vehicle. In this paper, we consider the method for improving the cornering performance of independent front steering system and in-wheel motor used electric vehicle with the compensated outer wheel angle and direct yaw moment control. Simulation results show that the method can improve the cornering performance of 4 wheel electric vehicle. We also apply the steering motor failure to steer the vehicle turned by the torque difference without steering. This paper describes an independent front steering and driving, consist of three parts; Vehicle Model, Control Algorithm for independent steering and driving and simulation. First, vehicle model is application of TruckSim software for independent front steering and 4 wheel driving. Second, control algorithm describes the reduced sideslip and direct yaw moment method in view of cornering performance. Last is simulation and verification.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제33권11호
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• pp.924-931
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• 2009

The two-dimensional turbulent flow around the horn-type rudder has been examined in the present study by using the commercial code FLUENT. The standard ${\kappa}-{\epsilon}$ model is used as a closure relationship. The geometry of horn rudder is based on the NACA 0020 airfoil. The simulations for various angle attack (${\alpha}$) and yaw angle(${\delta}$) are carried out. The effect of Reynolds number is also investigated in this study. The cavitation is more possible when the yaw angle is $6^{\circ}$ and it is more serious as Reynolds number increases.

• International Journal of Automotive Technology
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• 제7권2호
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• pp.201-208
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• 2006

This paper describes the control philosophy of ESP(Electronic Stability Program) which consists of the stability control the fault diagnosis and the fault tolerant control. Besides the functional performance of the stability control, robustness of control and fault diagnosis is focused to avoid the unnecessary activation of the controller. The look-up tables are mentioned to have the accurate target yaw rate of the vehicle and obtained from vehicle tests for the whole operation range of the steering wheel angle and the vehicle speed. The wheel slip control with a design goal of wheel slip invariance is implemented for the yaw compensation and the target wheel slip is determined by difference between the target yaw rate and actual yaw rate. Since the ESP has a high severity level and the robust control is required, the robustness margin for the stability control is determined according to several uncertainties and the robust fault diagnosis is performed. Both computer simulation and test results are shown in this paper.

• Journal of Ship and Ocean Technology
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• 제6권3호
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• pp.26-36
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• 2002

Yaw-checking and course-keeping ability in IMO's ship rnanoeuvrability standards is reviewed from the viewpoint of safe navigation. Three kinds of virtual series-ships, which have different course instability, are taken as test models. The numerical simulation on Z-test is carried out in order to examine the correlation between known manoeuvrability in spiral characteristics and various kinds of overshoot angle. Then simulator experiments are executed with series-ships in a curved, narrow waterway by five pilots in order to examine the correlation between known manoeuvrability and degree of manoeuvring difficulty. IMO criteria for yaw-checking and course-keeping ability are discussed and new criteria are proposed.

• Journal of Navigation and Port Research
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• 제27권6호
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• pp.631-638
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• 2003

Yaw-checking and course-keeping ability in IMO's ship manoeuvrability standards are reviewed from the viewpoint of safe navigation. Three kinds of virtual series-ships, which have different course instability, are taken as test models. The numerical simulation on Z-test is carried out in order to examine the correlation between known manoeuvrability in spiral characteristics and various kinds of overshoot angle. Then simulator experiments are executed with series-ships in a curved, narrow waterway by six operators(five active pilots and one ex-captain) in order to examine the correlation between known manoeuvrability and degree of manoeuvring difficulty. IMC criteria for yaw-checking and course-keeping ability are discussed and revised criteria are proposed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.856-859
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• 1996

In this paper, a coarse alignment algorithm for strapdown inertial navigation system is proposed and evaluated analytically. The algorithm computes roll and pitch angles of the vehicle using accelerometer outputs, and then determines yaw angle with gyro outputs. It is referred, as two-step coarse alignment in this work. With the geometric relation between sensor outputs and roll, pitch and yaw angles, the algorithm error is analytically derived and compared with the previous coarse alignment algorithm introduced by Britting. The results show that the proposed two-step coarse alignment algorithm has better performance for pitch angle computation.