• Proceedings of the KSR Conference
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• 2009.05b
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• pp.233-237
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• 2009

In this study, we suggest that several approaches to evaluate the collision acceleration value of a car in the article 35 and the guideline 16 of Korean rolling stock safety regulation. There are various methods to evaluate collision acceleration such as; a displacement comparison method by the double integration of filtered acceleration data, a velocity comparison method by the integration of filtered acceleration data, an analysis method of time-velocity curve, or a differential method of time-velocity curve. We compared these methods one another using 1D dynamic simulation model composed of nonlinear dampers, springs and bars, and masses. Also, we applied these methods to a hybrid model, which is made of 3D shell element model and 2D collision dynamics model, in order to evaluate whether 1D force-displacement curve modeling for energy absorbing structures have an effect on the collision acceleration levels or not.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.258-262
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• 2017

In this paper, we propose a new collision detection algorithm for human-robot collaboration. We use an IMU sensor located at the tip of the manipulator and the kinematic behavior of the manipulator to detect the unexpected collision between the robotic manipulator and environment. Unlike other method, the developed algorithm uses only the kinematic relationship between the manipulator joint and the end effector. Therefore, the collision estimation signal is not affected by the error of the dynamics model. The proposed collision detection algorithm detects the collision by comparing the estimated acceleration of the end effector derived from the position, velocity and acceleration trajectories of the robot joints with the actual acceleration measured by the sensor. In simulation, we compare the performance of our method with the conventional Residual Observer (ROB). Our method is less sensitive to the load variation because of the independency on the dynamic modeling of the manipulator.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.5
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• pp.477-485
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• 2010

In this study, we suggested several approaches to evaluate the collision acceleration of a carbody under the article 16 of the Korean rolling stock safety regulations. There are various methods to evaluate the rigid body accelerations such as the displacement comparison method by double integration of filtered acceleration data, the velocity comparison method by direct integration of filtered acceleration data, and the analysis method of a velocity-time curve. We compared these methods one another using the 1D dynamic simulation model of Korean high-speed EMU composed of nonlinear springs or bars, dampers, and masses. From the simulation results, the velocity-time curve analysis method and the displacement comparison method are recommended to filter high frequency oscillations and evaluate the maximum and average accelerations of a carbody after a train collision.

• Earthquakes and Structures
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• v.3 no.5
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• pp.675-694
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• 2012

The 2008 Iwate-Miyagi Nairiku earthquake ($M_w$ 6.9, $M_{jma}$ 7.2) occurred on 14 June 2008 in Japan. The amplification and asymmetric waveform of the vertical acceleration at the ground surface recorded by accelerometers at station IWTH25, situated 3 km from the source, were remarkable in two ways. First, the vertical acceleration was extremely large (PGA = 38.66 $m/s^2$ for the vertical component, PGA = 42.78 $m/s^2$ for the sum of the three components). Second, an unusual asymmetric waveform, which is too far above the zero acceleration axis, as well as large upward spikes were observed. Using a multidegree-of-freedom (MDF) system consisting of a one-dimensional continuum subjected to vertical acceleration recorded at a depth of 260 m below ground level, the present paper clarifies numerically that these singular phenomena in the surface vertical acceleration records occurred as a result of the jumping and collision of a layer in vertical motion. We herein propose a new mechanism for such jumping and collision of ground layers. The unexpected extensive landslides that occurred in the area around the epicenter are believed to have been produced by such jumping under the influence of vertical acceleration.

• Journal of the Korea Computer Graphics Society
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• v.25 no.2
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• pp.11-18
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• 2019

In this paper, we propose a framework that can perform acceleration collision detection efficiently by using a cone based collision area in a particle-based system which requires collision detection with many objects. Three conditions determine particle and cone-based collision regions: 1) If there is a cone position within the radius of the adjacent particle, 2) In the case where the position of the adjacent particle exists in the cone area, 3) When adjacent particles exist between two vectors forming a cone area. As a result, it is defined that when the above conditions are all satisfied, the particle and the region of a cone have collided. In this paper, we automatically update the area of the cone, which is the collision detection area, according to the particle movement. Determine the direction and length of the cone based on the position and velocity of the particle to calculate the dynamic change of the cone. Collision detection is performed quickly using only the particles in the finally calculated area. The acceleration method proposed in this paper is simple to implement because it is executed with a closed form equation instead of explicitly creating the tree data structure, and collision inspection performance is improved in all results.

• Journal of Auto-vehicle Safety Association
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• v.11 no.3
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• pp.37-42
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• 2019

This paper presents an autonomous acceleration planning algorithm for pedestrian collision avoidance at urban. Various scenarios between pedestrians and a vehicle are designed to maneuver the planning algorithm. To simulate the scenarios, we analyze pedestrian's behavior and identify limitations of fusion sensors, lidar and vision camera. Acceleration is optimally determined by considering TTC (Time To Collision) and pedestrian's intention. Pedestrian's crossing intention is estimated for quick control decision to minimize full-braking situation, based on their velocity and position change. Feasibility of the proposed algorithm is verified by simulations using Carsim and Simulink, and comparisons with actual driving data.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.297-310
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• 2022

Road facilities such as CCTV poles have potential risk of collision accidents with a car. A collision detection algorithm installed in the facility allows the collision accident to be known remotely. Most collision detection algorithms are operated by simply focusing on whether a collision have occurred, because these methods are used to measure only acceleration data from a 3-axis sensor to detect collision. However, it is difficult to detect other detailed information such as malfunction of the sensor, collision direction and collision strength, because it is not known without witness the accident. Therefore, we proposed enhanced detection algorithm to get the collision direction, and the collision strength from the tilt of the facility after accident using a 9-axis sensor in this paper. In order to confirm the performance of the algorithm, an accuracy evaluation experiment was conducted according to the data measurement cycle and the invocation cycle to an detection algorithm. As a result, the proposed enhanced algorithm confirmed 100% accuracy for 50 weak collisions and 50 strong collisions at the 9-axis data measurement cycle of 10ms and the invocation cycle of 1,000ms. In conclusion, the algorithm proposed is expected to provide more reliable and detailed information than existing algorithm.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.81-86
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• 2013

This paper presents the lane change system for collision avoidance. The proposed algorithm for the collision avoidance consists of path generation and path following. Using a calculated TTC (Time to Collision), partial braking is operated and collision avoidance path is generated considering relative distance, velocity and acceleration. Based on the collision avoidance path, desired yaw angle and yaw rate are calculated for the automated path following. The lateral controller is designed by a Lyapunov function approach using 3 D.O.F vehicle model and vehicle parameters. The required steering angle is determined from wheel velocity, longitudinal and lateral velocity in order to follow the desired yaw angle and yaw rate. This system is developed MATLAB/Simulink and its performance is evaluated using the commercial software CarSim.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.820-825
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• 2008

In the article 16 of the domestic rolling stock crashworthiness regulations, the collision acceleration level during collision accidents should remain under the maximum 7.5g and the average 5g. By the way, the accelerations obtained in crash simulations and tests contain many kinds of high frequency components due to numerical oscillations or noisy signals. So, this paper aims to develop reliable post-processing methods to filter high frequency oscillations and extract the rigid body motions of passenger rail cars. For this study we used the 1-dimensional dynamic model of KHST (Korean high-speed train), and evaluated acceleration data at the driver's area in the first power car and the passenger area in the following trailer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.199-206
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• 2011

In Korea, the current design codes for the bridge vessel collision load are based on AASHTO LRFD code which derived from the mean collision forces of the Woisin's test. To estimate the conservativeness of the code, in this study, the mean forces of head on collisions were evaluated from the mass-acceleration relationship of vessel and the deformation-kinetic energy relationship of bow those obtained from the series of nonlinear finite element analysis, and the mean forces were compared to that in AASHTO design code. As results, the variations of the mean forces versus the sizes of vessels were represented similar tendency, even those of the code are very conservative. However, the variations of mean collision force versus those of collision speeds were dominated by the plastic deformation of bow and it was differ from those of the code that have linear relationship with the collision speeds.