< PreviousKyoungtaek Kwak·Seunghoon Kang·Jaedong Yoo·Kyungdug Seo·Youngchul Shin·Kyungsup Chun·Jaekyu Lee 8 자동차안전학회지:제15권,제1호,2023 Fig. 2 Comparison of the Typical and Clamshell Hood for Luxury Cars Fig. 4 3D Scanning Image for 3 mm (Intentional Misalignment of Front End Module) Fig. 3 Hood Latch Mechanism that Absorbs Lateral Distribution of Panel Location form. Fig. 2 shows the comparison of the typical and clamshell hood for the same luxury car. As depicted in Fig. 2, the perimeter of clamshell hood is longer than that of typical one so it is easily understood that the quality of gap and flushness of clamshell hood should be the key considerations of the engineering design. Hence, in order to realize the high-quality alignment of the clamshell hood and body panel, the newly devised hood latch that effectively absorbs the lateral displacement needs to be applied. 1.2. Hood Latch Mechanism to Absorb Lateral Distribution Fig. 3 shows the hood latch mechanism that absorbs the lateral distribution of panel location. Basically, the gap between the striker and base plate of hood latch is 2 mm for both sides so it alleviates the misalignment of hood panel as possible as it can. Also, the pop-up lever is simultaneously applied to suppress the lateral movement of panel by compressing the striker and claw for the vertical direction. 1.3. Benefit and Challenge of Newly Devised Hood Latch Mechanism From this mechanism, the quality of gap and flushness of panel is verified from the component measurement as follows. Fig. 4 shows 3D scanning image for 3 mm- lateral misalignment of front end module. In case of typical latch, the amount of lateral movement of hood panel is the same as that of the misalignment of front end module. On the contrary, the newly devised hood latch that absorbs distribution makes misalignment dramatically small so it is clear that it helps a lot to secure high-quality of gap and flushness of a hood system. However, there is a gap between striker and latch for the new one so it should be noted that the excessive lateral dynamic movement can cause catastrophic disaster such as physical failure of the hood locking system, i.e. it leads to flying away of the hood panel under driving condition. In this paper, the equation of motion of hood system is derived by Lagrangian method, and the parameters to implement numerical analysis are acquired from CATIA. Especially, the input data processing correlated to the actual response of the system is prepared, and the proper low-pass filter is applied. The numerical analysis is conducted by MATLAB, and the predicted results are correlated to the actual ones. Also, the engineering design guide to make the system robust is suggested from parameter study. Moreover, the actual tests to verify the system are implemented in both vehicle and component level, and the complemented test criteria to validate the system is also suggested from this study.A Research on Dynamic Behavior of Clamshell Hood to Secure the Safety and Durability Performance 자동차안전학회지:제15권,제1호,2023 9 Fig. 5 Parameters and External Loads of Clamshell Hood SystemFig. 6 A Schematic Diagram of Hood System 2. Prediction and Verification of Dynamic Behavior of Hood System 2.1. Analysis of Dynamic Behavior of Clamshell Hood for the Safety and Durability Performance 2.1.1. Definition of Parameters and External Loads In order to derive the equation of motion, the para- meters of the system need to be defined. Fig. 5 shows parameters and external loads of clamshell hood system. As shown in the figure above, a total of 15 para- meters are acquired from CATIA, and three external loads are obtained from the specification of each part. A total of nine displacements - a (1.674 m), b (1.066 m), l (0.565 m), L G (0.507 m), L L (0.023 m), L W (0.572 m), L B (0.936 m), L N (1.057 m), and δ (0.002 m) - are defined. It is noted that 3 external loads of lifter force F L (375 N), weatherstrip force F W (63.8 N), and over-slam bumper force F B (243.3 N) are given in the specification of each part. Also, the mass of hood system m (17.8 kg) is known so the normal force N (182.6 N) exerted on the hood latch can be calculated from the equilibrium equation. Also, mass moment of inertia with respect to the center of gravity I G (8.611 kg) is obtained, and the friction coefficient (μ) is assumed to be 0.35. Then, the stiffness of hinge and latch can be acquired from CATIA static analysis. Since hood hinges are always attached to hood panel, they can be modeled as spring components as depicted in Fig. 5. Thus, the transverse stiffness k T (1,113 N/mm) and longitudinal stiffness k L (62.5 N/mm) are obtained from static analysis. On top of that, the longitudinal stiffness of hood latch k B (3,620 N/mm) only plays a role when the striker contacts the plate of hood latch because there is a gap between striker and latch plate. 2.1.2. Derivation of Equation of Motion for Clamshell Hood System Fig. 6 shows a schematic diagram of hood system on driving condition. In driving condition, the motion of a vehicle contains translational and angular motion so they are defined as Xc, Yc, and θ, respectively. It should be noted that they generate inertial force on hood system so the generalized coordinates of the system can be defined as X, Y, and α, respectively. Especially, the friction force is generated because of the contact between internally installed Kyoungtaek Kwak·Seunghoon Kang·Jaedong Yoo·Kyungdug Seo·Youngchul Shin·Kyungsup Chun·Jaekyu Lee 10 자동차안전학회지:제15권,제1호,2023 pop-up claw lever and striker. Therefore, the direction of friction force can be defined as the signum function whose direction is always opposite to the translational velocity of hood panel. In order to derive the governing equations of the system, the Lagrangian equation of motion used as follows. (2~4) , where (1) Eq. (1) is represented as the augmented Lagrange equation of motion. In this equation, q is generalized coordinate, and Q q is non-conservative work term. Also, T is the kinetic energy, and V is the potential energy of the system, respectively. In case that the system has kinematic constraints, the relationship of the constraint , and the Lagrange multipliers need to be considered to derive the governing equation. However, if there is no kinematic constraint in the system, the term of Lagrange multiplier of is unnecessary. As shown in Fig. 6, there is no kinematic constraint so is zero. Therefore, the equation of motion of the system is expressed as follows. cos sin cos sin sin cos sin sin cos sin cos sincos cos sin (2) The non-conservative work terms of Q X and Q Y are considered on the hood latch area due to the friction and contact force created from latch and striker. The gap between striker and latch is denoted as δ (2 mm) so the values of Q X and Q Y are obtained from the following relationships. If cos is smaller than -δ, the non-conservative work terms are expressed as follows. cos sin cos cos (3) sin cos cos sin (4) Also, if the striker does not contact the lateral surface on the hood latch where cos is greater than -δ, and smaller than δ, the following relationships can be obtained. cos sin (5) sin cos (6) Finally, if cos is greater than δ, the following relationships are acquired. cos sin cos cos (7) sin cos cos sin (8) 2.1.3. Input Data Processing and Numerical Analysis In order to apply the most severe driving condition, the Belgian CAE model is basically used to extract input data. In this model, the translational accelerations ( , ) are obtained, and the angular terms ( , , ) can be acquired in a vector manipulation from MATLAB. However, the input data obtained from CAE analysis are not always appropriate to predict the specific system for a certain purpose so they need to be properly correlated to the actual phenomenon in some cases. In this research, the inherent characteristics of the vibration induced from the road surface need to be considered. A Research on Dynamic Behavior of Clamshell Hood to Secure the Safety and Durability Performance 자동차안전학회지:제15권,제1호,2023 11 (a) Data Acquisition Location (b) (m/s 2 ) vs. time (s) (c) (m/s 2 ) vs. time (s) (d) (rad/s 2 ) vs. time (s) (e) (rad/s) vs. time (s) (f) (rad) vs. time (s) Fig. 8 Input Data for Belgian Driving Condition Fig. 7 The Camera Installation on Front End Module and Captured Image of Video Footage in Belgian Road (a) Displacement vs. Time (b) Displacement vs. Time considering Clearance Fig. 9 The Numerical Analysis of a Hood System in Belgian Driving Condition Fig. 7 shows the camera installation on a front end module and captured image of video footage in Belgian road. Actually, the actual vehicle response observed in the video footage is about 7 Hz. However, the input data originally calculated from Belgian CAE analysis is far from this actual frequency, which is about 16 Hz. Therefore, the low pass filter that makes input become more precise is needed to consider base excitation. (5) The sampling frequency, cut off frequency, and filter order are defined as 1,000 Hz, 10 Hz, and the 10 th order, respectively. Then, the driving frequency becomes closely analogous to the actual one. Fig. 8 shows input data for Belgian driving condition with low pass filter. Then, the numerical analysis is conducted by using these inputs. Fig. 9 shows the numerical analysis of a hood system in Belgian driving condition. As depicted in figure above, it is obviously seen that there is no contact between striker and latch so the system is sufficiently robust to secure the safety and durability performance. Also, even if the clearance area is considered, the negligible contact that causes small contact forces occurs so it clearly appears that the high-quality of flushness and gaps and core perfor- mances of the clamshell hood system can be secured simultaneously.Kyoungtaek Kwak·Seunghoon Kang·Jaedong Yoo·Kyungdug Seo·Youngchul Shin·Kyungsup Chun·Jaekyu Lee 12 자동차안전학회지:제15권,제1호,2023 Fig. 11 Plot of External Loads vs. Latch Friction Force Fig. 10 Test Set-up to Measure the Friction due to the Latch and Striker 2.2. Analysis of Sensitivity for System Parameters 2.2.1. Friction Force exerted on Latch and Striker As depicted in Fig. 3, the pop-up lever is applied to suppress the lateral movement of panel by compressing the striker and claw for the vertical direction. It implies that this mechanism generates the proper friction force that controls the movement of hood panel under the circumstances of vehicle vibration. Theoretically, the friction force can be calculated from the equilibrium condition, and its value is 63.9 N. However, this value incorporates the resisting load such as over-slam bumper force so it is necessary to obtain the pure friction generated by latch and striker themselves. Thus, this value is measured from the following test, and Fig. 10 shows test set-up to measure the friction due to the latch and striker. As shown in this figure, hood latch is fixed and the push-pull gauge is installed to measure the minimum moving force to overcome the friction force created by the surface between latch and striker. The measured friction force is 51.0 N, and it is noted that there are no resisting forces so the measured value is smaller than the predicted value of 63.9 N from equilibrium equation. Therefore, it is understood that this predicted value incorporates the conditions of external loads such as lifter force of 375.0 N, overslam bumper force of 243.3 N, hood weight of 174.4 N, and weatherstrip force of 63.8 N, which are obtained from the internal engineering specification of each part, respectively. It should be noted that the friction force of the system is always greater than 51.0 N unless the latch system is broken. However, the minimum criteria for each component to secure the friction force needs to be defined to verify the robustness of safety of the system. Fig. 11 shows a plot of external loads vs. latch friction force. The minimum friction existing area can be expressed as the right area where the friction is greater than 51.0 N. In other words, the friction is naturally greater than 51.0 N because it is generated by the pop-up lever mechanism of hood latch itself. If the friction force is reduced, the movement of hood essentially increases. Therefore, it is important to have the sufficient friction force to suppress the unintentional movement of hood. As shown in this figure, it is seen that the overslam bumper reaction force and the hood weight are the most sensitive factors to reduce the friction. Therefore, the parameter study of them needs to be implemented to confirm the stable performance of safety and durability. 2.2.2. Sensitivity of Overslam Bumper Reaction Force Fig. 12 shows the displacement vs. time at bumper force of 200 N. It is obviously seen that, as the overslam bumper reaction force is reduced, the friction force is also reduced. As seen in Fig. 12, it is clearly seen that there is no contact between striker and latch because the A Research on Dynamic Behavior of Clamshell Hood to Secure the Safety and Durability Performance 자동차안전학회지:제15권,제1호,2023 13 Fig. 12 Plot of Displacement vs. Time @ Bumper Force of 200N Fig. 13 Plot of Displacement vs. Time @ Hood Weight of 250N Fig. 14 Plot of Displacement vs. Time @ 10% increase of hinge stiffness pop-up lever mechanism creates enough friction force in the latch. In other words, even if the overslam bumper reaction forces are lost by some reasons, there will not be any undesirable movement of hood panel. From the simulation, the contact between latch and striker starts from the friction of 22 N. Therefore, in order to secure the stable essential performance of the system, it is suggested that the minimum friction of hood latch needs to be greater than 50 N before durability test, and 30 N after durability test, respectively. 2.2.3. Sensitivity of Hood Weight Fig. 13 shows the displacement vs. time at hood weight of 250 N. As shown in this figure above, the contact is recognized because of the increase of hood weight. It is naturally understood that the amplitude of the response should increase when the hood weight increases because of the inertia effect. From the simulation, the contact between latch and striker starts from the hood weight of 225 N. Therefore, in order to secure the stable key performance of the system, it is suggested that the allowable hood mass needs to be less than 22 kg. 2.2.4. Sensitivity of Hood Hinge Stiffness In order to ascertain the effect from the increase of hood hinge stiffness, the prediction of dynamic behavior of hood panel is implemented under the slightly augmented hinge stiffness value. Fig. 14 shows the displacement vs. time at 10% increase of hinge stiffness. As shown in the figure above, it is seen that the lateral stiffness of hood hinge does not have an influence on the movement of hood panel. There seem to be no change of dynamic behavior of hood panel as the change of stiffness of hinge. 2.2.5. Sensitivity of Air Flow When a vehicle is moving, there exists aerodynamically induced load on hood latch retention system. Figure 15 shows the types of aerodynamically induced loads in driving condition. As shown in this figure, air flow induces two types of loads on the surface of hood. The vertical force plays Kyoungtaek Kwak·Seunghoon Kang·Jaedong Yoo·Kyungdug Seo·Youngchul Shin·Kyungsup Chun·Jaekyu Lee 14 자동차안전학회지:제15권,제1호,2023 Fig. 15 Types of Aerodynamically Induced Loads Fig. 16 Displacement vs. Time for 250N Lateral Induced Load Fig. 17 Test Rig Setup and Test sample for an Oblique Condition a role in suppressing lateral movement of hood because it raises the friction of hood latch and striker. However, the lateral force created by the lateral air flow affects a lateral movement of panel. In a reference, (6) lateral force can be generated up to 250 N when a 2 door Coupe drives at the speed of 272 km/h. This amount of lateral force is corresponding to the input of 10% for the Belgian condition so the predicted results are obtained from the numerical analysis as well. Fig. 16 shows the displacement vs. time for 250 N lateral induced load. As shown in Fig. 16, the lateral movement is not observed at the numerical analysis and it is hardly seen that a vibration is recognized at the speed of 200 km/h. Thus, the aerodynamically induced loads do not seem to affect the undesirable movement of clamshell hood panel. 2.3. Vehicle and Component Level Verification 2.3.1. Vehicle Level Verification In order to verify the safety and durability performance of the system, it is necessary to confirm major four tests in a vehicle level, i.e. there are Belgian, combined road, fleet, and open-close durability tests, respectively. From these tests, there are no functional failures for the whole conditions. Typically, small scratches on the surface of a striker occur, but it does not result in the functional failure such as breakage and corrosion of the system. Thus, it is seen that the reliability of the safety and durability of the system is verified from the standpoint of vehicle level. 2.3.2. Component Level Verification Basically, hood latch needs to have a sufficient strength to hold a hood panel assembly so it is validated by the resistance of the vertical static load. It is noted that the gap between latch base plate and striker to absorb the distribution so the direction of the force exerted on the hood latch needs to be considered from the perspective of the degree of severity. Fig. 17 shows a test rig setup and test sample for an oblique condition. In this setup, the oblique angle is 35 degrees and the amount of strength is over 7,000 N. Typically, the amount of hood latch strength for the vertical normal direction needs to be greater than 5,400 N so it is clearly seen that the strength of this hood latch is sufficient to have an expected performance. 3. Conclusion The equation of motion of hood system is derived A Research on Dynamic Behavior of Clamshell Hood to Secure the Safety and Durability Performance 자동차안전학회지:제15권,제1호,2023 15 from Lagrangian equation, and the numerical analysis is implemented by using MATLAB. The predicted results are obtained from the numerical simulation, and it is shown that there is no contact between striker and latch base plate, i.e., it is indicated that the safety and durability performances are sufficiently secured for the system. Especially, they are correlated to the actual video footage recorded from Belgian road test, and the predicted results are well in coincidence with the actual dynamic behavior. Then, the parameter study is conducted to figure out the sensitivity to affect the movement of hood panel. It is noted that the friction force generated from the latch mechanism and striker needs to be secured, and the resisting force of overslam bumper and the weight of hood panel are major key factors to have an influence on changing this friction. In consideration with the loss of resisting force of overslam bumper, it is suggested that the minimum friction force generated by hood latch pop up lever needs to be greater than 50 N before hood opening and closing durability test, and the force should be greater than at least 30 N after the durability test, respectively. Also, in consideration with the weight of hood system, it is suggested that the allowable mass of hood panel needs to be less than 22 kg to secure the friction force. For reference, the stiffness of hood hinge and the aerodynamically induced loads on the surface of hood panel do not create the undesirable lateral vibration of hood in driving condition. Besides, the safety and durability of clamshell hood system is verified on not only vehicle but also component level. A total of four safety and durability tests on a vehicle level show that there is not any kind of functional failure. Also, the strength test of the part for the oblique direction is also conducted and it is shown that the sufficient performance is validated as well. From this study, it is obvious that the catastrophic failure such as flying away of hood panel in driving condition is sufficiently prevented. Moreover, it can be said that the high quality of gap and flushness is effectively realized by the lateral adjustment implemented from the appropriate gap between hood latch and striker. References (1)http://wall.alphacoders.com/big.php?i=884590&l ang=German (2)Jerry H. Ginsberg, 2010, Advanced Engineering Dynamics, 2 nd edition, pp. 245~308. (3)J. L. Merriam, L. G. Kraige, J. N. Bolton, 2018, Merriam’s Engineering Mechanics: Dynamics, 9 th edition, pp. 184~225. (4)Dara W. Childs, 2003, Dynamics in Engineering Practice, 4 th edition, pp. 348~554. (5)Singiresu S. Rao, 2011, Mechanical Vibrations, 5 th edition in SI units, pp. 259~362. (6)James Nelsen and All Seyam, 2019, “Aerodynamically Induced Loads on Hood Latch and Hood Retention Systems”, SAE Technical Paper 2019-01-0657, doi:10.4271/2019-01-065716 ◎ 논 문 http://dx.doi.org/10.22680/kasa2023.15.1.016 K-City 가상주행환경 고도화를 통한 자율주행시스템 검증 환경 구축 이빈희 * ·허관회 ** ·이장우 *** ·김남우 *** ·윤종민 **** ·조성우 ***** Development of Autonomous Driving System Verification Environment through Advancement of K-City Virtual Driving Environment Beenhui Lee * , Kwanhoe Huh ** , Jangu Lee *** , Namwoo Kim *** , Jongmin Yoon **** , Seonwoo Cho ***** Key Words: Autonomous driving(자율주행), CarMaker(카메이커), Virtual proving ground(가상시험환경), Virtual driving environment(가상주행환경), K-City(K-City) ABSTRACT Recently, the importance of simulation in a virtual driving environment as well as real road-based tests for autonomous vehicle testing is increasing. Real road tests are being actively conducted at K-City, an autonomous driving test bed located at the Korea Automobile Safety Test & Research Institute of the Transportation Safety Authority. In addition, the need to advance the K-City virtual driving environment and build a virtual environment similar to the autonomous driving system test environment in real road tests is increasing. In this study, for K-City of Korea Automobile Safety Test & Research Institute, using detailed drawings and actual field data, K-City virtual driving environment was advanced, and similarity verification was verified through comparative analysis with actual K-City. * IPG Automotive Korea, 주임연구원 ** IPG Automotive Korea, 부장 *** IPG Automotive Korea, 연구원 **** IPG Automotive Korea, 이사 ***** 한국교통안전공단 자동차안전연구원, 평가연구실장 E-mail: beenhui.lee@ipg-automotive.com 1. 서 론 자율주행 시스템 테스트를 위해 다양한 테스트베드가 구축되어 있다. 미국 역시 자율주행 시스템 평가를 위해 M-City라는 자율주행차량 평가용 테스트베드를 구축하 였다. 국내에도 자동차안전연구원의 K-City라는 이름의 자 율주행 시스템 안전성 평가 테스트베드가 구축되어 있다. (4) 이처럼 실제 테스트베드에서 자율주행 시스템 평가가 진행되고 있으며, 실제 환경에서 구현하기 어려운 시나리 오의 경우 시뮬레이션 환경에서의 실험을 진행하고 있다. 본 연구는 Lee et al. (1) 의 ‘자율주행시스템 개발을 위한 FMTC 가상주행환경 고도화 개발’의 후속 연구로써 자동 차안전연구원의 K-City를 대상으로 계측 데이터로 구 성된 OpenDrive 파일로 구성된 도로모델을 자사 프로그 램인 CarMaker를 이용하여 고도화 작업을 진행하고자 한다. 또한 실제 K-City와의 비교분석을 통한 유사도 검 증과 이를 이용한 Vehicle-in-the-Loop(이하, VIL) 테스트를 통해 자율주행시스템과의 연동성을 검증하고 자 한다. 자동차안전학회지: 제15권, 제1호, pp. 16∼26, 2023 논문접수일: 2022.8.3, 논문수정일(1차: 2023.2.20, 2차: 2023.3.17), 게재확정일: 2023.3.23K-City 가상주행환경 고도화를 통한 자율주행시스템 검증 환경 구축 자동차안전학회지:제15권,제1호,2023 17 Fig. 1 Virtual driving environment components (1) 2. 가상주행환경 고도화 개요 및 선행 연구 고찰 본 장에서는 K-City 가상주행환경 고도화 진행 시 이 전 연구인 Lee et al. (1) 에서 진행한 FMTC 가상주행환경 구축과의 차이점을 확인하고 선행 연구 고찰을 통해 K-City 가상주행환경 고도화 및 VIL 테스트를 통한 자율 주행시스템과의 연동성 검증 연구의 배경을 확인하고자 한다. 2.1. K-City 가상주행환경 고도화 개요 K-City 가상주행환경 고도화를 진행하기 앞서 이전 연구로 진행되었던 FMTC 가상주행환경 구축과의 차이 점에 대하여 이야기 하고자 한다. FMTC 가상주행환경은 톨게이트, 교통 및 안전 표지판, 신호등 및 차선, 노면 표시 등이 구성되어 있는 FMTC를 가상시뮬레이션 환경에서 활용할 수 있도록 실제와 유사한 가상주행환경으로 구축 된 바 있다. 본 연구에서 진행되는 K-City 가상주행환경은 도심부, 교외도로, 고속도로 및 터널 구간, 스쿨존 등의 기존 FMTC 가상주행환경보다 확장된 도로 구성 요소를 포함하고 있 다. 이에 따라 K-City 가상주행환경은 FMTC 가상주행 환경 고도화 연구의 후속 연구로써, 기존 작업 내용에 더 하여 터널 및 건물 등의 정적 객체와 실험구간 분리에 따 른 교통 표지판을 포함하고 있다. 따라서 K-City 가상주 행환경 고도화 연구 또한 Lee et al. (1) 에서 정의한 도로환 경모델 구축 시 사용된 용어에 대한 정의를 따른다. 이에 대한 내용은 Fig. 1에서 확인할 수 있다. (1) 2.2. 선행 연구 고찰 국내에 구축되어 있는 자율주행 시스템 테스트베드인 K-City에서의 실차 실험이 지속적으로 이루어지고 있다. 이에 따라 실제 환경과 유사한 K-City 가상주행환경 구 축 및 실제 K-City 환경을 활용하기 위한 다양한 연구들 이 수행되고 있다. Lee et al. (1) 은 상용 software를 이용하여 서울대학교 시흥캠퍼스에 있는 FMTC를 가상환경에서 활용할 수 있 도록 모델링 하였고, 실제 환경과 유사한 센서 거동을 모 사하기 위해 가상주행환경 고도화를 진행하였다. Lee et al. (2) 은 상용 software를 이용하여 가상 K-City를 구성하 였고, 실제 사고 상황을 바탕으로 시뮬레이션 시나리오를 도출하여 Level 3 자율주행차량의 끼어들기 상황 시 측방 의 위험상황 인식 범위를 제안하였다. Kim et al. (3) 은 자율 주행 시스템 개발 및 검증을 위해 가상 K-City를 구축하 고, 실제 K-City와 가상 K-City간의 주행 데이터를 비교 함으로써 가상 주행 환경의 타당성을 검증하였다. Ko et al. (4) 은 실제 K-City 내 다양한 주행환경을 조성하여 가 혹 상황에서의 자율주행 시스템 기술 개발이 가능한 시스 템을 구축하고자 진행되고 있는 고도화 사업에 대하여 발 표한 바 있다. Son et al. (6) 은 K-City가상주행환경 중 고 속도로에서의 Vehicle-in-the-Loop 테스트를 통한 VILS 시스템을 제안하였다. 기존 진행되었던 연구에서는 K-City의 도로 외형에 집중된 가상 K-City 구축이 주로 이루어졌다. 이에 본 논 문에서는 상세 도면 및 실제 K-City 현장 검증을 통하여 실제 K-City 도로 환경과 K-City 가상주행환경이 유사 한 환경을 가질 수 있도록 K-City 가상주행환경 고도화 를 진행하였다. 또한 고도화가 진행된 K- City 가상주행 환경에서 VIL 테스트를 진행함으로써 자율주행시스템 검 증에 활용할 수 있음을 확인하였다. 3. 가상주행환경 고도화 본 장에서는 K-City 가상주행환경 고도화 작업에 따른 가상주행환경 구성을 확인하고자 한다. K-City 가상주행 환경 구축 및 고도화 작업은 IPG Automotive의 CarMaker 를 이용하여 작업이 진행되었다. 3.1. 가상주행환경 고도화 K-City는 자동차전용도로, 도심부도로, 스쿨존과 커Next >