When path tracking using look-ahead distance about the lateral error method and the velocity change method tracking comparison

Jun-Beom Park,Seong-Ho Bae,Bo-Seung Koo,Jung-Ha Kim 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10

Method of improving the safety of autonomous vehicles are diverse. In particular, Path Tracking phase which is the last step and important to operate an autonomous vehicle. Method of Path tacking are diverse. Kinematic and dynamic methods is typically methods. In this study, Among Kinematic method, Pure pursuit is used by using the path tracking. Commonly pure pursuit is used to path tracking of mobile robots. Pure pursuit is selected target point and is path traced When selecting the tracking target point, the traveling speed is low or, in certain cases, to extract the following target point at a fixed distance. However, the speed and the path of autonomous vehicle is continually changing. Therefore, the selection method of tracking a target point of the fixed distance, can inhibit the behavioral stability of the vehicle. Also affect the path tracking performance. Therefore, changing of the tracking target point is advantageous.

Accurate Path Tracking by Adjusting Look-Ahead Point in Pure Pursuit Method

안준우,신세호,김민성,박재흥 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.1

Path tracking is an essential aspect of the navigational process of self-driving cars. Especially, accurate pathtracking is important for not only normal urban roads but also narrow and complex roads such as parking lot and alleyway. The pure pursuit method is one of the geometric path-tracking methods. Using this method, the look-ahead point can be selected far away and the control input is computed in real-time, which is advantageous when the given path is not smooth or when the path is specified using waypoints. Moreover, this method is more robust to localization errors than the modelbased path-tracking method. However, the original pure pursuit method and its variants have limited tracking performance. Therefore, this paper proposes a new method that heuristically selects a look-ahead point by considering the relationship between a vehicle and a path. Using this new look-ahead point, the vehicle can stably converge to the desired path and track the path without encountering the cutting-corner problem. The proposed method was tested using simulation and our selfdriving car platform. Our results show that the vehicle tracks the desired path more accurately using our proposed algorithm than using the previous pure pursuit methods.

Off-Road Machinery System Engineering ; Development of a Path Generation and Tracking Algorithm for a Korean Auto-guidance Tillage Tractor

( Xiong Zhe Han ),( Hak Jin Kim ),( Hee Chang Moon ),( Hoon Je Woo ),( Jung Hun Kim ),( Young Joo Kim ) 한국농업기계학회 2013 바이오시스템공학 Vol.38 No.1

Purpose: Path planning and tracking algorithms applicable to various agricultural operations, such as tillage, planting, and spraying, are needed to generate steering angles for auto-guidance tractors to track a point ahead on the path. An optimal coverage path algorithm can enable a vehicle to effectively travel across a field by following a sequence of parallel paths with fixed spacing. This study proposes a path generation and tracking algorithm for an auto-guided Korean tractor with a tillage implement that generates a path with C-type turns and follows the generated path in a paddy field. A mathematical model was developed to generate a waypoint path for a tractor in a field. This waypoint path generation model was based on minimum tractor turning radius, waypoint intervals and LBOs (Limit of Boundary Offsets). At each location, the steering angle was calculated by comparing the waypoint angle and heading angle of the tractor. A path following program was developed with Labview-CVI to automatically read the waypoints and generate steering angles for the tractor to proceed to the next waypoint. A feasibility test of the developed program for real-time path tracking was performed with a mobile platform traveling on flat ground. The test results showed that the developed algorithm generated the desired path and steering angles with acceptable accuracy.

태양광 전력모델을 포함한 장기체공 무인기의 3차원 경로계획 및 유도

오수헌 ( Su-hun Oh ),김갑동 ( Kap-dong Kim ),박준현 ( Jun-hyun Park ) 한국항행학회 2016 韓國航行學會論文誌 Vol.20 No.5

본 논문에서는 태양광 장기체공 무인기의 전력모델을 포함한 3차원 경로계획과 유도에 대하여 기술한다. 본 논문에서 사용한 Dubins curve는 계산속도가 빨라 경로계획에 곧바로 적용이 가능하다는 장점이 있다. 하지만 Dubins curve의 경로생성 문제는 2차원 평면에서 정의되기 때문에 실제 항공기의 경로계획을 위해 Randal W. Beard에 의해 수행된 비행 경로각의 한계를 고려하여, 고도 차이에 따라 선회경로를 추가하는 방식의 3차원 Dubins 경로생성 알고리즘을 활용하였다. 본 논문에서 사용한 항공기 모델은 Aileron이 없기 때문에 Rudder를 사용하여 횡축 방향 제어기를 설계하였으며, 비선형 경로추종 유도기법을 사용하여 경로추종 시뮬레이션을 수행하였다. 고도조건에 따른 예제를 생성하였으며, 시뮬레이션 결과 생성된 경로를 잘 추종하는 것을 확인하였다. 마지막으로 태양에너지 수율에 대한 계산식을 통해 태양광 장기체공 무인기의 전력 시스템을 모델링하여 48시간 연속비행 시뮬레이션을 실시하였고, 이에 대한 시뮬레이션 결과를 제시하였다. This paper introduces 3-dimensional path planning and guidance including power model for high altitude long endurance (HALE) UAV using solar energy. Dubins curve used in this paper has advantage of being directly available to apply path planning. However, most of the path planning problems using Dubins curve are defined in a two-dimensional plan. So, we used 3-dimensional Dubins path generation algorithm which was studied by Randal W. Beard. The aircraft model which used in this paper does not have an aileron. So we designed lateral controller by using a rudder. And then, we were conducted path tracking simulations by using a nonlinear path tracking algorithm. We generate examples according to altitude conditions. From the path tracking simulation results, we confirm that the path tracking is well on the flight path. Finally, we were modeling the power system of HALE UAVs and conducting path tracking simulation during 48hours. Modeling the amount of power generated by the solar cell through the calculation of the solar energy yield. And, we show the 48hours path tracking simulation results.

Development of a Path Generation and Tracking Algorithm for a Korean Auto-guidance Tillage Tractor

Han, Xiong-Zhe,Kim, Hak-Jin,Moon, Hee-Chang,Woo, Hoon-Je,Kim, Jung-Hun,Kim, Young-Joo Korean Society for Agricultural Machinery 2013 바이오시스템공학 Vol.38 No.1

Purpose: Path planning and tracking algorithms applicable to various agricultural operations, such as tillage, planting, and spraying, are needed to generate steering angles for auto-guidance tractors to track a point ahead on the path. An optimal coverage path algorithm can enable a vehicle to effectively travel across a field by following a sequence of parallel paths with fixed spacing. This study proposes a path generation and tracking algorithm for an auto-guided Korean tractor with a tillage implement that generates a path with C-type turns and follows the generated path in a paddy field. A mathematical model was developed to generate a waypoint path for a tractor in a field. This waypoint path generation model was based on minimum tractor turning radius, waypoint intervals and LBOs (Limit of Boundary Offsets). At each location, the steering angle was calculated by comparing the waypoint angle and heading angle of the tractor. A path following program was developed with Labview-CVI to automatically read the waypoints and generate steering angles for the tractor to proceed to the next waypoint. A feasibility test of the developed program for real-time path tracking was performed with a mobile platform traveling on flat ground. The test results showed that the developed algorithm generated the desired path and steering angles with acceptable accuracy.

카메라 기반 다중 파티클 필터 및 가중 비용 함수를 이용하는 자율주행 모빌리티의 경로 추종 제어 알고리즘 개발

김세환,오광석 한국자동차공학회 2024 한국 자동차공학회논문집 Vol.32 No.1

Model uncertainty and changes in sensor specifications in autonomous mobility can have a negative impact on path tracking. Therefore, in this paper, we are proposing a path tracking control algorithm based on multi-particle filtering and a weighted cost function. This algorithm is designed to ensure path tracking, even when there are changes in camera specifications. A pixel-based control error was derived by using multiple particle filters for path tracking, instead of image processing techniques. A simplified error dynamic was designed, based on the derived pixel-based control error. Then, the desired steering angle was derived after applying weights to the cost function, which was designed by using the sliding approach and Lyapunov to reduce control errors. Next, the path tracking performance was evaluated by using two different cameras on an S-curved path based on autonomous mobility. The evaluation led us to confirm reasonable desired path tracking results, even when using cameras with different specifications.

경로 추적 방식의 AGV를 위한 경로 계획

도주철,김정민,정경훈,우승범,김성신 한국로봇학회 2010 로봇학회 논문지 Vol.5 No.4

This paper presents a study of path-planning method for AGV(automated guided vehicle) based on path-tracking. It is important to find an optimized path among the AGV techniques. This is due to the fact that the AGV is conditioned to follow the predetermined path. Consequently, the path-planning method is implemented directly affects the whole AGV operation in terms of its performance efficiency. In many existing methods are used optimization algorithms to find optimized path. However, such methods are often prone with problems in handling the issue of inefficiency that exists in system's operation due to inherent undue time delay created by heavy load of complex computation. To solve such problems, we offer path-planning method using modified binary tree. For the purpose of our experiment, we initially designed a AGV that is equiped with laser navigation, two encoders, a gyro sensor that is meant to be operated within actual environment with given set of constrictions and layout for the AGV testing. The result of our study reflects the fact that within such environments, the proposed method showed improvement in its efficiency in finding optimized path.

경로 추종 제어를 위한 다양한 구동기 조합의 비교 연구

김진우,임성진 한국자동차공학회 2024 한국 자동차공학회논문집 Vol.32 No.1

This paper presents a comparative study on the effects of multiple actuator combinations on path tracking control. First, the state-space model with a lookahead distance is derived from a 2-DOF bicycle model and a target path. There are several actuators for path tracking: front-wheel steering(FWS), rear-wheel steering(RWS), 4-wheel steering(4WS), and 4-wheel independent steering/driving/braking(4WIS/4WID/4WIB). A control input is composed through front-wheel steering, 4-wheel steering, and the control yaw moment. Then, the control yaw moment is converted into tire forces generated by FWS, RWS, RWIS, 4WS, 4WIS, 4WID, and 4WIB. The controller is designed based on the model predictive control (MPC). To check the effects of these actuators on path tracking, a simulation is done on a vehicle simulation package. Simulation results show that additional actuators, except for FWS and 4WS, have little impact on path tracking performance.

Path Tracking Controller Design and Simulation for Korean Lunar Lander Demonstrator

Yang, Sungwook,Son, Jongjun,Lee, Sangchul The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1

In Korea, Lunar exploration program has been prepared with the aim of launching in the 2020's. As a part of it, a lunar lander demonstrator was developed, which was the model for verifying the system such as structure, propulsion, and control system, before launching into the deep space. This paper deals with the path tracking performance of the lunar lander demonstrator with respect to the thruster controller based on Pulse Width Pulse Frequency Modulator (PWPFM) and Pulse Width Modulator (PWM). First, we derived equations of motion, considering the allocation of the thrusters, and designed the path tracking controller based on Euler angle. The signal generated from the path tracking controller is continuous, so PWPFM and PWM modulator are adopted for generating ON/OFF signal. Finally, MATLAB simulation is performed for evaluating the path tracking ability. We compared the path tracking performances of PWPFM and PWM based thrust controller, using performance measures such as the total impulse and the position error with respect to the desired path.

Path Tracking Controller Design and Simulation for Korean Lunar Lander Demonstrator

Sungwook Yang,Jongjun Son,Sangchul Lee 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1

In Korea, Lunar exploration program has been prepared with the aim of launching in the 2020’s. As a part of it, a lunar lander demonstrator was developed, which was the model for verifying the system such as structure, propulsion, and control system, before launching into the deep space. This paper deals with the path tracking performance of the lunar lander demonstrator with respect to the thruster controller based on Pulse Width Pulse Frequency Modulator (PWPFM) and Pulse Width Modulator (PWM). First, we derived equations of motion, considering the allocation of the thrusters, and designed the path tracking controller based on Euler angle. The signal generated from the path tracking controller is continuous, so PWPFM and PWM modulator are adopted for generating ON/OFF signal. Finally, MATLAB simulation is performed for evaluating the path tracking ability. We compared the path tracking performances of PWPFM and PWM based thrust controller, using performance measures such as the total impulse and the position error with respect to the desired path.