• Title/Summary/Keyword: Longitudinal acceleration

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Climbing Angle Estimation in Yawing Motion by UIO (UIO를 이용한 선회 시 등판각 추정)

  • Byeon, Hyeongkyu;Kim, Hyunkyu;Kim, Inkeun;Huh, Kunsoo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.5
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    • pp.478-485
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    • 2015
  • Availability of the climbing angle information is crucial for the intelligent vehicle system. However, the climbing angle information can't be measured with the sensor mounted on the vehicle. In this paper, climbing angle estimation system is proposed. First, longitudinal acceleration obtained from gyro-sensor is compared with the actual longitudinal acceleration of the vehicle. If the vehicle is in yawing motion, actual longitudinal acceleration can't be approximated from time derivative of wheel speed, because lateral velocity and yaw rate affect actual longitudinal acceleration. Wheel speed and yaw rate can be obtained from the sensors mounted on the vehicle, but lateral velocity can't be measured from the sensor. Therefore, lateral velocity is estimated using unknown input observer with nonlinear tire model. Simulation results show that the compensated results using lateral velocity and yaw rate show better performance than uncompensated results.

Development of an Adaptive Feedback based Actuator Fault Detection and Tolerant Control Algorithms for Longitudinal Autonomous Driving (적응형 되먹임 기반 종방향 자율주행 구동기 고장 탐지 및 허용 제어 알고리즘 개발)

  • Oh, Kwangseok;Lee, Jongmin;Song, Taejun;Oh, Sechan;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.12 no.4
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    • pp.13-22
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    • 2020
  • This paper presents an adaptive feedback based actuator fault detection and tolerant control algorithms for longitudinal functional safety of autonomous driving. In order to ensure the functional safety of autonomous vehicles, fault detection and tolerant control algorithms are needed for sensors and actuators used for autonomous driving. In this study, adaptive feedback control algorithm to compute the longitudinal acceleration for autonomous driving has been developed based on relationship function using states. The relationship function has been designed using feedback gains and error states for adaptation rule design. The coefficients in the relationship function have been estimated using recursive least square with multiple forgetting factors. The MIT rule has been adopted to design the adaptation rule for feedback gains online. The stability analysis has been conducted based on Lyapunov direct method. The longitudinal acceleration computed by adaptive control algorithm has been compared to the actual acceleration for fault detection of actuators used for longitudinal autonomous driving.

Longitudinal motion characteristics of a ship according to the location (선내 위치에 따른 선박의 종운동 특성)

  • Kang, Il-Kwon;Kim, Min-Seok;Park, Byung-Soo;Hong, Jin-Keun;Jeong, Seong-Jae;Ham, Sang-Jun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.2
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    • pp.147-154
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    • 2012
  • In head sea, a ship has mainly the longitudinal motion such as vertical acceleration and pitch. In that case, the motion characteristics of a ship will have changed as the location different from each of place vertically and horizontally on board. The author carried out an experiment about the ship's vertical acceleration and pitch according to the location for the head sea, and analyzed the data with the aid of the statistical and spectral analyzing method to get the motion characteristics of the vessels. The response of vertical acceleration and pitch not deeply depend on the decks vertically, but displayed the relative big different value horizontally even if same deck. The biggest response of vertical acceleration and pitch among the accommodations was shown at scientist room, but the value of it not reached to the minimum requirement of ISO 2631-1 for working on board.

Development of Throttle and Brake Controller for Autonomous Vehicle Simulation Environment (자율주행 시뮬레이션 환경을 위한 차량 구동 및 제동 제어기 개발)

  • Kwak, Jisub;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.14 no.1
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    • pp.39-44
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    • 2022
  • This paper presents a development of throttle and brake controller for autonomous vehicle simulation environment. Most of 3D simulator control autonomous vehicle by throttle and brake command. Therefore additional longitudinal controller is required to calculate pedal input from desired acceleration. The controller consists of two parts, feedback controller and feedforward controller. The feedback controller is designed to compensate error between the actual acceleration and desired acceleration calculated from autonomous driving algorithm. The feedforward controller is designed for fast response and the output is determined by the actual vehicle speed and desired acceleration. To verify the performance of the controller, simulations were conducted for various scenarios, and it was confirmed that the controller can successfully follow the target acceleration.

A New Shift Algorithm using a Longitudinal Accelerometer (수평 가속도계를 활용간 새로운 변속 알고리듬)

  • 박진호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.168-174
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    • 2004
  • A shift algorithm of an automatic transmission is decided by the compromise between the performance and the fuel economy of the vehicle. But because in the traditional shia algorithm, throttle opening and vehicle speed are used to decide the shift points, the actual load of the vehicle is not exactly considered. In this paper, to consider the actual load, that is, the road grade and the vehicle acceleration, the longitudinal accelerometer is used to decide the shift points. As the result, the performance and the fuel economy of the vehicle which adapts the new shift algorithm are shown better than the traditional one.

Observer Based Adaptive Control of Longitudinal Motion of Vehicles (관측자를 이용한 직진 주행 차량의 적응 제어)

  • Kim, Eung-Seok;Kim, Dong-Hun;Yang, Hai-Won
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.50 no.3
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    • pp.130-135
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    • 2001
  • In this paper, an observer-based adaptive controller is proposed to control the longitudinal motion of vehicles. The standard gradient method will be used to estimate the vehicle parameters, mass, time constant, etc. The nonlinear model between the driving force and the vehicle acceleration will be chosen to design the state observer for the vehicle velocity and acceleration. It will be shown that the proposed observer is exponentially stable, and that the adaptive controller proposed on this paper is stable. It will be proved that the errors of the relative distance, velocity and acceleration converge to zero asymptotically fast, and that the overall system is also asymptotically stable. The simulation results are presented to investigate the effectiveness of the proposed method.

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Development of longitudinal acceleration wave decomposition method with single point measurement (단일 위치에서의 측정을 이용한 가속도 종파 분리 방법의 개발)

  • Jung, B.;Park, Y.;Park, Youn-Sik
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.629-633
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    • 2006
  • We investigated a new longitudinal acceleration wave decomposition method in time domain. The proposed method separates up- and down-stream waves with an axial strain and axial acceleration measured at a single point on the transmission path. The advantages such as low computation load and easy implementation would be possible by developing time domain under the following assumptions; low frequency range, uniform cross sectional area and elastic wave propagation. We confirmed the feasibility and performance of the method through experiment using Split Hopkinson Pressure Bar (SHPB). The method can be effective in several applications, including active vibration control with wave view point, where real time wave decomposition is necessary.

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Development of Vehicle Longitudinal Controller Fault Detection Algorithm based on Driving Data for Autonomous Vehicle (자율주행 자동차를 위한 주행 데이터 기반 종방향 제어기 고장 감지 알고리즘 개발)

  • Yoon, Youngmin;Jeong, Yonghwan;Lee, Jongmin;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.2
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    • pp.11-16
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    • 2019
  • This paper suggests an algorithm for detecting fault of longitudinal controller in autonomous vehicles. Guaranteeing safety in fault situation is essential because electronic devices in vehicle are dependent each other. Several methods like alarm to driver, ceding control to driver, and emergency stop are considered to cope with fault. This research investigates the fault monitoring process in fail-safe system, for controller which is responsible for accelerating and decelerating control in vehicle. Residual is computed using desired acceleration control command and actual acceleration, and detection of its abnormal increase leads to the decision that system has fault. Before computing residual for controller, health monitoring process of acceleration signal is performed using hardware and analytic redundancy. In fault monitoring process for controller, a process model which is fitted using driving data is considered to improve the performance. This algorithm is simulated via MATLAB tool to verify performance.

Vehicle Longitudinal Velocity Estimation on Inclined Road (경사진 노면에서의 차량의 종 속도 추정)

  • Lee, Sang-Yeob;Kim, In-Keun;Lee, Dong-Hun;Huh, Kun-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.1
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    • pp.14-19
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    • 2012
  • On-line and real-time information of the longitudinal velocity is the essential factor for the Advanced Vehicle Control Systems such as ABS(Anti-lock Brake System), TCS(Traction Control System), ESC (Electronic Stability Control) etc. However, the longitudinal velocity cannot be easily measured or calculated during braking maneuvering. A new algorithm is presented for the estimation of the longitudinal velocity with the measurements of the vehicle longitudinal/lateral acceleration, steering angle and yaw rate. The algorithm is designed utilizing the Extended Kalman Filter based on the 3 degree of freedom vehicle model. In order to compensate for the biased sensor signal on the inclined road, the inclined angle is also estimated. The performance of the proposed estimation algorithm is evaluated in field tests.

Vehicle Mass and Road Grade Estimation for Longitudinal Acceleration Controller of an Automated Bus (자율주행 버스의 종방향 제어를 위한 질량 및 종 경사 추정기 개발)

  • Jo, Ara;Jeong, Yonghwan;Lim, Hyungho;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.12 no.2
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    • pp.14-20
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    • 2020
  • This paper presents a vehicle mass and road grade estimator for developing an automated bus. To consider the dynamic characteristics of a bus varying with the number of passengers, the longitudinal controller needs the estimation of the vehicle's mass and road grade in real-time and utilizes the information to adjust the control gains. Discrete Kalman filter is applied to estimate the time-varying road grade, and the recursive least squares algorithm is adopted to account for the constant mass estimation. After being implemented in MATLAB/Simulink, the estimators are evaluated with the dynamic model and experimental data of the target bus. The proposed estimators will be applied to complement the algorithm of the longitudinal controller and proceed with algorithm verification.