Browsing by Subject "ACC"

Now showing 1 - 3 of 3
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    Design and modeling of adaptive cruise control system using petri nets with fault tolerance capabilities
    (2018) Chandramohan, Nivethitha Amudha; Li, Lingxi
    In automotive industry, driver assistance and active safety features are main areas of research. This thesis concentrates on designing one of the famous ADAS system feature called Adaptive cruise control. Feature development and analysis of various functionalities involved in the system control are done using Petri Nets. A background on the past and current ACC research is noted and taken as motivation. The idea is to implement the adaptive cruise control system in Petri net and analyze how to provide fault tolerance to the system. The system can be evaluated for various cases. The ACC technology implemented in di erent cars were compared and discussed. The interaction of the ACC module with other modules in the car is explained. The cruise system's algorithm in Petri net is used as the basis for developing Adaptive Cruise Control system's algorithm. The ACC system model is designed using Petri nets and various Petri net functionalities like place invariant, transition invariant and reachability tree of the model are analyzed. The results are veri ed using Matlab. Controllers are introduced for ideal cases and are implemented in Petri nets. Then the error cases are considered and fault tolerance techniques are carried out on the model to identify the fault places.
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    Design of Switching Strategy for Adaptive Cruise Control Under String Stability Constraints
    (2010) Zhai, Yao; Chen, Yaobin; Widmann, Glenn R.; Li, Lingxi
    An Adaptive Cruise Control (ACC) system is a driver assistance system that assists a driver to improve driving safety and driving comfort. The design of ACC controller often involves the design of a switching logic that decides where and when to switch between the two modes in order to ameliorate driving comfort, mitigate the chance of a potential collision with the preceding vehicle while reduce long-distance driving load from the driver. In this thesis, a new strategy for designing ACC controller is proposed. The proposed control strategy utilizes Range vs. Range-rate chart to illustrate the relationship between headway distance and velocity difference, and then find out a constant deceleration trajectory on the chart, which the following vehicle is controlled to follow. This control strategy has a shorter elapsed time than existing ones while still maintaining a relatively safe distance during transient process. String stability issue has been addressed by many researchers after the adaptive cruise control (ACC) concept was developed. The main problem is when many vehicles with ACC controller forming a vehicle platoon end to end, how the control algorithm is designed to ensure that the spacing error, which is the deviation of the actual range from the desired headway distance, would not amplify as the number of following vehicles increases downstream along the platoon. In this thesis, string stability issues have been taken into consideration and constraints of parameters of an ACC controller are derived to mitigate steady state error propagation.
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    Plant error compensation and jerk control for adaptive cruise control systems
    (2012-05) Meadows, Alexander David; Li, Lingxi; Chen, Yaobin; Widmann, Glenn R.; King, Brian
    Some problems of complex systems are internal to the system whereas other problems exist peripherally; two such problems will be explored in this thesis. First, is the issue of excessive jerk from instantaneous velocity demand changes produced by an adaptive cruise control system. Calculations will be demonstrated and an example control solution will be proposed in Chapter 3. Second, is the issue of a non-perfect plant, called an uncertain or corrupted plant. In initial control analysis, the adaptive cruise control systems are assumed to have a perfect plant; that is to say, the plant always behaves as commanded. In reality, this is seldom the case. Plant corruption may come from a variation in performance through use or misuse, or from noise or imperfections in the sensor signal data. A model for plant corruption is introduced and methods for analysis and compensation are explored in Chapter 4. To facilitate analysis, Chapter 2 discusses the concept of system identification, an order reduction tool which is employed herein. Adaptive cruise control systems are also discussed with special emphasis on the situations most likely to employ jerk limitation.