平行泊车轨迹规划及控制算法研究

发布时间：2019-02-09 08:14

【摘要】：由于路边泊车不规范，导致的交通拥堵、车辆刮擦等问题已成为交通管理的一大难题。为此，自动泊车、辅助泊车已经成为车辆主动安全技术的研发重点。依据停车位空间的大小，路边平行泊车的方法可以分为前进式和后退式两种方式。本文针对前进式平行泊车，在考虑泊车空间需求的前提下，，提出了基于B样条的轨迹规划和基于多段圆弧的轨迹规划的建模方法；针对后退式平行泊车，在物理限制和非完整约束前提下，提出了能够适应环境动态变化的快速轨迹优化方法以及兼顾模型误差和扰动的反馈控制器。本研究是省基金资助项目“基于交通态势评估的道路安全推理研究”子课题的研究成果，即，针对平行泊车而开展的专项研究，该项研究成果的主要贡献如下所述。前进式平行泊车：（1）在泊车空间相对充裕的条件下，根据Ackermann转向几何建立了车辆简化的泊车运动学模型，并分析车辆停泊时的多约束问题，综合考虑泊车轨迹的设计要求以及B样条曲线的特点，提出了基于B样条曲线理论的轨迹生成方法，以轨迹曲率最小化为目标，对前进式平行泊车进行一步泊车入位的轨迹规划。（2）在泊车空间相对狭小的条件下，提出了多步进退式的泊车方法。采用多段相切圆弧的方法分割泊车轨迹曲线，考虑泊车运动中可能发生的多种碰撞，建立相应的约束函数，分别以泊车位和曲线曲率最小为优化目标，求解出泊车轨迹的相关参数。后退式平行泊车：（3）提出了新的轨迹生成方法，该方法由快速几何路径规划和路径跟踪优化求解两部分组成。其中，几何路径规划由求解一组静态优化问题来完成，而障碍物由基于闵可夫斯基的不等式约束来描述；路径跟踪采用了系统理论中flatness属性建立车辆系统动态，并以线性二阶差分方程的形式表示。（4）提出了一个轨迹追踪反馈控制器，为此将误差系统转换成链式系统，采用积分逆推方法计算控制输入，并利用Barbalat引理证明了这个闭环系统的稳定性。
[Abstract]:Traffic jams and scratches have become a major problem in traffic management due to irregular on-street parking. Therefore, automatic parking and auxiliary parking have become the focus of vehicle active safety technology research and development. According to the size of parking space, the method of parallel parking can be divided into two types: forward and backward. In this paper, a method of trajectory planning based on B-spline and trajectory planning based on multi-segment arc is proposed, considering the demand of parking space. For backward parallel parking, a fast trajectory optimization method and a feedback controller which can adapt to the dynamic changes of the environment and take into account the model errors and disturbances are proposed under the premise of physical constraints and nonholonomic constraints. This research is the research result of the project "Road Safety reasoning based on Traffic situation Assessment", which is a special research on parallel parking. The main contributions of this research are as follows. Forward parallel parking: (1) under the condition of relatively abundant parking space, a simplified parking kinematics model is established according to the Ackermann steering geometry, and the multi-constraint problem is analyzed. Considering the design requirements of parking trajectory and the characteristics of B-spline curve, a trajectory generation method based on B-spline curve theory is proposed. The aim of this method is to minimize the curvature of the trajectory. A one-step parking trajectory planning for forward parallel parking. (2) under the condition of relatively small parking space, a multi-step, forward and backward parking method is proposed. The method of multi-segment tangent arc is used to divide the parking track curve, considering the possible collision in parking movement, the corresponding constraint function is established, and the minimum parking space and curve curvature are respectively taken as the optimization objective. The parameters of the parking track are calculated. Backward parallel parking: (3) A new trajectory generation method is proposed, which consists of two parts: fast geometric path planning and path tracking optimization. Geometric path planning is accomplished by solving a set of static optimization problems, while obstacles are described by inequality constraints based on Minkowski. The flatness attribute in the system theory is used to establish the vehicle system dynamics, which is expressed as the linear second-order difference equation. (4) A trajectory tracking feedback controller is proposed. For this reason, the error system is converted into a chain system, and the control input is calculated by the integral inverse method. The stability of the closed-loop system is proved by using Barbalat Lemma.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U491.7

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