Improvement of Working Quality of Trailing Implements by Hitching Position Control

本研究的目标是实现挂车技能要求驾驶的简便化驾驶和自主行驶。在拖车驾驶中存在两个主要问题。第一种是经常观察到的趋势，拖车比拖拉机在里面跑，这种现象被广为人知的“偏离跟踪”。第二个问题是拖车在倒车机动中的运动在控制意义上变得不稳定，为了解决这些问题，本研究提出了一种新的方法，通过使用液压缸控制拖车的悬挂位置来减少或消除拖车的脱轨。首先，从几何关系出发，计算出消除脱轨所需的搭载位置相对于机构中心的偏移量。结果表明，在一定的转向角范围内，脱轨现象可以消除，当转向角超过一定值时，会出现脱轨现象，并随转向角的增大而增大，当转向角和转向角超过极限时，系统就会失控。但是，研究发现其偏离轨道的减速性能与前人提出的方向盘转向方法几乎相当。然后构建了实验搭便车位置控制器，并进行了验证实验。实验证实，在测试条件下，偏移量小于5 cm。在此基础上，对挂车倒车控制理论进行了研究。在本研究中，我们将行进路径设计为极坐标下的多项式函数表示的曲线。通过模拟误差的仿真研究，验证了采用最优控制理论设计的局部线性化反馈控制器，利用路径方程可以准确、安全地导航拖车。

Objectives of this research are to realize easier driving and autonomous traveling in skill requested driving of trailers. There are two main problems in trailer driving. The first is the tendency observed frequently the trailer run inside than a tractor, this phenomenon is widely known as "off tracking". The second problem is the motion of trailer becomes unstable in backing up maneuver in the sense of control To solve these problems, in this study novel approach to reduce or eliminate the off tracking of trailer by controlling the hitching position of the trailer by using hydraulic cylinders. Firstly the required offset of hitching position from the center of the mechanism for elimination of off tracking has been calculated from the geometrical relations. As a result, the off tracking can be eliminated up to the certain steering angle of the tractor determined by geometrical constraints, but above the limit, off tracking appeared, and increased with steering angle of tractor, the finally the system became uncontrollable when the steering and of the tractor exceeded the limit. But, the off tracking reduction performance was found to be almost equal that of wheel steering method proposed in previous researches. Then the experimental hitching position controller was constructed, and verification experimental was conducted. It confirmed by the experiments that off tracking was lesser than 5cm in testing conditions. Following this research, control theory for backing up of trailer was investigated. In this study, we designed the traveling path as a curve expressed by the polynomial function on the polar coordinates. It has been verified by simulation studies involving simulated error that the trailer could be navigated accurately and safety when the path equation was used with locally linearized feedback controller designed by optimal control theory.