拖拉机沿曲线路径的跟踪控制

近年关于农业用车轮型移动机器人的研究很多,但主要集中在直线行走方面。该研究进行了沿给定的曲线路径跟踪控制的研究。首先由给定的曲线路径生成四元状态空间,其次在利用预见控制求得车辆的未来值和目标值的基础上,利用最优控制理论设计跟踪控制器。最后在牧草地上对正弦路径和圆形路径进行了跟踪实验。试验结果为：车辆以1.5 m/s的速度行驶时,在很小转弯半径时最大误差可控制在35 cm以内。

On-tracking control of tractor running along curved paths

Aging of farmers and shortage of agricultural workforce have necessitated the development of agricultural automation in the world. Many automatic vehicle guidance researches have been done, however, most of them are related to navigating a wheel-type farm mobile robot along rectilinear paths. This paper proposes an automatic tractor guidance system that enables the tractor to run autonomously along the curved path on meadow. First, a curved path was given in the form of a plane figure. Four-dimension state-vector space was reconstructed from a given path using kinematics vehicle equation. Second, linearization for vehicle equations was performed in the neighborhood of "future points", as defined in preview control theory. Then linear quadratic(LQ) method was utilized to design the on-tracking controller. Finally, field tests were conducted with the proto type tractor equipped with the developed controller. The travel speed was set at 1.5 m/s. Results indicated that the maximum deviations were 35 cm when the tractor follows sinusoidal path and circular paths.