The pure pursuit model is widely used in the path tracking control system of agricultural machinery.However,system oscillations occur easily at high speed.Aiming to improve the stability of the trajectory tracking system of automatic rice transplanter,a path tracking method based on fuzzy control was proposed to adjust the lookahead distance of pure pursuit model.Firstly,the kinematic model of the transplanter was established by considering the automatic steering system as first-order model.Secondly,by linearizing the kinematic model,the stability condition of pure pursuit model was analyzed while tracking a straight line.Based on the stability condition,fuzzy control model was established to adjust the lookahead distance of pure pursuit model,with taking the speed and lateral deviation as inputs and the lookahead distance as output.To construct the experimental platform,automatic transformation was carried on with Yanmar VP6E rice transplanter.Finally,to verify the availability of proposed method at different speeds,the experiments were carried out at high speed of 1.0 m/s and low speed of 0.3 m/s.Compared with the traditional pure pursuit model with fixed lookahead distance,the method proposed can avoid oscillation at high speed and track the target path quickly at low speed.It was proved that this method can effectively improve the stability of the pure pursuit path tracking system.%为了提高自动导航插秧机路径跟踪系统的稳定性,提出了一种利用模糊控制调整纯追踪模型前视距离的路径跟踪方法.在考虑自动转向系统一阶惯性环节的情况下,建立插秧机运动学模型,分析了在跟踪直线时纯追踪模型的稳定性条件;基于此稳定性条件,以速度和横向偏差为输入,以前视距离为输出,建立模糊控制模型实时调整纯追踪模型的前视距离;以洋马VP6E型水田插秧机为实验平台对所提出方法进行了实验验证,结果证明,该方法能有效提高路径跟踪系统的稳定性.
展开▼
