基于坡度和PID混合控制方法的坡地农机稳速控制方法

Hybrid Controller for Steady Speed of Agricultural Machinery on Slopes

摘要:

农业机械的速度稳定控制可提升作业质量与效率。针对农田坡度变化对无人作业农机速度稳定性的影响，本文提出一种混合控制方法，由坡度控制器与比例-积分-微分（PID）控制器组成混合控制器。农机速度受纵向力影响，包括与坡度相关的常规力和难以估计的滑动摩擦力等。针对常规力设计了坡度控制器；针对滑动摩擦力采用PID控制器。通过混合2种控制器，可动态调节油门开度与制动总泵压力，确保农机在坡地农田中稳定行驶。在目标速度为7km/h仿真测试中，实现了速度稳定控制，均方根误差0.11km/h，平均绝对百分比误差1.6%。实际试验平台的田间试验结果表明，本方法有效，在不同坡度条件下能稳定控制速度，验证了混合控制器具有更优的控制性能，实现了农机行驶速度的精准控制，能满足农机作业的稳定性要求。

Abstract:

Steady speed control of agricultural machinery can improve operating quality and efficiency. To address the impact of farmland slope variations on the speed stability of unmanned operation agricultural machinery, a hybrid control method was proposed. This method included a hybrid controller composed of a slope-based controller and a proportional-integral-derivative (PID) controller. The speed of agricultural machinery was influenced by longitudinal forces, which were divided into two parts: one part was slope-related forces and conventional resistance, and the other was hard-to-estimate forces, such as sliding friction. For the first part, a slope-based controller was designed;for the second part, a PID controller was implemented. By combining these two controllers, the system can dynamically adjust the throttle opening and the brake master cylinder pressure, ensuring steady speed travel on sloping farmland. Simulation tests at a target speed of 7km/h demonstrated that the proposed controller maintained a stable speed, achieving a root mean square error of 0.13km/h and a mean absolute percentage error of 1.6%. Field tests on a practical experimental platform validated the method’s effectiveness, with results showing consistent control performance across varying slope conditions. The proposed controller demonstrated superior control performance. Experimental data verified that this method can achieve precise control of the agricultural machinery’s movement speed, meeting the stability requirements for agricultural operations.