Authors

Abstract

The accuracy of tractor plowing is an important link to ensure the quality of agricultural crops. The integrated control of draft-position in plowing is an effective plowing precision control technology which can be used to improve the tractor's plowing efficiency. The hydraulic system of the tractor hitch has the characteristics of large load and complex working environment. A differential and integral sliding mode adaptive controller (DI-SMAC) is designed for the tractor hitch hydraulic system with strong nonlinearity, uncertainty and time-varying parameters. Compared with the traditional PID controller, integral sliding mode adaptive controller(I-SMAC) and differential and integral sliding mode adaptive controller(DI-SMAC) in the electro-hydraulic hitch control system, the numerical simulation verifies the advantages of the differential and integral sliding mode adaptive controller. The real test platform of the agricultural tractor is built. The test results show that the DI-SMAC can realize the integrated control function of draft-position. In the position control mode, there is no static error, and the anti-interference ability is strong; Under the draft control mode, compared with the traditional PID controller, the range of traction error of differential and integral sliding mode controller is reduced by 32.9%, and the standard deviation is reduced by 38.6%; When the weight coefficient is changed, the traction force and tillage depth fluctuation are different with different weight coefficients. It shows that the DI-SMAC is stable and effective, and the developed method is expected to provide technical support for the fine plowing operation of tractors.

Abstract in Chinese

拖拉机犁耕作业精度是保证农业作物种植质量的重要环节。犁耕作业中的力位综合控制是一种有效的犁耕作业精度控制技术，可用于提高拖拉机的犁耕作业效率。本研究以拖拉机电液悬挂为研究对象，综合考虑拖拉机位姿状态和地面起伏和土壤沉陷对电液悬挂控制的影响，建立拖拉机机组电液悬挂动力学数学模型。拖拉机悬挂装置液压系统的负载质量大，作业环境复杂。针对拖拉机悬挂装置液压系统的强非线性、不确定性和参数时变性等特点，设计了微分与积分自适应滑模控制器。通过仿真对比传统PID控制器、积分滑模自适应控制器和微分与积分滑模自适应控制器，验证了微分与积分滑模自适应控制器的优越性。搭建实车试验平台，结果表明：采用微分与积分滑模自适应控制器，在位置控制模式下，基本无静差，抗干扰能力强；力控制模式下，相比传统PID控制器，微分与积分滑模控制器牵引力误差的极差降低了32.9%，标准方差降低了38.6%；力位综合控制模式下，不同权重系数牵引力和耕深波动也不同。说明微分与积分滑模自适应控制器是稳定有效的，所开发的方法有望为拖拉机精细犁耕作业提供技术支持。