后轮驱动大功率拖拉机牵引力-滑转率联合自动控制方法  

Integrated control method of traction & slip ratio for rear-driving high-power tractors

作　　者：张硕[1] 杜岳峰[1] 朱忠祥[1] 毛恩荣[1] 刘进一[1] 石晶[1] 

机构地区：[1]中国农业大学现代农业装备优化设计北京市重点实验室,北京100083

出　　处：《农业工程学报》2016年第12期47-53,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：现代农业装备与技术协同创新中心资助项目(NZXT01201401)

摘　　要：针对后轮驱动大功率拖拉机犁耕作业工况,提出了大功率拖拉机牵引力-滑转率联合自动控制方法。基于Freescale MC9S12XS128型微处理器开发了联合控制器硬件系统;采用PID（proportion integral derivative）控制算法,制定了牵引力PID控制和滑转率开关控制的联合控制策略,基于模块化设计开发了联合控制软件系统;进行了牵引力控制、牵引力与滑转率联合控制的田间实车对比试验,分析了2种不同控制方法下滑转率、牵引力和耕深的控制效果,验证了联合控制系统的性能。试验结果表明：当设定滑转率阀值区间0.1～0.2,牵引力阀值6 000 N时,联合控制下的实际耕深平均误差为1.45 cm,均方根误差为2.79 cm;实际牵引力平均误差为270.73 N,均方根误差为366.23 N;滑转率采样时间50 s,阀值区间以内43.78 s,有效控制时间范围为88%。与单独的牵引力控制相比,实际耕深、牵引力的平均误差和均方根误差均明显减小,实际滑转率的控制效率有较大提高。结果表明,该文提出的大功率拖拉机牵引力-滑转率联合自动控制方法,可以实现牵引力和滑转率的双目标联合控制,能够满足实际生产的农艺要求。Ploughing with rear-driving tractors plays an important role in agricultural production during which the electronic-hydraulic hitch system is regularly adjusted for desired performance. In operation, severe driving wheel slip easily occurs because of the complex terrestrial environment and the frequent changing of operating load. Studies show that tractors have a higher traction efficiency when slip ratio is between 0.1 and 0.15; however, when slip ratio is larger than 0.2, the efficiency drops dramatically while the soil texture is destroyed, the tires are worn faster and the energy consumption is increasing. Therefore the effective control of the 2WD tractors＇ driving slip is highly desired. In this paper, both the structure of the electro-hydraulic hitch and the working principle of 2WD tractor＇s driving slip system are firstly analyzed. Then the integrated control of traction and slip-rate based on PID（proportional integral differential） is proposed. The integrated control method that contains a control factor with 2 detailed control objectives is presented. The automatic control system mainly performs the traction control while constantly monitoring the changes of slip ratio. When the slip ratio is in the desired range mentioned above, the traction control continues; when the slip ratio is out of range, the controller switches to slip rate control, which outputs a voltage signal to the electromagnetic proportional control valve（if the slip ratio is smaller than 0.1, proportional descent control valve works with an input voltage of 0.5 V; if the slip ratio is greater than 0.2, proportional lift control valve works with an input voltage of 4.5 V）; and it returns to traction control once the slip is addressed. According to the characteristics of heavy tractor electro-hydraulic hitch,taking account of the complex operating condition of ploughing, an integrated automatic controller is developed for the electro-hydraulic hitch system based on microprocessor MC9S12XS128 of Freescale. At the same time, t

关 键 词：拖拉机 控制 农业机械 滑转率 牵引力 联合控制 对比试验 

分 类 号：S219.032.4[农业科学—农业机械化工程] TP273.2[农业科学—农业工程]