【作者】 任丽春；

【导师】 汪小旵；

【作者基本信息】 南京农业大学 ， 检测技术与自动化装置， 2011， 硕士

【摘要】 风送式喷雾技术由于减少了农药的雾滴漂移、增加了附着率,可使得环境污染的风险大大降低。风送式喷雾效果的主要影响因素之一是风机的转速,但目前风送式喷雾风机转速大都是由档位控制,很难得到精确的转速,大大影响了喷雾效果。为此,本文首次提出并设计了风送式喷雾风机的液压无级调速控制系统,为实现更好的风送式喷雾效果提供途径。本文以3WZ600型自走式果园风送定向喷雾机平台为基础,以单片机控制技术为核心,采用直流步进电机调速技术,设计了风送式喷雾风机液压无级调速控制系统。建立液压无级变速系统模型并分析,采用模糊控制策略,进行试验验证。主要内容如下：1、根据系统精度及稳定度要求、控制对象特性及作业环境,完成了单片机硬件系统、步进电机及驱动器、丝杆和传感器的选型及设计,并对执行机构与控制对象的连接装置进行合理调整。2、建立液压无级变速系统模型,结合实际运行情况进行模型分析；根据专家知识和实践经验设计了模糊控制器。利用Simulink对理想的液压无级变速系统模型添加不同干扰模拟实际运行过程,并采用模糊控制进行了仿真,结果表明模糊控制具有较好的动态响应,对于不同的干扰都有很好的抗干扰性,符合本系统控制需求。3、完成喷雾风机转速无级调节系统设计,分别有风机转速检测、液压无级变速系统和转速控制系统,其中包括液晶显示、按键功能、风速检测、模糊控制和归零的程序设计。为提高系统可靠性与稳定性添加的归零程序采用绝对零位法,实际应用中,消除了由液压无级变速系统延时问题带来的风机反转和不稳定问题。试验结果表明,本系统运行稳定、可靠,符合预期设计要求。更多还原

【Abstract】 The air assisted spraying technology, which greatly reduces the droplet drift, and has good adhesion, significantly reduces the risk of environmental pollution. One of the most important factors affecting spray effect is the fan speed. But until now, fan speed of the air-blast sprayer at home and abroad is mostly controlled by the operator through the gears, which had not only the unattainable required accuracy, but also the poor scheduling. Therefore, this article firstly proposed and designed the hydraulic stepless speed regulation control system of the air-blast sprayer, which provided a way for better spray.Based on the platform of the orchard self-propelled air-blast sprayer with type 3WZ600, the air-blast sprayer fan hydraulic stepless speed regulation control system was designed, which focused on SCM control technology, and adopted DC stepper motor speed control technology. The hydraulic continuously variable transmission system model was established and analyzed, which used the fuzzy control strategy and verified by the experiments. Main contents were as follows:1. According to the system accuracy and stability requirements, the controlled object characteristics and the operating environment, the selections of microcontroller hardware system, stepper motor and devices, screw and sensor were finished. Simultaneously, the connected device between actuator and controlled object was adjusted reasonably.2. The ideal model of the hydraulic continuously variable transmission was established and analyzed with the actual operation. The ideal model of the hydraulic continuously variable transmission, added different disturbances to reflect the actual operating conditions, was simulated with fuzzy control strategy using Simulink. The results showed that the fuzzy controller had better dynamic response and good immunity with different interferences, which met the needs of control system.3. The software and hardware designs of air-blast sprayer fan speed regulation control system were finished, which were composed of speed detection、the hydraulic continuously variable transmission system and speed control system, including programs of LCD display、key detection speed detection and fuzzy control. The return-to-zero program for system reliability and stability adopted Absolute-Zero method, which eliminated the problem of the fan reversal and instability, caused by the delay of the hydraulic continuously variable transmission in practical application.Experiments showed that the system met the expected requirements, stable and reliable.更多还原