考虑风扰的对靶喷雾机械臂药液喷洒动力学建模与试验

Modeling and Testing on Liquid Pesticide Spray of Serial Manipulator Target Weeding Robot Considering Wind Disturbance

为实现对靶标杂草的有效覆盖和提高对靶施药精度,减少药液浪费和生态污染,采用基于二自由度机械臂的对靶施药方式,优化了除草机器人的对靶喷施性能;除草机器人药液喷洒模型的建立是提高对靶喷施精度的关键,在考虑风扰的前提条件下,根据液滴粒子轨迹动力学方程,结合机械臂连杆和关节变量参数,建立液滴喷洒轨迹模型,并推导得到液滴理论沉积覆盖区域;在此基础上通过计算机数值模拟,分析了喷头位姿、车速和风速对液滴落地沉积覆盖区域的影响,并对靶标点进行了坐标重构;在室内搭建了小型开口直流低速风洞并进行药液喷洒验证试验,利用图像处理技术获取试验的液滴落地沉积覆盖区域,对比其与理论沉积覆盖区域,形心误差范围为4.1~7.2 mm,区域匹配误差范围为9.1%~17.8%。试验结果表明:理论沉积覆盖区域与试验测定的结果误差较小,两者具有较高的一致性。

In order to effectively cover target weeds, improve the precision of target spray and reduce liquid pesticide waste and ecological pollution, the target spray method based on two-degree-of-freedom manipulator was adopted＇ to optimize the target spray performance of the weeding robot. The establishment of the liquid pesticide spray model of weeding robot was the key to improve the precision of the target spray. Under the premise of considering the wind disturbance, according to the dynamics equation of the droplet particle trajectory, combined with the manipulator link and the joint variable parameters, the model of droplet spray was established and the theoretical covering area was derived. Based on this, the influence of nozzle pose, vehicle velocity and wind speed on the covering area of liquid pesticide droplet was analyzed by computer numerical simulation, and coordinate reconstruction was carried out on the nozzle spray point. A small opening direct-current low-speed wind tunnel was built indoors and the liquid pesticide spray model validation tests were conducted. The actual droplet covering area was obtained by image processing technology, which was compared with the theoretical droplet covering area, the area centroid error range was 4. 1 - 7.2 mm, and the area matching error range was 9. 1% -17.8%. The experimental results showed that the error of the theoretical covering area compared with the measured test results was small and had a high consistency with the test results. This research can be used as a reference for the construction to target spray equipment and technology of related robots.