摘要
果实采摘是农业种植生产过程中最耗时费力的环节。为了实现果实的良好抓取,本研究设计了一款结构精简、具有自适应性的柔性机械手,该机械手由柔性手指、气动元件、手腕和底座组成,基于3D打印制作,装配简单。其中,气动元件和柔性手指由柔性材料打印而成,手腕为具有柔性的一体件打印而成;利用气动元件的伸缩功能实现对手腕的驱动,带动柔性手指自适应变形抓取果实。结合常曲率变形和D-H坐标法建立了单手腕的运动学模型。在此基础上,进行了柔性机械手功能性验证试验和安全测试试验。试验结果表明,柔性机械手具有适应果实的形状进行自适应抓取的功能,对表皮较为脆弱的果实没有损伤;气动元件满足使用要求,可以完成对手腕的动作驱动。研究结果将为机械手柔性抓取结构的设计提供参考价值。
With the development of computer and automation control technology, robots have gradually entered the field of agricultural production.China is a big agricultural country. The application of agricultural robots can improve labor productivity and product quality, improve working conditions, solve the problem of labor shortage, and promote the intellectualization of agricultural production process. Fruit harvesting is the most time-consuming and laborious part of agricultural production. Since the skin of fruit is relatively fragile, it is easy to cause damage in the process of grasping. Therefore, it is necessary for the grasping device to have some flexibility. As the end of the picking, robot directly acts on the part of the grasping object, the manipulator has attracted more and more attention of scientific researchers because of its light weight, small size, low energy consumption, high flexibility and low cost. Manipulator is the core component of robot, which is installed on the end of picking robot and acting on the object directly. In order to improve universality and flexibility, reduce the damage to the fruits, and shorten the design cycle, the flexible manipulator with simple structure and self-adaptive was designed to achieve favorable grasp of fruits. The manipulator developed based on 3D printing has the advantages of rapid prototyping, low experimental cost and easy to assemble, etc. Flexible manipulator consists of flexible finger, wrist, base and pneumatic components. Its general action process is open, grasp, move and put down. However, flexible manipulator combines the two processes of moving and putting down into swallowing, which reduces the execution of the motion and improves the grasping performance and efficiency of the manipulator. Pneumatic components and wrist are printed from flexible materials and the material is thermoplastic urethane and polylactic acid respectively. The wrist is an integral part with flexibility. The use of pneumatic components can achieve the wrist bending, driving flexible fingers self-adaptive deformation to grasp the fruit. The manipulator is placed on the vertical sliding platform of the four-wheel platform, which can move up and down, and the four-wheel platform can move freely in all directions. The single wrist has two rotational degrees of freedom. The kinematics model of single wrist is established by combining constant curvature deformation and D-H coordinate method. On this basis, the functional validation test and safety test of flexible manipulator were carried out. In the safety test, the thin pressure sensor was used as the detection element of the contact force signal between the finger and the grasping object. The experiment results show that the pneumatic components of the flexible manipulator meet the design requirements and the driving wrist is flexible. The manipulator has certain flexibility, and can adapt to the shape of the fruit for self-adaptive grasping. The self-adaptive grasping effect of the manipulator is obvious, and the fruit skin is intact. Moreover, the flexible manipulator has a favorable self-adaptive function based on the structural design and the complexity of the control system is deduced. In addition, it will provide reference value for the design of the flexible grasping mechanism.
作者
高国华
董增雅
孙晓娜
王皓
Guohua Gao;Zengya Dong;Xiaona Sun;Hao Wang(College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology,Beijing 100124, China)
出处
《智慧农业》
2019年第1期85-95,共11页
Smart Agriculture
基金
国家自然科学基金(51675011)
关键词
柔性机械手
3D打印
运动学
自适应
接触力
flexible manipulator
3D printing
kinematics
self-adaptive function
contact force
