面向草莓抓取的气动四叶片软体抓手研制

农林业中果蔬的自动化采摘需求日趋强烈,末端抓手是实现无损采摘的关键。传统的末端抓手以刚性结构居多,现有的各种柔性抓手也存在抓取力不足、包覆性不佳等缺点。本文以草莓的无损采摘为研究对象,提出将草莓外部轮廓曲线作为设计曲线,设计了一种新型气动四叶片软体抓手。首先,对软体抓手的结构做仿真优化,提出一种安全地附着在目标物表面的设想。然后,在进行草莓表面的最小破坏应力试验的基础上,测试了软体抓手的末端力,验证了其实现无损抓取的可行性。再次,利用动态捕捉技术,研究了软体抓手叶面的弯曲变形规律。最后,选择使用弧线型气体通道的软体抓手进行了草莓抓取测试,结果证明了气动四叶片软体抓手可以实现草莓的无损抓取,抓取成功率达90%,破损率为2%,表明所研制的四叶片软体抓手用于草莓抓取时具有良好的稳定性和实用性,可用于草莓采摘的末端执行器。本研究也可为其他易损果蔬的采摘技术提供理论基础和技术支撑。

Development of pneumatic four blade soft grasp for grabbing strawberry

The increasing demand for automatic picking robots of fruits and vegetables drives the study of the end-grabber realizing non-destructive picking. However, most traditional end grips are rigid structures, and the existing flexible grips also have shortcomings such as insufficient grasping force and poor coating. A new type of pneumatic four-blade soft grip was designed to realize the non-destructive picking of strawberry, which used the contour curve of strawberry as the design curve for the first time. Firstly, the structure of the software grip was simulated and optimized, thus an idea of safely attaching to the target surface was put forward. Then, both the minimum failure stress on surface of the strawberry and the end force of the software grip were test, and the feasibility of nondestructive grasping was verified based on these results. Thirdly, the bending deformation law of the soft grip leaf surface was studied using the dynamic capture technology. Finally, the soft gripper with arcs gas channel of strawberry grab was used to test the actual grasping ability. Results showed that the four blade pneumatic gripper soft could realize nondestructive fetching, the success rate was 90%, and the damage rate was 2%. It is proved that the developed four gripper for strawberry scraping blade soft has a good stability and practicability, and can be used to strawberry picking at the end of the actuator. This study can also provide theoretical basis and technical support for the picking technology of other fragile fruits and vegetables.