Studying the Methods of Harvesting Garden Strawberry with Robotic Machines

Abstract

The paper presents a description of a newly developed device for the robotic harvesting of garden strawberry. The device features versatility, the simplicity of design, ease of adaptation to an automated platform. (Research purpose) To study the conditions for harvesting garden strawberry with robotic machines, develop a method for picking berries and determine the parameters of the working element for robotic harvesting, taking into account the mechanical impact on berries and the degree of the berry damage. (Materials and methods) The authors prepared an experimental methodology of studying the physical-and-mechanical properties of garden strawberry and calculated the critical speed of the impact of berries when picked by the working element. To prove the effectiveness of the working element operation, a comprehensive analysis of the physical-and-mechanical parameters of berries was carried out. (Results and discussion) The study has shown that the strength of garden strawberry is largely dependent on such major factors as cultivation conditions, as well as the variety and size of berries. It has been found that the specific strength of various parts of berries ranges from 0.0094 to 0.0262 kilogram-force per square meter. The skin of the Zenga-Zengana and Rarekot varieties has proved to possess the greatest strength, while that of the Festivalnaya variety - the smallest one. The authors have shown that the base and the tops of berries are about 1.2 times stronger than the skin of their rest part. It has been found that the berry shell has the property of elasticity. When berries are squeezed, their deformation is proportional to the load applied. The authors have proposed a design of a moving robotic platform with a cutting working element mounted on a manipulator. As a result, berry removal can be implemented by cutting the stem with the least damage. (Conclusions) The authors have proposed a device for the robotic harvesting of garden strawberry, which is distinguished among its counterparts by its ability to significantly reduce the mechanical impact on the target object, as well as preserve the appearance and quality characteristics of berries.