Research of collision restitution coefficient between Camellia oleifera fruits and inverted umbrella-type collection devices based on high-speed camera technology

At present, most of the collection parts in the mechanized harvesting of Camellia oleifera fruits adopt inverted umbrella-type collection devices, with various forms such as human-machine combination, automation, and intelligence, but the collection mechanism has not been studied. This paper conducted experiments on the determination of the collision restitution coefficient between Camellia oleifera fruits and umbrella cloth in the collection mechanism, to provide a theoretical basis for the optimal design of the inverted umbrella-type collection device for Camellia oleifera fruits.

Using the designed and developed measuring device for the coefficient of restitution of umbrella-surface collision to simulate the fruit dropping and collecting parts during the mechanized harvesting process of Camellia oleifera fruits. Combine two high-speed cameras to record and analyze the test process. Through single - factor preliminary selection tests and multi - factor orthogonal tests, explore the effects of fruit dropping height, umbrella cloth material, tension force on the umbrella cloth, and the angle between the umbrella -cloth and the horizontal plane on the coefficient of restitution of the collision between Camellia oleifera fruits and the umbrella cloth. Determine the primary- and -secondary order of the influence of each factor on the coefficient of restitution of the collision between Camellia oleifera fruits and the umbrella cloth and the significance level of each factor. After conducting performance measurement tests on the prototype through optimized design, the fruit collection rate and concentration rate are obtained.

1) The analysis shows that the primary and secondary order of the influence of the four factors on the collision restitution coefficient is: the angle between umbrella cloth and horizontal plane, umbrella cloth material, tension force of umbrella cloth, fruit dropping height; 2) The selected optimal parameter combination is the angle between umbrella cloth and horizontal plane of 25°, umbrella cloth material of canvas, and tension force of umbrella cloth of 20 N. 3) Through performance measurement tests on the inverted umbrella-type collection device optimized in design, the fruit collection rate is 95.29%, and the fruit concentration rate is 93.41%.

This research reveals the main influencing factors of the restitution coefficient when Camellia oleifera fruits collide with the umbrella cloth, and presents an optimal parameter combination. It provides references for the optimal design of the inverted umbrella-type Camellia oleifera fruit collection device and a theoretical basis for improving the fruit collection rate and concentration rate of the Camellia oleifera fruit collection device.