**1. Introduction**

Dandelion (*Taraxacum mongolicum*) is a perennial herb that is rich in vitamins A and C and nutrient elements such as potassium [1–4] and that has high medicinal value [5,6] and economic value [7]. Dandelion leaves with extremely high medicinal value are commonly picked and sold as an herbal medicine (to considerable economic benefit). The harvesting of dandelion seeds requires suitable timeliness. Dandelion seeds need to be harvested quickly, or mature seeds will detach from the plants and fall with the wind, which brings difficulties to harvesting and reduces the yield of dandelion seeds. In order to meet the needs of food or medicine, people began to try to plant dandelion artificially. However, due to the special structure of dandelion seeds, the existing seed collection machine cannot be applied to the collection of dandelion seeds. After the maturation of dandelion, the seed collection process becomes complex, requiring a lot of manpower and material resources, and the collection efficiency is very low, which is not conducive to the artificial cultivation of dandelion.

At present, dandelion seed harvesters are hardly studied by foreign researchers. Some Chinese researchers have studied the mechanized harvesting of dandelion seeds. Xie [8] designed a handheld dandelion seed harvesting device which can initially achieve the

**Citation:** Qu, Z.; Lu, Q.; Shao, H.; Liu, L.; Wang, X.; Lv, Z. Design and Testing of a Self-Propelled Dandelion Seed Harvester. *Agriculture* **2023**, *13*, 917. https://doi.org/10.3390/ agriculture13040917

Academic Editors: Cheng Shen, Zhong Tang and Maohua Xiao

Received: 13 March 2023 Revised: 11 April 2023 Accepted: 12 April 2023 Published: 21 April 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

purpose of dandelion seed collection, save labor and material resources to a certain extent, and improve the speed of collection. Zhang [9] designed a cross-walking remote-controlled dandelion seed harvester based on the principle of a vacuum cleaner. The adsorption seed collection device is connected with the walking device and with a car structure, and the height of the car body is adjustable. As the dandelion harvester can operate at different heights, multi-line dandelion seeds can be quickly harvested, and the efficiency of dandelion harvesting operations can be improved. Yin [10] devised a dandelion seed harvester on which the rocker is equipped with a seed-drawing disc, allowing seeds to be drawn into the seed storage tank. The harvester solves the time-consuming and laborious problems of artificial picking, although it still needs operators to bend over for a long time, leading to high labor intensity and low operational efficiency. Zhang [11] designed a dandelion seed harvester that draws seed–pappus mixtures of dandelion into the separation drum through an air-suction pipeline to separate seeds from pappi. Wang [12] designed a dandelion seed collection device. The controller can adjust the width of the feed port according to the actual data through image processing; moreover, the working powers of the servo-motor, vibration motor, and scattering motor can also be adjusted, which allows better harvesting. However, most relevant research on the topic in China is still in its infancy, and since the harvesters have not been verified as reliable in the field, they cannot be applied to practical production.

Aiming to improve the harvesting rate, reduce harvesting loss, decrease labor intensity, and increase the degree of mechanization, a self-propelled dandelion seed harvester was designed according to agronomic requirements for harvesting dandelion seeds and material characteristics of dandelion plants and seeds. By analyzing the collection and separation processes of dandelion seeds, the main factors that affect the collection rate were determined. Then, the collection and separation devices were designed, and their parameters were analyzed. Taking the forward speed, wind velocity of blowers, and rate of rotation of the drum as experimental factors, and taking the collection rate as the evaluation index, quadratic regression orthogonal rotating field tests were conducted. In this way, the optimal combination of operation parameters was determined. By conducting field tests, the harvesting quality of the harvester was assessed and the design was verified as being both reasonable and reliable.

#### **2. The Structure and Working Mechanism**
