Article
Precision Landing Test and Simulation of the
Agricultural UAV on Apron
Yangyang Guo
1,2,3,4,†
, Jiaqian Guo
1,2,3,†
, Chang Liu
1,2,3
, Hongting Xiong
1,2,3
, Lilong Chai
4,
*
and Dongjian He
1,2,3,
*
1
College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China;
yangyang.guo@uga.edu (Y.G.); guojiaqian@nwafu.edu.cn (J.G.); ripper_liu1016@163.com (C.L.);
18804636217@163.com (H.X.)
2
Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs,
Yangling 712100, China
3
Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service,
Yangling 712100, China
4
Department of Poultry Science, College of Agricultural and Environmental Sciences, University of Georgia,
Athens, GA 30602, USA
* Correspondence: lchai@uga.edu (L.C.); hdj168@nwsuaf.edu.cn (D.H.)
† Authors contributed equally to this paper.
Received: 3 April 2020; Accepted: 12 June 2020; Published: 14 June 2020
Abstract:
Unmanned aerial vehicle (UAV) has been used to assist agricultural production.
Precision landing control of UAV is critical for application of it in some specific areas such
as greenhouses or livestock/poultry houses. For controlling UAV landing on a fixed or mobile
apron/platform accurately, this study proposed an automatic method and tested it under three
scenarios: (1) UAV landing at high operating altitude based on the GPS signal of the mobile apron;
(2) UAV landing at low operating altitude based on the image recognition on the mobile apron;
and (3) UAV landing progress control based on the fixed landing device and image detection to
achieve a stable landing action. To verify the effectiveness of the proposed control method, apron at
both stationary and mobile (e.g., 3 km/h moving speed) statuses were tested. Besides, a simulation
was conducted for the UAV landing on a fixed apron by using a commercial poultry house as a model
(135 L
×
15 W
×
3 H m). Results show that the average landing errors in high altitude and low
altitude can be controlled within 6.78 cm and 13.29 cm, respectively. For the poultry house simulation,
the landing errors were 6.22
±
2.59 cm, 6.79
±
3.26 cm, and 7.14
±
2.41cm at the running speed
of 2 km/h, 3 km/h, and 4 km/h, respectively. This study provides the basis for applying the UAV in
agricultural facilities such as poultry or animal houses where requires a stricter landing control than
open fields.
Keywords:
unmanned aerial vehicle; mobile apron; precision landing; image detection; poultry house
1. Introduction
The unmanned aerial vehicle (UAV) information acquisition technology has been applied in
agricultural operations and it plays an important role in the development of precision agriculture
[
1
–
3
]. UAV has been used for agricultural information acquisition [
4
–
8
], pesticide spraying [
9
–
11
],
disease detection [
12
–
14
]. In recent years, the research of UAV has been focused on navigation and control
direction. Among them, precision landing is a critical area in the field of UAV control study [15–18].
Visual navigation, as an effective navigation technology, receives increasing attentions. It mainly
uses computer vision technology to obtain positioning parameter information [
19
,
20
]. This technology
can obtain information through common low-cost devices and has broad application prospects in
Sensors 2020, 20, 3369; doi:10.3390/s20123369 www.mdpi.com/journal/sensors
