A LiDAR Sensor-Based Spray Boom Height Detection Method and the Corresponding Experimental Validation.

Hanjie Dou,Changyuan Zhai,Xiu Wang,Liping Chen,Xueguan Zhao,Songlin Wang

doi:10.3390/s21062107

Abstract

Sprayer boom height (Hb) variations affect the deposition and distribution of droplets. An Hb control system is used to adjust Hb to maintain an optimum distance between the boom and the crop canopy, and an Hb detection sensor is a key component of the Hb control system. This study presents a new, low-cost light detection and ranging (LiDAR) sensor for Hb detection developed based on the principle of single-point ranging. To examine the detection performance of the LiDAR sensor, a step height detection experiment, a field ground detection experiment, and a wheat stubble (WS) height detection experiment as well as a comparison with an ultrasonic sensor were performed. The results showed that the LiDAR sensor could be used to detect Hb. When used to detect the WS height (HWS), the LiDAR sensor primarily detected the WS roots and the inside of the WS canopy. HWS and movement speed of the LiDAR sensor (VLiDAR) has a greater impact on the detection performance of the LiDAR sensor for the WS canopy than that for the WS roots. The detection error of the LiDAR sensor for the WS roots is less than 5.00%, and the detection error of the LiDAR sensor for the WS canopy is greater than 8.00%. The detection value from the LiDAR sensor to the WS root multiplied by 1.05 can be used as a reference basis for adjusting Hb, and after the WS canopy height is added to the basis, the value can be used as an index for adjusting Hb in WS field spraying. The results of this study will promote research on the boom height detection method and autonomous Hb control system.

Highlights

5% as a reference basis for adjusting Hb and add the height of the wheat stubble (WS) canopy to this basis as an index for adjusting Hb. This method can reduce the effects of an uneven WS canopy on the detection accuracy of the light detection and ranging (LiDAR) sensor, which is more suitable for Hb detection in WS field spraying
The results obtained from a step height detection experiment, a field ground detection experiment, and a WS height detection experiment as well as a comparison of the LiDAR sensor developed in this study with an ultrasonic sensor showed that the LiDAR sensor could satisfactorily reflect changes in Hb and be used to detect Hb
The distances detected by the LiDAR and ultrasonic sensors differed within the WS canopy, and the LiDAR sensor primarily detected the WS roots and the inside of the WS canopy

Summary

Introduction

As the level of agricultural mechanization in China has increased, boom sprayers have become the primary implements for spraying operations in fields due to their relatively good nozzle atomization performance, relatively large operating widths, and relatively high operating efficiency [1,2,3]. To improve the uniformity of the application of pesticides and reduce droplet drift during the field spraying process, it is necessary to maintain an optimum distance between the boom and the crop canopy [8,9,10]. It is vitally important to monitor and adjust the distance between the boom and the crop canopy in real-time

Objectives

Methods

Results

Discussion

Conclusion