Ground surface detection method using ground penetrating radar signal for sugarcane harvester base-cutter control

Abstract

Sugarcane harvesters, which can automatically adjust the base-cutter height according to the topography, have attracted increasing interest. Existing ground probing approaches mainly rely on contact machineries, which exhibit slow responses and damage sugarcane plants. This paper presents a rapid and non-contact terrain sensing method using ground penetrating radar (GPR) to realise the automatic height control of the base-cutter. In this study, a 1.6-GHz air-coupled GPR antenna was first mounted on a knockdown roller to measure the vertical distance between the ground and the antenna. The geographic relationship between the detection height and cutter cylinder length was established, based on which the base-cutter height was adjusted by changing the cylinder length. The obtained GPR signal was analysed to locate the ground surface. Post-process techniques were used to enhance the GPR signal contrast between the air and ground layer. To evaluate the penetrating ability and accuracy of the GPR method, sugarcane stalks were densely placed on the soil surface to mimic the extreme conditions of sugarcane fields. The influences of the height/depth of respective highlands/potholes, slope of the ground, and the moisture content of the soil on the GPR imaging were systematically investigated. The numerical and laboratory results confirmed the high accuracy of the proposed GPR method. Hence, a field experiment was conducted, and the soil surface was clearly visualised by GPR imaging. This study demonstrates the significant potential of the GPR-based method for the detection of a sugarcane field surface, which verifies its feasibility for use in manufactured automatic sugarcane harvesters. • A ground penetrating radar (GPR) was proposed to sense sugarcane terrain. • Simulation and lab experiments were used to investigate the GPR penetration ability. • The GPR can clearly visualise the ground layer, even when covered with stalks. • A 1.6-GHz GPR antenna achieved high ground detection accuracy in a field survey.