Research On Ridge Height Detection Based On Frequency Modulated Continuous Wave Radar

The comprehensive mechanization of sugarcane production is considered to be a method that can effectively reduce the planting cost of sugarcane and improve the economic benefits of planting,among which the automation of sugarcane harvesting machinery has been the most difficult bottleneck to break through.At present,the biggest technical problem facing the automation of sugarcane harvesting machinery is to automatically adjust the cutting head height of the sugarcane harvesting machine with the change of the height of sugarcane ridges,so as to ensure that the cutting head is always at a certain distance from the soil surface of sugarcane ridges.In China,the sugarcane land is mainly distributed in the hilly areas in the south of China,where the terrain is undulating and the sugarcane ridge is uneven,and the surface of the ridge is often covered by vegetation such as weeds and sugarcane leaves.The common measurement method of sugarcane ridge height is not suitable for real-time detection of the ridge height,and it is difficult to realize the automatic adjustment of the cutter head position with the change of the ridge height.The sugarcane harvester introduced from abroad can not adapt to the actual situation of sugarcane fields in China and the automatic height adjustment of the cutter head of the domestic sugarcane harvester is still in the research and test stage.Based on the technical difficulties of the existing automatic detection system of sugarcane ridge height,this paper proposed an automatic detection scheme of sugarcane ridge height based on Frequency Modulated Continuous Wave(FMCW)radar.Refer to Chinese and foreign literature on the plan feasibility analysis,using Matlab simulation interface,build the GUI for sugarcane ground vegetation parameters,radar system simulation analysis,the basic parameters to determine the appropriate radar system,analysis and calculation of FMCW radar rf front-end modules performance requirements,design of FMCW radar rf front-end circuit.The PCB layout of RF front end was made by Cadence software,and the hardware test and simulation test were carried out.The main research contents of this paper are as follows:(1)Refer to literature to determine the feasibility of the scheme.Referring to domestic and foreign literatures on sugarcane harvester and radar ranging under complex circumstances,analyzing the technical bottleneck of sugarcane harvesting machinery automation,understanding the principle and advantages of FMCW radar,and clarifying the feasibility of the scheme.(2)Modeling and simulation to further determine the feasibility of the scheme from the perspective of simulation.Penetration depth of the radar signal by the radar the wavelength of the electromagnetic scattering coefficient decision with the media,according to the actual situation of the sugarcane harvest environment,using Matlab software to sugarcane,sugarcane soil cover of vegetation establishment of electromagnetic scattering model,analysis of FMCW radar under different system parameters influence on sugarcane planting height detection,build simulation GUI interface.It is convenient to change the simulation parameters and determine the optimal working frequency and bandwidth of the radar RF front-end system.(3)Hardware implementation and performance test of FMCW radar RF front-end system.This paper analyzes the performance requirements of the FMCW radar RF front end system,selects the appropriate RF chip for the design of the FMCW radar RF front end,completes the RF front end hardware test,verifies the integrity of its function.To meet the requirements of the design of small volume,low cost,according to the principle of FMCW radar and cane to the actual situation,design radar frequency synthesizers rf front-end module,the transmitting front-end module and receiving front-end module PCB schematic diagram and the hardware implementation scheme,making the PCB layout and performance testing,guarantee of radar rf front-end system can work normally.(4)Simulate sugarcane harvesting environment,test and data processing and analysis.Weeds,plant stems and leaves,and soil were used to simulate the sugarcane ridge environment for simulation tests.Radar echo signals under different test distances and different vegetation coverage thickness were tested and recorded respectively.Matlab software was used to process and analyze the echo signals.By applying the Cell Averge Constant False Alarm Rate(CA-CFAR)detection method and the binary decision accumulation theory to signal processing,the interference caused by vegetation cover and noise was solved,and more accurate automatic detection data of ridge height was obtained.