The Analysis Of LiDAR System Based On MEMS Scanning Mirror

With the emergence of highly intelligent devices such as unmanned aerial vehicles,unmanned vehicles and intelligent robots,the machine vision problem of intelligent devices has been a hot topic.LiDAR(Light Detection And Ranging)has the advantages of fast measurement speed,easy integration,high accuracy and other advantages are also considered for the field of machine vision,miniaturized LiDAR is suitable such applications.In this thesis,a LiDAR system based on MEMS two-dimensional scanning mirror is studied and researched for LiDAR application.In this thesis,the basic theory of MEMS scanning mirror,working principle,structural design,process and performance testing are in-depth studied,while the send and receive principles of the LiDAR system are studied.The laser driver,receiver reception and laser ranging circuit in the LiDAR system are designed and realized.Firstly,this thesis makes an in-depth analysis of the transmitter and receiver system of the LiDAR system.When laser is emitted by the laser,the energy loss occurs when the atmospheric energy is absorbed by the atmosphere.At the same time,the energy loss occurs due to the Lambertian radiation during the reflection process.Then,combined with the actual demand of lidar system,the transmitting part and receiving part of the LiDAR system are designed and tested.The LiDAR transmitting part mainly includes the design and test of high power pulsed laser drive circuit and the working principle of MEMS scanning mirror.The LiDAR receiving part includes the design of weak echo signal photoelectric conversion circuit,the echo amplifier circuit and the discriminating circuit at high precision.In the end,this thesis carries out the prototype and test of the LiDAR system based on MEMS scanning mirror,meanwhile test the signal of the laser transmitting circuit and the laser receiving circuit.The consequence shows that the laser radar has the maximum range of 70 m and the ranging accuracy is less than 5cm under normal temperature indoor environment.