Design Of Lidar Ranging Based On MEMS Micromirrors

With the rise of driverless technology in recent years,the lidar is widely used in many fields such as mapping,robotics,security and so on,the market enthusiasm of lidar has been stimulated all over the world.However,at present,the mature products in the market exist many problems,such as high price,technology monopoly,no access to open source code of key algorithms and so on.Therefore,the thesis designs a Laser lidar ranging device based on a MEMS micromirrors.the laser transmitting module,receiving signal module and MEMS micro mirror control module are designed in the thesis.The main research contents of the thesis are summarized as follows:1.Based on the analysis of existing lidar ranging methods and comparison with the performance advantages and disadvantages of the existing ranging methods,the TOF time-of-flight ranging method is finally selected,which has advantages such as over long ranging distance and more suitable for unmanned technology.Then the optical path scanning scheme of lidar is designed,that the non-coaxial optical path design is applied.The design method has many advantages such as greatly reducing the number of transmitting and receiving modules,reducing the manufacturing cost as well as the size of the volume and better satisfying the requirements of unmanned technology.2.The overall scheme of the proposed MEMS lidar ranging device is designed,then the hardware of each module is selected,and then the function of each module is developed.Function modules mainly include laser transmitting module,receiving module and micro mirror control module.Finally,the function of the proposed ranging device is realized.3.The software design of the designed ranging system is completed based on C# language in the environment of visual studio 2017.Considering the communication mode between ranging system and the upper computer,the serial communication mode is adopted for the data interaction.Finally,the ranging function is realized and the data can be clearly displayed in the upper computer.4.The designed lidar ranging device is tested,the reasons of ranging error are analyzed.The system is modified based on analysis.For laser energy,the transmitting lens with more focusing function is used to gather laser energy,while for micro mirror control,the PID control method is used to replace the original open-loop control.Finally,the experiment results shows that the measuring distance of the improved ranging device reaches more than 5m,and the measured error is within 10 mm.