Study On Low-cost Multi-line Lidar Optical System

Driverless car is the ultimate direction of development,including internet companies like Google,Baidu and traditional car manufacturers like Audi,BMW are vigorously developing fully automatic or semi-automatic intelligent driving technology.The environment perception technology is the most basic and important in unmanned technology,because the lidar has good directivity,strong anti-interference and high precision,it is currently recognized as the most safe and accurate means of environmental perception.But currently mainstream vehicular navigation type lidar on the market,including Velodyne 64,32,16 line lidar and IBeo 8,4 line lidar,the cost is very high,so the research of low cost lidar for unmanned driving is very important.Firstly,this paper studies the status quo of vehicular lidar at home and abroad,and mainstream vehicular navigation type lidars are analyzed from performance and cost,so the key of reducing cost is illustrated.Secondly,according to the navigation type lidar application scenario,the performance index and a low-cost vehicular lidar scheme is proposed,and the technical route and cost is analyzed.Then,the parameter design and optical design for ranging module is done,so we can find the key of low cost and the optimization plan is put forward.Besides,the scanning module is studied and a new low-cost hybrid solid state scanning scheme is put forward.Finally,a experiment is done and the results are compared with the simulation results.Through the analysis of the cost of mainstream vehicular lidar,the keys of reducing the cost are reducing the number of APD,avoiding to use APD array,ranging and scanning system optimization design,etc.In the top scheme,the two lasers,single APD and double pyramid rotating mirror are adopted.In ranging module,the laser,APD,fast and slow axis collimation lens,optical fiber coupling len,optical fiber collimating len and receive len are degisned.Through a cost analysis,we can find the key for cost reduction is the fast axis collimating lens,so fast axis collimation lens of single spherical and aspherical,two pieces of spherical cylindrical lens combination three ways to carry on the design and simulation analysis,and we find two pieces of cylindrical lens combination efficiency is about 80%of the original aspherical lens.In scaning module,we put forward a new scanning scheme of multi-mirror array to replace the single mirror.Through the power modeling and performance modeling for new hybrid solid state scanning plan and the original plan,the scanning angle of new plan will decrease by about 15 degrees,but the cost and volume can be reduced a lot.Finally,in the experiment,the ranging performance of the optical system is verified,and three kinds of plans for fast axis collimator were compared,the experimental results and simulation results are similar.