Research On Excavator's Dynamic Simulation Test System Based On 3D Reconstruction

With the advancement of the modernization of our country,construction machinery has been widely used in many fields.At the same time,the hydraulic excavator accounted for 30% of them.However,the foundation of the hydraulic excavator' research and development of our country is still weak relatively.The main parts relied on importing from developed countries and the core technologies of the hydraulic excavator are still controlled and monopolized by developed countries.If all of the design and optimization of hydraulic excavator use real test,may cause long research and development cycle,high cost and low efficiency.The dynamic simulation test system of the excavator based on the hydraulic loading test bed can take part of the actual vehicle test work,and some research and development work can be carried out in the laboratory to reduce the risk and cost of the actual vehicle test.The research and development of the excavator adopts the way of real vehicle test accompanied of the indoor simulation reproduction,which can avoid some limitations of the real vehicle test,effectively improve the efficiency of design and optimization and shorten the research and development cycle.In this paper,the virtual reality technology is applied to the research and development of hydraulic excavator,and the dynamic simulation system of excavator operation process based on “virtual reality fusion” is developed.The “virtual reality fusion” mainly includes the fusion of the virtual scene with the real scene operating environment;with the operator handling the virtual excavator to complete the excavation operation cycle,the fusion of the pilot handle manipulation and the synchronization playback of the cylinder pressure data of work device.In order to ensure to simulate the real process of excavating the soil,through the pressure sensor,the pressure data of each hydraulic cylinder and the pilot control valve during the digging of the real excavator are collected.Based on the RGBD sensor,the 3D reconstruction based on the actual operating environment of the excavator is completed by the acquisition of point cloud,down-sampling,filtering,registration and 3D reconstruction.At the same time,in order to ensure the normal loading of the excavator's actual measured pressure data in the simulation system,the paper adopts the method of analyzing the characteristics of the pressure data,and divides the process into five stages of lowering bucket,the excavation of the soil,lifting bucket and turn,Unloading the soil and returning,through the motion information tips in the virtual environment,to achieve the match between the pilot operation and the playback of working load.The main tasks completed by this paper are as follows:1.Collected the data from the 3D scene of the hydraulic excavator by Kinect v2 with the form of point cloud,and calibrated the outer parameters for the Kinect;2.According to redundancy and noise of the point cloud collected from Kinect,this paper adopts voxel grid filter to downsampling the point cloud,and uses the method of the average distance to get rid of the outlier and the method of neighbor propagation to get rid of the outlier cluster.At the same time,uses the improved bilateral filtering algorithm to deal with the noise mixed with the real data;3.According to characteristics about the curvature,Euclidean distance and the angle,get the rough matching registration point from multi perspectives of the point cloud and use the four element method to complete the initial registration of point cloud.By modifying the method calculating the distance of the nearest point and redefining the distance between the two point cloud of the ICP algorithm,improved the traditional ICP algorithm and completed the precise registration of point cloud based on multi perspectives;4.Proposing the optimal solution to get the point's position and the problem of defining the non-Delaunay triangle which is very time-consuming in the traditional algorithm inserted point by point to reconstruct the triangular surface,completed the surface reconstruction and virtual scene modeling of hydraulic excavator based on real working environment;5.The pressure signal data required for the experimental platform was collected by the excavator,and the characteristics of the pressure signal data were analyzed,and the various stages of the excavator operation were determined in reverse.The kinematic model of the excavator working device was established,and the physical modeling of the ground in the virtual scene was carried out.Based on the particle system,the real effect of the excavation and the soil dumping in the virtual scene was realized.Finally,through the operator in the experimental platform to manipulate the excavation in the virtual scene,the excavator work device completed a job cycle pressure loading.