工业机器人虚拟仿真中混合层次包围盒碰撞检测技术的研究与应用

发布时间：2018-03-24 23:05

本文选题：工业机器人　切入点：混合层次包围盒　出处：《广东工业大学》2017年硕士论文

【摘要】：虚拟现实是借助计算机、硬件设备、力学反馈等设备,实现与真实世界高度相似的虚拟环境的技术。碰撞检测是虚拟现实领域中的关键问题,随着机器人虚拟仿真技术的飞速发展,仿真环境中对碰撞检测的效率与精准性要求也随之提升,然而单一包围盒碰撞检测算法在大规模虚拟环境中通常因精准性不足、效率低产生穿透或延迟现象,无法实时检测到碰撞发生,严重影响仿真环境的真实性。本文以Unity3D引擎结合三维建模软件,开发了工业机器人虚拟仿真场景,研究了机器人在运动仿真过程中可能发生的多种复杂碰撞情况,针对单一层次包围盒算法在精确性与效率上的不足提出了一种高效的混合层次包围盒碰撞检测算法,并完成算法实现过程中每个步骤的详细设计。后在工业机器人虚拟仿真环境中通过示教作业仿真实验验证了本文所提出的碰撞检测算法所具有的优势。具体地,本文主要工作如下:首先,通过SolidWorks、3ds Max建模软件完成工业机器人虚拟仿真场景中设备与环境的建模,并利用Unity3D引擎搭建虚拟仿真场景。后针对虚拟环境中机器人轨迹规划提出一种机器人空间圆弧轨迹插补算法,利用圆弧所在空间建立新坐标系并计算圆弧上各插补点,后将点变换到原坐标系中,最后映射到关节空间中各关节角以实现空间圆弧轨迹插补,为后续机器人复杂运动仿真奠定了基础。其次,对层次包围盒技术进行总结分析,针对单一层次包围盒碰撞检测算法存在穿透、漏检以及精准性和效率不能满足要求的问题,提出了一种基于AABB与OBB的混合层次包围盒碰撞检测算法,通过自顶向下的方法构造物体的层次包围盒树,在粗略检测阶段使用AABB,在精准检测阶段使用OBB;针对基元相交测试中传统的三角面片测试效率低的问题,提出了一种基于空间正投影法与光线跟踪法结合的三角面片相交测试算法,优化了检测速度;后采用基于时空相关性的加速遍历方法实现对混合层次包围盒树的遍历优化,在时间复杂度上很好地满足了检测的要求。最后经模型碰撞实验验证,本文所研究算法相较于单一AABB层次包围盒算法在效率,精准性和稳定性上都有所提升。最后,在本文所开发的工业机器人虚拟仿真环境中首先实现机器人运动过程中可能发生的多种复杂碰撞情况的检测验证;后在虚拟环境中实现机器人的示教编程仿真,通过虚拟示教方式获取轨迹示教点并完成仿真作业实验,在整个过程中实现对多种复杂碰撞情况的检测;最后在机器人弧焊仿真实验中结合碰撞检测技术与Unity3D中的粒子系统实现焊接物理效果仿真,进一步验证了本文所研究的碰撞检测算法具有良好的精准性、实时性、稳定性,可较好地满足复杂虚拟场景中的碰撞检测要求。
[Abstract]:Virtual reality (VR) is a kind of virtual environment which is highly similar to the real world by means of computer, hardware, mechanical feedback, etc. Collision detection is a key problem in the field of virtual reality. With the rapid development of robot virtual simulation technology, the efficiency and accuracy of collision detection in simulation environment are also improved. However, the single bounding box collision detection algorithm is usually due to the lack of accuracy in large-scale virtual environment. In this paper, the virtual simulation scene of industrial robot is developed by using Unity3D engine and 3D modeling software, which can not detect collision in real time and seriously affect the reality of simulation environment. In this paper, a variety of complex collision situations that may occur in the process of robot motion simulation are studied, and an efficient hybrid hierarchy bounding box collision detection algorithm is proposed for the lack of accuracy and efficiency of the single-level bounding box algorithm. The detailed design of each step in the realization of the algorithm is completed, and the advantages of the proposed collision detection algorithm are verified by the simulation experiment of teaching assignment in the virtual simulation environment of industrial robot. The main work of this paper is as follows: firstly, the modeling of equipment and environment in the virtual simulation scene of industrial robot is completed by SolidWorks 3DS Max. Then a robot space arc trajectory interpolation algorithm is proposed for the robot trajectory planning in the virtual environment. A new coordinate system is established in the space where the arc is located and the interpolation points on the arc are calculated. Then the point is transformed into the original coordinate system, and the angle of each joint in the joint space is mapped to realize the interpolation of the space arc trajectory, which lays the foundation for the subsequent robot complex motion simulation. Secondly, the hierarchical bounding box technology is summarized and analyzed. Aiming at the problems of single level bounding box collision detection algorithm, such as penetrating, missing detection, accuracy and efficiency, a hybrid hierarchical bounding box collision detection algorithm based on AABB and OBB is proposed. The hierarchical bounding box tree of objects is constructed by top-down method, AABB is used in rough detection, and OBBin is used in precision detection. In this paper, a triangulation intersection test algorithm based on spatial orthographic projection and ray tracing is proposed to optimize the detection speed, and then the hybrid hierarchy bounding box tree is traversed by an accelerated traversal method based on temporal and spatial correlation. Finally, the model collision experiments show that the proposed algorithm is more efficient, accurate and stable than the single AABB hierarchy bounding box algorithm. Finally, the model collision experiments show that the proposed algorithm can improve the efficiency, accuracy and stability of the algorithm compared with the single AABB hierarchy bounding box algorithm. In the virtual simulation environment of industrial robot developed in this paper, the detection and verification of many kinds of complex collisions that may occur in the course of robot movement are realized first, and then the simulation of robot teaching and programming is realized in the virtual environment. The trajectory teaching point is acquired by virtual teaching method, and the simulation experiment is completed, and the detection of various complex collision situations is realized in the whole process. Finally, in the robot arc welding simulation experiment combined with collision detection technology and particle system in Unity3D to achieve welding physical effect simulation, further verify that the collision detection algorithm studied in this paper has good accuracy, real-time, stability. It can meet the requirements of collision detection in complex virtual scene.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242.2;TP391.9

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