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为了对连杆空间力矩传感器进行动态补偿,提出了适用于求取串联机器人任意连杆中任意一点处所受的内力和内力矩的算法.该算法采用连杆假想截断原理利用牛顿-欧拉方程推导而出.推导过程综合考虑了串联机器人是否处于静态以及末端是否受外力作用的情况,以及串联机器人的关节是否是回转关节的情况.然后利用该算法计算动态补偿值,构建了基于连杆力矩传感器动态补偿的笛卡儿阻抗控制器.最后在HIT/DLR Hand II五指灵巧手上进行了实验验证.实验结果一方面验证了该算法的有效性,另一方面也验证了本文所构建的笛卡儿阻抗控制器的有效性. 相似文献
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本文讨论了机器人层次结构几何模型,其高层为机器人树,低层为连杆树,连杆点为基本体,根据这一模型,机器人图形显示隐藏线和面的消隐可在3个层次上分别依次进行;基本体-→连杆-→机器人,单个基本体的消隐通过确定其各面的优先级来实现,连杆的消隐通过确定组成连杆的各基本之间的显示优先级实现,机器人消隐只需对连杆排序,此算法降低了计算量,提高了效率,已用于机器人图形仿真上。 相似文献
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安凯 《计算机测量与控制》2014,22(11):3528-3531
针对一种六关节机械臂,导出了各关节和末端的坐标,对可能与舱体碰撞的机械臂的几个连杆,将其上面的各点表示成两端关节坐标的函数,并由此给出了该点与舱体碰撞的检查方法;该方法不仅能检查机械臂关节与舱体的碰撞,而且能够检查机械臂连杆上任何位置与舱体的碰撞;对可能发生相互碰撞的机械臂的每对连杆,将其上面的各点表示成两端关节坐标的函数,并由此给出了每对连杆相互碰撞的检查方法;该方法不仅能检查机械臂两连杆两端关节的相互碰撞,而且能够检查机械臂两连杆上任何位置之间的相互碰撞;仿真结果证实了两种碰撞检查方法可行性和有效性。 相似文献
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本文旨在系统地解决长臂冗余机器人喷涂复杂管道内表面的避障问题.首先基于空间插值提出在线碰撞检测方法,该方法不仅适用于不同形状的管道,而且检测精度随着模型采样密度的增加而增加.机器人末端连杆位姿由目标点位姿约束确定,不能通过机器人的冗余自由度进行避障调节.针对喷涂机器人末端必然碰撞情况,提出放宽目标点姿态约束的方法,利用碰撞检测确定末端最快避障方向,计算最小姿态变化矩阵,达到该情况下的避障要求.同时利用管道虚拟轴线与各关节最快避障方向优化冗余机器人其他关节的避障能力.喷涂复杂管道内表面的仿真实验验证了本文方法的有效性,解决了机器人末端必然碰撞问题,优化了机器人的避障能力.与现有方法相比,该方法可以处理更为复杂的管道避障问题. 相似文献
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When working with milling or polishing robots and large workpieces it is necessary to check not only the milling or polishing tool for collision, but it is also necessary to check the remaining arms of the robot for collision. In most of the cases the arms of the robot do not collide with the workpiece and so applying an existing collision detection algorithm to the arms of the robot slows the process down. In this paper, we present an algorithm for quickly assuring non-collisions, which is especially targeted at collisions of the arms of the robot with a workpiece. The algorithm is based on an extended voxel structure. More precisely, we extend a voxel structure by adding distance values to the corner of the voxels and by linking empty voxels to non-empty voxels to accelerate finding the desired voxel. This ensures that we only need to consider a small subset of the triangles describing the workpiece’s surface, namely those triangles that are close to the possible collision area. The triangles within each non-empty voxel are stored in a bsp-tree. For empty voxels, we save information about the distances to the mesh. This setup speeds up the point-to-mesh distance calculation, especially for points close to the mesh. The extra distance information in empty voxels enables a fast distance estimation and hence a fast early collision check. 相似文献
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碰撞检测是虚拟现实技术、机器人技术与动画仿真技术等领域中一个关键的环节,其基本任务是确定两个或多个物体彼此之间是否发生接触或穿透。本文阐述了碰撞检测的一般结构、常见的几种分类标准。重点介绍了目前最主要的三种碰撞检测算法,基于包围盒方法的碰撞检测算法,基于图像空间的碰撞检测算法,基于距离场的碰撞检测算法,对它们各自的优缺点做了比较分析。最后预测了碰撞检测算法的未来发展方向。 相似文献
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为了提高虚拟环境中碰撞检测的实时性和有效性,提出了一种基于可能碰撞集的碰撞检测方法.该方法首先通过预测环境中刚体在当前帧和下一帧之间的可能运动轨迹来构建一个各边与世界坐标系各坐标轴平行,且包围该运动轨迹的包围盒;然后利用空间平铺技术来快速检测与某一平铺单元同时相交的轨迹包围盒,即可得到当前帧的可能碰撞集;接着对可能碰撞集中的刚体对进行最早碰撞时间tmin的求解,并根据tmin进行排序;最后只对具有最小tmin值的刚体对进行碰撞检测.仿真试验结果表明,与目前已有的碰撞检测算法相比,该方法简单、快速,不仅可以有效解决多个刚体环境中碰撞发生的次序问题,同时,该方法还能保证碰撞检测的完整性和唯一性.另外,理论和实践也证明了该方法的正确性和有效性. 相似文献
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《Computers & Industrial Engineering》2004,47(1):45-60
Computer-aided repulsive force control of collision avoidance is presented in this paper. A repulsive force is artificially created using the distances between the robot links and obstacles, which are generated by a simplified distance computation algorithm. This distance computation algorithm is based on the Gilbert-Johnson-Keerthi algorithm. Control gains in the repulsive force control model are selected based on traditional control design and genetic algorithms. Results on shortest distance computation and collision detection are presented. Real-time manipulator collision avoidance control has achieved. A repulsive force gain is introduced through the approaches for definition of link coordinate frames and kinematics computations. The safety distance between objects is affected by the repulsive force gain. Safety zone can be adjustable by the repulsive force gain which is selected by a specified fitness function of the genetic algorithm. 相似文献
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In this paper, we present a fast attack algorithm to find two-block collision of hash function MD5. The algorithm is based on the two-block collision differential path of MD5 that was presented by Wang et al. in the Conference EUROCRYPT 2005. We found that the derived conditions for the desired collision differential path were not sufficient to guarantee the path to hold and that some conditions could be modified to enlarge the collision set. By using technique of small range searching and omitting the computing steps to check the characteristics in the attack algorithm, we can speed up the attack of MD5 efficiently. Compared with the Advanced Message Modification technique presented by Wang et al., the small range searching technique can correct 4 more conditions for the first iteration differential and 3 more conditions for the second iteration differential, thus improving the probability and the complexity to find collisions. The whole attack on the MD5 can be accomplished within 5 hours using a PC with Pentium4 1.70GHz CPU. 相似文献
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针对非均匀网络环境下链路层的能耗控制问题,提出了一种基于链路级功率控制的分簇路由算法(CLPC算法)。CLPC算法基于最优连通功率成簇,并利用双信道机制和干扰反制策略在网络层解决链路层的冲突重传及信道访问公平性等问题,以期达到提高网络整体性能的目的。最优连通功率机制可以减少网络中节点间的冲突域,降低节点间的竞争强度;双信道机制则通过控制信道和数据信道分别对数据分组和控制分组进行收发,来降低数据传输的冲突概率,提高信道的空间复用率;干扰反制策略通过对具有高发射功率的干扰节点进行反制,来保障低发射功率的节点在共享信道上的公平性。实验仿真结果表明,CLPC算法进一步提高了网络的能量有效性和网络有效吞吐量。 相似文献
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《Computer Vision, Graphics, and Image Processing》1990,49(1):95-103
This paper presents a methodology to include obstacles moving with uncertainty in path planning algorithms. Around each moving obstacle, a collision zone is defined indicating a high collision likelihood space. These zones are treated as stationary obstacles providing the input to a path planning algorithm. Samples of moving obstacles' positions are assumed to be available. Three models of motion for moving obstacles are considered: (1) obstacles moving randomly, (2) obstacles whose motion is structured but consists of random parameters, (3) obstacles whose motion is predictable as a function of time. Simulation examples yielding collision zones are presented. 相似文献