排序方式: 共有35条查询结果,搜索用时 0 毫秒
31.
蔡琴 《四川大学学报(自然科学版)》2017,54(1):76-80
针对机器人避障轨迹控制过程中存在的路径优化以及如何躲避大障碍物或者是多障碍物的情况,本文提出一种基于狄克斯特拉算法与贝塞尔曲线的机器人移动避障实时控制改进算法,该算法引入机器人与目标终点路径的速度分量,采用狄克斯特拉算法进行移动轨迹路径优化,进而采用贝赛尔曲线修订优化路径,以此满足动态约束条件.仿真结果表明:相对于改进人工势场算法,本文构建的改进算法使得机器人移动时间缩短,机器人避障运动规划明显改善,具有较强的鲁棒性. 相似文献
32.
在深入分析星钟和星历分离的广域差分原理的基础上, 利用简易的广域差分仿真平台, 分析了这种原理在差分站时间同步时采用的绝对分离, 以及在主差分站同步、副差分站时间不同步时采用相对分离这两种方法的异同, 分两步给出了副差分站不同步时卫星钟差一站式改正方法, 提出并重点讨论了星钟二次改正的逆向推理算法. 仿真分析得出当差分站采用码相位的伪距测量时, 采用这种钟差改正方法可以实现5~7 ns的授时精度, 当差分站采用载波相位平滑伪距时, 这种钟差改正方法可以实现1~3 ns的授时精度. 相似文献
33.
A Prioritized Medium Access Control (P-MAC) protocol is proposed for wireless routers of mesh networks with quality-of-service provisioning. The simple yet effective design of P-MAC offers strict service differentiation for prioritized packets. A Markov model is developed to yield important performance matrices including the packet blocking probability due to queue overflow and the packet reneging probability due to delay bound. It is further proved that the service time of P-MAC approximates exponential distribution, and can be effectively estimated. The analytic models with preemptive and non-preemptive schemes, validated via simulations, show that P-MAC can effectively support traffic differentiation and achieve very low packet dropping (both reneging and blocking) probabilities when the traffic load is below the channel capacity. When the network is overloaded, P-MAC can still maintain extremely stable and high channel throughput. Moreover, it is demonstrated that P-MAC performs superior in multihop networks, further proving the advantages of the proposed protocol. 相似文献
34.
Modeling Car-Following Dynamics During the Starting and Stopping Process Based on a Spring System Model 总被引:1,自引:0,他引:1
Car-following models describe how one vehicle follows the preceding vehicles.ln order to better model and explain car-following dynamics,this paper categorizes the state of a traveling vehicle into three sub-processes:the starting(acceleration)process,the car-folloing process,and the stopping(deceleration)process.The stating process primarily involves vehicle acceleration behavior.The stopping process involves not only car-following behavior but also deceleration behavior.This paper regards both the stopping process and the starting process as spring systems.The car-following dynamics during the starting process and the stopping process is modeled in this paper.The parameters of the proposed models,which are represented in the form of trigonometric functions,possess explicit hysical meaning and definitive ranges.We have calibrated the model of the starting process using data form the Traffic Engineering Handbook and ob-tained reasonable results.Compared with traditional stimulus-response car-following mo 相似文献
35.
了解转录因子GATA-2基因在ANLL中的表达和突变情况,方法:采用RT-PCR检测85例ANLL病人外周血单个核细胞中GATA-2基因的表达情况,PCR产物进一步经单链构象多态性(SSCP)分析以了解基因突变情况。结果:绝大多数ANLL都表达了GATA-2基因(89.4%),SSCP分析发现一例M2型的PCR产物出现异常迁移带,核苷序列分析显示在GATA-2基因第892位的核苷酸出现点突变,即第 相似文献