基于多轴运动控制卡的伺服控制系统研究

以工控机为核心 ,应用研华三轴运动控制卡PCL 832 ,建立了机器人用数控焊接变位机的高精度控制系统 .研究分析了焊接变位机的位置控制精度、速度和运动轨迹的控制过程 ,给出了负载变化和速度变化的位置控制结果 ,其结果满足与弧焊机器人配合使用的精度要求 .

焊接机器人系统协同运动分析及仿真

当前焊接机器人与变位机协同作业时,受到运动复杂性的影响,导致协同运动不佳的问题。提出一种焊接机器人与变位机协同系统的运动模型及目标路径跟踪仿真系统。首先建立协同运动系统的坐标系和运动数学模型,给出焊接机器人系统协同运动分析,通过数学关系表述其协同运动关系;并给出了以船形焊为焊接最佳焊接位置时的焊接机器人与变位机的轨迹规划方法;建立了基于SimMechanics-Solidworks平台的仿真系统;以两圆柱相交的相贯线焊缝为例进行仿真验证,仿真结果表明工件上各点均可达,目标路径运动满足实际要求;各关节运行平稳,无突变可以较好完成焊接任务。验证了所提出的方法的正确性,为以后的研究奠定了基础。

Assessing proprioception:A critical review of methods

To control movement,the brain has to integrate proprioceptive information from a variety of mechanoreceptors.The role of proprioception in daily activities,exercise,and sports has been extensively investigated,using different techniques,yet the proprioceptive mechanisms underlying human movement control are still unclear.In the current work we have reviewed understanding of proprioception and the three testing methods:threshold to detection of passive motion,joint position reproduction,and active movement extent discrimination,all of which have been used for assessing proprioception.The origin of the methods,the different testing apparatus,and the procedures and protocols used in each approach are compared and discussed.Recommendations are made for choosing an appropriate technique when assessing proprioceptive mechanisms in different contexts.

Sagaing Fault slip and deformation in Myanmar observed by continuous GPS measurements

The Sagaing Fault is a major tectonic structure between the Indian Plate and Sunda Plate. The fault measures 1200 km along north-south and cuts through the centre of Myanmar. Many urban areas lie along the fault. As a result, Myanmar has established a continuous Global Positioning System （cGPS） network across the Sagaing Fault since 2011. The cGPS network consists of eight cGPS stations that form two transects across the fault. The data analysis covers a period of four years from 2011 to 2014. GAMIT, GLOBK, and TRACK software suite packages are used for GPS data processing and analysis. This study consists of two main objectives. The first objective is to analyse the Myanmar cGPS network ob- servations in order to measure the moving rate and direction of movement for each cGPS station using GAMIT/GLOBK software packages. The second objective is to investigate the co-seismic moving rate associated with the earthquake event using TRACK kinematic positioning program. The analysis results indicate that the east side of the Sagaing Fault moves southeastward at the average rate of approximately 32-40 mm/a, whereas the west side of the fault moves northeastward at the rate of about 31-35 mm/a. For co-seismic analysis, two cGPS stations are analysed in connection with the 2012 M6.8 Thabeikkyin earthquake. These stations are located 50-60 km away from the epicentre. The GPS data analysis clearly showed that the station at the east side of the Sagaing Fault immediately moved south by 15.0 cm, whereas the station at the west side of the fault moved north by 3.0 cm. In conclusion, this study demonstrates that the Sagaing Fault＇s tectonic activities can be monitored by cGPS observations using geodetic processing techniques. We believe that such investigation brings contribution to better understand of the tectonic activities in Myanmar and South East Asia.

Three-dimensional crustal deformation before and after the Wenchuan earthquake in Guanzhong and adjacent regions

The recent plethora of GPS observations compensates for the 20-year-old lack in vertical displacement data for the Guanzhong region. The 2001—2007 three-dimensional（3D） crustal deformation data suggest regional movement with a horizontal velocity of 3—7 mm/a,predominantly from SSE in the west to SE in the east, and vertical inherited movement with velocity of -7 mm/a to 4 mm/a. After the Wenchuan earthquake, the GPS data suggest that the effect of the earthquake on the regional deformation is greater in the west than the east.The horizontal displacement increased during 2007—2008; however, the reverse was observed in 2008—2009. The vertical displacement in the western part of the region increased in 2008 and has been gradually returning to normal since 2009; however, in the eastern part,the effect of the earthquake remains.

脉动生产线模式下飞机总装配关键技术研究

脉动生产线是一种先进的飞机装配生产组织模式,通过装配流程梳理、站位设置与任务量划分,可极大地提升装配效率。基于此,以某型号飞机总装配为需求,针对生产线规划布局、数字化支撑定位调姿系统以及飞机站位间移动等关键技术及难点开展研究,最终形成一套满足飞机总装配需求、可实施的总装配技术方案,并应用于某型飞机的总装配,在提高装配质量、缩短生产周期、降低劳动强度方面发挥出了显著的作用。

Context-Aware Adaptive Routing for Opportunistic Network

Opportunistic networking-forwarding messages in a disconnected mobile ad hoc network via any encountered nodes offers a new mechanism for exploiting the mobile devices that many users already carry. However, forwarding messages in such a network is trapped by many particular challenges, and some protocols have contributed to solve them partly. In this paper, we propose a Context-Aware Adaptive opportunistic Routing algorithm（CAAR）. The algorithm firstly predicts the approximate location and orientation of the destination node by using its movement key positions and historical communication records, and then calculates the best neighbor for the next hop by using location and velocity of neighbors. In the unpredictable cases, forwarding messages will be delivered to the more capable forwarding nodes or wait for another transmission while the capable node does not exist in the neighborhood. The proposed algorithm takes the movement pattern into consideration and can adapt different network topologies and movements. The experiment results show that the proposed routing algorithm outperforms the epidemic forwarding（EF） and the prophet forwarding（PF） in packet delivery ratio while ensuring low bandwidth overhead.