Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase, as well as the design of locomotion systems, performance evaluation, and control strategy verifi...Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase, as well as the design of locomotion systems, performance evaluation, and control strategy verification during the R&D phase. The currently used simulation methods for lunar rovers have several disadvantages such as poor fidelity for wheel-soil interaction mechanics, difficulty in simulating rough terrains, and high complexity making it difficult to realize mobility control in simulation systems. This paper presents an approach for the construction of a virtual simulation system that integrates the features of 3D modeling, wheel-soil interaction mechanics, dynamics analysis, mobility control, and visualization for lunar rovers. Wheel-soil interaction experiments are carried out to test the forces and moments acted on a lunar rover’s wheel by the soil with a vertical load of 80 N and slip ratios of 0, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.6. The experimental results are referenced in order to set the parameters’ values for the PAC2002 tire model of the ADAMS/Tire module. In addition, the rough lunar terrain is simulated with 3DS Max software after analyzing its characteristics, and a data-transfer program is developed with Matlab to simulate the 3D reappearance of a lunar environment in ADAMS. The 3D model of a lunar rover is developed by using Pro/E software and is then imported into ADAMS. Finally, a virtual simulation system for lunar rovers is developed. A path-following control strategy based on slip compensation for a six-wheeled lunar rover prototype is researched. The controller is implemented by using Matlab/Simulink to carry out joint simulations with ADAMS. The designed virtual lunar rover could follow the planned path on a rough terrain. This paper can also provide a reference scheme for virtual simulation and performance analysis of rovers moving on rough lunar terrains.展开更多
For the concerted motion of rocker lunar rover, the pitch angle of rocker of a rocker lunar rover in uneven terrain must be calculated. According to the character of passive shape-shifting adaptive suspension of rocke...For the concerted motion of rocker lunar rover, the pitch angle of rocker of a rocker lunar rover in uneven terrain must be calculated. According to the character of passive shape-shifting adaptive suspension of rocker lunar rover, the model of rocker lunar rover and the model of terrain were both simplified. The pitch angle of rocker was calculated using forward solving, reverse solving and the method of offsetting the curve of terrain respectively. Because of the banishment of the nonlinearity of equation sets of calculation by reverse solving, the calculation of the pitch angle based on reverse solving was programmed by means of MATLAB. Simulations were carried out by means of ADAMS. The result verified the validity of the calculation based on reverse solving. It provides the theoretical foundation for motion planning and path planning of rocker lunar rover. As applications of the calculation of pitch angle of rocker, the multi-attribute decision making of path based on the concerted motion planning and the predictive control on lunar rover based on the Markov prediction model were introduced.展开更多
为在月球建立长期驻留的月面科研基地,实现局部网络的通信覆盖,提出了月球通信塔(lunar communication tower,LCT)的模型设计方法和多基站的部署方案。通过对月面探测任务与月表多设施通信网络的需求分析,设计了LCT的功能模块和模型结...为在月球建立长期驻留的月面科研基地,实现局部网络的通信覆盖,提出了月球通信塔(lunar communication tower,LCT)的模型设计方法和多基站的部署方案。通过对月面探测任务与月表多设施通信网络的需求分析,设计了LCT的功能模块和模型结构。引入基于地理信息的覆盖场强预测模型,结合月表地形对通信链路的损耗影响,评估了多基站通信塔的有效覆盖与传输速率指标。在部署方案上,首先,在月球南极光照区范围内采用遍历法得到覆盖平均场强最大的主基站部署位置;随后,采用遗传算法最大化主基站半径10 km范围内的覆盖场强,对月球表面特定区域进行搜索,获取多个副基站的最佳部署位置;最后,针对集中式和分布式通信塔主、副基站的部署方案,进行了对应于CCSDS Proximity-1协议、长期演进(long term evolution,LTE)、Wi-Fi制式下覆盖性和传输速率的仿真分析,充分验证了月表多设施通信网络建设的可行性。展开更多
针对月球南极光照暗弱、阴影区域众多、月面形貌要素单一弱纹理,给影像立体匹配和三维地形重建带来极大挑战和困难的问题,提出了一种可信度引导的高效立体匹配算法(Efficient Confidence-guided Stereo Matching,ECSM),通过评估非支撑...针对月球南极光照暗弱、阴影区域众多、月面形貌要素单一弱纹理,给影像立体匹配和三维地形重建带来极大挑战和困难的问题,提出了一种可信度引导的高效立体匹配算法(Efficient Confidence-guided Stereo Matching,ECSM),通过评估非支撑点的可信度来更新支撑点点集,构建三角网并利用三角形顶点的可信度重新估算其内部视差,提高匹配精度和效率。在此基础上,构建了月面摄影测量三维地形重建方法,并采用月球勘测轨道器(Lunar Reconnaissance Orbiter,LRO)窄角相机高分辨率影像数据,开展月球南极沙克尔顿(Shackleton)坑缘区域地形重建的验证实验。比较分析不同立体匹配算法生成的视差图和数字高程模型(Digital Elevation Model,DEM),结果表明:所提出的算法在处理月面弱纹理和重复纹理区域影像方面具有可靠性。将生成的DEM与德国宇航中心(Deutsches Zentrum für Luft-und Raumfahrt,DLR)制作的同区域DEM以及美国国家航空航天局(National Aeronautics and Space Administration,NASA)的月球轨道激光高度计DEM(LDEM)进行对比分析,高程和坡度信息方面都表现出较高的一致性,验证了该方法的可行性和有效性,为月球南极探测着陆区选择提供可靠的数据方法基础。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 50975059, Grant No. 61005080)Postdoctoral Foundation of China (Grant No. 20100480994)+1 种基金Postdoctoral Foundation of Heilongjiang Province, Foundation of Chinese State Key Laboratory of Robotics and Systems (Grant No. SKLRS200801A02)College Discipline Innovation Wisdom Plan of China (111 Project, Grant No. B07018)
文摘Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase, as well as the design of locomotion systems, performance evaluation, and control strategy verification during the R&D phase. The currently used simulation methods for lunar rovers have several disadvantages such as poor fidelity for wheel-soil interaction mechanics, difficulty in simulating rough terrains, and high complexity making it difficult to realize mobility control in simulation systems. This paper presents an approach for the construction of a virtual simulation system that integrates the features of 3D modeling, wheel-soil interaction mechanics, dynamics analysis, mobility control, and visualization for lunar rovers. Wheel-soil interaction experiments are carried out to test the forces and moments acted on a lunar rover’s wheel by the soil with a vertical load of 80 N and slip ratios of 0, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.6. The experimental results are referenced in order to set the parameters’ values for the PAC2002 tire model of the ADAMS/Tire module. In addition, the rough lunar terrain is simulated with 3DS Max software after analyzing its characteristics, and a data-transfer program is developed with Matlab to simulate the 3D reappearance of a lunar environment in ADAMS. The 3D model of a lunar rover is developed by using Pro/E software and is then imported into ADAMS. Finally, a virtual simulation system for lunar rovers is developed. A path-following control strategy based on slip compensation for a six-wheeled lunar rover prototype is researched. The controller is implemented by using Matlab/Simulink to carry out joint simulations with ADAMS. The designed virtual lunar rover could follow the planned path on a rough terrain. This paper can also provide a reference scheme for virtual simulation and performance analysis of rovers moving on rough lunar terrains.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50375032)the 111 Project (Grant No.B07018)
文摘For the concerted motion of rocker lunar rover, the pitch angle of rocker of a rocker lunar rover in uneven terrain must be calculated. According to the character of passive shape-shifting adaptive suspension of rocker lunar rover, the model of rocker lunar rover and the model of terrain were both simplified. The pitch angle of rocker was calculated using forward solving, reverse solving and the method of offsetting the curve of terrain respectively. Because of the banishment of the nonlinearity of equation sets of calculation by reverse solving, the calculation of the pitch angle based on reverse solving was programmed by means of MATLAB. Simulations were carried out by means of ADAMS. The result verified the validity of the calculation based on reverse solving. It provides the theoretical foundation for motion planning and path planning of rocker lunar rover. As applications of the calculation of pitch angle of rocker, the multi-attribute decision making of path based on the concerted motion planning and the predictive control on lunar rover based on the Markov prediction model were introduced.
文摘为在月球建立长期驻留的月面科研基地,实现局部网络的通信覆盖,提出了月球通信塔(lunar communication tower,LCT)的模型设计方法和多基站的部署方案。通过对月面探测任务与月表多设施通信网络的需求分析,设计了LCT的功能模块和模型结构。引入基于地理信息的覆盖场强预测模型,结合月表地形对通信链路的损耗影响,评估了多基站通信塔的有效覆盖与传输速率指标。在部署方案上,首先,在月球南极光照区范围内采用遍历法得到覆盖平均场强最大的主基站部署位置;随后,采用遗传算法最大化主基站半径10 km范围内的覆盖场强,对月球表面特定区域进行搜索,获取多个副基站的最佳部署位置;最后,针对集中式和分布式通信塔主、副基站的部署方案,进行了对应于CCSDS Proximity-1协议、长期演进(long term evolution,LTE)、Wi-Fi制式下覆盖性和传输速率的仿真分析,充分验证了月表多设施通信网络建设的可行性。
文摘针对月球南极光照暗弱、阴影区域众多、月面形貌要素单一弱纹理,给影像立体匹配和三维地形重建带来极大挑战和困难的问题,提出了一种可信度引导的高效立体匹配算法(Efficient Confidence-guided Stereo Matching,ECSM),通过评估非支撑点的可信度来更新支撑点点集,构建三角网并利用三角形顶点的可信度重新估算其内部视差,提高匹配精度和效率。在此基础上,构建了月面摄影测量三维地形重建方法,并采用月球勘测轨道器(Lunar Reconnaissance Orbiter,LRO)窄角相机高分辨率影像数据,开展月球南极沙克尔顿(Shackleton)坑缘区域地形重建的验证实验。比较分析不同立体匹配算法生成的视差图和数字高程模型(Digital Elevation Model,DEM),结果表明:所提出的算法在处理月面弱纹理和重复纹理区域影像方面具有可靠性。将生成的DEM与德国宇航中心(Deutsches Zentrum für Luft-und Raumfahrt,DLR)制作的同区域DEM以及美国国家航空航天局(National Aeronautics and Space Administration,NASA)的月球轨道激光高度计DEM(LDEM)进行对比分析,高程和坡度信息方面都表现出较高的一致性,验证了该方法的可行性和有效性,为月球南极探测着陆区选择提供可靠的数据方法基础。
