柔性绳索结构因质量轻、高柔性和可设计性强等特点,在航空航天及机器人等工程领域得到广泛应用.由于几何大变形与材料非线性等因素影响,利用非线性有限元等高精度方法分析这类柔性结构的动力学特性时,存在模型复杂、计算量大和难以高效...柔性绳索结构因质量轻、高柔性和可设计性强等特点,在航空航天及机器人等工程领域得到广泛应用.由于几何大变形与材料非线性等因素影响,利用非线性有限元等高精度方法分析这类柔性结构的动力学特性时,存在模型复杂、计算量大和难以高效仿真等问题.文章改进了起源于计算机图形学的XPBD(extended position based dynamics)算法,设计了新的约束函数与迭代方法,使其适用于柔性绳索结构的动力学仿真.主要贡献包括:引入旋转向量以更准确描述结构姿态,基于Cosserat弹性杆理论设计了更精确的约束函数,采用约束能量作为迭代收敛判据以提高仿真精度,提出分组求解约束的方法提高迭代计算效率.还以索-杆复合结构为例验证了改进算法的有效性:与ADAMS软件相比,改进算法具有更好的稳定性,且计算效率大致相当;与原XPBD算法相比,改进算法显著提高了求解精度.改进算法引入了旋转向量,使约束函数的设计更灵活,计算框架也更利于并行化,具有在复杂柔性结构动力学仿真中进一步应用的优势和潜力.展开更多
Background Compared with traditional thoracotomy,video-assisted thoracoscopic surgery(VATS)has less minor trauma,faster recovery,higher patient compliance,but higher requirements for surgeons.Virtual surgery training ...Background Compared with traditional thoracotomy,video-assisted thoracoscopic surgery(VATS)has less minor trauma,faster recovery,higher patient compliance,but higher requirements for surgeons.Virtual surgery training simulation systems are important and have been widely used in Europe and America.Augmented reality(AR)in surgical training simulation systems significantly improve the training effect of virtual surgical training,although AR technology is still in its initial stage.Mixed reality has gained increased attention in technology-driven modern medicine but has yet to be used in everyday practice.Methods This study proposed an immersive AR lobectomy within a thoracoscope surgery training system,using visual and haptic modeling to study the potential benefits of this critical technology.The content included immersive AR visual rendering,based on the cluster-based extended position-based dynamics algorithm of soft tissue physical modeling.Furthermore,we designed an AR haptic rendering systems,whose model architecture consisted of multi-touch interaction points,including kinesthetic and pressure-sensitive points.Finally,based on the above theoretical research,we developed an AR interactive VATS surgical training platform.Results Twenty-four volunteers were recruited from the First People's Hospital of Yunnan Province to evaluate the VATS training system.Face,content,and construct validation methods were used to assess the tactile sense,visual sense,scene authenticity,and simulator performance.Conclusions The results of our construction validation demonstrate that the simulator is useful in improving novice and surgical skills that can be retained after a certain period of time.The video-assisted thoracoscopic system based on AR developed in this study is effective and can be used as a training device to assist in the development of thoracoscopic skills for novices.展开更多
文摘柔性绳索结构因质量轻、高柔性和可设计性强等特点,在航空航天及机器人等工程领域得到广泛应用.由于几何大变形与材料非线性等因素影响,利用非线性有限元等高精度方法分析这类柔性结构的动力学特性时,存在模型复杂、计算量大和难以高效仿真等问题.文章改进了起源于计算机图形学的XPBD(extended position based dynamics)算法,设计了新的约束函数与迭代方法,使其适用于柔性绳索结构的动力学仿真.主要贡献包括:引入旋转向量以更准确描述结构姿态,基于Cosserat弹性杆理论设计了更精确的约束函数,采用约束能量作为迭代收敛判据以提高仿真精度,提出分组求解约束的方法提高迭代计算效率.还以索-杆复合结构为例验证了改进算法的有效性:与ADAMS软件相比,改进算法具有更好的稳定性,且计算效率大致相当;与原XPBD算法相比,改进算法显著提高了求解精度.改进算法引入了旋转向量,使约束函数的设计更灵活,计算框架也更利于并行化,具有在复杂柔性结构动力学仿真中进一步应用的优势和潜力.
基金the National Science Foundations of China(62062069,62062070,62005235).
文摘Background Compared with traditional thoracotomy,video-assisted thoracoscopic surgery(VATS)has less minor trauma,faster recovery,higher patient compliance,but higher requirements for surgeons.Virtual surgery training simulation systems are important and have been widely used in Europe and America.Augmented reality(AR)in surgical training simulation systems significantly improve the training effect of virtual surgical training,although AR technology is still in its initial stage.Mixed reality has gained increased attention in technology-driven modern medicine but has yet to be used in everyday practice.Methods This study proposed an immersive AR lobectomy within a thoracoscope surgery training system,using visual and haptic modeling to study the potential benefits of this critical technology.The content included immersive AR visual rendering,based on the cluster-based extended position-based dynamics algorithm of soft tissue physical modeling.Furthermore,we designed an AR haptic rendering systems,whose model architecture consisted of multi-touch interaction points,including kinesthetic and pressure-sensitive points.Finally,based on the above theoretical research,we developed an AR interactive VATS surgical training platform.Results Twenty-four volunteers were recruited from the First People's Hospital of Yunnan Province to evaluate the VATS training system.Face,content,and construct validation methods were used to assess the tactile sense,visual sense,scene authenticity,and simulator performance.Conclusions The results of our construction validation demonstrate that the simulator is useful in improving novice and surgical skills that can be retained after a certain period of time.The video-assisted thoracoscopic system based on AR developed in this study is effective and can be used as a training device to assist in the development of thoracoscopic skills for novices.
