Cooperative haptic manipulation of virtual environments

虚拟环境的协作触觉操作是指当几个可能远程的用户一起与虚拟对象交互时，为他们提供物理上准确的双手力觉。这种操作在基于虚拟环境的训练应用中是有益的，该应用需要多个用户的灵活操作，包括许多外科手术。协作触觉可以消除当前单点触觉的严重灵巧性和知觉限制。在外科培训中，协作触觉可以：(I)为需要双手参与的手术提供经验，如缝合；(Ii)使专业外科医生能够指导具有不同水平经验的外科新手，无论是现场还是远程；以及(Iii)允许多名外科医生合作练习和/或计划针对患者特定解剖的挑战性手术。当前具有触觉反馈的模拟器仅允许对包括可变形对象或刚性对象的相对简单的虚拟环境进行单手、单用户、点状操纵。此外，现有的实现通常包括特定于模拟的触觉渲染算法。因此，它们为有限数量的互动提供力量反馈，作为训练工具影响有限。拟议的研究集中于为多个可能是远程的用户提供物理上精确的力，同时他们一起操纵包括软组织和硬组织的复杂的虚拟解剖结构，并通过各种建模形式进行模拟。为此，将向每个触觉设备提供工具与骨、组织、肌肉和韧带之间相互作用的本地模型。这些局部模型将通过控制与全局仿真同步。在复杂的模拟或远程交互造成的延迟情况下，预测将提高局部模型的精度。在这项工作中开发的建模、仿真和控制方法也将用于远程机器人(远程外科手术)和虚拟现实的其他领域，如协作设计/原型制作和娱乐。

Cooperative haptic manipulation of virtual environments refers to providing several, possibly remote users with physically-accurate force sensations in both hands when they together interact with virtual objects. Such manipulations are beneficial in virtual environment-based training applications that require dexterous manipulations by multiple users, including many surgical procedures. Cooperative haptics can remove the severe dexterity and perceptual limitations of current single point haptics. In surgical training, cooperative haptics can: (i) provide experience for procedures that involve both hands, like suturing; (ii) enable expert surgeons to mentor novice surgeons with various levels of experience, on site or from a remote location; and (iii) allow several surgeons to cooperatively practice and/or plan challenging procedures on patient-specific anatomy. Current simulators with haptic feedback enable only single handed, single user, point-like manipulations of relatively simple virtual environments comprising either deformable or rigid objects. Furthermore, existing implementations typically include simulation-specific haptic rendering algorithms. Therefore, they provide force feedback for a restricted number of interactions and have limited impact as training tools. The proposed research focuses on providing physically-accurate forces to multiple, possibly remote users while they together manipulate complex virtual anatomy comprising soft and hard tissues and simulated via a variety of modeling formalisms. To this end, a local model of the interaction between the tool and bone, tissue, muscle, and ligaments will be supplied to each haptic device. These local models will be synchronized with the global simulation via control. Prediction will improve the local model accuracy in the face of delays due to complex simulations or to remote interaction. The modeling, simulation, and control approaches developed during this work will also be of use in telerobotics (telesurgery) and in other areas of virtual reality, like collaborative design/prototyping and entertainment.