实时力觉交互中的虚拟力计算及渲染方法

虚拟力计算和渲染是虚拟现实力觉显示系统的核心技术。针对人与虚拟环境通过工具进行接触交互的任务,讨论了提高力觉显示逼真度的方法。静态物体采用三角片模型,运动的虚拟工具采用质点模型。用均匀划分包围盒方法和基于三角片元素拓扑关系及最短距离迭代的方法,分别解决虚拟力计算的碰撞检测和碰撞响应问题。针对物体几何特征逼真度显示给出了渲染判据,实现了逼真度和稳定性的矛盾折衷。基于力觉交互设备Phantom,开发了力觉仿真系统平台,通过感知具有典型几何特征的物体形状,验证了虚拟力计算和渲染方法的有效性。

Force Computation and Rendering Method for Real-time Force Display

This paper discusses force computation and rendering method for simulating contact interaction between handheld tool and static environment. Static object in virtual environment is modeled using triangle mesh, and dynamic tool is modeled using point-based model. Based on principle analysis of the haptic display device, the difficulty of virtual force computation is explained firstly. Then, virtual force computation process are divided into two phases, collision detection and collision response. In first phase, uniformed spatial partition method is used to accelerate collision detection; in second phase, minimal distance iteration method combined neighborhood topology is utilized. Force-rendering method is introduced to achieve the tradeoff between fidelity and stability, and rendering criteria is proposed to meet the requirement for displaying different geometry features on the virtual object. Haptic display platform is constructed using Phantom, and several objects with typical geometry features are selected to evaluate system performance. Good fidelity and stability result indicate the validity of the force computation and rendering method.