虚拟手的姿态控制与变形仿真

Attitude Control and Deformation Simulation of Virtual Hand

iHandRehab应用机器人技术与虚拟现实技术对手部损伤患者进行康复训练。主动模式下的训练任务需要在虚拟环境中模拟人手抓持和释放物体的真实过程,难点集中在虚拟手与刚性物体接触时的姿态控制和局部变形计算。根据人手的组织结构和运动特征将食指和拇指简化为3指节串联机构,通过改变各关节的旋转角度来实现虚拟手的自由运动。虚拟抓持过程中以手指的运动学模型为基础,结合前后指节需要满足的约束关系确定虚拟手的最终姿态。指节和物体分别采用点壳和距离场模型进行碰撞检测,根据点壳上碰撞点的嵌入信息计算虚拟手在接触区域的局部变形量。实验结果表明:模型能够实时准确地模拟人手抓持刚性物体时的真实状态。

The hand rehabilitation system iHandRehab combines robotics with virtual reality to do rehabilitation training for hand injury patients. The training tasks in active mode require us to simulate the process of hand grasping/releasing object in virtual environment. The difficulties are concentrated in posture control and local deformation calculation of hand when it was grasping rigid object. This paper simplifies the index and thumb finger into serial mechanism with 3 phalanges respectively and confirms the final posture of virtual hand according to the constraints among phalanges during virtual grasping. The phalange and object are respectively modeled as pointshell and distance field in collision detection, and puts forward to calculate the local deformation in contact region based on the insertion information of collision points. The experimental results show that this model could accurate- ly simulate the real state of human hand when it is grasping rigid object.