基于离散能量法的牙体预备仿真力觉渲染算法

在力觉交互的虚拟现实系统中,力的逼真度和系统稳定性是系统的两个重要性能.在力觉交互虚拟现实牙医培训系统中,通过力反馈设备作用在医生手上的力直接影响培训质量.采用四面体剖分建立人类牙齿的实体模型.结合经验公式和实验数据,提出了一种牙体预备虚拟切削力模型,研究了保证系统稳定性和虚拟力逼真度的算法,并利用离散能量法对等采样间隔的切削力序列进行渲染处理,使得力信号在力的逼真度和系统稳定性之间得到优化解,较好地消除了力序列中的高频振动,从而改善了力觉交互虚拟现实牙医培训系统的性能.

Haptic rendering algorithm based on discrete energy optimization method of preparation of human tooth

Fidelity and stability are two keys of performance of virtual reality haptic interaction system. In virtual reality haptic interaction system of dental preparation, force acting on dentist who receives training is a key factor of training effect. Volumetric model of human tooth was constructed based on laser scanning data and tetrahedral division of tooth model was implemented. A method to calculate cutting force was proposed by combining empirical formula and experimental data. Optimum haptic rendering algorithm was studied to guaranteeing fidelity and stability of that haptic system. In order to solve the contradiction between fidelity and stability, haptic rendering algorithm based on discrete energy optimization algorithm was proposed. That algorithm processed force series with constant time difference. As a result, optimized cutting force signals between fidelity and stability were obtained. Experimental results show that this algorithm restrains vibration in high frequency of haptic device. Performances of human machine interactive haptic dental training system are improved.