Precise deformation of rheologic object under MSD models with many voxels and calibrating parameters
Precise deformation of rheologic object under MSD models with many voxels and calibrating parameters
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DOI：
10.1109/robot.2004.1308104
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发表时间：
2004-09
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影响因子：
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通讯作者：
R. Nogami;H. Noborio;Fumiaki Ujibe;H. Fujii
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文献类型：
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作者：
R. Nogami;H. Noborio;Fumiaki Ujibe;H. Fujii
MSD（质量-弹簧-阻尼器）模型可以有效地计算弹性体、粘弹性体、流变体等多种材料的形状变形。由于这个原因，动态动画可以在个人计算机及其流行的加速板上在视频帧速率内制作。MSD模型的问题是如何保持每个变形的形状精度。为此，我们用随机化算法标定了基本MSD单元中Voigt部分的阻尼系数和弹簧系数，以及其它部分的阻尼系数，这些系数是在捕捉真实的流变体的多个表面点下标定的。然而，不幸的是，形状精度不够。为了克服这个问题，我们在以下五个方面改进了我们以前的方法：（1）MSD模型中的体素数量从75增加到600。(2)将MSD单元中Voigt长度与其它部分长度的比值作为基本单元的弹簧和阻尼系数的校正参数。(3)区分基本单元的四个未知参数，以在每个体素中和每个体素上进行校准。此外，区分参数以在虚拟流变对象的表面和核心区域之间进行校准。(4)为了提高标定速度，采用遗传算法代替随机算法。(5)局部和全局体积常数条件中的每一个或两者被添加到先前的方法中。总之，我们调查的形状变形，体积分辨率，和校准参数的数量在几个MSD模型代表一个流变对象之间的关系。此外，我们提高变形精度，不仅增加体积分辨率，但也有一些校准参数，或通过添加每个或两个体积常数条件。
The MSD (Mass-Spring-Damper) model efficiently calculates shape deformation of many kinds of materials such as elastic, visco-elastic, and rheologic objects. For this reason, dynamic animation can be made in a personal computer and its popular acceleration board within the video-frame rate. The problem of MSD model is how to maintain shape precision of each deformation. For this purpose, we have calibrated coefficients of damper and spring of Voigt part and a coefficient of damper of the other part in the basic MSD element under many surface points capturing a real rheologic object by the randomized algorithm. Nevertheless, the shape precision is not unfortunately enough. To overcome this, we improve our previous approach in the following five points: (1) The number of voxels in the MSD model increases from 75 to 600. (2) The ratio between lengths of Voigt and the other parts in the MSD element is added to three coefficients of spring and dampers of the basic element as calibrating parameters. (3) Four unknown parameters of the basic element are distinguished to calibrate in and on each voxel. In addition, the parameters are distinguished to calibrate among surface and core areas of a virtual rheologic object. (4) In order to speed up the calibration, we use GA (Genetic Algorithm) in replace of RA (Randomized Algorithm). (5) Each or both of local and global volume constant conditions are added into the previous approach. In conclusion, we investigate relations between shape deformation, volume resolution, and number of calibrated parameters in several MSD models representing a rheologic object. Also, we improve deformation precision by increasing not only volume resolution but also number of calibration parameters or by adding each or both of volume constant conditions.