Deploying Properties of Para-Cylinder with Side Polygonal Elements and Its Application to Simple Actuator

通过对部分由边三角形构件组成的可折叠准圆柱展开试验，研究了边三角形构件的形状和布置、折痕长度和周向数等几何参数对完全展开时展开方式、展开速度、内压和最大载荷的影响。在展开过程中，侧边构件的应变也进行了解析分析。得到的主要结果如下：1。通过对纸张进行实际折叠，发现水平折叠、螺旋折叠和重复螺旋折叠三种不同的折叠方式均可制成可折叠的准圆柱体。当对圆柱体进行完美折叠时，圆柱体的横截面变成各种多边形。考虑桁架构件而不是圆柱侧面的折痕，对构件的应变进行了解析估计。分析结果表明，螺旋折叠的圆柱在展开过程中的应变要比其他两种折叠方式的圆柱小得多。2 .对于在对筒折叠截面上出现的多边形边数N，由于桁架构件的应变较小，N较大的筒体优先考虑。对各种可折叠圆柱展开试验的结果与桁架构件应变分析的预测结果吻合较好。实验中显示最大可展开载荷的准圆柱体是N = 9的螺旋折叠圆柱体。在实验范围内，这种可折叠气缸可能是简单执行器的最佳选择。

In this study, a series of expanding tests for some foldable para-cylinders which consist of side triangular members were carried out to investigate the influences of the geometrical parameters such as the shape and the arrangement of side triangular members, the length of creases and the circumferential number of the side members on the unfolding manner, the expanding speed, the inside pressure and the maximum payload during perfect unfolding. The strain in the side members during unfolding is also examined analytically. The principal results obtained are as follows:1. By folding a paper actually, it was found that three different types of folding, horizontal folding spiral folding and repeated spiral folding, can make a foldable para-cylinder. When the para-cylinders were perfectly folded, the cross section of the cylinders become various polygons.2. Considering truss members instead of the creases on the side of a cylinder, the strains of members were estimates analytically. The analysis results showed that the strains of para-cylinders with spiral folding during unfolding are much smaller than those of cylinders with other two folding manners. Concerning the number of the polygon side which appears in the cross-section of the para-cylinder folded, N, the cylinder with larger N is preferred because of smaller strain in the truss members.3. The results of expanding experiments for various foldable para-cylinders agreed well with the prediction by the strain analysis of truss members. The para-cylinder which showed the largest deployable payload in the experiments is a cylinder with spiral folding and N = 9. In the range of experiments, this foldable cylinder may be the best choice for a simple actuator.