在本文中,我们介绍了径向收缩的软环形致动器的设计和建模。该致动器由环形软体和刚性外壳组成,旨在实现加压时的径向收缩。单个圆形气室同心嵌入由失蜡法创建的致动器内部。构建了有限元法 (FEM) 模型来预测促动器的变形。同时,公式化了控制方程来表征变形的准静态状态。它是基于最小总势能原理推导的,并通过射击法进行数值求解。该理论模型提供了对单个气室变形的见解,并揭示了几何参数对变形的影响。进行了捕获致动器特定输入压力下变形的实验,以验证 FEM 和理论模型。最后,说明了这种新型致动器的潜在应用。重试错误原因
FIG. 1. Schematics of a soft ring-shaped actuator. (a) The physical prototype of the actuator. (b) The structure of the soft body. Color images are available online.重试错误原因
in Figure 1b. The rigid casing encloses the top, bottom, and outer wall of the soft body. The inner radius of the rigid casing is the same as that of soft body, exposing the inner wall of the soft body to the free space. The pneumatic system powers the actuator. The inner wall of the soft body can deform under pressurization. One hole in the outer wall of the rigid casing is for the connection of a pneumatic tube. The pressurized air delivered through the tube results in the expansion of the air chamber. Owing to the constraints of the rigid casing on the covered walls, soft body expands radially inwards, leading the contracting movement. In addition, the adjacent edges of the soft body and rigid casing are glued together to prevent sliding. The rigid casing comprises the bottom part and top part, both of which are connected and clamped together. The single circular air chamber is the unique feature of this design that guarantees the contraction remains circular.重试错误原因
It is noted that the inner radius (R_(0))\left(R_{0}\right) and height (L)(L) of the soft body are two primary independent variables when designing the actuator, whereas the rest of the geometric parameters are constants or dependent on these two variables. A baseline set of these two parameters are R_(0)=40.0mmR_{0}=40.0 \mathrm{~mm} and L=30.0mmL=30.0 \mathrm{~mm}. The dimension was chosen for the investigation of the deformation performance. An additional four variations of this parameter set are selected to evaluate the influence of these two parameters on the performance of actuators. The values of geometrical parameters are as demonstrated in Table 1. The wall thickness of the soft body (H_(0))\left(H_{0}\right) and the wall thickness of the rigid casing (H_(c))\left(H_{c}\right) are kept at a constant of 5.0 mm . The width of the air chamber (a) was a constant 30.0 mm .重试错误原因
The ring-shaped actuator was fabricated through a multistep molding procedure involving a lost-wax approach. The lost-wax method was chosen because it allows for the design of complex internal air channels. ^(34){ }^{34} The main fabrication procedure for the actuator consists of four steps depicted in Figure 2. In this procedure, the module and rigid casing were constructed by three-dimensional (3D) printers (Prusa i3; Prusa Research, Czech Republic) with acrylonitrile butadiene styrene plastic. The silicone rubber (Ecoflex-0030 silicone; Smooth-On, Inc.) was chosen due to its tensile modulus similar to the biological organ such as skin and muscular organs. In the first step, the uncured material was poured into the 3D printed mold to create the part of the soft body with a C-shaped cross section as can be seen in Figure 2a. Second, the wax (Beeswax; Jacquard, New Zealand) was melted and poured into the rubber mold to formulate the wax core. The重试错误原因
Table 1. Five Variations of Geometrical重试错误原因
Parameters of the Soft Body重试错误原因