An isoperimetric formulation to predict deformation behavior of pneumatic fiber reinforced elastomeric actuators

Automatic design of fiber-reinforced soft actuators for trajectory matching

“…To realize actuators capable of replicating complex motions, we use segments consisting of a cylindrical elastomeric tube surrounded by fibers arranged in a helical pattern at a characteristic fiber angle α ( Fig. 2A) (23,24), because it has been shown that by varying the fiber angle and materials used, these segments can be easily tuned to achieve a wide range of motions (17)(18)(19)(20)(21). When the elastomeric tube is of uniform stiffness, the segment undergoes some combination of Significance Fluid-powered elastomeric soft robots have been shown to be able to generate complex output motion using a simple control input such as pressurization of a working fluid.…”

“…This methodology can be readily extended to other applications that require mimicking or assisting biological motions. axial extension, radial expansion, and twisting about its axis upon pressurization (17)(18)(19). In contrast, when the tube is composed of two elastomers of different stiffness, pressurization produces a bending motion (25,26).…”

“…Although their inherent compliance, easy fabrication, and ability to achieve complex output motions from simple inputs have made soft robots very popular (10,11), there is growing recognition that the development of methods for efficiently designing actuators for particular functions is essential to the advancement of the field. To this end, some research groups have begun focusing their efforts on modeling and characterizing soft actuators (12)(13)(14)(15)(16)(17)(18)(19)(20). In particular, significant progress has been made on solving the forward kinematics problem (16)(17)(18)(19) and even on using dynamic modeling to perform motion planning (14).…”

“…To this end, some research groups have begun focusing their efforts on modeling and characterizing soft actuators (12)(13)(14)(15)(16)(17)(18)(19)(20). In particular, significant progress has been made on solving the forward kinematics problem (16)(17)(18)(19) and even on using dynamic modeling to perform motion planning (14). However, the practical problem of designing a soft actuator to achieve a particular motion remains an issue.…”

“…Here, we focus on fiber-reinforced actuators (17)(18)(19)(20)(21), and given a particular trajectory, we find the optimal design parameters for an actuator that will replicate that trajectory upon pressurization. To achieve this goal, we first use a nonlinear elasticity approach to derive analytical models that provide a relationship between the actuator design parameters (geometry and material properties) and the actuator deformation as a function of pressure for each motion type of interest (extending, expanding, twisting, and bending).…”