Nonlinear Kinematics and Force Analyses of A Cable-Driven Soft Finger

Soft robotics have been one of the most popular research topics in the fields of robotics and automation due to their advantages of higher flexibility and safer operations. Researches of soft robots are more complicated than the ones of traditional rigid robots because it’s harder to control the movements of soft robots, or estimate their force reactions. Finite Element Analysis (FEA) could be used to analyze how the soft robot deforms but nonlinear FEA is required for large-deformation analysis. Another method to analyze the soft robot movement is to perform experiments and parametrically model the motions. A cable-driven soft finger was designed and utilized for the nonlinear kinematics analysis. The soft finger was made of Polydimethylsiloxane (PDMS) with 3D-printed bone structures. Parametric Denavit-Hartenberg (DH) Functions were used to mathematically describe the motions of soft robots under various levels of actuations. Furthermore, the gripping force of the soft finger was estimated based on a simple force model. The proposed nonlinear kinematics and force analysis could be applied to various kinds of soft robotics mechanisms.