Static Analysis and Design Strategy of Two Antagonistically Actuated Joints

Abstract

This paper compares the static performances of two types of antagonistically actuated joints: a revolute (R) joint and an antiparallelogram (X) joint. Both joints are equipped with lateral springs and actuated with two opposite cables running through the springs. The comparative study is conducted on the basis of their wrench-feasible workspace and stiffness. A methodology is proposed for the optimal design of each joint. Eventually, an R-joint and an X-joint, optimized for the same prescribed wrench-feasible workspace, are compared on the basis of their maximal actuation forces.

Optimal design and comparative study of two antagonistically actuated tensegrity joints

“…C. 22. It is apparent that the value of P (η) increases as the specified θ rm increases, which in turn means that the springs should be stronger (higher k) or the linear mass density (ρ) must be smaller.…”

“…A comparative study of the R-and X-joints, designed to possess an identical WFW with the same stiffness values at rest and at WFW boundary, has been presented by the authors in [22]. Such a design process would be useful in developing bio-mimicking mechanisms where the desired stiffness values might be known exactly at the center and bounds of the WFW.…”

“…The rest of this paper is organized as follows: the static models of the R-and X-joints are presented in Section 2, the conditions for design of these joints are listed in Section 3. It is remarked that parts of Sections 2 and 3, on the derivation of static models can also be found in the authors' previous publication [22]. A strategy to obtain the feasible design space and the optimal design is developed for R-joint in Section 4 and for X-joint in Section 5.…”