Artificial Muscles as Actuators in Symmetrical Structure

Abstract

Artificial muscles made of SCP (super coiled polymer) such as nylon 6 and nylon 6, 6, due to the character of attraction when heated and extension when cool down, have many novel applications as actuators. Using artificial muscles as actuators to take place of actuators like motors in traditional engineering designs has advantages such as reducing the size and weight of the model. But when applied to symmetrical structures, artificial muscles need to be assigned symmetrically, attentions should be paid that some of none heated muscles in working states may work as loads while some of other muscles are heated. Taking hyperredundant robot joint, which is a typical model of symmetrical structure, as an example. Motors, cables and springs of traditional hyperredundant robot can be replaced by SCP artificial muscles as actuators, which enables the reduction of structure size, reducing the number of components and the cost of model. But unavoidable, in this symmetrical structure, when muscle of one side is heated and contracting will leads to the extension of muscle on the opposite side. Under this circumstance, the side effect of the extended muscle is not negligible and needed to be analyzed. In this article, the model simplification and design of symmetrical structure of hyperredundant robot joint which SCP artificial muscles are applied to and the force analysis method of the structure are demonstrated. By calculation, the feasibility of replacements of SCP artificial muscles in the symmetrical structure are inferred. A 3D printed model is made and experiment result shows that SCP artificial muscles can be applied to symmetrical structure.