A Novel Scaffold Reinforced Actuator with Tunable Attitude Ability for Grasping

Owing to high compliance, adaptiveness, and easy controllability, soft actuators are widely adopted in soft grippers to graspirregularlyshapedorfragileobjects.Thespecificmotionscan be preprogrammed into the flexible and constrained structures of the actuator, which provides an inexpensive and convenient method for desired motions. However, most preprogrammed structures cannot change the constraints on the actuator to achieve differ- ent kinds of deformations, which limits the motion diversities of actuators. This article proposes a scaffold reinforcement mecha- nism, where rotatable scaffolds distribute on the surface of the soft structure. The orientation adjustments of the scaffolds can change the deformation constraint of the actuator, which results in different kinds of motions. Based on the scaffold reinforcement mechanism, a scaffold-reinforced actuator is proposed, which can achievebendingmotionandcomplexhelicalmotioninthe3-Dspace by properly adjusting the orientation of the scaffolds. In addition, both the kinematic and mechanical models are proposed to forecast the behavior of the actuator when driven by cable displacement or tension force. Experimental results verify the validity of the theoretical model, and the actuator can achieve an independent control of bending and helical motion, which can be adopted in applications where both high dexterity and flexibility are required.