A Flytrap-inspired Soft Manipulator Driven by Single Airbag*

Inspired by the mechanism of the predatory action of the flytrap, a single soft airbag shape-driven manipulator is proposed. Base on the analysis of the movement mechanism of the flytrap and the geometric structure of the manipulator, through the expansion control of a single sphere elastic airbag and the passive contraction of elastic tendons, the opening action and closing action of different angles of the manipulator is achieved. As a further extension, through the control of the elastic airbag with different shapes, the shape actuators with different action trajectories is completed. By combining a long elastic airbag with a soft flexible spring, a soft bionic arm is completed, which can achieve contractile motion on a linear path. The experimental system was built, and the grabbing experiments of two-claw soft manipulator and three-claw soft manipulator were completed by low cost common industrial materials, which verified the feasibility of the scheme. The 3D printing technique has been used to implement the spiny bionic structure of the flytrap, which further improves the grabbing ability of the soft manipulator to different shape objects. The soft manipulator can achieve the grasping and lifting of an object with 10-15 times the weight of its own.