Design and Modeling of a Retractable Flexible Arm Inspired by the Nycticorax Violaceus

Rigid robotic arms have strong load capacity and mature control schemes, but they are often not suitable for working in narrow spaces with multiple obstacles. Flexible robotic arms can bend more freely, but they have weaker load capacity and are not suitable for fine manipulation. In view of this, inspired by the biological structure of the Nycticorax Violaceus, a novel scalable flexible robotic arm for addressing complex spatial fault-tolerant manipulation requirements is proposed in this paper. The robotic arm can be concealed within a shell at the end of a rigid arm without affecting the normal use of the rigid arm. When needed, it can extend from the shell of the rigid arm, serving as a flexible auxiliary operating end attached to the rigid arm base for large curvature bending. This paper presents the structural design of a flexible arm and provides kinematic and dynamic models for the flexible arm extension operation. Through a case study, the kinematic and dynamic models proposed in this paper are validated.