Research on Self-Stiffness Adjustment of Growth-Controllable Continuum Robot (GCCR) Based on Elastic Force Transmission

Abstract

Continuum robots have good adaptability in unstructured and complex environments. However, affected by their inherent nature of flexibility and slender structure, there are challenges in high-precision motion and load. Thus, stiffness adjustment for continuum robots has consistently attracted the attention of researchers. In this paper, a stiffness adjustment mechanism (SAM) is proposed and built in a growth-controllable continuum robot (GCCR) to improve the motion accuracy in variable scale motion. The self-stiffness adjustment is realized by antagonism through cable force transmission during the length change of the continuum robot. With a simple structure, the mechanism has a scarce impact on the weight and mass distribution of the robot and required no independent actuators for stiffness adjustment. Following this, a static model considering gravity and end load is established. The presented theoretical static model is applicable to predict the shape deformations of robots under different loads. The experimental validations showed that the maximum error ratio is within 5.65%. The stiffness of the robot can be enhanced by nearly 79.6%.

Underactuated Humanoid Peeling Approach for Pickled Mustard Tuber Based on Metamorphic Constraints

“…The spring system consists of four sets, each consisting of two tension springs and three compression springs. The tension springs are used to cut the pickled mustard tuber, while the compression springs are used to maintain the relative position of the upper and lower peeling claws [23]. The proposed pickled mustard tuber peeling mechanism has three degrees of freedom, namely X, Y, and theta [24].…”