Multimodal Deformation in Tensegrity Manipulators: Preprogrammable Bend-Twist Modules for Dexterous Grasping Inspired...

Area of Science:

• Robotics and Mechanical Engineering
• Soft Robotics and Continuum Manipulation

Background:

• Tensegrity-based continuum manipulators (TCMs) offer adaptive conforming capabilities for unstructured environments.
• Actuation redundancy in TCMs complicates dexterous manipulation control.
• Existing designs require significant effort to resolve coupling effects between rigid and flexible components.

Purpose of the Study:

• To propose a modular TCM with enhanced segmented actuation for simplified control.
• To enable decoupled bending and twisting motions for multimodal deformation.
• To reduce control complexity in continuum manipulator systems.

Main Methods:

• Development of preprogrammable bend-twist modules (PBTMs) with enhanced segmented actuation.
• Design of a preprogramming template for in situ twisting capabilities.
• Derivation of a dynamic model using natural coordinates and clustered cable (CTC) elements.

Main Results:

• The enhanced actuation strategy effectively decouples adjacent segments and separates curvature/directional control.
• Numerical analysis revealed the effect of CTC rest length on cable slack and in situ twist motion.
• A prototype manipulator demonstrated versatile multimodal deformation for object wrapping and obstacle avoidance.

Conclusions:

• The proposed modular TCM with PBTMs offers a feasible paradigm for reduced control complexity.
• The design enables simplified mechanical integration and control implementation for continuum manipulators.
• The manipulator's ability to conform to objects of varying shape and pose was experimentally validated.