Related Experiment Video
Updated: Dec 29, 2025

Design and Fabrication of an Elastomeric Unit for Soft Modular Robots in Minimally Invasive Surgery
Published on: November 14, 2015
Design of a tether-driven minimally invasive robotic surgical tool with decoupled degree-of-freedom wrist
Karthik Chandrasekaran1, Asokan Thondiyath1
1Department of Engineering Design, Indian Institute of Technology Madras, Chennai, India.
Background:
Dexterous surgical tool wrists used in tele-operated robotic surgery typically have mechanically coupled pitch and yaw degree of freedom (DoF). This leads to complex control requirements.
Materials And Methods:
The design of a robotic surgical tool with a mechanically decoupled dexterous wrist which uses stationary tether guides to guide drive tethers is presented. The tethers are routed through the plane of symmetry of the tool and follow law of belting to mechanically decouple the wrist. An optimization procedure for the placement of the stationary tether guides to minimize the change in tether length is presented.
Results:
Experimental and analytical results confirm the decoupled motion capability of the wrist. Also, the change in length of tether segments over the operating range of motion was found to be very small.
Conclusion:
A prototype has been fabricated through metal 3D printing and integrated to a tele-operated robotic setup to demonstrate its utility in surgical application.

