Optimisation of an articulated instrument for enhanced dexterity in minimally invasive therapy

Summary

The benefits for patients of minimally invasive surgery are reduced trauma, hospitalisation and recovery time. The growth in the number of these procedures is dependent upon the development of articulated tools with enhanced dexterity. In this paper, we examine trends in articulated instrument development and present our own articulated manipulator for minimally invasive surgery (AMMIS). The AMMIS is a single degree-of-freedom compact mechanism, with 180d` bi-directional articulation capability. It can support a surgical tool, exert necessary forces with a moderate driving force and respond quickly. Furthermore, its configuration can be modified and optimised for specific surgical tasks. To this end, we develop criteria for evaluating the optimal performance of articulated tools. These criteria include reachable and dexterous workspaces, force magnification, potential backlash, tip path curvature and maximum articulation angle per link. Using these criteria we outline a procedure for optimisation and determine an optimal AMMIS configuration for the specific task of suturing. A clinician's perspective on the scope and usefulness of AMMIS is presented in the conclusion.

Keywords:

• articulation
• dexterity
• force magnification
• mechanism
• optimisation
• work-space