Dynamic modeling and analysis of the instrument arm based on the physical properties of soft tissues

Abstract

Surgical robot is a hotspot problem of the current research. This paper presents the dynamical analysis of an instrument arm for minimally invasive surgical robot. Firstly, the study presents a general dynamics modeling method, by which a dynamical model of the instrument arm is established and verified by simulation, then a general force of the trocar point is considered and related analysis is performed. Considering the diversity of the reaction force, one-dimensional force is added separately at the operating point and some simulations are performed based on the dynamic model. Secondly, mechanical characterization of soft tissues is researched based on the indentation experiments, where the constitutive models for compression and relaxation are derived and added to the dynamical model to establish a complete dynamic model with the property of soft tissues. Lastly, the trocar force is analyzed in detail where the instrument arm is found to be sensitive to the tiny force based on the simulation results, and then a force sensing strategy of contact force on soft tissues is presented. Comprehensively, dynamical analysis for the instrument arm will provide an important basis for its control.