A Novel Explicit Analytical Multibody Approach for the Analysis of Upper Limb Dynamics and Joint Reactions Calculation Considering Muscle Wrapping

Alessandro Ruggiero,Alessandro Sicilia

doi:10.3390/app10217760

Abstract

The aim of this paper is to present an explicit analytical biomechanical multibody procedure able to be implemented in the solution of the musculoskeletal systems inverse dynamics problems. The model is proposed in formal multibody analysis and implemented in the Matlab numerical environment. It is based on the constraint kinematical behaviour analysis and considers both linear muscle actuators and curved ones, by calculating the geodesic muscle path over wrapping surfaces fixed to the bodies. The model includes the Hill muscle approach in order to evaluate both the contractile elements’ actions and the passive ones. With the aim to have a first validation, the model was applied to the dynamical analysis of the “arm26” OpenSim model, an upper limb subjected to external forces of gravity and to known kinematics. The comparison of results shows interesting matching in terms of kinematical analysis, driving forces, muscles’ activations and joint reactions, proving the reliability of the proposed approach in all cases in which it is necessary to achieve in-silico explicit determinations of the upper limb dynamics and joint reactions (i.e., in joint tribological optimization).

Highlights

In the framework of biomechanics, the dynamics of the human body plays an important role: it is necessary to apply knowledge of the joint contact forces during certain human kinematics motion to analyse the joint loading, and to define the synovial joints tribological behaviour and mechanical performances
In the above scientific framework, the aim of this paper is to develop, step by step, an explicit analytical multibody model representing the “core model” of a novel algorithm written by the authors in the Matlab environment, able to solve the inverse dynamics of upper limb musculoskeletal systems, allowing the explicit control of the involved variables
The results regarding the simulation of the upper limb subjected to gravity during a simple kinematics are discussed

Summary

Introduction

In the framework of biomechanics, the dynamics of the human body plays an important role: it is necessary to apply knowledge of the joint contact forces during certain human kinematics motion to analyse the joint loading, and to define the synovial joints (hip, knee, ankle, etc.) tribological behaviour and mechanical performances. The in vitro or in vivo approaches to study biomechanical phenomena, are characterised by a wide deviation of the measurement results Since they are dependent on many parameters and vary from subject to subject [12,13,14], many experiments are required to define an average behaviour of a certain physical system. For these reasons, the in silico approach is becoming a very suitable way to overcome the described issues, and many software, able to solve numerically dynamical musculoskeletal systems, have been developed by researchers, such as OpenSim, AnyBody, etc.

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Conclusion