Dynamic Modeling of Fiber-Reinforced Soft Manipulator: A Visco-Hyperelastic Material-Based Continuum Mechanics Approach

Abstract

Robot-assisted surgery is gaining popularity worldwide and there is increasing scientific interest to explore the potential of soft continuum robots for minimally invasive surgery. However, the remote control of soft robots is much more challenging compared with their rigid counterparts. Accurate modeling of manipulator dynamics is vital to remotely control the diverse movement configurations and is particularly important for safe interaction with the operating environment. However, current dynamic models applied to soft manipulator systems are simplistic and empirical, which restricts the full potential of the new soft robots technology. Therefore, this article provides a new insight into the development of a nonlinear dynamic model for a soft continuum manipulator based on a material model. The continuum manipulator used in this study is treated as a composite material and a modified nonlinear Kelvin-Voigt material model is utilized to embody the visco-hyperelastic dynamics of soft silicone. The Lagrangian approach is applied to derive the equation of motion of the manipulator. Simulation and experimental results prove that this material modeling approach sufficiently captures the nonlinear time-and rate-dependent behavior of a soft manipulator. Material model-based closed-loop trajectory control was implemented to further validate the feasibility of the derived model and increase the performance of the overall system.

TMTDyn: A Matlab package for modeling and control of hybrid rigid–continuum robots based on discretized lumped systems and reduced-order models

“…Deriving the EOM for modeling hybrid rigid–continuum body mechanisms has been a challenge in soft robotic research (Boyer, 2014; Burgner-Kahrs et al, 2015; Rus and Tolley, 2015; Sadati et al, 2017b). The Newton–Euler method (Jung et al, 2011), Lagrange dynamics (Godage et al, 2016; Mustaza et al, 2019), the PVW (Sadati et al, 2017a, 2016; Trivedi et al, 2008), TMT methods for deriving the Lagrange dynamics (Sadati et al, 2018b), and Bond graph approaches (Sutar and Pathak, 2017) have been used to derive the EOM of such systems. Here, we disregard the Cosserat rod dynamics (Till and Rucker, 2017), FEM (Coevoet et al, 2017), and the Moving Least Squares Material Point Method (MLS-MPM) (Hu et al, 2018), methods that result in a system of differential equations that are not inherently compatible with control design methods for rigid-body systems.…”

A proposed soft pneumatic actuator control based on angle estimation from data-driven model

“…The bending angles were measured using a camera (Microsoft HD-3000 LifeCam), and images were then processed by the MATLAB software. All the data points were then synchronized together to obtain the desired model, which could be presented by equation (6)…”

“…5 However, bending could be produced by extending one side of the actuator while limiting the other side's stretching or radial expansion. 6 Considering these advantages, FEAs were used to develop different soft robotic grippers and assistive/rehabilitation gloves. [7][8][9][10][11][12][13] Pneumatic-based FEA actuators are called soft pneumatic actuators (SPAs).…”

“…Both are simple in design, effective and easy to manufacture, yet their modeling and control are very challenging. Recently, SPAs modeling and characterization were tested using experimental approaches, 14 and finite element modeling (FEM) alone 15 or combined with analytical modeling 6,16,17 and/or data-driven models. 18 The FEM, in particular, has been used extensively for the modeling and designing of soft robotics, as it accounts for all the necessary physical quantities that otherwise can be difficult to model.…”

Liquid‐Metal‐Enhanced Wire Mesh as a Stiffness Variable Material for Making Soft Robotics

“…To achieve this purpose, shape memory alloys, magnetic fluids, jamming method, and room temperature liquid metal have been used in attempts so far. Pneumatic actuators, such as inflated meshes and pneumatic channels inflated against reinforcing fibers, are also considered as good options for stiffness regulation due to its swift response and high‐regulation accuracy. In addition, wire mesh, especially metal wire mesh, is one common option in the fabrication of soft robotics .…”