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

Abstract

A reliable, accurate, and yet simple dynamic model is important to analyzing, designing, and controlling hybrid rigid–continuum robots. Such models should be fast, as simple as possible, and user-friendly to be widely accepted by the ever-growing robotics research community. In this study, we introduce two new modeling methods for continuum manipulators: a general reduced-order model (ROM) and a discretized model with absolute states and Euler–Bernoulli beam segments (EBA). In addition, a new formulation is presented for a recently introduced discretized model based on Euler–Bernoulli beam segments and relative states (EBR). We implement these models in a Matlab software package, named TMTDyn, to develop a modeling tool for hybrid rigid–continuum systems. The package features a new high-level language (HLL) text-based interface, a CAD-file import module, automatic formation of the system equation of motion (EOM) for different modeling and control tasks, implementing Matlab C-mex functionality for improved performance, and modules for static and linear modal analysis of a hybrid system. The underlying theory and software package are validated for modeling experimental results for (i) dynamics of a continuum appendage, and (ii) general deformation of a fabric sleeve worn by a rigid link pendulum. A comparison shows higher simulation accuracy (8–14% normalized error) and numerical robustness of the ROM model for a system with a small number of states, and computational efficiency of the EBA model with near real-time performances that makes it suitable for large systems. The challenges and necessary modules to further automate the design and analysis of hybrid systems with a large number of states are briefly discussed.

Editorial: Soft Robotic Modeling and Control: Bringing Together Articulated Soft Robots and Soft-Bodied Robots

“…Sadati et al introduce an open-source Matlab package for simulating continuum soft robots. The package is called TMTDyn and can be used for designing and testing control algorithms.…”

Stiffness Imaging With a Continuum Appendage: Real-Time Shape and Tip Force Estimation From Base Load Readings

“…Variable Curvature (VC) kinematics, based on rotation matrices and Cosserat rod theory are used to model the static mechanics of the appendage [1], [23]. The local physical curvilinear coordinates are…”

Control Oriented Modeling of Soft Robots: The Polynomial Curvature Case

“…Digital Object Identifier 10.1109/LRA.2019.2955936 control [4], feedback dynamic control [5]. However, the research in modeling soft robots goes now much further than constant curvature approximations, with fascinating theoretical and experimental results [6]- [10]. It is worth underlying that the present letter does not aim to compete with existing models for accurately or efficiently simulate the robot -task for which these methods are well suited.…”