DOI: 10.5061/dryad.kwh70rzd7
title: Data and simulation model files for: Variable-stiffness morphing wheel inspired by the surface tension of a liquid drop

description: Wheels have been commonly used for locomotion in mobile robots and
 transportation systems due to their simple structure and energy
 efficiency. However, the performance of wheels in overcoming obstacles is
 limited compared to their advantages in driving on normal flat ground.
 Here, we present a variable stiffness wheel inspired by the surface
 tension of a liquid drop. In a liquid drop, as the cohesive force of the
 outermost liquid molecules increases, the net force pulling the liquid
 molecules inward also increases. This leads to high surface tension,
 resulting in the liquid droplet reverting to a circular shape from its
 distorted shape induced by gravitational forces. Similarly, the shape and
 stiffness of the wheel can be controlled by changing the traction force at
 the outermost smart chain block. As the tension of the wire spokes
 connected to each chain block increases, the wheel characteristics reflect
 those of a general circular-rigid wheel, which has an advantage in
 high-speed locomotion on normal flat ground. Conversely, the modulus of
 the wheel decreases as the tension of the wire spoke decreases, and the
 wheel can be easily deformed according to the shape of obstacles. This
 makes the wheel suitable for overcoming obstacles without requiring
 complex control or sensing. Based on this mechanism, the wheel is applied
 to a 2-wheeled wheelchair system weighing 120 kg, and the state transition
 between a circular high-modulus state and a deformable low-modulus state
 is realized in real-time when the wheelchair drives in an outdoor
 environment.
description: This dataset is the raw data gathered from the experiment using
 the stiffness-variable morphing wheel in the article titled
 "Variable-stiffness morphing wheel inspired by the surface tension of
 a liquid drop". For measurements of wheel modulus, the two load cells
 (CSBA-50L, CAS Ins.) at the hub structure and one load cell (CSBA-50L, CAS
 Ins.) at the indenter were used in the experiment. A laser displacement
 sensor (ODSL 96B M, Leuze) was used to measure the positions of the
 indenter and hub structure. The data was collected with the NI DAQ module
 (cDAQ-9172, NI-9215, National Instrument) and LabVIEW software.
 Computer-aided design (CAD) files provide detailed shapes and dimensions
 of the major components of the morphing wheel and mobile platform that
 were used to generate this dataset. The simulation model files were
 developed to simulate the deformation characteristics of the morphing
 wheel both on a flat surface and while overcoming obstacles, focusing on
 changes in its modulus.
description: # Data and simulation model files for: Variable-stiffness morphing wheel
 inspired by the surface tension of a liquid drop
 [https://doi.org/10.5061/dryad.kwh70rzd7](https://doi.org/10.5061/dryad.kwh70rzd7) ## Overview This dataset contains the data, CAD, and simulation model generated from the experiments using the variable-stiffness morphing wheel. The presented dataset is necessary for generating figures and results for the paper titled 'Variable-stiffness morphing wheel inspired by the surface tension of a liquid drop'. ## Data from the figures The measured data necessary to reproduce the figures in the paper titled 'Variable-stiffness morphing wheel inspired by the surface tension of a liquid drop'. ## CAD The shape and size information of the components and platform used in the paper * Smart chain structure: The size and detailed shape of the smart chain structure, which consists of the outer structure of the stiffness-variable morphing wheel. * Stiffness-variable module in a 4-wheeled vehicle: The configuration of the stiffness-variable module that was implemented in the 4-wheeled vehicle. * 4-wheeled vehicle platform: The configuration of the 4-wheeled vehicle platform consists of four stiffness-variable modules. * Large-sized smart chain structure: The size and detailed shape of the smart chain structure, consisting of the large-sized wheel. * Soft structure in the large-sized morphing wheel: The size and shape of the honeycomb-like polymer structure embedded within the large-sized morphing wheel. * Stiffness-variation module in a 2-wheeled wheelchair: The configuration of the stiffness-variable module that was implemented in the 2-wheeled wheelchair system. * 2-wheeled wheelchair platform: The configuration of the 2-wheeled wheelchair platform consists of two stiffness-variable modules to control the stiffness of the large-sized morphing wheel. ## Simulation model Recurdyn model files to generate the simulation results of the morphing wheel * model_flat_surface: Simulation of the behavioral characteristics of the morphing wheel during stiffness variation on a flat surface * model_obstacle: Simulation of the behavioral characteristics of the morphing wheel during stiffness variation for overcoming obstacles