DOI: 10.5061/dryad.mpg4f4r66
title: CSAPSO-BPNN based modeling of end airbag stiffness of nursing transfer robot

description: The use of nursing transfer robots is a vital solution to the problem of
 daily mobility difficulties for semi-disabilities. However, the fact that
 care-receivers have different physical characteristics leads to force
 concentration during human-robot interaction, which affects their comfort.
 To address this problem, this study installs an array of double
 wedge-shaped airbags onto the end-effector of a robot, and analyses airbag
 mechanical properties. Firstly, this study performed the mechanical
 testing and data collection of the airbag, including its external load and
 displacement, at various gas masses. Then the performance of the Back
 Propagation (BP) neural network is improved by using chaos (C) theory and
 simulated annealing particle swarm optimization (SAPSO), resulting in the
 establishment of the CSAPSO-BP neural network. By this method, a fitting
 model is developed to determine the mechanical parameters of the
 wedge-shaped airbag stiffness, and the fitting relation of external
 load-displacement is obtained. Data analyses show that the wedge-shaped
 airbag stiffness increases quadratically, linearly, and with a constant
 rate as the gas mass increases. The airbag stiffness regulation and model
 describe its 3 distinct phases with quadratic, linear, and linear
 invariant characteristics as the gas mass changes. These findings
 contribute to the structural optimization of airbags.
description: Fig. 2 depicts the test
 platform for the end airbag of the nursing transfer robot, which includes
 a universal material test machine, data acquisition system, double
 wedge-shaped airbag, airbag control system, gas mass flow meter, and air
 pump. The air pump serves as the air source for inflating airbags, while
 the control system enables the inflation and deflation of each airbag. The
 airbag mechanical parameters are evaluated by using the universal material
 test machine, while the data acquisition system is used to obtain
 mechanical parameters associated with airbag
 stiffness. Before conducting the mechanical parameter
 tests, the first step is to determine the range of tests for the airbag
 gas mass and external load. The gas mass flow meter is used to measure the
 airbag’s gas mass (the product of cumulative gas flow rate and density).
 The external load test range is dependent on the adult body weight and the
 number of airbags being directly loaded. Since most adults weigh between
 40–120kg, and 8 wedge-shaped airbags are loaded directly onto a human
 body, the external load range for each airbag falls within 11.53–34.58N.
 To meet actual load requirements, the external load test range is enlarged
 by a 1.5 factor, resulting in a range of 0–51.88N.
 The mechanical test of the
 wedge-shaped airbag aims to evaluate its stiffness parameters such as gas
 mass, external load, original height of the airbag (vertical height under
 no-load), displacement (the difference between original height and height
 under load), among others. It is vital to note that the tiny gas mass
 inside the airbag greatly impacts the accuracy of the mechanical parameter
 test results. Therefore, as a starting point, the gas mass just filling
 the airbag (1.29g) is used as the initial experimental group, with an
 increment of 0.258g per group and a maximum gas mass of
 4.902g.
description: # CSAPSO-BPNN based modeling of end airbag stiffness of nursing transfer
 robot
 [https://doi.org/10.5061/dryad.mpg4f4r66](https://doi.org/10.5061/dryad.mpg4f4r66) Before conducting the mechanical parameter tests, the first step is to determine the range of tests for the airbag gas mass and external load. The gas mass flow meter is used to measure the airbag’s gas mass (the product of cumulative gas flow rate and density). The external load test range is dependent on the adult body weight and the number of airbags being directly loaded. Since most adults weigh between 40–120kg, and 8 wedge-shaped airbags are loaded directly onto a human body, the external load range for each airbag falls within 11.53–34.58N. To meet actual load requirements, the external load test range is enlarged by a 1.5 factor, resulting in a range of 0–51.88N. The mechanical test of the wedge-shaped airbag aims to evaluate its stiffness parameters such as gas mass, external load, original height of the airbag (vertical height under no-load), displacement (the difference between original height and height under load), among others. It is vital to note that the tiny gas mass inside the airbag greatly impacts the accuracy of the mechanical parameter test results. Therefore, as a starting point, the gas mass just filling the airbag (1.29g) is used as the initial experimental group, with an increment of 0.258g per group and a maximum gas mass of 4.902g. ## Description of the data and file structure The file named input is the input data for the BP neural network, i.e. the mass of the gas in the airbag. The file named target is the output data of the neural network, i.e. the external load applied to the airbag.