This project focuses on the development of synthetic soft tissue simulants, to replicate human tissue mechanical behavior, facilitating the study of human-exoskeleton interactions without human participants. Simulants are designed to cover a rigid robotic leg used as testing benchmark for lower limb exoskeletons, developed at the CSIC Research Centre in Madrid. The objective is to enhance the realism of this testing benchmark, by selecting materials that mimic human tissue responses under compressive and shear stresses, im proving upon the previously used simulant (Ecoflex OO-30™ material, 1.3 cm thickness), referred to as “baseline simulant”, which was too stiff for the current application. Two approaches were used: application-oriented testing and material characterization. Application-oriented testing was first conducted on 10 human subjects and the baseline simulant and then on newly developed simulants, including Ecoflex OO-30™, Ecoflex OO 10™, and Ecoflex OO-10™ with 10%wt Silicone Thinner™ (referred to as ”Ecoflex OO-10T”) at thicknesses of 1 cm, 2 cm, and 3 cm. Ecoflex OO-10T, in a 3 cm thickness, provided the best performance, offering greater compressibility and allowing for displacement similar to those allowed by human tissues to be reached. Material characterization was performed using a Zwick Roell Z005 machine, following standardized protocols. All the three materials exhibited non-linear behavior. The deviation from linearity was assessed with a power law fitting. Having identified just small deviations from linearity, elastic (E) and shear (G) moduli could be compared with literature data. The results showed that the average elastic moduli and shear moduli of Ecoflex OO-10™ (E = 162.5 ± 1.2 kPa, G = 24.4 ± 1.4 kPa) and Ecoflex OO-10T (E = 149.4 ± 3.8 kPa, G = 17.0 ± 0.8 kPa) fell within the range of human tissues, confirming their suitability for mimicking human soft tissue mechanical behavior.
This project focuses on the development of synthetic soft tissue simulants, to replicate human tissue mechanical behavior, facilitating the study of human-exoskeleton interactions without human participants. Simulants are designed to cover a rigid robotic leg used as testing benchmark for lower limb exoskeletons, developed at the CSIC Research Centre in Madrid. The objective is to enhance the realism of this testing benchmark, by selecting materials that mimic human tissue responses under compressive and shear stresses, im proving upon the previously used simulant (Ecoflex OO-30™ material, 1.3 cm thickness), referred to as “baseline simulant”, which was too stiff for the current application. Two approaches were used: application-oriented testing and material characterization. Application-oriented testing was first conducted on 10 human subjects and the baseline simulant and then on newly developed simulants, including Ecoflex OO-30™, Ecoflex OO 10™, and Ecoflex OO-10™ with 10%wt Silicone Thinner™ (referred to as ”Ecoflex OO-10T”) at thicknesses of 1 cm, 2 cm, and 3 cm. Ecoflex OO-10T, in a 3 cm thickness, provided the best performance, offering greater compressibility and allowing for displacement similar to those allowed by human tissues to be reached. Material characterization was performed using a Zwick Roell Z005 machine, following standardized protocols. All the three materials exhibited non-linear behavior. The deviation from linearity was assessed with a power law fitting. Having identified just small deviations from linearity, elastic (E) and shear (G) moduli could be compared with literature data. The results showed that the average elastic moduli and shear moduli of Ecoflex OO-10™ (E = 162.5 ± 1.2 kPa, G = 24.4 ± 1.4 kPa) and Ecoflex OO-10T (E = 149.4 ± 3.8 kPa, G = 17.0 ± 0.8 kPa) fell within the range of human tissues, confirming their suitability for mimicking human soft tissue mechanical behavior.
Investigation and development of synthetic soft-tissues to improve the study of physical human-exoskeletons interaction with robotic dummies
MARIUZZO, GIORGIA
2023/2024
Abstract
This project focuses on the development of synthetic soft tissue simulants, to replicate human tissue mechanical behavior, facilitating the study of human-exoskeleton interactions without human participants. Simulants are designed to cover a rigid robotic leg used as testing benchmark for lower limb exoskeletons, developed at the CSIC Research Centre in Madrid. The objective is to enhance the realism of this testing benchmark, by selecting materials that mimic human tissue responses under compressive and shear stresses, im proving upon the previously used simulant (Ecoflex OO-30™ material, 1.3 cm thickness), referred to as “baseline simulant”, which was too stiff for the current application. Two approaches were used: application-oriented testing and material characterization. Application-oriented testing was first conducted on 10 human subjects and the baseline simulant and then on newly developed simulants, including Ecoflex OO-30™, Ecoflex OO 10™, and Ecoflex OO-10™ with 10%wt Silicone Thinner™ (referred to as ”Ecoflex OO-10T”) at thicknesses of 1 cm, 2 cm, and 3 cm. Ecoflex OO-10T, in a 3 cm thickness, provided the best performance, offering greater compressibility and allowing for displacement similar to those allowed by human tissues to be reached. Material characterization was performed using a Zwick Roell Z005 machine, following standardized protocols. All the three materials exhibited non-linear behavior. The deviation from linearity was assessed with a power law fitting. Having identified just small deviations from linearity, elastic (E) and shear (G) moduli could be compared with literature data. The results showed that the average elastic moduli and shear moduli of Ecoflex OO-10™ (E = 162.5 ± 1.2 kPa, G = 24.4 ± 1.4 kPa) and Ecoflex OO-10T (E = 149.4 ± 3.8 kPa, G = 17.0 ± 0.8 kPa) fell within the range of human tissues, confirming their suitability for mimicking human soft tissue mechanical behavior.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/78080