Al-Dahiree, O.S.; Ghazilla, R.A.R.; Tokhi, M.O.; Yap, H.J.; Gul, M. Design and Characterization of a Low-Cost and Efficient Torsional Spring for ES-RSEA. Sensors2023, 23, 3705.
Al-Dahiree, O.S.; Ghazilla, R.A.R.; Tokhi, M.O.; Yap, H.J.; Gul, M. Design and Characterization of a Low-Cost and Efficient Torsional Spring for ES-RSEA. Sensors 2023, 23, 3705.
Al-Dahiree, O.S.; Ghazilla, R.A.R.; Tokhi, M.O.; Yap, H.J.; Gul, M. Design and Characterization of a Low-Cost and Efficient Torsional Spring for ES-RSEA. Sensors2023, 23, 3705.
Al-Dahiree, O.S.; Ghazilla, R.A.R.; Tokhi, M.O.; Yap, H.J.; Gul, M. Design and Characterization of a Low-Cost and Efficient Torsional Spring for ES-RSEA. Sensors 2023, 23, 3705.
Abstract
The design of torsional springs for Series Elastic Actuators (SEAs) is challenging, especially when it comes to balancing good stiffness characteristics and efficient torque robustness. This study focuses on the design of a lightweight, low-cost, and compact torsional spring for use in rotary series elastic actuator (ES-RSEA) of lumbar support exoskeleton. The exoskeleton is used as an assistive device to prevent lower back injuries. The torsion spring was designed following design for manufacturability (DFM) principles, focusing on minimal space and weight. The design process consisted of determining the potential topology and optimizing the selected topology parameters through finite element method (FEM) to reduce equivalent stress. The prototype was made using a waterjet cutting process with low-cost material (AISI-4140-alloy) and tested using a custom-made test rig. The results showed that the torsion spring had a linear torque-displacement relationship with 99% linearity, and the deviation between FEM simulation and experimental measurements was less than 2%. The torsion spring has a maximum torque capacity of 45.7 Nm and a stiffness of 440 Nm/rad. The proposed torsion spring is a promising option for lumbar support exoskeletons and similar applications requiring high stiffness, low weight-to-torque ratio, and cost-effectiveness.
Keywords
Force sensor; series elastic actuator; SEA; torsion spring; lumbar support; wearable robot exoskeleton; lifting task; FEM
Subject
Engineering, Mechanical Engineering
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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