Optimal Design of the Elastic Unit for the Serial Elastic Hip Joint of the Lower Extremity Exoskeleton
This paper presents an optimal design method of the Elastic Unit for the Serial Elastic Hip Joint of the Lower Extremity Exoskeleton. The elastic element is a compact torsional elastomer. The design of the elastomer should meet the changes of the torque and stiffness of the hip joint during the movement of the human lower limbs. The design process is realized in two steps. Firstly, determining a basic element for the topology that meets the design criteria. Secondly, iterating in the ANSYS Workbench and optimizing its parameters to minimize the Von Mises Stress (making it less than the yield limit of the material used). After the theoretical results being calculated in the ANSYS Workbench, the torsional deformation angle of the elastomer is obtained by applying the torque simulation with different gradients. Besides, the experimental data is recorded and imported into MATLAB, and the stiffness curve is fitted by the least square method to verify whether the stiffness and linearity meet the design requirements. Finally, the simulation results of torsional elastomer can be obtained that the torque is 50 Nm, flexible Angle is 3°.
KeywordsSeries elastic actuator Lower extremity exoskeleton robot Hip joint Elastomer Optimization design
- 1.Hurst J, Rizzi A, Hobbelen D (2004) Series elastic actuation: potential and pitfalls. In: International conference on climbing and walking robotsGoogle Scholar
- 3.Yang J (2014) Control method and experimental research on elastic actuation of exoskeleton robot. Master’s thesis of Harbin Institute of TechnologyGoogle Scholar
- 4.Robinson DW (2000) Design and analysis of series elasticity in closed-loop actuator force control. Doctoral dissertation of Massachusetts Institute of TechnologyGoogle Scholar
- 5.Tagliamonte NL, Sergi F, Carpino G et al (2010) Design of a variable impedance differential actuator for wearable robotics applications. In: 2010 IEEE/RSJ international conference on intelligent robots and systems, IEEE, pp 2639–2644Google Scholar
- 7.Kim S, Bae J (2014) Development of a lower extremity exoskeleton system for human-robot interaction. In: 2014 11th international conference on ubiquitous robots and ambient intelligence (URAI), IEEE, pp 132–135Google Scholar