Multi-objective Design Optimization and Control Strategy for Digital Hydraulically Driven Knee Exoskeleton




Knee exoskeleton, Hydraulic drives, Digital hydraulics, Design optimization


This article presents a multi-objective design optimization strategy to determine an optimal design of digital hydraulically driven knee exoskeleton. To satisfy the overall goal of compact and lightweight design, four key design objectives are defined. Via genetic algorithm based multi-objective optimization technique, the pareto-optimal set of designs is determined and the trade-offs between the design objectives are analysed. Via decisions based on component availability and user-comfort, the dimensionality of the pareto-front is reduced to two and an exoskeleton design is selected that offers a good compromise between the design objectives.

For the actuation of the exoskeleton, an energy efficient control strategy is proposed which consists of using passive control during the stance phase and simplified model predictive control during the swing phase. The operation of the chosen knee exoskeleton design and the control strategy is investigated via numerical simulations. The results indicate that the exoskeleton successfully tracks the desired knee motion and delivers the required knee torque.


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Author Biographies

Rituraj, Institute of Machine Design and Hydraulic Drives, Johannes Kepler University, Linz, Austria

Rituraj received his B.Tech. degree from IIT Guwahati, India in 2013 and his Ph.D. degree from Purdue University, USA in 2020. During his direct-Ph.D. at Maha Fluid Power Research Center, he worked on numerical modelling of External Gear Machines. Currently, he is a postdoctoral researcher at Institute of Machine Design and Hydraulic Drives in JKU, Austria where he is working on the development of hydraulically driven exoskeletons. His overall research interests include numerical and experimental study of hydraulic components and systems.

Rudolf Scheidl, Institute of Machine Design and Hydraulic Drives, Johannes Kepler University, Linz, Austria

Rudolf Scheidl received his M.Sc. of Mechanical Engineering and Doctor of Engineering Sciences degrees at Vienna University of Technology. He has research and development experience in agricultural machinery (Epple Buxbaum Werke), continuous casting technology (Voest-Alpine Industrieanlagenbau) and paper mills (Voith). Since 1990, he is a full Professor of Mechanical Engineering at Johannes Kepler University, Austria. His research topics include hydraulic drive technology and mechatronic design.


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How to Cite

Rituraj, & Scheidl, R. . (2023). Multi-objective Design Optimization and Control Strategy for Digital Hydraulically Driven Knee Exoskeleton. International Journal of Fluid Power, 24(02), 271–298.




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