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BY 4.0 license Open Access Published by De Gruyter September 18, 2019

Mobile compressed gas supply for active orthoses and exo-skeletons

  • Peter P. Pott EMAIL logo , Laura Schwenkel , Swantje Janzen and Pia Mühlbauer


In this study a basic principle for the gas supply of a pneumatic actuation for a mobile active knee joint orthosis is described. Instead of using a compressor or a bulky pressure reservoir, the system is supplied with pressurized gas directly from a thermodynamic process to reduce size and weight of the device. To achieve this goal a literature search was performed identifying chemical processes. These options were then analysed and evaluated considering the aspects energy density, safety, eco-friendliness, and technical feasibility of the construction. The expansion of liquified carbon dioxide with phase change achieves the best result due to its high level of safety and the simple technical feasibility of the system. However, CO2cools down considerably during the expansion, so heating up again to room temperature is necessary. Therefore, the technical construction includes a passive and an active heat exchanger.

Published Online: 2019-09-18
Published in Print: 2019-09-01

© 2019 by Walter de Gruyter Berlin/Boston

This work is licensed under the Creative Commons Attribution 4.0 Public License.

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