An efficient leg with series–parallel and biarticular compliant actuation: design optimization, modeling, and control of the eLeg

Wesley Roozing* (Corresponding Author), Zeyu Ren, Nikos G Tsagarakis

*Corresponding author for this work

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    We present the development, modeling, and control of a three-degree-of-freedom compliantly actuated leg called the eLeg, which employs both series- and parallel-elastic actuation as well as a bio-inspired biarticular tendon. The leg can be reconfigured to use three distinct actuation configurations, to directly compare with a state-of-the-art series-elastic actuation scheme. Critical actuation design parameters are derived through optimization. A rigorous modeling approach is presented using the concept of power flows, which are also used to demonstrate the ability to transfer mechanical power between ankle and knee joints using the biarticular tendon. The design principles and control strategies were verified both in simulation and experiment. Notably, the experimental data demonstrate significant improvements of 65–75% in electrical energy consumption compared with a state-of-the-art series-elastic actuator configuration.

    Original languageEnglish
    Pages (from-to)1-17
    Number of pages17
    JournalInternational journal of robotics research
    Early online date16 Dec 2019
    Publication statusPublished - 16 Dec 2019



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