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Research thread aimed at developing systematic methods of achieving complex robotic behaviors, including stable and robust bipedal locomotion, by leveraging tools from nonlinear control theory.

The field of nonlinear control has demonstrated success towards realizing complex robotic behaviors, including bipedal locomotion. Most importantly, nonlinear controllers account for the full system dynamics, allowing for theoretical guarantees. However, when a human is introduced into the system, our knowledge of the system dynamics decreases. Thus, a critical step to maintaining theoretic guarantees in cases when a human is part of the system, such as the case with lower-body assistive devices, is to better define the theoretical conditions underlying provably robust and stable locomotion. Once we better understand these notions, we can develop systematic methods of achieving robust and stable locomotion on a variety of bipedal platforms.

To date, my research towards bipedal locomotion has included systematically tuning controller gains for a CLF-QP on Cassie, incorporating musculoskeletal models into a gait genreation framework to achieve natural multi-contact walking on the AMPRO3 dual-actuated prosthesis, generating robust limit cycles for both the Atalante exoskeleton and the AMBER-3M biped by leveraging Saltation matrices, and developing methods for active ankle stabilization on Atalante.

  1. Synthesizing Robust Walking Gaits via Discrete-Time Barrier Functions with Application to Multi-Contact Exoskeleton Locomotion
    Maegan Tucker, Kejun Li, and Aaron D Ames
    In In Review 2023
  2. Humanoid Robot Co-Design: Coupling Hardware Design with Gait Generation via Hybrid Zero Dynamics
    Adrian B Ghansah, Jeeseop Kim, Maegan Tucker, and 1 more author
    In 2023 IEEE Conference on Decision and Control (CDC) 2023
  3. An input-to-state stability perspective on robust locomotion
    Maegan Tucker, and Aaron D Ames
    IEEE Control Systems Letters 2023
  4. Input-to-State Stability in Probability
    Preston Culbertson, Ryan K Cosner, Maegan Tucker, and 1 more author
    In 2023 IEEE Conference on Decision and Control (CDC) 2023
  5. Learning controller gains on bipedal walking robots via user preferences
    Noel Csomay-Shanklin, Maegan Tucker, Min Dai, and 2 more authors
    In 2022 International Conference on Robotics and Automation (ICRA) 2022
  6. Natural Multicontact Walking for Robotic Assistive Devices via Musculoskeletal Models and Hybrid Zero Dynamics
    Kejun Li, Maegan Tucker, Rachel Gehlhar, and 2 more authors
    IEEE Robotics and Automation Letters 2022
  7. Robust Locomotion: Leveraging Saltation Matrices for Gait Optimization
    Maegan Tucker, Noel Csomay-Shanklin, and Aaron D Ames
    arXiv preprint arXiv:2209.10452 2022
  8. Stabilization of Exoskeletons through Active Ankle Compensation
    Thomas Gurriet, Maegan Tucker, Claudia Kann, and 2 more authors
    arXiv preprint arXiv:1909.11848 2019