Online DCM Trajectory Adaptation for Push and Stumble Recovery during Humanoid Locomotion

Mesesan, George; Englsberger, Johannes; Ott, Christian

doi:10.1109/icra48506.2021.9560808

Cited by 9 publications

(7 citation statements)

References 20 publications

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“…Stepping for balance recovery and locomotion in the presented framework will require appropriately designed swing dynamics and low-energy touchdown, so that the controller can regulate the accumulated momentum during the subsequent double stance phase. Using reduced models, the stepping location and CoM references can be computed and re-adjusted in real-time [30], [31]. The implementation of stepping strategies links an improvement in performance of our current work with our next goal: autonomous locomotion with paraplegic users.…”

Section: Limitations Comparison and Enhancementsmentioning

confidence: 90%

Implementation and Tuning of Momentum-Based Controller for Standing Balance in a Lower-limb Exoskeleton with Paraplegic User

Prieto,

Keemink,

Asseldonk

et al. 2024

Preprint

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Lower limb exoskeletons (LLEs) are wearable devices that can restore the movement autonomy of paraplegic users. LLEs can restore the users’ ability to stand upright and walk. However, most of the commercially available and clinically used LLEs rely on the user maintaining balance through the use of crutches. Recent improvements in the design and control of LLEs and other legged robots allow for autonomous balance control. In this work, we implement and evaluate a momentum-based standing balance controller in the Symbitron LLE, consisting of eight active (torque-controlled) and two passive joints. We first investigate how gain tuning of the center of mass tracking control law, part of a multi-task optimal controller, affects balancing performance. We apply pushes on different device locations while in parallel-stance, compare the response for different gains, and derive heuristic guidelines for controller tuning given the control architecture, high-level goals, and hardware limitations. Next, we show how this controller successfully prescribes joint torques to the LLE to maintain balance with a paraplegic user. The LLE can autonomously balance the user and reject mediolateral and anteroposterior pushes in the order of 60 N at hip height (and 40 N at shoulder height) while standing in parallel-stance, staggered-stance with both feet at the same height, and staggered-stance with a height difference of 0.05 m between the feet. This work presents a viable control strategy for torque-controlled light-weight under-actuated LLEs to keep the balance of paraplegic users during stance, which is a necessary starting point towards autonomous balance control during gait.

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Section: Limitations Comparison and Enhancementsmentioning

confidence: 90%

Implementation and Tuning of Momentum-Based Controller for Standing Balance in a Lower-limb Exoskeleton with Paraplegic User

Prieto,

Keemink,

Asseldonk

et al. 2024

Preprint

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“…For example, Englsberger et al (2011) present a bipedal walking control approach based on the LIP and the CP dynamics. Mesesan et al (2021) introduced a trajectory adaptation for push and stumble recovery based on the CP. Kamioka et al (2018) are optimizing the ZMP and footsteps based on the CP for a LIP.…”

Section: Previous Workmentioning

confidence: 99%

Robust inverse dynamics by evaluating Newton–Euler equations with respect to a moving reference and measuring angular acceleration

Gießler

Waltersberger

2023

Auton Robot

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Maintaining stability while walking on arbitrary surfaces or dealing with external perturbations is of great interest in humanoid robotics research. Increasing the system’s autonomous robustness to a variety of postural threats during locomotion is the key despite the need to evaluate noisy sensor signals. The equations of motion are the foundation of all published approaches. In contrast, we propose a more adequate evaluation of the equations of motion with respect to an arbitrary moving reference point in a non-inertial reference frame. Conceptual advantages are, e.g., getting independent of global position and velocity vectors estimated by sensor fusions or calculating the imaginary zero-moment point walking on different inclined ground surfaces. Further, we improve the calculation results by reducing noise-amplifying methods in our algorithm and using specific characteristics of physical robots. We use simulation results to compare our algorithm with established approaches and test it with experimental robot data.

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“…This section provides an overview of the simplified model of the robot and the DCM [14]- [16], [19]- [21].…”

Section: Introductionmentioning

confidence: 99%

“…The control inputs, representing the reaction strategies, are calculated through the optimal control problem based on pattern-based walking. Taking into account the Linear Inverted Pendulum with Flywheel Model (LIPFM) dynamics and the relationship between the error of Divergent Component of Motion (DCM) [14]- [16], [19]- [21] and the strategies, the NMPC method is employed. To implement the proposed NMPC method on actual bipedal robot hardware, the problem must be solved in real-time.…”

mentioning

confidence: 99%

Seamless Reaction Strategy for Bipedal Locomotion Exploiting Real-Time Nonlinear Model Predictive Control

Choe

Kim

Hong

et al. 2023

IEEE Robot. Autom. Lett.

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This paper presents a reactive locomotion method for bipedal robots enhancing robustness and external disturbance rejection performance by seamlessly rendering several walking strategies of the ankle, hip, and footstep adjustment. The Nonlinear Model Predictive Control (NMPC) is formulated to take into account nonlinear Divergent Component of Motion (DCM) error dynamics that predicts the future states of the robot in response to the walking strategies. This formulated NMPC enables the seamless application of these strategies improving push disturbance rejection performance. The proposed controller is validated in simulation and through an experiment on a bipedal robot platform, Gazelle, which confirms its effectiveness in realtime.

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Online DCM Trajectory Adaptation for Push and Stumble Recovery during Humanoid Locomotion

Cited by 9 publications

References 20 publications

Implementation and Tuning of Momentum-Based Controller for Standing Balance in a Lower-limb Exoskeleton with Paraplegic User

Implementation and Tuning of Momentum-Based Controller for Standing Balance in a Lower-limb Exoskeleton with Paraplegic User

Robust inverse dynamics by evaluating Newton–Euler equations with respect to a moving reference and measuring angular acceleration

Seamless Reaction Strategy for Bipedal Locomotion Exploiting Real-Time Nonlinear Model Predictive Control

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