Whole-body balance stability regions for multi-level momentum and stepping strategies

Peng, William Z.; Mummolo, Carlotta; Song, Hyunjong; Kim, Joo H.

doi:10.1016/j.mechmachtheory.2022.104880

Cited by 7 publications

(1 citation statement)

References 46 publications

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“…The definitions of stability states considered here (Peng et al, 2022) are with respect to a specific contact configuration (SS or DS balanced) or transition (steppable), where a balanced state is a state from which a given biped can maneuver such that its (SS or DS) contact can be indefinitely maintained and a steppable state is one from which a desired step is achievable before any undesired contact occurs (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Balance stability characteristics of human walking with preferred, fast, and slow speeds

Peng

Kim

2022

Proceedings of the 7th International Digital Human Modeling Symposium -

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This work presents a model-based method of evaluating and quantifying stability characteristics of human walking in the sagittal plane. The stability criteria used for this analysis are boundaries in the state space of the center of mass (COM), which represent the maximum capability of a human to maintain balance in single support (SS) and double support (DS) phases or to make a desired step without falling. Complete models of the system dynamics, biomechanical characteristics, its contact interaction with the ground, and gait parameters, are considered. Experimental human COM trajectories during walking are analyzed against computed stability boundaries to quantify the nature of human gait across walking speeds. Stability comparisons with other robotic platforms, an exoskeleton and a humanoid robot, are also provided.

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Section: Introductionmentioning

confidence: 99%

Balance stability characteristics of human walking with preferred, fast, and slow speeds

Peng

Kim

2022

Proceedings of the 7th International Digital Human Modeling Symposium -

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Three-dimensional variable center of mass height biped walking using a new model and nonlinear model predictive control

Xie,

Wang,

Luo

et al. 2024

Mechanism and Machine Theory

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Switched electromechanical dynamics for transient phase control of brushed DC servomotor

Peng

Song

Czarkowski

et al. 2022

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Robotic tasks often exceed the scope of steady-state or periodic behavior, which necessitates generally-applicable models of actuators intended to generate transient or aperiodic motion. However, existing electromechanical models of servomotors typically omit consideration of the switching power converter circuits required for directional, speed, or torque control. In this study, a multi-domain framework is established for switched electromechanical dynamics in servomotor systems for their analysis and control in general aperiodic tasks including transient phases. The switched electromechanical dynamics is derived from the individual models of the internal DC motor, gear train, and H-bridge circuit. The coupled models comprehensively integrate all possible distinct switching configurations of on-state, off-state, and dead time. A combination of cycle averaging with piecewise analytical solutions of the non-smooth dynamics is introduced to handle different temporal scales from high-frequency electrical to low-frequency mechanical variables. System parameters were estimated from experimental data using a dual-servomotor test platform. The model was validated for predictive accuracy against measured data in two distinct tasks—dynamic braking of a pendulum system and sinusoidal trajectory following. The model was also used to formulate the servomotor power consumption, which was implemented for optimal control demonstration and energy analysis. In particular, the servomotor power consumption model provided true optimality (minimization) when compared with the squared rotor torque and the positive rotor mechanical power that are commonly used as proxy models. While the focus of this work is on permanent-magnet, armature-controlled brushed DC servomotors, the approach is applicable to general electromechanical systems with switching-based control.

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Whole-body balance stability regions for multi-level momentum and stepping strategies

Cited by 7 publications

References 46 publications

Balance stability characteristics of human walking with preferred, fast, and slow speeds

Balance stability characteristics of human walking with preferred, fast, and slow speeds

Three-dimensional variable center of mass height biped walking using a new model and nonlinear model predictive control

Switched electromechanical dynamics for transient phase control of brushed DC servomotor

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