Composing Dynamical Systems to Realize Dynamic Robotic Dancing

Kolathaya, Shishir; Ma, Wen-Loong; Ames, Aaron D.

doi:10.1007/978-3-319-16595-0_25

Cited by 3 publications

(8 citation statements)

References 15 publications

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“…, ε N } with each ε i belonging to the set (0, 1) for all the human-inspired controllers in each domain D v as defined in Eqs. (32) and (34), O = ι 0 (O Z ) is an exponentially stable periodic orbit for the full-order dynamics of the multi-domain hybrid system Eq. (2).…”

Section: Resultsmentioning

confidence: 99%

“…[43] we know that the human-inspired controllers as defined in Eqs. (32) and (34) are Lipschitz continuous and belong to the rapidly exponential stable-control Lyapunov function (RES-CLF) based control set K ε as defined in ref. [43] which therefore illustrates the proof of this theorem.…”

Section: Resultsmentioning

confidence: 99%

“…Multi-domain robotic locomotion can be formally modeled as a hybrid control system, 31,32 which is given by the following tuple:…”

Section: Hybrid System Modelmentioning

confidence: 99%

“…With the feedback control laws Eqs. (32) and (34) in hand, the next step is to find such a parameter set α that a hybrid periodic orbit can be obtained for the multi-domain locomotion system. Guided by this objective , an optimization problem that yields the parameter set α will be presented in the next section.…”

Section: Control Law Constructionmentioning

confidence: 99%

“…(4) and the human-inspired controller defined as in Eqs. (32) and (34) , has PHZD if e (S e ∩ PZ α sor(e) ) ⊂ PZ α tar(e) (40) for each transition e ∈ E. Therefore, in the case of AMBER2 with three transitions, i.e., e ∈ E R , three sets of PHZD constraints have to be constructed. For the case of ATRIAS with two transitions, i.e., e ∈ E S , two sets of PHZD constraints have to be developed correspondingly.…”

Section: Partial Hybrid Zero Dynamicsmentioning

confidence: 99%

See 4 more Smart Citations

Multi-contact bipedal robotic locomotion

Zhao¹,

Hereid²,

Ma³

et al. 2015

Robotica

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This paper presents a formal framework for achieving multi-contact bipedal robotic walking, and realizes this methodology experimentally on two robotic platforms: AMBER2 and Assume The Robot Is A Sphere (ATRIAS). Inspired by the key feature encoded in human walkingmulti-contact behavior-this approach begins with the analysis of human locomotion and uses it to motivate the construction of a hybrid system model representing a multi-contact robotic walking gait. Human-inspired outputs are extracted from reference locomotion data to characterize the human model or the spring-loaded invert pendulum (SLIP) model, and then employed to develop the human-inspired control and an optimization problem that yields stable multi-domain walking. Through a trajectory reconstruction strategy motivated by the process that generates the walking gait, the mathematical constructions are successfully translated to the two physical robots experimentally.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…Multi-domain robotic locomotion can be formally modeled as a hybrid control system, 31,32 which is given by the following tuple:…”

Section: Hybrid System Modelmentioning

confidence: 99%

Section: Control Law Constructionmentioning

confidence: 99%

Section: Partial Hybrid Zero Dynamicsmentioning

confidence: 99%

See 3 more Smart Citations

Multi-contact bipedal robotic locomotion

Zhao¹,

Hereid²,

Ma³

et al. 2015

Robotica

Self Cite

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Dynamic Walking on Slippery Surfaces : Demonstrating Stable Bipedal Gaits with Planned Ground Slippage

Ames

2019

2019 International Conference on Robotics and Automation (ICRA)

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Dynamic bipedal robot locomotion has achieved remarkable success due in part to recent advances in trajectory generation and nonlinear control for stabilization. A key assumption utilized in both theory and experiments is that the robot's stance foot always makes no-slip contact with the ground, including at impacts. This assumption breaks down on slippery low-friction surfaces, as commonly encountered in outdoor terrains, leading to failure and loss of stability. In this work, we extend the theoretical analysis and trajectory optimization to account for stick-slip transitions at point foot contact using Coulomb's friction law. Using AMBER-3M planar biped robot as an experimental platform, we demonstrate for the first time a slippery walking gait which can be stabilized successfully both on a lubricated surface and on a rough no-slip surface. We also study the influence of foot slippage on reducing the mechanical cost of transport, and compare energy efficiency in both numerical simulations and experimental measurements.

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Adaptive Feedback Regulator for Powered Lower-Limb Exoskeleton under Model Uncertainty

Thakkar,

Paredes,

Hereid

2021

Preprint

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This paper presents a neural network (NN) based adaptive feedback regulator to ensure the lateral and longitudinal stability and regulate the desired walking velocity of a lowerlimb exoskeleton under model uncertainty. The traditional model-based controllers for lower-limb exoskeletons often fail to stabilize the robot or accurately track the desired behaviors under model uncertainties or external disturbances. This paper proposes a neural network (NN) based online adaptive regulator that compensates for the unknown changes in model parameters and external disturbances by modifying the nominal joint trajectory. A gradient descent-based delta rule is implemented to update the weights of a single layer NN, which can be efficiently performed online by design. We demonstrate the performance of the presented regulator on ATALANTE, a fully actuated lower limb exoskeleton designed for paraplegic patients. The simulation results show that the proposed approach noticeably improves stability and the tracking performance of the system, despite significant changes in model parameters and large adversarial pushes.

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Composing Dynamical Systems to Realize Dynamic Robotic Dancing

Cited by 3 publications

References 15 publications

Multi-contact bipedal robotic locomotion

Multi-contact bipedal robotic locomotion

Dynamic Walking on Slippery Surfaces : Demonstrating Stable Bipedal Gaits with Planned Ground Slippage

Adaptive Feedback Regulator for Powered Lower-Limb Exoskeleton under Model Uncertainty

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