Papers by Eve Charbonneau
Sports Biomechanics, Mar 23, 2022
In acrobatic sports, twisting fast before piking allows athletes to enlarge their scoring potenti... more In acrobatic sports, twisting fast before piking allows athletes to enlarge their scoring potential. Since planning the arm and hip movements to twist fast is unintuitive, optimal control appears as a powerful and risk-free tool. To our knowledge, predictive simulations of human motion did not include self-collision avoidance constraints resulting potentially in unrealistic solutions. Our objective was to generate innovative and realistic twisting techniques for forward somersaults ending in pike position by solving an optimal control problem including non-collision constraints. Optimal techniques for one, two, or three twists before piking were generated by minimising the duration of the twisting and piking phases. The model was composed of five segments with one degree of freedom at the chest and two at the hips and shoulders. We explored local minima using a multi-start approach. Solutions were further analysed to assess the impact of non-collision constraints, the segments' contribution to twist creation, and their stability. For each desired number of twists, one relevant solution was chosen. Optimisation showed that trampolinists could attempt new acrobatics: forward triple twisting somersault ending in pike position. This research also shows that non-collision constraints strongly modify the optimal techniques without impairing significantly their performance.
Multibody System Dynamics, Oct 7, 2020
Looking for new arm strategies for better twisting performances during a backward somersault is o... more Looking for new arm strategies for better twisting performances during a backward somersault is of interest for the acrobatic sports community while being a complex mechanical problem due to the nonlinearity of the dynamics involved. As the pursued solutions are not intuitive, computer simulation is a relevant tool to explore a wider variety of techniques. Simulations of twisting somersaults have mainly been realized with planar arm motions. The aim of this study was to explore the outcomes of using 3D techniques, with the demonstration that increasing the fidelity of the model does not increase the level of control complexity on the real system. Optimal control was used to maximize twists in a backward straight somersault with both types of models. A multistart approach was used to find large sets of near-optimal solutions. The robustness of these solutions was then assessed by modeling kinematic noise during motion execution. The possibility of using quaternions for representing orientations in this numerical optimization problem was discussed. Optimized solutions showed that 3D techniques generated about two additional twists compared to 2D techniques. The robustness analysis revealed clusters of highly twisting and stable 3D solutions. This study demonstrates the superiority of 3D solutions for twisting in backward somersault, a result that can help acrobatic sports athletes to improve their twisting performance.
bioRxiv (Cold Spring Harbor Laboratory), Feb 27, 2021
Musculoskeletal simulations are useful in biomechanics to investigate the causes of movement diso... more Musculoskeletal simulations are useful in biomechanics to investigate the causes of movement disorder, to estimate non-measurable physiological quantities or to study the optimality of human movement. We introduce Bioptim, an easy-to-use Python framework for biomechanical optimal control, handling musculoskeletal models. Relying on algorithmic differentiation and the multiple shooting formulation, Bioptim interfaces nonlinear solvers to quickly provide dynamically consistent optimal solutions. The software is both computationally efficient (C++ core) and easily customizable, thanks to its Python interface. It allows to quickly define a variety of biomechanical problems such as motion tracking/prediction, muscle-driven simulations, parameters optimization, multiphase problems, etc. It is also intended for real-time applications such as moving horizon estimation and model predictive control. Six contrasting examples are presented, comprising various models, dynamics, objective functions and constraints. They include data-driven simulations (i.e., a multiphase muscle driven gait cycle and an upper-limb real-time moving horizon estimation of muscle forces) and predictive simulations (i.e., a muscle-driven pointing task, a twisting somersault with a quaternion-based model, a position controller using external forces, and a multiphase torque-driven maximum-height jump motion).
Social Science Research Network, 2022
Musculoskeletal simulations are useful in biomechanics to investigate the causes of movement diso... more Musculoskeletal simulations are useful in biomechanics to investigate the causes of movement disorder, to estimate non-measurable physiological quantities or to study the optimality of human movement. We introduce Bioptim, an easy-to-use Python framework for biomechanical optimal control, handling musculoskeletal models. Relying on algorithmic differentiation and the multiple shooting formulation, Bioptim interfaces nonlinear solvers to quickly provide dynamically consistent optimal solutions. The software is both computationally efficient (C++ core) and easily customizable, thanks to its Python interface. It allows to quickly define a variety of biomechanical problems such as motion tracking/prediction, muscle-driven simulations, parameters optimization, multiphase problems, etc. It is also intended for real-time applications such as moving horizon estimation and model predictive control. Six contrasting examples are presented, comprising various models, dynamics, objective functio...
Applied Sciences
Aerial twisting techniques are preferred by trampoline coaches for their balanced landings. As th... more Aerial twisting techniques are preferred by trampoline coaches for their balanced landings. As these techniques are not intuitive, computer simulation has been a relevant tool to explore a variety of techniques. Up to now, twisting somersaults were mainly simulated using arm abduction/adduction only (2D). Our objective was to explore more complex (3D) but still anatomically feasible arm techniques to find innovative and robust twisting techniques. The twist rotation was maximized in a straight backward somersault performed by a model including arm abduction/adduction with and without changes in the plane of elevation. A multi-start approach was used to find a series of locally optimal performances. Six of them were retained and their robustness was assessed by adding noise to the first half of the arm kinematics and then reoptimizing the second half of the skill. We found that aerial twist performance linearly correlates with the complexity of arm trajectory. Optimal techniques shar...
Multibody System Dynamics
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Papers by Eve Charbonneau