2PAC: Two Point Attractors for Center of Mass Trajectories in Multi Contact Scenarios

Steve Tonneau 1 Andrea Prete 1 Julien Pettré 2 Nicolas Mansard 1
1 LAAS-GEPETTO - Équipe Mouvement des Systèmes Anthropomorphes
LAAS - Laboratoire d'analyse et d'architecture des systèmes [Toulouse]
2 Lagadic - Visual servoing in robotics, computer vision, and augmented reality
CRISAM - Inria Sophia Antipolis - Méditerranée , Inria Rennes – Bretagne Atlantique , IRISA_D5 - SIGNAUX ET IMAGES NUMÉRIQUES, ROBOTIQUE
Abstract : Synthesizing motions for legged characters in arbitrary environments is a long-standing problem that has recently received a lot of attention from the computer graphics community. We tackle this problem with a procedural approach that is generic, fully automatic and independent from motion capture data. The main contribution of this paper is a point-mass-model-based method to synthesize Center Of Mass trajectories. These trajectories are then used to generate the whole-body motion of the character. The use of a point mass model often results in physically inconsistent motions and joint limit violations. We mitigate these issues through the use of a novel formulation of the kinematic constraints which allows us to generate a quasi-static Center Of Mass trajectory, in a way that is both user-friendly and computationally efficient. We also show that the quasi-static constraint can be relaxed to generate motions usable for applications of computer graphics (on average 83% of a given trajectory remain physically consistent). Our method was integrated in our open-source contact planner and tested with different scenarios-some never addressed before-featuring legged characters performing non-gaited motions in cluttered environments. The computational efficiency of our trajectory generation algorithm (under ten ms to compute one second of motion) enables us to synthesize motions in a few seconds, one order of magnitude faster than state-of-the-art methods.
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Contributor : Steve Tonneau <>
Submitted on : Tuesday, October 10, 2017 - 2:32:58 PM
Last modification on : Friday, October 13, 2017 - 1:17:32 AM


  • HAL Id : hal-01609055, version 1


Steve Tonneau, Andrea Prete, Julien Pettré, Nicolas Mansard. 2PAC: Two Point Attractors for Center of Mass Trajectories in Multi Contact Scenarios. 2017. 〈hal-01609055〉



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