TY - GEN
T1 - On the Derivation of the Contact Dynamics in Arbitrary Frames
T2 - 2022 IEEE-RAS 21st International Conference on Humanoid Robots, Humanoids 2022
AU - Kleff, Sebastien
AU - Carpentier, Justin
AU - Mansard, Nicolas
AU - Righetti, Ludovic
N1 - Funding Information:
1Tandon School of Engineering, New York University, Brooklyn, NY 2LAAS-CNRS, Université de Toulouse, CNRS, Toulouse 3Artificial and Natural Intelligence Toulouse Institute (ANITI), Toulouse 4Inria - Département d’Informatique de l’École Normale Supérieure, PSL Research University, Paris, France This work was in part supported by the National Science Foundation (grants 1825993, 1932187, 1925079 and 2026479), Meta Platforms Inc., and ANR Dynamo-grade (ANR-21-LCV3-0002)
Publisher Copyright:
© 2022 IEEE.
PY - 2022
Y1 - 2022
N2 - Contact dynamics relies on the simultaneous satisfaction of constraints at the robot body level and at the contact level. At both levels, various formulations can be chosen that all must lead to the same results, given the same hypothesis, hence the little importance of their details. Yet when using it in an optimal control problem, a particular formulation is often imposed by the task to be performed by the robot. In this paper, we detail the formulation of the contact quantities (force, movement) in an arbitrary frame imposed by the task. In that case, we will show that we are typically not interested in working in the local frame (attached to the robot contact point), nor in the world frame, but in a user-defined frame centered at the contact location with a fixed orientation in the world. The derivations can then be used for 6D, 3D or normal (pure-sliding) contact. We implemented the corresponding derivatives on top of the contact dynamics of the rigid-body dynamics library Pinocchio in the optimal control solver Crocoddyl. We show that a unique formulation is able to handle several operational orientations, by achieving several surfacing tasks in model predictive control with the robot Talos.
AB - Contact dynamics relies on the simultaneous satisfaction of constraints at the robot body level and at the contact level. At both levels, various formulations can be chosen that all must lead to the same results, given the same hypothesis, hence the little importance of their details. Yet when using it in an optimal control problem, a particular formulation is often imposed by the task to be performed by the robot. In this paper, we detail the formulation of the contact quantities (force, movement) in an arbitrary frame imposed by the task. In that case, we will show that we are typically not interested in working in the local frame (attached to the robot contact point), nor in the world frame, but in a user-defined frame centered at the contact location with a fixed orientation in the world. The derivations can then be used for 6D, 3D or normal (pure-sliding) contact. We implemented the corresponding derivatives on top of the contact dynamics of the rigid-body dynamics library Pinocchio in the optimal control solver Crocoddyl. We show that a unique formulation is able to handle several operational orientations, by achieving several surfacing tasks in model predictive control with the robot Talos.
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U2 - 10.1109/Humanoids53995.2022.10000208
DO - 10.1109/Humanoids53995.2022.10000208
M3 - Conference contribution
AN - SCOPUS:85146318209
T3 - IEEE-RAS International Conference on Humanoid Robots
SP - 512
EP - 517
BT - 2022 IEEE-RAS 21st International Conference on Humanoid Robots, Humanoids 2022
PB - IEEE Computer Society
Y2 - 28 November 2022 through 30 November 2022
ER -