This paper presents a method for humanoid push recovery in the general context of multiple non-coplanar contacts. The method consists of a controller that minimizes the kinetic energy of a perturbed whole body humanoid system, while controlling the support change to achieve the stabilization (or push recovery) of the system. The controller uses a simple model based approach to determine the necessity of support change and in this case to approximate a new contact position that allows to stabilize the system. The controller is tested on a simulated humanoid robot and it succeeds in stabilizing the robot in coplanar and non-coplanar environments.

This paper presents a new computational approach for humanoid push recovery in a generalized noncoplanar multicontact context. Our approach is based on a simplified model and consists of two main steps. The first one predicts whether the perturbed system can be stopped in a final static state while maintaining fixed contacts with the environment. This prediction can be seen as a dynamic stability indicator. The second one consists of a strategy that stabilizes the system, when stability cannot be reached, through a contact change chosen as the best one among a set of a priori possible contact changes.

While realizing a task, human-beings are able to use grasping inside their environment in order to keep the most stable balance. Although such a behavior is quite natural for humans, it is very difficult to find the best formulation to adapt human motion to humanoid robots. This paper proposes a conceptually simple framework of human posture control based on optimization which takes into account grasp and friction and achieves robustness against external disturbances. A new stability criteria is also introduced. Contrary to most other approaches, our method deals not only with unilateral contacts with friction but also with bilateral grasps. This allows for arbitrarily pulling, pushing or twisting on a handhold. Additionally, and in contrast to classical methods based on ZMP, our method also accounts for contacts not being all in the same plane.