MPC-based humanoid pursuit-evasion in the presence of obstacles

Abstract

We consider a pursuit-evasion problem between humanoids in the presence of obstacles. In our scenario, the pursuer enters the safety area of the evader headed for collision, while the latter executes a fast evasive motion. Control schemes are designed for both the pursuer and the evader. They are structurally identical, although the objectives are different: the pursuer tries to align its direction of motion with the lineof-sight to the evader, whereas the evader tries to move in a direction orthogonal to the line-of-sight to the pursuer. At the core of the control architecture is a Model Predictive Control scheme for generating a stable gait. This allows for the inclusion of workspace obstacles, which we take into account at two levels: during the determination of the footsteps orientation and as an explicit MPC constraint. We illustrate the results with simulations on NAO humanoids.

A behavior-based framework for safe deployment of humanoid robots

“…Wrapping up, we may say that adapt_footsteps takes into account the presence of unexpected stationary objects in the robot path at two levels: in the cost function of the footstep orientation QP, and through the introduction of a collision avoidance constraint in the footstep position QP as well as in IS-MPC. Results in a variety of environments prove that this strategy is effective for collision-free locomotion (De Simone et al 2017). As shown in the next two sections, this will be confirmed by both our simulations and experiments.…”

Closed-loop MPC with Dense Visual SLAM - Stability through Reactive Stepping

“…Footsteps, CoM and ZMP trajectories are chosen accordingly. This work has previously been demonstrated for open-loop control of a NAO humanoid robot, including pursuit avoidance scenarios in the presence of obstacles [21]. However, it has never been demonstrated applied to large-scale humanoids such as HRP-4.…”

Humanoid Robots in Aircraft Manufacturing: The Airbus Use Cases

“…Alternative ones investigate the more general concept of boundedness [13]. One approach to integrate safety guidelines with respect to surrounding humans is to adapt the current goal of the robot w.r.t the current state of the environment [14]. One can also integrate collision mitigation and passive safety constraints directly in a combination of stages (i) and (ii) [12].…”

“…Override behaviors (e.g., emergency stop) will stop the execution of the current task and lead to a state from which normal operation can only be resumed by means of human intervention. Temporary override behaviors (e.g., evasion [14]) will also suspend task execution, but only for the limited amount of time needed to handle the safety concerns, after which task execution is automatically resumed. Finally, proactive behaviors (e.g., human visual tracking or footstep adaptation) do not stop the task, but try to increase the overall safety level by calling for a modification of the current robot activity.…”