KPI: A Promptable Kernel for Physical Interaction on Humanoids

What happened

arXiv:2609.36151v1 Announce Type: new Abstract: Humanoids now walk, balance and reach with remarkable generality: one whole-body tracking policy follows references from a human, or from an end-to-end policy. That generality travels in the trajectory, and a trajectory alone carries limited information about the interaction it should produce: at contact, the executing controller determines how the robot behaves.

Single-task policies usually reach hard interactions by optimising trajectory and controller together in simulation; general stacks usually assume a preset or hand-chosen controller. Instead of a controller fixed before the task, the trajectory source sends a contract: per direction, track, comply, or hold a force range.

From tracking error and a wrench estimate, the kernel adapts the arms' stiffness, damping, reference and feedforward toward it at contact rate. In the winch demonstration, the humanoid is able to turn a crank to hoist a second robot fully off the ground.