Control
Sliding Surface
A sliding surface is the manifold in state space, defined by a switching function s(x) = 0, on which a sliding mode controller constrains the system to evolve. The surface is designed so that motion restricted to it exhibits the desired stable dynamics — for example, s = de + Le forces tracking error e to decay exponentially. Controller design then reduces to guaranteeing finite-time reaching and invariance of the surface.
Why it matters for physical AI
Surface design is where control objectives are encoded in sliding mode methods, translating tracking specifications for arms and vehicles into geometric constraints with provable convergence.
Build physical AI
Put these concepts to work on real hardware
Axol is a dual-arm robot built for physical AI — teleoperate it, collect demonstrations, and deploy learned policies out of the box.