{"id":612267,"date":"2019-09-06T13:00:39","date_gmt":"2019-09-06T20:00:39","guid":{"rendered":"https:\/\/www.microsoft.com\/en-us\/research\/?post_type=msr-research-item&p=612267"},"modified":"2019-10-02T12:11:09","modified_gmt":"2019-10-02T19:11:09","slug":"non-linear-invariants-for-control-command-systems","status":"publish","type":"msr-video","link":"https:\/\/www.microsoft.com\/en-us\/research\/video\/non-linear-invariants-for-control-command-systems\/","title":{"rendered":"Non-linear Invariants for Control-Command Systems"},"content":{"rendered":"
Control theorists know for long that quadratic invariants, that is ellipsoids, are a good solution to bound the behavior of linear controllers, which constitute the heart of most control-command systems. They designed methods to synthesize such invariants using some convex optimization techniques, namely semidefinite programming solvers. The first part of this talk will briefly introduce those methods.<\/p>\n
In practice, these techniques heavily rely on numerical computations performed using floating-point arithmetic, raising stringent soundness questions about their results. We will thus investigate solutions to formally validate such results and see that this is feasible with only a small overhead.<\/p>\n
Finally, we present a simple implementation in the Alt-Ergo SMT solver and comparison with other state-of-the-art SMT solvers on non-linear real arithmetic benchmarks. We also introduce an implementation in the Coq proof assistant with a reflexive tactic enabling to automatically discharge polynomial inequalities proofs. Benchmarks indicate that we are able to formally address problems that would otherwise be untractable with other state-of-the-art methods.<\/p>\n