Systems and methods for evaluating stability of software code for control systems
View Patent ↗In one embodiment, a method of evaluating stability of software code for a control system includes receiving a set of initial trajectories by a semidefinite programming solver module, and determining one or more candidate Lyapunov functions based on the set of initial trajectories. The method further includes performing a plurality of simulations using a model of the control system to create a set of discovered trajectories, and evaluating the set of discovered trajectories to determine one or more counterexample trajectories that violate one or more Lyapunov conditions. If one or more counterexample trajectories are discovered, then the method includes inputting the set of discovered trajectories including the one or more counterexample trajectories into the semidefinite programming solver module, and determining, by the semidefinite programming solver module, one or more additional candidate Lyapunov functions from the set of initial trajectories and the set of discovered trajectories.
1. A method of evaluating stability of software code for a control system, the method comprising:
receiving a set of initial trajectories;
determining, by a semidefinite programming solver module, one or more candidate Lyapunov functions based on the set of initial trajectories;
performing a plurality of simulations using a model of the control system to create a set of discovered trajectories; and
evaluating the set of discovered trajectories to determine one or more counterexample trajectories that violate one or more Lyapunov conditions, wherein if one or more counterexample trajectories are discovered:
inputting the set of discovered trajectories including the one or more counterexample trajectories into the semidefinite programming solver module; and
determining, by the semidefinite programming solver module, one or more additional candidate Lyapunov functions based on the set of initial trajectories and the set of discovered trajectories.
2. The method of claim 1 , further comprising, if no candidate Lyapunov functions are found, indicating instability of the software code.
3. The method of claim 1 , further comprising, if no counterexample trajectories are discovered, indicating stability of the software code.
4. The method of claim 1 , wherein the set of initial trajectories comprise simulated trajectories and/or experimental trajectories.
5. The method of claim 1 , further comprising, if no counterexample trajectories are discovered, performing a convex optimization on the set of initial trajectories and the set of discovered trajectories to determine an invariant set of trajectories.
6. The method of claim 5 , wherein the convex optimization is provided by the sum-of-squares technique.
7. The method of claim 5 , further comprising:
executing the software code in the control system to obtain experimental data; and
comparing the experimental data to the invariant set of trajectories.
8. The method of claim 1 , wherein the set of discovered trajectories are evaluated to determine the one or more counterexample trajectories by a non-convex, global optimization process.
9. The method of claim 1 , wherein the model of the control system is a continuous state-space model.
10. The method of claim 1 , further comprising:
executing the software code in the control system to obtain experimental trajectories; and
inputting the experimental trajectories into the semidefinite programming solver module to determine one or more candidate Lyapunov functions.
11. A computer-program product for use with a computing device for evaluating stability of software code for a control system, the computer-program product comprising:
a non-transitory computer-readable medium storing computer-executable instructions that, when executed by the computing device, cause the computing device to:
receive a set of initial trajectories;
determine one or more candidate Lyapunov functions based on the set of initial trajectories using a semidefinite programming solver module;
perform a plurality of simulations using a model of the control system to create a set of discovered trajectories; and
evaluate the set of discovered trajectories to determine one or more counterexample trajectories that violate one or more Lyapunov conditions, wherein, if one or more counterexample trajectories are discovered, the computer-executable instructions further cause the computing device to:
input the set of discovered trajectories including the one or more counterexample trajectories into the semidefinite programming solver module; and
determine one or more additional candidate Lyapunov functions based on the set of initial trajectories and the set of discovered trajectories.
12. The computer-program product of claim 11 , wherein if no candidate Lyapunov functions are found, the computer-executable instructions cause the computing device to indicate instability of the software code.
13. The computer-program product of claim 11 , wherein if no counterexample trajectories are discovered, the computer-executable instructions cause the computing device to indicate stability of the software code.
14. The computer-program product of claim 11 , wherein the set of initial trajectories comprise simulated trajectories and/or experimental trajectories.
15. The computer-program product of claim 11 , wherein if no counterexample trajectories are discovered the computer-executable instructions cause the computing device to perform a convex optimization on the set of initial trajectories and the set of discovered trajectories to determine an invariant set of trajectories.
16. The computer-program product of claim 15 , wherein the convex optimization is provided by the sum-of-squares technique.
17. The computer-program product of claim 11 , wherein the set of discovered trajectories are evaluated to determine the one or more counterexample trajectories by a non-convex, global optimization process.
18. The computer-program product of claim 11 , wherein the software code is for one or more vehicle systems.
19. A method of evaluating stability of software code for a control system, the method comprising:
receiving a set of initial trajectories;
determining, by a semidefinite programming solver module, one or more candidate Lyapunov functions based on the set of initial trajectories;
performing a plurality of simulations of the control system to create a set of discovered trajectories; and
evaluating the set of discovered trajectories to determine one or more counterexample trajectories that violate one or more Lyapunov conditions, wherein:
if no candidate Lyapunov functions are found, indicating instability of the software code;
if one or more counterexample trajectories are discovered:
inputting the set of discovered trajectories including the one or more counterexample trajectories into the semidefinite programming solver module; and
determining, by the semidefinite programming solver module, one or more additional candidate Lyapunov functions based on the set of initial trajectories and the set of discovered trajectories; and
if no counterexample trajectories are discovered, performing a convex optimization on the set of initial trajectories and the set of discovered trajectories to determine an invariant set of trajectories.
20. The method of claim 19 , wherein the software code is for one or more vehicle systems.