A computational method for the synthesis of time-optimal feedback control laws for linear nilpotent systems is proposed. The method is based on the use of the bang-bang theorem, which leads to a characterization of the time-optimal trajectory as a parameter-dependent polynomial system for the control switching sequence. A deflated Newton’s method is then applied to exhaust all the real roots of the polynomial system. The root-finding procedure is informed by the Hermite quadratic form, which provides a sharp estimate of the number of real roots to be found. In the second part of this paper, the polynomial systems are sampled and solved to generate a synthetic dataset for the construction of a time-optimal deep neural network (NN)—interpreted as a binary classifier—via supervised learning. Numerical tests in integrators of increasing dimension assess the accuracy, robustness, and real-time control capabilities of the approximate control law.
| [1] |
Albi, G., Bicego, S., Herty, M., Huang, Y., Kalise, D., Segala, C.: Data/moment-driven approaches for fast predictive control of collective dynamics. In: Daniilidis, A., Grüne, L., Haunschmied, J., Tragler, G. (eds) Model Predictive Control. Dynamic Modeling and Econometrics in Economics and Finance, vol. 31, pp. 29–54. Springer, Cham (2025)
|
| [2] |
Azmi B, Kalise D, Kunisch KOptimal feedback law recovery by gradient-augmented sparse polynomial regression. J. Mach. Learn. Res., 2021, 22(48): 1-32
|
| [3] |
Basu, S., Pollack, R., Roy, M.: Algorithms in Real Algebraic Geometry. Algorithms and Computation in Mathematics, 2nd ed. Springer, Berlin, Heidelberg (2006)
|
| [4] |
Bellman R, Glicksberg I, Gross OOn the “bang-bang” control problem. Q. Appl. Math., 1956, 14: 11-18.
|
| [5] |
Ben-Or M, Kozen D, Reif JThe complexity of elementary algebra and geometry. J. Comput. Syst. Sci., 1986, 32: 251-264.
|
| [6] |
Bicego S, Kalise D, Pavliotis GAComputation and control of unstable steady states for mean field multiagent systems. Proc. Roy. Soc. A, 2025, 481: 20240476.
|
| [7] |
Bonnard, B., Cots, O., Privat, Y., Trélat, E.: Zermelo navigation on the sphere with revolution metrics. In: Ivan Kupka Legacy: a Tour Through Controlled Dynamics. Volume 12 of AIMS on Applied Mathematics, pp. 35–65. American Institute of Mathematical Sciences, Springfield (2023)
|
| [8] |
Brown, K., Gearhart, W.: Deflation techniques for the calculation of further solutions of a nonlinear system. Numerische Mathematik 16, 334–342 (1970/1971)
|
| [9] |
Charalampidis, E., Boullé, N., Farrell, P., Kevrekidis, P.: Bifurcation analysis of stationary solutions of two-dimensional coupled Gross-Pitaevskii equations using deflated continuation. Commun. Nonlinear Sci. Numer. Simul. 87, 105255 (2020)
|
| [10] |
Chen, C.-T., Desoer, C.: A proof of controllability of Jordan form state equations. IEEE Trans. Autom. Control 13, 195–196 (1968)
|
| [11] |
Cipriani, C., Scagliotti, A., Wöhrer, T.: A minimax optimal control approach for robust neural ODEs. In: 2024 European Control Conference (ECC), pp. 58–64. IEEE (2024)
|
| [12] |
Cohen, C.: Formalization of a sign determination algorithm in real algebraic geometry. https://inria.hal.science/hal-03274013 (2021)
|
| [13] |
Cox, D., Little, J., O’Shea, D.: Ideals, Varieties, and Algorithms. Undergraduate Texts in Mathematics, 4th ed. Springer, Cham (2015)
|
| [14] |
Dolgov, S., Kalise, D., Saluzzi, L.: Data-driven tensor train gradient cross approximation for Hamilton-Jacobi-Bellman equations. SIAM J. Sci. Comput. 45(5), A2153–A2184 (2023)
|
| [15] |
Dubé TThe structure of polynomial ideals and Gröbner bases. SIAM J. Comput., 1990, 19(4): 750-773.
|
| [16] |
Farrell P, Birkisson A, Funke SDeflation techniques for finding distinct solutions of nonlinear partial differential equations. SIAM J. Sci. Comput., 2015, 37(4): A2026-A2045.
|
| [17] |
Gaillard, L., Safey El Din, M.: Solving parameter-dependent semi-algebraic systems. In: International Symposium on Symbolic and Algebraic Computation, pp. 447–456 (2024)
|
| [18] |
Grayson, D., Stillman, M.: Macaulay2, a software system for research in algebraic geometry. Available at https://macaulay2.com (2026)
|
| [19] |
Karg B, Lucia SEfficient representation and approximation of model predictive control laws via deep learning. IEEE Trans. Cybern., 2020, 50(9): 3866-3878.
|
| [20] |
Kingma, D., Ba, J.: Adam: a method for stochastic optimization. In: Bengio, Y., LeCun, Y. (eds) International Conference on Learning Representations, ICLR 2015, San Diego, CA, USA, May 7–9, 2015 (2015)
|
| [21] |
LaSalle, J.: Time optimal control systems. Proc. Natl. Acad. Sci. USA 45, 573–577 (1959)
|
| [22] |
Li, L., Wang, L., Li, H.: An efficient spectral trust-region deflation method for multiple solutions. J. Sci. Comput. 95(32) (2023)
|
| [23] |
Lopez, J., Maluccio, K., Sottile, F., Yahl, T.: Realroots, version 0.1. Macaulay2 package. Available at https://macaulay2.com/doc/Macaulay2/share/doc/Macaulay2/RealRoots/html/index.html (2026)
|
| [24] |
Nakamura-Zimmerer, T., Gong, Q., Kang, W.: Adaptive deep learning for high-dimensional Hamilton-Jacobi-Bellman equations. SIAM J. Sci. Comput. 43(2), A1221–A1247 (2021)
|
| [25] |
Oster, M., Saluzzi, L., Wenzel, T.: A comparison study of supervised learning techniques for the approximation of high dimensional functions and feedback control. Dyn. Games Appl. 15, 454–480 (2025)
|
| [26] |
Park, H., Regensburger, G.: Gröbner Bases in Control Theory and Signal Processing. De Gruyter, Berlin, Boston (2007)
|
| [27] |
Patil D, Mulla A, Chakraborty D, Pillai HComputation of feedback control for time optimal state transfer using Groebner basis. Syst. Control Lett., 2015, 791-7.
|
| [28] |
Patil DU, Chakraborty DComputation of time optimal feedback control using Groebner basis. IEEE Trans. Autom. Control, 2014, 59(8): 2271-2276.
|
| [29] |
Phuoc Le H, Safey El Din MSolving parametric systems of polynomial equations over the reals through Hermite matrices. J. Symb. Comput., 2022, 112: 25-61.
|
| [30] |
Pontryagin, L., Boltyanskii, V., Gamkrelidze, R., Mishchenko, E.: The Mathematical Theory of Optimal Processes. A Pergamon Press Book. The Macmillan Company, New York (1964). (Translated by D. E. Brown)
|
| [31] |
Rauscher, F., Sawodny, O.: Efficient online trajectory planning for integrator chain dynamics using polynomial elimination. IEEE Robot. Autom. Lett. 6(3) (2021)
|
| [32] |
Sylvester JOn a remarkable modification of Sturm’s theorem. Lond. Edinb. Dublin Philos. Mag. J. Sci., 1853, 5: 446-456.
|
| [33] |
Vu DC, Pham MD, Nguyen TTH, Nguyen TVA, Nguyen TLTime-optimal trajectory generation and observer-based hierarchical sliding mode control for ballbots with system constraints. Int. J. Robust Nonlinear Control, 2024, 34(11): 7580-7610.
|
| [34] |
Walther U, Georgiou T, Tannenbaum AOn the computation of switching surfaces in optimal control: a Gröbner basis approach. IEEE Trans. Autom. Control, 2001, 46(4): 534-540.
|
| [35] |
Wang Y, Hu C, Li Z, Lin S, He S, Zhu YTime-optimal control for high-order chain-of-integrators systems with full state constraints and arbitrary terminal states. IEEE Trans. Autom. Control, 2025, 70(3): 1499-1514.
|
Funding
Air Force Office of Scientific Research(FA8655-26-1-B011)
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