S S symmetry Article Minimum Time Problem Controlled by Affine Connection Constantin Udriste *,†,‡ and Ionel Tevy ‡ Department of Mathematics and Informatics, Faculty of Applied Sciences, University Politehnica of Bucharest, Splaiul Independentei 313, Sector 6, 060042 Bucharest, Romania;
[email protected] * Correspondence:
[email protected]; Tel.: +40-745-371-684 † Second address: Academy of Romanian Scientists, Ilfov 3, Sector 5, 050044 Bucharest, Romania. ‡ These authors contributed equally to this work. Abstract: Geometrically, the affine connection is the main ingredient that underlies the covariant derivative, the parallel transport, the auto-parallel curves, the torsion tensor field, and the curvature tensor field on a finite-dimensional differentiable manifold. In this paper, we come up with a new idea of controllability and observability of states by using auto-parallel curves, and the minimum time problem controlled by the affine connection. The main contributions refer to the following: (i) auto- parallel curves controlled by a connection, (ii) reachability and controllability on the tangent bundle of a manifold, (iii) examples of equiaffine connections, (iv) minimum time problem controlled by a connection, (v) connectivity by stochastic perturbations of auto-parallel curves, and (vi) computing the optimal time and the optimal striking time. The connections with bounded pull-backs result in bang–bang optimal controls. Some significative examples on bi-dimensional manifolds clarify the intention of our paper and suggest possible applications. At the end, an example of minimum striking time with simulation results is presented. Keywords: affine connections; auto-parallel curves; minimum time optimal control; stochastic connectivity MSC: 53B05; 49K15; 70Q05; 60H10 Citation: Udriste, C.; Tevy, I.