Saddle–node bifurcation of invariant cones in 3D piecewise linear systems

In this work, the existence of a saddle–node bifurcation of invariant cones in three-dimensional continuous homogeneous piecewise linear systems is considered. First, we prove that invariant cones for this class of systems correspond one-to-one to periodic orbits of a continuous piecewise cubic system defined on the unit sphere. Second, let us give the conditions for which the sphere is foliated by a continuum of periodic orbits. The principal idea is looking for the periodic orbits of the continuum that persist when this situation is perturbed. To do this, we establish the relationship between the invariant cones of the three-dimensional system and the periodic orbits of two planar hybrid piecewise linear systems. Next, we define two functions whose zeros provide the invariant cones that persist under the perturbation. These functions will be called Melnikov functions and their properties allow us to state some results about the existence of invariant cones and other results about the existence of saddle–node bifurcations of invariant cones, which is the principal goal of this paper.

► The existence of invariant cones in three-dimensional piecewise linear systems is related to the stability of the origin. ► The invariant cones correspond to periodic orbits of planar hybrid piecewise linear systems. ► The Melnikov theory can be generalized to these hybrid systems. ► Its application give us results about the existence, uniqueness and bifurcations of invariant cones.