Hopf bifurcation analysis and ultimate bound estimation of a new 4-D quadratic autonomous hyper-chaotic system

Abstract

Based on Lorenz system, a new four-dimensional quadratic autonomous hyper-chaotic attractor is presented in this paper. It can generate double-wing chaotic and hyper-chaotic attractors with only one equilibrium point. Several properties of the new system are investigated using Lyapunov exponents spectrum, bifurcation diagram and phase portraits. Using the center manifold and normal form theories, the local dynamics, the stability and Hopf bifurcation at the equilibrium point are analyzed. To obtain the ellipsoidal ultimate bound, the ultimate bound of the proposed system is theoretically estimated using Lagrange multiplier method, Lagrangian function and local maximizer point. By properly choosing P and Q matrices, an estimation of the ultimate bound region, as a function of the Lagrange coefficient, is obtained using local maximizer point and reduced Hessian matrix. To demonstrate the evolution of the bifurcation and to show the ultimate bound region, numerical simulations are provided.