Non-Lipschitz dynamics; Underactuated mechanical system; Uniform stability; Vertically transverse functions Control system analysis; Control system stability; Dynamics; Electric drives; Mechanics; Nonlinear control systems; Stability; Stabilization; System stability; Autonomous systems; Equilibrium point; Function approaches; Lipschitz; Stability analysis; Under-actuated mechanical systems; Uniform stability; Uniqueness of solution; Closed loop control systems