Problem Equation Φ，'=Q4 is computationally feasible However A good estimate of the equilibrium position is needed as a starting point for iterative computation The difficulty associated with unstable equilibrium configuration The principle of minimum total potential energy is employed in order to avoid the difficulty• A good estimate of the equilibrium position is needed as a starting point for iterative computation • The difficulty associated with unstable equilibrium configuration is computationally feasible T A Equation  q   Q However The principle of minimum total potential energy is employed in order to avoid the difficulty Problem