Abstract:

The swing is regarded as a variable length simple pendulum. Based on the normalized Gauss function，the velocity of pendulum ball relative to pendulum rod is designed. On this basis，the nonlinear dynamic differential equation of swing is established，and the motion of swing is simulated numerically based on this mathematic model，the motion，work and energy transformation mechanism of swing are obtained.

Key words: swing, parametric self-excited oscillation, mathematic model, numerical simulation