Research on Planar Double Compound Pendulum Based on RK-8 Algorithm

Establishing the Lagrangian equation of double complex pendulum system and obtaining the dynamic differential equation, we can analyze the motion law of double compound pendulum with application of the numerical simulation of RK-8 algorithm. When the double compound pendulum swings at a small angle, the Lagrangian equation can be simplified and the normal solution of the system can be solved. And we can walk further on the relationship between normal frequency and swing frequency of double pendulum. When the external force of normal frequency is applied to the double compound pendulum, the forced vibration of the double compound pendulum will show the characteristics of beats.