@Graham 

Thanks for your concern. I've been able to linearize my system too. However, I have few concerns using MapleSim. I tried simulating double pendulum system on both MapleSim as well as Simulink. Using same parameters and ICs for simulations on both the platforms, I found out that position trajectories were very much different. I derived EOMs  manually and made a block diagram on Simulink and got results which were different from what I obtained using MapleSim. What could be the reason for this?

See the attached image for the analytical model of the system i'm working on. I hope seeing it, you'd be able to help appropriately...