When simulating the cartpole problem as an FMU in PyFMI I get different results giving the same input depending on if I use "model exchange" or "co-simulation". The ME results are correct, the CS results seem completely off.
Model exchange results
model = load_fmu(fmu='CartPole.fmu',
kind='ME')
model.set('theta_0', 0)
model.set('m_cart', 20)
model.set('m_pole', 5)
model.set('length', 2)
model.set('poleCartConnection.density', 0)
model.set('f', 0)
res = model.simulate(start_time=0, final_time=10)
plt.plot(res['f'])
plt.plot(res['x'])
plt.plot(res['x_dot'])
plt.plot(res['theta'])
plt.plot(res['theta_dot'])
plt.legend(['f', 'x', 'x_dot', 'theta', 'theta_dot'])
plt.show()
compared to (i.e. exactly the same but using CS instead of ME)
model = load_fmu(fmu='CartPole.fmu',
kind='CS')
model.set('theta_0', 0)
model.set('m_cart', 20)
model.set('m_pole', 5)
model.set('length', 2)
model.set('poleCartConnection.density', 0)
model.set('f', 0)
res = model.simulate(start_time=0, final_time=10)
plt.plot(res['f'])
plt.plot(res['x'])
plt.plot(res['x_dot'])
plt.plot(res['theta'])
plt.plot(res['theta_dot'])
plt.legend(['f', 'x', 'x_dot', 'theta', 'theta_dot'])
plt.show()
co-simulation results with default ncp
I suspect its due to the solver settings, but these cannot be set in the CS case? When I set the 'ncp' to a very high number, the error gets reduced. Many thanks in advance for your replies!
co-simulation results with high ncp
Cheers
