from gekko import GEKKO
import numpy as np
import matplotlib.pyplot as plt

t = np.linspace(0,1,101)
m = GEKKO(remote=False); m.time=t

d = m.Param(np.cos(2*np.pi*t)+3)
g = m.Var(d[0])
J  = m.CV(0)
J.STATUS=1; J.SPHI=J.SPLO=0
J.WSPHI=1000; J.WSPLO=1
r = m.MV(0,lb=-1,ub=1); r.STATUS=1
m.Equations([g.dt()==r, J==d-g])
m.options.IMODE=6; m.solve()

plt.plot(t,g,'b:',label='Production')
plt.plot(t,d,'r-',label='Demand')
plt.plot(t,r,'k--',label='Ramp Rate')
plt.legend(); plt.grid(); plt.show()