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## PathSim Example for PID-controller

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# IMPORTS ===============================================================================

import numpy as np

import matplotlib.pyplot as plt

from pathsim import Simulation, Connection

from pathsim.blocks import Source, Integrator, Amplifier, Adder, Scope, PID

from pathsim.solvers import RKCK54, RKBS32

# SYSTEM SETUP AND SIMULATION ===========================================================

#plant gain

K = 0.4

#pid parameters

Kp, Ki, Kd = 1.5, 0.5, 0.1

#source function

def f_s(t):

if t>60: return 0.5

elif t>20: return 1

else: return 0

#blocks

spt = Source(f_s)

err = Adder("+-")

pid = PID(Kp, Ki, Kd, f_max=10)

pnt = Integrator()

pgn = Amplifier(K)

sco = Scope(labels=["s(t)", "x(t)", r"$\epsilon(t)$"])

blocks = [spt, err, pid, pnt, pgn, sco]

connections = [

Connection(spt, err, sco[0]),

Connection(pgn, err[1], sco[1]),

Connection(err, pid, sco[2]),

Connection(pid, pnt),

Connection(pnt, pgn)

]

#simulation initialization

Sim = Simulation(blocks, connections, Solver=RKCK54)

# Run Example ===========================================================================

if __name__ == "__main__":

#run the simulation for some time

Sim.run(100)

sco.plot(lw=2)

plt.show()