4.3 KiB
routh_table
This repo is belong to Control System class contains with Automated Routh Table Calculator based on Python. This code 100% original made by my hand :), please leave some notes if you're going to use it. Thanks!
Libraries
Libraries that used in this program is numpy and pandas. numpy works to define and perform array while pandas is the final form after numpy.array to simplify the presentation. They imported by write..
import numpy as np
import pandas as pd
RouthStability Class
This class contains lots of procedures to simplify our Routh Stability Table Generator process.
def __init__(self, den):
self.den = np.array([float(item) for item in den.split()])
self.deg = len(self.den)
The constructor __init__ takes string of coefficiens from polynomial, extract the number, and load into class variable. It also define self.deg variable to save array's length, reducing number to calling len() function
def set_k(self, k):
self.den = np.append(self.den, float(k))
self.deg += 1
This function only takes one number from user and append it to self.den which defined as gain (constant). Also self.deg will increase by one
def calc_routh(self):
height = (self.deg+1)//2
arr = np.zeros((height + 2,height))
for index in range(self.deg):
if index % 2 == 0:
arr[0][index//2] = self.den[index]
else:
arr[1][(index-1)//2] = self.den[index]
for i in range(2, height+2):
for j in range(height-1):
arr[i][j] = (arr[i-1][0]*arr[i-2][j+1] - arr[i-2][0]*arr[i-1][j+1])//2
arr[i][j] += 0
self.df = pd.DataFrame(arr)
self.show_tab()
if self.is_stable() == True:
print("SYSTEM IS STABLE")
else:
print("SYSTEM IS UNSTABLE")
calc_routh(self) as the core process of this class contains initialization and process about Routh Stability Process. Firstly, it define an empty zero (basically it filled with zeros) and iteratively being inserted by self.den (refering to Routh Table principle). After that, each cell will be updated by calculating Routh Table formula. Routh Table defined as numpy.ndarray and converted to pandas.DataFrame to simplify the presentation of table. self.show_tab() is called to print the Routh Table and self.is_stable() to check system's stability.
def show_tab(self):
print(self.df)
This function print the Routh Table, should be called only if Routh Table is generated by calc_routh
def get_table(self):
return self.df
This function return pandas.DataFrame contained by Routh Table
def is_stable(self):
flag = True
for item in self.df[0]:
if item < 0: flag = False
return flag
This function check the first column's value from Routh Table. The system is define as stable if and only if all the value is positive, else it's unstable
def get_poly(self, x):
total = 0
for i in range(self.deg):
total += self.den[self.deg-i-1]*(x**i)
print(total)
return total
This function initialize x value as variable on self.den polynomial and return the total
Testing 1
The testing can follow below example:
# First Testing
den = input("Enter your polynomial: ")
k_in = input("Enter your K: ")
rs = RouthStability(den)
rs.set_k(k_in)
rs.calc_routh()
It takes coefficient of polynomial and K from user, insert it into RouthStability class as constructor parameter, insert the K value, and generate Routh Table. The result can be found below:
Enter your polynomial: 1 2 3 4 5
Enter your K: 6
0 1 2
0 1.0 3.0 5.0
1 2.0 4.0 6.0
2 1.0 2.0 0.0
3 0.0 3.0 0.0
4 -2.0 0.0 0.0
SYSTEM IS UNSTABLE
Testing 2
Enter your polynomial: 12 56 37 80
Enter your K: 17
0 1 2
0 12.0 37.0 17.0
1 56.0 80.0 0.0
2 556.0 476.0 0.0
3 8912.0 0.0 0.0
4 2121056.0 0.0 0.0
SYSTEM IS STABLE
Testing 3
Enter your polynomial: 1.2 6.81 7.31
Enter your K: 3.141
0 1
0 1.20 7.310
1 6.81 3.141
2 23.00 0.000
3 36.00 0.000
SYSTEM IS STABLE
Notes
Contact nanda.r.d@mail.ugm.ac.id for more information
Links
You can access the source code here github.com/nandard/routh_table.git