119 lines
3.2 KiB
Python
119 lines
3.2 KiB
Python
#! /usr/bin/env python
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# -*- coding: utf-8 -*-
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# vim:fenc=utf-8
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#
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# Copyright © 2019 <pavle.portic@tilda.center>
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#
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# Distributed under terms of the BSD 3-Clause license.
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import argparse
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import numpy as np
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import csv
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from scipy.integrate import odeint
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DEFAULT_RESOLUTION = 6
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DEFAULT_TMAX = 30
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DEFAULT_DT = 0.01
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DEFAULT_L1 = 1
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DEFAULT_L2 = 1
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DEFAULT_M1 = 1
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DEFAULT_M2 = 1
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# The gravitational acceleration (m.s-2).
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g = 9.81
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def deriv(y, t, L1, L2, m1, m2):
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theta1, z1, theta2, z2 = y
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c, s = np.cos(theta1 - theta2), np.sin(theta1 - theta2)
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theta1dot = z1
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z1dot = (m2 * g * np.sin(theta2) * c - m2 * s * (L1 * z1**2 * c + L2 * z2**2) - (m1 + m2) * g * np.sin(theta1)) / L1 / (m1 + m2 * s**2)
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theta2dot = z2
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z2dot = ((m1 + m2) * (L1 * z1**2 * s - g * np.sin(theta2) + g * np.sin(theta1) * c) + m2 * L2 * z2**2 * s * c) / L2 / (m1 + m2 * s**2)
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return theta1dot, z1dot, theta2dot, z2dot
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def solve(L1, L2, m1, m2, tmax, dt, y0):
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t = np.arange(0, tmax + dt, dt)
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y = odeint(deriv, y0, t, args=(L1, L2, m1, m2))
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return y[:, 0], y[:, 2]
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def gen_simulation_model_params(theta_resolution):
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search_space = np.linspace(0, 2 * np.pi, theta_resolution)
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for theta1_init in search_space:
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for theta2_init in search_space:
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yield theta1_init, theta2_init
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def simulate_pendulum(theta_resolution, dt=DEFAULT_DT, tmax=DEFAULT_TMAX, L1=DEFAULT_L1, L2=DEFAULT_L2, m1=DEFAULT_M1, m2=DEFAULT_M2):
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for theta1_init, theta2_init in gen_simulation_model_params(theta_resolution):
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y0 = np.array([theta1_init, 0, theta2_init, 0])
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theta1, theta2 = solve(L1, L2, m1, m2, tmax, dt, y0)
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yield theta1_init, theta2_init, theta1[-1], theta2[-1]
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def convert_results(results):
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for r in results:
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yield {
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'theta1_init': r[0],
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'theta2_init': r[1],
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'theta1': r[2],
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'theta2': r[3],
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}
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def write_csv(file_name, results):
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with open(file_name, 'w', newline='') as csvfile:
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fieldnames = ['theta1_init', 'theta2_init', 'theta1', 'theta2']
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writer = csv.DictWriter(csvfile, fieldnames=fieldnames, delimiter=',')
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writer.writeheader()
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writer.writerows(results)
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def main():
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parser = argparse.ArgumentParser()
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parser.add_argument(
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'results_file',
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help="Filename where the results will be stored, in CSV format"
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)
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parser.add_argument(
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'-r',
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'--resolution',
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metavar='NUM',
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type=int,
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default=DEFAULT_RESOLUTION,
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help="Resolution, %d by default" % DEFAULT_RESOLUTION
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)
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parser.add_argument(
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'--tmax',
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metavar='NUM',
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type=float,
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default=DEFAULT_TMAX,
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help="Simulation time, %f by default" % DEFAULT_TMAX
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)
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parser.add_argument(
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'--dt',
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metavar='NUM',
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type=float,
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default=DEFAULT_DT,
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help="Simulation time step, %f by default" % DEFAULT_DT
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)
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args = parser.parse_args()
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results = simulate_pendulum(
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theta_resolution=args.resolution,
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dt=args.dt,
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tmax=args.tmax,
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)
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converted_results = convert_results(results)
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write_csv(args.results_file, converted_results)
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if __name__ == '__main__':
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main()
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