moorepants

>>> R = ReferenceFrame('R')
>>> A = R.orientnew('A', rotation) # rotation is just the args need to set a direction cosine matrix with some method
>>> B = R.orientnew('B', rotation)

# At this point reference frame A know about R, reference frame B knows
# about R, but A and B don't know about each other. But each frame has unit
# vectors available to work with.

>>> v = a * A.x + b * A.y

moorepants

####Frames
Seabottom = SM.ReferenceFrame('Seabottom')
Barge_Frame = Seabottom.orientnew('Barge_Frame', 'Body', [phi_barge, theta_barge, psi_barge], 'XYZ')  #roll, pitch, yaw: phi, theta, psi
"""So in the line above you set the body fixed xyz angles (these
are Euler angles) of the barge, but in the line below you set the angular
velocity vector as Space fixed rotations. Before you set the angular velocity with explicit generalized speeds you should run this:

In [2]: Barge_Frame.ang_vel_in(Seabottom)
Out[2]: (sin(psi_barge)*theta_barge' + cos(psi_barge)*cos(theta_barge)*phi_barge')*Barge_Frame.x + (-sin(psi_barge)*cos(theta_barge)*phi_barge' + cos(psi_barge)*theta_barge')*Barge_Frame.y + (sin(theta_barge)*phi_barge' + psi_barge')*Barge_Frame.z

moorepants

import numpy as np
from scipy.optimize import leastsq
import pandas
import matplotlib.pyplot as plt
from dtk.process import butterworth
from dtk.systemid import ARX

df = pandas.read_csv('RandomSlowSpeed1.txt', delimiter='\t')
sample_rate = 100.0  # hz
cutoff = 6.0  # hz

moorepants

#!/usr/bin/env python

# standard library
import os
import zipfile

# external
from scipy.io import savemat

# local

moorepants

function pendsi;
% System identification on a simple pendulum system
% The problem was described and solved by shooting in Vyasarayani et al., Multibody Syst Dyn (2011) 26:411–424
% Here we use Direct Collocation

	global problem
	close all
	tic
	
	% run a simulation to generate data

moorepants

This is XeTeX, Version 3.1415926-2.5-0.9999.3 (TeX Live 2013/Debian) (format=xelatex 2014.8.6)  6 AUG 2014 09:14
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**sympy-0.7.5-git.tex
(./sympy-0.7.5-git.tex
LaTeX2e <2011/06/27>
Babel <3.9h> and hyphenation patterns for 2 languages loaded.
(./sphinxmanual.cls
Document Class: sphinxmanual 2009/06/02 Document class (Sphinx manual)

moorepants

Testing results.

Timing the functions.

Timing: cython
cython time: 0.00288254904747 s

Timing: numpy_broadcast
numpy_broadcast time: 0.00597401690483 s

moorepants

(inverted-pendulum-id)moorepants@moorepants-2170p:inverted-pendulum-sys-id(master)$ conda info
Current conda install:

             platform : linux-64
        conda version : 3.6.4
  conda-build version : 1.3.3
       python version : 2.7.8.final.0
     requests version : 2.4.1
     root environment : /home/moorepants/anaconda  (writable)
  default environment : /home/moorepants/anaconda/envs/inverted-pendulum-id

moorepants

#!/usr/bin/env python

"""This derives the equations of motion for a point mass pendulum on a
laterally moving base, i.e. the classic inverted pendulum on a moving cart.

  iy
  ^       E
  |        o m
  |     l /      |
  |      /       v g

moorepants

moorepants@moorepants-2170p:sympy(0.7.6)$ bin/test
================================================================ test process starts =================================================================
executable:         /home/moorepants/anaconda/bin/python  (2.7.8-final-0) [CPython]
architecture:       64-bit
cache:              yes
ground types:       python 
random seed:        57272380
hash randomization: on (PYTHONHASHSEED=362442982)

sympy/assumptions/tests/test_assumptions_2.py[5] .....                                                                                            [OK]