Source Code for Script script-demo_makeInchwormCSV_py

 1  from numpy import * 
 2  import sys 
 3   
 4 -def inchworm(phi): 
 5    """Programmatic definition of inchworm gait""" 
 6    crv = 0.25 
 7    ass = 0.35 
 8    crv0 = 0.1 
 9    W =array([0, -0.75,-2,0,2,0.75]) 
10    N = len(W) 
11    if phi<0.33: 
12      a = (phi-0.33/2)*6 
13      res = (-ones(N)*pi*crv - W*a*ass) 
14    elif phi>=0.33 and phi<0.66: 
15      a = -(phi-0.5)*6 
16      b = 1-(phi-0.33)*3     
17      res = (-ones(N)*pi*((crv-crv0)*b+crv0) - W*b*ass) 
18    elif phi>=0.66: 
19      a = -(phi-(1.66/2))*6 
20      b = (phi-0.66)*3     
21      res = (-ones(N)*pi*((crv-crv0)*b+crv0) + W*b*ass)     
22    return res 
23   
24  if __name__!="__main__": 
25    raise "Don't run me" 
26   
27  # Our modules are oriented in the [1,-1,1,1,-1] directions relative to each 
28  #   other but we've found that we want the first and last modules to 
29  #   counter-rotate to get the gait right. 
30  signs = array([1,-1,1,1,-1]) 
31  sg = -signs 
32  sg[0] *= -1 
33  sg[-1] *= -1 
34   
35  # Create the CSV file headings 
36  sys.stdout.write('"t","w1","w2","w3","w4","w5"\n') 
37  # Sample 300 points, without the final point (since 1 is the same as 0) 
38  for phi in linspace(0,1,30,endpoint=False): 
39    s = inchworm(phi) 
40    line = ("%.3g," % phi) + ",".join(  
41      [ "%d" % (18000.0/pi*val) for val in s[1:]*sg ] ) 
42    sys.stdout.write(line+"\n") 
43   
44  sys.stderr.write(""" 
45  This program is a quick hack for creating a gait table for an inchworm gait.   
46  To use this program, pipe its output into a .csv file 
47  """) 
48