Source Code for Module mbdyn.bindings.forces

  1  #!/usr/bin/env python 
  2  # -*- coding: utf-8 -*- 
  3  # 
  4  # This file is part of MBDyn sim suite. 
  5  # Copyright (C) 2007 André ESPAZE, as part of a Master thesis supervised by 
  6  # Martin O.L.Hansen (DTU) and Nicolas Chauvat (Logilab) 
  7   
  8  # MBDyn sim suite is free software; you can redistribute it and/or modify 
  9  # it under the terms of the GNU General Public License as published by 
 10  # the Free Software Foundation; either version 2 of the License, or 
 11  # (at your option) any later version. 
 12  # 
 13  # This program is distributed in the hope that it will be useful, 
 14  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 15  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 16  # GNU General Public License for more details. 
 17  # 
 18  # You should have received a copy of the GNU General Public License 
 19  # along with this program; if not, write to the Free Software 
 20  # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
 21  # 
 22  """The classes implemented in the force group.  
 23  This module introduces an interface between the instances from the swigModule 
 24  and the forces available for the user. For example for setting the  
 25  value of a force, a numpy array is provided and the C++ vector object,  
 26  Vec3, is filled by the method. 
 27   
 28  The two MBDyn extensions are  
 29  L{BindingsForce<mbdyn.bindings.forces.BindingsForce>} and  
 30  L{BindingsCouple<mbdyn.bindings.forces.BindingsCouple>} that can set  
 31  their value at each time step. They are however supposed to be managed  
 32  by the L{mbdyn.elts.force} module. 
 33   
 34   
 35  All the classes are contained into L{FORCE_CLASS}, then used 
 36  by L{mbdyn.bindings.groups}. 
 37  """ 
 38  import numpy as N 
 39  from mbdyn.bindings.elements import Force 
 40   
 41   
 42 -class StructuralForce(Force): 
 43      """The communication with the MBDyn structural force. 
 44      """ 
 45   
 46 -    def __init__(self, c_inst=None): 
 47          Force.__init__(self, c_inst) 
 48          self.value = N.zeros((3, 1)) 
 49   
 50 -    def fill_value(self): 
 51          """Fill the value from the C++ interface into 
 52          the numpy array""" 
 53          for i in range(3): 
 54              self.value[i] = self.c_inst.Finterface.get_value(i) 
 55   
 56 -    def get_value(self): 
 57          """Return a copy of the force value""" 
 58          self.fill_value() 
 59          return self.value.copy() 
 60   
 61 -    def get_driver_amplitude(self): 
 62          """Return the amplitude of the MBDyn driver""" 
 63          return self.c_inst.get_driver_amplitude() 
 64   
 65   
 66 -class ConservativeForce(StructuralForce): 
 67      """The conservative force of MBDyn.  
 68      """ 
 69   
 70 -    def __repr__(self): 
 71          mess = "ConservativeForce with label %s in MBDyn" 
 72          return mess % str(self.label) 
 73   
 74   
 75 -class BindingsForce(ConservativeForce): 
 76      """A MBDyn conservative force on which the value can be set  
 77      at every time step. This object is a MBDyn extension on which 
 78      the C{AssRes} method, called at each iteration, has been  
 79      transformed. 
 80      """ 
 81       
 82 -    def fill_value(self): 
 83          """Do no perform any operation for a BindingsForce, 
 84          the value is always known.""" 
 85          pass 
 86       
 87 -    def get_value(self): 
 88          """Return a copy of the force value""" 
 89          return self.value.copy() 
 90   
 91 -    def set_value(self, array): 
 92          """Set the value on the MBDyn C++ instance. 
 93   
 94          @type array: numpy array 
 95          @param array: a vector of size 3x1 
 96          """ 
 97          for i in range(3): 
 98              self.value[i] = array[i] 
 99              self.c_inst.F.set_value(i, float(array[i])) 
100   
101 -    def __repr__(self): 
102          mess = "BindingsForce with label %s in MBDyn" 
103          return mess % str(self.label) 
104   
105   
106 -class ConservativeCouple(StructuralForce): 
107      """The MBDyn conservative couple""" 
108   
109 -    def __repr__(self): 
110          mess = "ConservativeCouple with label %s in MBDyn" 
111          return mess % str(self.label) 
112   
113   
114 -class BindingsCouple(ConservativeCouple): 
115      """A MBDyn conservative couple on which a value can be set at each time  
116      step. This object is a MBDyn extension.  
117      """ 
118   
119 -    def fill_value(self): 
120          """Do not fill the couple value because the value is always  
121          known""" 
122          pass 
123       
124 -    def get_value(self): 
125          """Return a copy of the value vector""" 
126          return self.value.copy() 
127   
128 -    def set_value(self, array): 
129          """Set the value of the torque to the MBDyn instance. 
130   
131          @type array: numpy array 
132          @param array: a vector of size 3x1 
133          """ 
134          for i in range(3): 
135              self.value[i] = array[i] 
136              self.c_inst.Value.set_value(i, float(array[i])) 
137   
138 -    def __repr__(self): 
139          mess = "BindingsCouple with label %s in MBDyn" 
140          return mess % str(self.label) 
141   
142   
143  FORCE_CLASS = {} 
144  FORCE_CLASS["general"] = Force 
145  FORCE_CLASS["conservative_force"] = ConservativeForce 
146  FORCE_CLASS["bindings_force"] = BindingsForce 
147   
148  FORCE_CLASS["conservative_couple"] = ConservativeCouple 
149  FORCE_CLASS["bindings_couple"] = BindingsCouple 
150