dynamics_sim.cpp

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/*
Copyright (C) 2002-2004  Etienne Lachance

This library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


Report problems and direct all questions to:

email: etienne.lachance@polymtl.ca or richard.gourdeau@polymtl.ca

-------------------------------------------------------------------------------
Revision_history:

2005/06/10: Etienne Lachance
    -The desired joint acceleration was missing in the computed torque method.

2006/05/19: Richard Gourdeau
    -Fix set_q, setq_p bug in xdot (reported by Philip Gruebele)
-------------------------------------------------------------------------------
*/

static const char rcsid[] = "$Id: dynamics_sim.cpp,v 1.6 2006/05/19 21:05:57 gourdeau Exp $";

#include "dynamics_sim.h"
#include "robot.h"

#ifdef use_namespace
namespace ROBOOP {
  using namespace NEWMAT;
#endif

Dynamics *Dynamics::instance = 0;


Dynamics::Dynamics(Robot_basic *robot_): robot(robot_)
{
  ndof = 1;
  dof_fix = 1;
  if(robot)
    {
      ndof = robot->get_dof();
      dof_fix = ndof + robot->get_fix();
    }

  q = ColumnVector(ndof); 
  q = 0;
  qp = ColumnVector(ndof);
  qp = 0;
  qpp = ColumnVector(ndof);
  qpp = 0;
  qd = ColumnVector(ndof);
  qd = 0.0;
  qpd = ColumnVector(ndof);
  qpd = 0;
  qppd = ColumnVector(ndof);
  qppd = 0;
  tau = ColumnVector(ndof);
  tau = 0.0;
  pd = ColumnVector(3); pd = 0;
  ppd = ColumnVector(3);
  ppd = 0;
  pppd = ColumnVector(3);
  pppd = 0;
  wd = ColumnVector(3);
  wd = 0;
  wpd = ColumnVector(3);
  wpd = 0;
  nsteps = 50;
  to = 0;
  tf = 0.1;
  dt = ((tf-to)/nsteps)/4.0;
  tf_cont = 1;

  first_pass_Kutta = true;
  instance = this;
}

Dynamics *Dynamics::Instance()
{
    return instance;
}

void Dynamics::set_dof(Robot_basic *robot_)
{
  ndof = 1;
  dof_fix = 1;
    robot = robot_;
  if(robot)
    {
      ndof = robot->get_dof();
      dof_fix = ndof + robot->get_fix();
    }
  q = ColumnVector(ndof); 
  q = 0;
  qp = ColumnVector(ndof);
  qp = 0;
  qpp = ColumnVector(ndof);
  qpp = 0;
  qd = ColumnVector(ndof);
  qd = 0.0;
  qpd = ColumnVector(ndof);
  qpd = 0;
  qppd = ColumnVector(ndof);
  qppd = 0;
  tau = ColumnVector(ndof);
  tau = 0.0;
  
  first_pass_Kutta = true;
}

void Dynamics::set_time_frame(const int nsteps_)
{ 
    nsteps = nsteps_; 
}

void Dynamics::set_final_time(const double tf)
{ 
    tf_cont = tf; 
}

void Dynamics::reset_time()
{
    first_pass_Kutta = true;
}

short Dynamics::set_controller(const Control_Select & control_)
{
    control = control_;
    if( (ndof != control.get_dof()) && (control.type != NONE) )
      {
        control.type = NONE;
        cerr << "Dynamics::set_controller: mismatch degree of freedom between robot and controller." << endl;
        return -1;
      }
    return 0;
}

short Dynamics::set_trajectory(const Trajectory_Select & path_select_)
{
    path_select = path_select_;

    if (control.space_type != path_select.type)
      {
        control.type = NONE;
        path_select.type = NONE;
        cerr << "Dynamics::set_trajectory: controller space and trajectory space are not compatible.\n" 
             << "                          Both should be in joint space or in cartesian space." << endl;
        return -1;
      }
    return 0;
}

ReturnMatrix Dynamics::set_robot_on_first_point_of_splines()
{
  ColumnVector qs(2*ndof);
  
  if(path_select.type == JOINT_SPACE)
    {
      if(path_select.path.p_pdot(0.0, qd, qpd))
        cerr << "Dynamics::set_robot_on_first_point_of_spines: invalid joint space path." << endl;
      else
        {
          tf_cont = path_select.path.get_final_time();
          robot->set_q(qd);
          qs.SubMatrix(1,ndof,1,1) = qd;
          qs.SubMatrix(ndof+1,2*ndof,1,1) = 0;
          qs.Release();
          return qs;
        }
    }
  else if(path_select.type == CARTESIAN_SPACE) // && quaternion active
    {
      if( (path_select.path.p_pdot_pddot(0.0, pd, ppd, pppd) == 0) && 
          (path_select.path_quat.quat_w(0.0, quatd, wd) == 0) )
        {
          Matrix Tobj(4,4); Tobj = 0;
          Tobj.SubMatrix(1,3,1,3) = quatd.R();
          Tobj.SubMatrix(1,3,4,4) = pd;
          Tobj(4,4) = 1;
          bool converge;
          robot->inv_kin(Tobj, 0, converge);
          
          if(converge)
            {
              tf_cont = path_select.path.get_final_time();
              q = robot->get_q();
              qs.SubMatrix(1,ndof,1,1) = q;
              qs.SubMatrix(ndof+1,2*ndof,1,1) = 0;
              
              qs.Release();
              return qs;
            }
        }
      else
        cerr << "Dynamics::set_robot_on_first_point_of_spines: invalid cartesian path." << endl;
    }
  
  q = robot->get_q();
  qs.SubMatrix(1,ndof,1,1) = q;
  qs.SubMatrix(ndof+1,2*ndof,1,1) = 0;
  qs.Release();
  return qs;
}

ReturnMatrix Dynamics::xdot(const Matrix & x)
{
   q = x.SubMatrix(1,ndof,1,1);        // joint position from state vecteur
   qp = x.SubMatrix(ndof+1,2*ndof,1,1);// " "   velocity    "           "
   robot->set_q(q);
   robot->set_qp(qp);

   if(robot)
   {
       switch (control.type)
       {
           case PD:
               if(path_select.type == JOINT_SPACE)
               {
                   if(path_select.path.p_pdot(time, qd, qpd))
                   {
                       xd = qp & qpp;                      
                       xd.Release(); 
                       return xd;
                   }
               }
               else if(path_select.type == CARTESIAN_SPACE)
                   cerr << "Dynamics::xdot: Cartesian path can not be used with CTM controller." << endl;

               tau = control.pd.torque_cmd(*robot, qd, qpd);

               break;

           case CTM:
               if(path_select.type == JOINT_SPACE)
               {
                   if(path_select.path.p_pdot(time, qd, qpd))
                   {
                       xd = qp & qpp;                      
                       xd.Release(); 
                       return xd;
                   }
               }
               else if(path_select.type == CARTESIAN_SPACE)
                   cerr << "Dynamics::xdot: Cartesian path can not be used with CTM controller." << endl;

               tau = control.ctm.torque_cmd(*robot, qd, qpd, qppd);

               break;

           case RRA:
               if(path_select.type == CARTESIAN_SPACE)
               {
                   if (path_select.path.p_pdot_pddot(time, pd, ppd, pppd) ||
                       path_select.path_quat.quat_w(time, quatd, wd)) 
                   {
                       xd = qp & qpp;
                       xd.Release();
                       return xd;
                   }
               }
               else if(path_select.type == JOINT_SPACE)
                   cerr << "Dynamics::xdot: Joint Space path can not be used with RRA controller." << endl;

               tau = control.rra.torque_cmd(*robot, pppd, ppd, pd, wpd, wd, quatd, dof_fix, dt);
               break;
           default:
               tau = 0;
       }
       qpp = robot->acceleration(q, qp, tau);
   }

   plot();

   xd = qp & qpp;  // state derivative

   xd.Release(); 
   return xd;
}

void Dynamics::Runge_Kutta4_Real_time()
{
    if(first_pass_Kutta)
    {
        h = (tf-to)/nsteps;
        h2 = h/2.0;
        time = to;
        x = set_robot_on_first_point_of_splines();
        first_pass_Kutta = false;
        return;
    }

    k1 = xdot(x) * h;
    time += h2;
    k2 = xdot(x+k1*0.5)*h;
    k3 = xdot(x+k2*0.5)*h;
    time += h2;
    k4 = xdot(x+k3)*h;
    x = x + (k1*0.5+ k2 + k3 + k4*0.5)*(1.0/3.0);
}

void Dynamics::Runge_Kutta4()
{
   x = set_robot_on_first_point_of_splines();
   h = (tf_cont - to)/nsteps;
   h2 = h/2.0;
   time = to;

   for (int i = 1; i <= nsteps; i++) {
           k1 = xdot(x) * h;
      k2 = xdot(x+k1*0.5)*h;
      k3 = xdot(x+k2*0.5)*h;
      k4 = xdot(x+k3)*h;
      x = x + (k1*0.5+ k2 + k3 + k4*0.5)*(1.0/3.0);
      time += h;
   }
}

#ifdef use_namespace
}
#endif