pr2_arm_kinematics.cpp

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/* Author: Sachin Chitta */
 
#include <pr2_arm_kinematics/pr2_arm_kinematics.h>
#include <geometry_msgs/PoseStamped.h>
#include <kdl_parser/kdl_parser.hpp>
#include <tf_conversions/tf_kdl.h>
#include "ros/ros.h"
#include <algorithm>
#include <numeric>
 
 
using namespace KDL;
using namespace tf;
using namespace std;
using namespace ros;
 
namespace pr2_arm_kinematics {
 
static const std::string IK_SERVICE = "get_ik";
static const std::string FK_SERVICE = "get_fk";
static const std::string IK_INFO_SERVICE = "get_ik_solver_info";
static const std::string FK_INFO_SERVICE = "get_fk_solver_info";
 
PR2ArmKinematics::PR2ArmKinematics(bool create_tf_listener):  node_handle_("~"),dimension_(7)
{
  urdf::Model robot_model;
  std::string tip_name, xml_string;
 
  while(!loadRobotModel(node_handle_,robot_model, xml_string) && node_handle_.ok())
  {
    ROS_ERROR("Could not load robot model. Are you sure the robot model is on the parameter server?");
    ros::Duration(0.5).sleep();
  }
 
  if (!node_handle_.getParam("root_name", root_name_)){
    ROS_FATAL("PR2IK: No root name found on parameter server");
    exit(-1);
  }
  if (!node_handle_.getParam("tip_name", tip_name)){
    ROS_FATAL("PR2IK: No tip name found on parameter server");
    exit(-1);
  }
 
  ROS_DEBUG("Loading KDL Tree");
  if(!getKDLChain(xml_string,root_name_,tip_name,kdl_chain_))
  {
    active_ = false;
    ROS_ERROR("Could not load kdl tree");
  }
  if(create_tf_listener) {
    tf_ = new TransformListener();
  } else {
    tf_ = NULL;
  }
 
  ROS_DEBUG("Advertising services");
  jnt_to_pose_solver_.reset(new KDL::ChainFkSolverPos_recursive(kdl_chain_));
  node_handle_.param<int>("free_angle",free_angle_,2);
 
  node_handle_.param<double>("search_discretization",search_discretization_,0.01);
  pr2_arm_ik_solver_.reset(new pr2_arm_kinematics::PR2ArmIKSolver(robot_model,root_name_,tip_name, search_discretization_,free_angle_));
  if(!pr2_arm_ik_solver_->active_)
  {
    ROS_ERROR("Could not load ik");
    active_ = false;
  }
  else
  {
 
    pr2_arm_ik_solver_->getSolverInfo(ik_solver_info_);
    pr2_arm_kinematics::getKDLChainInfo(kdl_chain_,fk_solver_info_);
    fk_solver_info_.joint_names = ik_solver_info_.joint_names;
 
    for(unsigned int i=0; i < ik_solver_info_.joint_names.size(); i++)
    {
      ROS_DEBUG("PR2Kinematics:: joint name: %s",ik_solver_info_.joint_names[i].c_str());
    }
    for(unsigned int i=0; i < ik_solver_info_.link_names.size(); i++)
    {
      ROS_DEBUG("PR2Kinematics can solve IK for %s",ik_solver_info_.link_names[i].c_str());
    }
    for(unsigned int i=0; i < fk_solver_info_.link_names.size(); i++)
    {
      ROS_DEBUG("PR2Kinematics can solve FK for %s",fk_solver_info_.link_names[i].c_str());
    }
    ROS_DEBUG("PR2Kinematics::active");
    active_ = true;
    fk_service_ = node_handle_.advertiseService(FK_SERVICE,&PR2ArmKinematics::getPositionFK,this);
    ik_service_ = node_handle_.advertiseService(IK_SERVICE,&PR2ArmKinematics::getPositionIK,this);
 
  }
}
 
PR2ArmKinematics::~PR2ArmKinematics()
{
  if(tf_ != NULL) {
    delete tf_;
  }
}
 
bool PR2ArmKinematics::isActive()
{
  if(active_)
    return true;
  return false;
}
 
bool PR2ArmKinematics::getPositionIK(moveit_msgs::GetPositionIK::Request &request,
                                     moveit_msgs::GetPositionIK::Response &response)
{
  if(!active_)
  {
    ROS_ERROR("IK service not active");
    return false;
  }
 
  if(!checkIKService(request,response,ik_solver_info_))
    return false;
 
  geometry_msgs::PoseStamped pose_msg_in = request.ik_request.pose_stamped;
  geometry_msgs::PoseStamped pose_msg_out;
  if(tf_ != NULL) {
    if(!convertPoseToRootFrame(pose_msg_in,pose_msg_out,root_name_, *tf_))
    {
      response.error_code.val = response.error_code.FRAME_TRANSFORM_FAILURE;
      return true;
    }
  } else {
    ROS_WARN_STREAM("No tf listener.  Can't transform anything");
    response.error_code.val = response.error_code.FRAME_TRANSFORM_FAILURE;
    return false;
  }
  request.ik_request.pose_stamped = pose_msg_out;
  return getPositionIKHelper(request, response);
}
 
//this assumes that everything has been checked and is in the correct frame
bool PR2ArmKinematics::getPositionIKHelper(moveit_msgs::GetPositionIK::Request &request,
                                           moveit_msgs::GetPositionIK::Response &response)
{
  KDL::Frame pose_desired;
  tf::poseMsgToKDL(request.ik_request.pose_stamped.pose, pose_desired);
 
  //Do the IK
  KDL::JntArray jnt_pos_in;
  KDL::JntArray jnt_pos_out;
  jnt_pos_in.resize(dimension_);
  for(int i=0; i < dimension_; i++)
  {
    int tmp_index = getJointIndex(request.ik_request.robot_state.joint_state.name[i],ik_solver_info_);
    if(tmp_index >=0)
    {
      jnt_pos_in(tmp_index) = request.ik_request.robot_state.joint_state.position[i];
    }
    else
    {
      ROS_ERROR("i: %d, No joint index for %s",i,request.ik_request.robot_state.joint_state.name[i].c_str());
    }
  }
 
  std::vector<KDL::JntArray> jnt_array;
  jnt_array.push_back(jnt_pos_out);
  int ik_valid = pr2_arm_ik_solver_->CartToJntSearch(jnt_pos_in,
                                                     pose_desired,
                                                     jnt_array,
                                                     (const double)(request.ik_request.timeout.toSec()));
  if(ik_valid == pr2_arm_kinematics::TIMED_OUT)
    response.error_code.val = response.error_code.TIMED_OUT;
  if(ik_valid == pr2_arm_kinematics::NO_IK_SOLUTION)
    response.error_code.val = response.error_code.NO_IK_SOLUTION;
 
  response.solution.joint_state.header = request.ik_request.pose_stamped.header;
 
  if(ik_valid >= 0)
  {
    response.solution.joint_state.name = ik_solver_info_.joint_names;
    response.solution.joint_state.position.resize(dimension_);
    for(int i=0; i < dimension_; i++)
    {
      response.solution.joint_state.position[i] = jnt_array[0](i);
      ROS_DEBUG("IK Solution: %s %d: %f",response.solution.joint_state.name[i].c_str(),i,jnt_array[0](i));
    }
    response.error_code.val = response.error_code.SUCCESS;
    return true;
  }
  else
  {
    ROS_DEBUG("An IK solution could not be found");
    return false;
  }
}
 
bool PR2ArmKinematics::getPositionFK(moveit_msgs::GetPositionFK::Request &request,
                                     moveit_msgs::GetPositionFK::Response &response)
{
  if(!active_)
  {
    ROS_ERROR("FK service not active");
    return false;
  }
 
  if(!checkFKService(request,response,fk_solver_info_))
    return false;
 
  KDL::Frame p_out;
  KDL::JntArray jnt_pos_in;
  geometry_msgs::PoseStamped pose;
  tf::Stamped<tf::Pose> tf_pose;
 
  jnt_pos_in.resize(dimension_);
  for(int i=0; i < (int) request.robot_state.joint_state.position.size(); i++)
  {
    int tmp_index = getJointIndex(request.robot_state.joint_state.name[i],fk_solver_info_);
    if(tmp_index >=0)
      jnt_pos_in(tmp_index) = request.robot_state.joint_state.position[i];
  }
 
  response.pose_stamped.resize(request.fk_link_names.size());
  response.fk_link_names.resize(request.fk_link_names.size());
 
  for(unsigned int i=0; i < request.fk_link_names.size(); i++)
  {
    ROS_DEBUG("End effector index: %d",pr2_arm_kinematics::getKDLSegmentIndex(kdl_chain_,request.fk_link_names[i]));
    ROS_DEBUG("Chain indices: %d",kdl_chain_.getNrOfSegments());
    if(jnt_to_pose_solver_->JntToCart(jnt_pos_in,p_out,pr2_arm_kinematics::getKDLSegmentIndex(kdl_chain_,request.fk_link_names[i])) >=0)
    {
      tf_pose.frame_id_ = root_name_;
      tf_pose.stamp_ = ros::Time();
      tf::poseKDLToTF(p_out,tf_pose);
      tf::poseStampedTFToMsg(tf_pose,pose);
      if(!transformPose(request.header.frame_id, pose, response.pose_stamped[i])) {
    response.error_code.val = response.error_code.FRAME_TRANSFORM_FAILURE;
    return false;
      }
      response.fk_link_names[i] = request.fk_link_names[i];
      response.error_code.val = response.error_code.SUCCESS;
    }
    else
    {
      ROS_ERROR("Could not compute FK for %s",request.fk_link_names[i].c_str());
      response.error_code.val = response.error_code.NO_IK_SOLUTION;
      return false;
    }
  }
  return true;
}
bool PR2ArmKinematics::transformPose(const std::string& des_frame,
                                     const geometry_msgs::PoseStamped& pose_in,
                                     geometry_msgs::PoseStamped& pose_out)
{
  if(tf_ != NULL) {
    try {
      tf_->transformPose(des_frame,pose_in,pose_out);
    }
    catch(...) {
      ROS_ERROR("Could not transform FK pose to frame: %s",des_frame.c_str());
      return false;
    }
  } else if(des_frame != root_name_){
    ROS_WARN_STREAM("No tf listener, can't transform to frame " << des_frame);
    return false;
  }
  return true;
}
} // namespace