pr2_arm_ik.h

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/* Author: Sachin Chitta */

#ifndef PR2_ARM_IK_H
#define PR2_ARM_IK_H

#include <urdf_model/model.h>
#include <Eigen/Core>
#include <Eigen/LU>// provides LU decomposition
#include <kdl/chainiksolver.hpp>
#include <moveit_msgs/GetPositionFK.h>
#include <moveit_msgs/GetPositionIK.h>
#include <moveit_msgs/GetKinematicSolverInfo.h>

namespace pr2_arm_kinematics
{
static const int NUM_JOINTS_ARM7DOF = 7;

static const double IK_EPS = 1e-5;

inline double distance(const urdf::Pose &transform)
{
  return sqrt(transform.position.x*transform.position.x+transform.position.y*transform.position.y+transform.position.z*transform.position.z);
}


inline bool solveQuadratic(const double &a, const double &b, const double &c, double *x1, double *x2)
{
  double discriminant = b*b-4*a*c;
  if(fabs(a) < IK_EPS)
  {
    *x1 = -c/b;
    *x2 = *x1;
    return true;
  }
  //ROS_DEBUG("Discriminant: %f\n",discriminant);
  if (discriminant >= 0)
  {
    *x1 = (-b + sqrt(discriminant))/(2*a);
    *x2 = (-b - sqrt(discriminant))/(2*a);
    return true;
  }
  else if(fabs(discriminant) < IK_EPS)
  {
    *x1 = -b/(2*a);
    *x2 = -b/(2*a);
    return true;
  }
  else
  {
    *x1 = -b/(2*a);
    *x2 = -b/(2*a);
    return false;
  }
}

inline bool solveCosineEqn(const double &a, const double &b, const double &c, double &soln1, double &soln2)
{
  double theta1 = atan2(b,a);
  double denom  = sqrt(a*a+b*b);

  if(fabs(denom) < IK_EPS) // should never happen, wouldn't make sense but make sure it is checked nonetheless
  {
#ifdef DEBUG
    std::cout << "denom: " << denom << std::endl;
#endif
    return false;
  }
  double rhs_ratio = c/denom;
  if(rhs_ratio < -1 || rhs_ratio > 1)
  {
#ifdef DEBUG
    std::cout << "rhs_ratio: " << rhs_ratio << std::endl;
#endif
    return false;
  }
  double acos_term = acos(rhs_ratio);
  soln1 = theta1 + acos_term;
  soln2 = theta1 - acos_term;

  return true;
}

class PR2ArmIK
{
public:

  PR2ArmIK();
  ~PR2ArmIK(){};

  bool init(const urdf::ModelInterface &robot_model, const std::string &root_name, const std::string &tip_name);

  void computeIKShoulderPan(const Eigen::Matrix4f &g_in, const double &shoulder_pan_initial_guess,std::vector<std::vector<double> > &solution) const;

  void computeIKShoulderRoll(const Eigen::Matrix4f &g_in, const double &shoulder_roll_initial_guess,std::vector<std::vector<double> > &solution) const;


  //  std::vector<std::vector<double> > solution_ik_;/// a vector of ik solutions

  void getSolverInfo(moveit_msgs::KinematicSolverInfo &info);

  moveit_msgs::KinematicSolverInfo solver_info_;

  EIGEN_MAKE_ALIGNED_OPERATOR_NEW

  private:

  void addJointToChainInfo(boost::shared_ptr<const urdf::Joint> joint,moveit_msgs::KinematicSolverInfo &info);

  bool checkJointLimits(const std::vector<double> &joint_values) const;

  bool checkJointLimits(const double &joint_value, const int &joint_num) const;

  Eigen::Matrix4f grhs_, gf_, home_inv_, home_;

  std::vector<double> angle_multipliers_;

  std::vector<double> solution_;

  double shoulder_upperarm_offset_, upperarm_elbow_offset_, elbow_wrist_offset_, shoulder_wrist_offset_, shoulder_elbow_offset_, torso_shoulder_offset_x_, torso_shoulder_offset_y_, torso_shoulder_offset_z_;

  std::vector<double> min_angles_;

  std::vector<double> max_angles_;

  std::vector<bool> continuous_joint_;

};
}
#endif// PR2_ARM_IK_H