/**
*
* @param jnt the KDL::Joint to convert (axis and origin expressed in the
* predecessor frame of reference, as by KDL convention)
* @param frameToTip the predecessor/successor frame transformation
* @param H_new_old_predecessor in the case the predecessor frame is being
* modified to comply to URDF constraints (frame origin on the joint axis)
* this matrix the transformation from the old frame to the new frame (H_new_old)
* @param H_new_old_successor in the case the successor frame is being
* modified to comply to URDF constraints (frame origin on the joint axis)
* this matrix the transformation from the old frame to the new frame (H_new_old)
*/
urdf::Joint toUrdf(const KDL::Joint & jnt,
const KDL::Frame & frameToTip,
const KDL::Frame & H_new_old_predecessor,
KDL::Frame & H_new_old_successor)
{
//URDF constaints the successor link frame origin to lay on the axis
//of the joint ( see : http://www.ros.org/wiki/urdf/XML/joint )
//Then if the JointOrigin of the KDL joint is not zero, it is necessary
//to move the link frame (then it is necessary to change also the spatial inertia)
//and the definition of the childrens of the successor frame
urdf::Joint ret;
ret.name = jnt.getName();
H_new_old_successor = getH_new_old(jnt,frameToTip);
ret.parent_to_joint_origin_transform = toUrdf(H_new_old_predecessor*frameToTip*(H_new_old_successor.Inverse()));
switch(jnt.getType())
{
case KDL::Joint::RotAxis:
case KDL::Joint::RotX:
case KDL::Joint::RotY:
case KDL::Joint::RotZ:
//using continuos if no joint limits are specified
ret.type = urdf::Joint::CONTINUOUS;
//in urdf, the joint axis is expressed in the joint/successor frame
//in kdl, the joint axis is expressed in the predecessor rame
ret.axis = toUrdf(((frameToTip).M.Inverse((jnt.JointAxis()))));
break;
case KDL::Joint::TransAxis:
case KDL::Joint::TransX:
case KDL::Joint::TransY:
case KDL::Joint::TransZ:
ret.type = urdf::Joint::PRISMATIC;
//in urdf, the joint axis is expressed in the joint/successor frame
//in kdl, the joint axis is expressed in the predecessor rame
ret.axis = toUrdf((frameToTip.M.Inverse(jnt.JointAxis())));
break;
default:
std::cerr << "[WARN] Converting unknown joint type of joint " << jnt.getTypeName() << " into a fixed joint" << std::endl;
case KDL::Joint::None:
ret.type = urdf::Joint::FIXED;
}
return ret;
}
int main()
{
KDLCollada kdlCollada;
vector <KDL::Chain> kinematicsModels;
const string filename = "puma.dae"; // loading collada kinematics model and converting it to kdl serial chain
if (!kdlCollada.load(COLLADA_MODELS_PATH + filename, kinematicsModels))
{
cout << "Failed to import " << filename;
return 0;
}
cout << "Imported " << kinematicsModels.size() << " kinematics chains" << endl;
for (unsigned int i = 0; i < kinematicsModels.size(); i++) // parsing output kdl serail chain
{
KDL::Chain chain = kinematicsModels[i];
cout << "Chain " << i << " has " << chain.getNrOfSegments() << " segments" << endl;
for (unsigned int u = 0; u < chain.getNrOfSegments(); u++)
{
KDL::Segment segment = chain.segments[u];
string segmentName = segment.getName();
cout << "Segment " << segmentName << " :" <<endl;
KDL::Frame f_tip = segment.getFrameToTip();
KDL::Vector rotAxis = f_tip.M.GetRot();
double rotAngle = f_tip.M.GetRotAngle(rotAxis);
KDL::Vector trans = f_tip.p;
cout << " frame: rotation " << rotAxis.x() << " " << rotAxis.y() << " " << rotAxis.z() << " " << rotAngle * 180 / M_PI << endl;
cout << " frame: translation " << trans.x() << " " << trans.y() << " " << trans.z() << endl;
KDL::RigidBodyInertia inertia = segment.getInertia();
KDL::Joint joint = segment.getJoint();
string jointName = joint.getName();
string jointType = joint.getTypeName();
KDL::Vector jointAxis = joint.JointAxis();
KDL::Vector jointOrigin = joint.JointOrigin();
cout << " joint name: " << jointName << endl;
cout << " type: " << jointType << endl;
cout << " axis: " << jointAxis.x() << " " <<jointAxis.y() << " " << jointAxis.z() << endl;
cout << " origin: " << jointOrigin.x() << " " << jointOrigin.y() << " " << jointOrigin.z() << endl;
}
}
return 0;
}
static inline YAML::Node extract(const std::string& start_link, const std::string& end_link, const KDL::Chain& chain)
{
std::string var_suffix = "_var";
std::string frame_suffix = "_frame";
std::string expression_name = "fk";
std::vector<YAML::Node> input_vars;
std::vector<YAML::Node> joint_frames;
YAML::Node frame_mul;
YAML::Node axis_angle_null;
axis_angle_null["axis-angle"].push_back(get_vector3(1, 0, 0));
axis_angle_null["axis-angle"].push_back(0);
int input_var_index = 0;
for (std::vector<KDL::Segment>::const_iterator it = chain.segments.begin(); it != chain.segments.end(); ++it)
{
KDL::Joint joint = it->getJoint();
std::string var_name = joint.getName() + var_suffix;
std::string frame_name = joint.getName() + frame_suffix;
YAML::Node joint_frame;
if (joint.getType() != KDL::Joint::None)
{
// Set input variable definition
YAML::Node input_var;
input_var[joint.getName() + var_suffix]["input-var"] = input_var_index;
input_var_index++;
input_vars.push_back(input_var);
// Set joint transform
YAML::Node translation;
YAML::Node rotation;
// Set joint axis
YAML::Node joint_axis = get_vector3(joint.JointAxis());
if (joint.getType() == KDL::Joint::TransAxis)
{
YAML::Node scale_vec;
scale_vec["scale-vector"].push_back(var_name);
scale_vec["scale-vector"].push_back(joint_axis);
translation["vector-add"].push_back(scale_vec);
translation["vector-add"].push_back(get_vector3(joint.JointOrigin()));
rotation = axis_angle_null;
}
else if (joint.getType() == KDL::Joint::RotAxis)
{
translation = get_vector3(joint.JointOrigin());
rotation["axis-angle"].push_back(joint_axis);
rotation["axis-angle"].push_back(var_name);
}
// Create frame and add to list
YAML::Node joint_transform;
joint_transform["frame"].push_back(rotation);
joint_transform["frame"].push_back(translation);
joint_frame[frame_name]["frame-mul"].push_back(joint_transform);
}
std::vector<YAML::Node> f_tip_nodes = get_frame_tip_nodes(*it);
for (std::vector<YAML::Node>::iterator f_tip_it = f_tip_nodes.begin(); f_tip_it != f_tip_nodes.end(); ++f_tip_it)
{
joint_frame[frame_name]["frame-mul"].push_back(*f_tip_it);
}
if (joint_frame.size() > 0)
{
joint_frames.push_back(joint_frame);
frame_mul.push_back(frame_name);
}
}
// Merge nodes
YAML::Node node;
for (std::vector<YAML::Node>::iterator it = input_vars.begin(); it != input_vars.end(); ++it)
{
node.push_back(*it);
}
for (std::vector<YAML::Node>::iterator it = joint_frames.begin(); it != joint_frames.end(); ++it)
{
node.push_back(*it);
}
YAML::Node fk_def;
fk_def[expression_name]["frame-mul"] = frame_mul;
node.push_back(fk_def);
return node;
}
int JointInvertPolarity(const KDL::Joint & old_joint, const KDL::Frame & old_f_tip, KDL::Joint & new_joint, KDL::Frame & new_f_tip)
{
switch(old_joint.getType())
{
case Joint::RotAxis:
case Joint::RotX:
case Joint::RotY:
case Joint::RotZ:
//\todo document this
new_f_tip = KDL::Frame(old_f_tip.M.Inverse(),-(old_f_tip.M.Inverse()*old_joint.JointOrigin()));
new_joint = Joint(old_joint.getName(),-(old_f_tip.M.Inverse()*old_f_tip.p), -(old_f_tip.M.Inverse()*old_joint.JointAxis()), Joint::RotAxis);
break;
case Joint::TransAxis:
case Joint::TransX:
case Joint::TransY:
case Joint::TransZ:
new_f_tip = KDL::Frame(old_f_tip.M.Inverse(),-(old_f_tip.M.Inverse()*old_f_tip.p));
new_joint = Joint(old_joint.getName(),-(old_f_tip.M.Inverse()*old_joint.JointOrigin()), -(old_f_tip.M.Inverse()*old_joint.JointAxis()), Joint::TransAxis);
break;
case Joint::None:
default:
new_f_tip = KDL::Frame(old_f_tip.M.Inverse(),-(old_f_tip.M.Inverse()*old_f_tip.p));
new_joint = Joint(old_joint.getName(), Joint::None);
break;
}
#ifndef NDEBUG
std::cerr << "Exiting joint polarity inversion, checking all is working" << std::endl;
double q = 0.83;
std::cerr << old_joint.pose(q)*old_f_tip*new_joint.pose(q)*new_f_tip << std::endl;
#endif
return 0;
}