Intelligent Coordinates

ArmarX contains a concept for Intelligent Coordinates that eases transformation into different coordinate frames. More...

Classes
class	FramedDirection
	FramedDirection is a 3 dimensional direction vector with a reference frame. More...
class	FramedOrientation
	The FramedOrientation class. More...
class	FramedPose
	The FramedPose class. More...
class	FramedPosition
	The FramedPosition class. More...
class	LinkedDirection
	direction vector (NOT a position vector) with an attached robotstate proxy for frame changes. More...
class	LinkedPose
	The LinkedPose class. More...
class	Pose
	The Pose class. More...
class	Quaternion
	The Quaternion class. More...
class	Vector3
	The Vector3 class. More...

Variables
std::string const	GlobalFrame = "Global"
	Variable of the global coordinate system.

Detailed Description

ArmarX contains a concept for Intelligent Coordinates that eases transformation into different coordinate frames.

Here, we mean with coordinates positions, orientation, and poses. These Intelligent Coordinates exist in 3 levels of "intelligence".

• The first level are just normal coordinates. They do not contain any information how to transform them in other coordinate frames (e.g. Pose).
• The second level are the framed coordinates (e.g. FramedPose). These contain the name and the agent of frame in which they currently are. To convert these the changeFrame() function can be called. One needs to give the new frame and the robot proxy to this function.
• The third level are the LinkedCoordinates (e.g. LinkedPose), which contain all the information needed to do frame transformations.

Frames of coordinates

The frame of FramedX or LinkedX is technically just a string. The possible values are the names of the robot nodes (use RobotViewer app of Simox to inspect them). For global poses exists the global constant string variable armarx::GlobalFrame located in the FramedPose.h. Use this variable if you specify global poses and an empty Agent-string. Empty frames should be avoided (though, an empty string is mostly considered as the global frame).

Creation of new FramedPositions

To create a new FramedPosition (FramedOrientation, FramedVector and FramedPose work analogously) one needs to know the position, the coordinate frame name and the agent name. The coordinate frame is usually the name of the RobotNode, e.g. the tcp of the robot. All nodes of a robot can be inspected with the Simox tool RobotViewer. The agent name can be retrieved via the RobotStateComponent like this:

std::string agentName = robotStateInterfacePrx->getRobotName();

So an example code for creating a new FramedPosition looks like this:

RobotStateComponentInterfacePrx robotStateInterfacePrx = ....; // you need to have this proxy
SharedRobotInterfacePrx robot = robotStateInterfacePrx->getSynchronizedRobot();
std::string agentName = robotStateInterfacePrx->getRobotName();
std::string frame = robot->getRoot()->getName();
Eigen::Vector3f pos;
pos << 100, 0, 0;
armarx::FramedPositionPtr position = new armarx::FramedPosition(pos, frame, agentName);

Refer to the Howto at get a proxy to learn how to obtain a proxy.

Change the frame of a FramedPosition

In ArmarX the most common coordinate type is the FramedX, e.g. FramedPosition. To change the frame in this coordinate type, you can call changeFrame() on the FramedPosition. You need to know the new frame, in which you want to transform the FramedPosition and a proxy to the robot proxy (e.g. getSynchronizedRobot):

armarx::RobotStateComponentInterfacePrx robotStateInterfacePrx = ....; // you need to have this proxy
armarx::SharedRobotInterfacePrx robot = robotStateInterfacePrx->getSynchronizedRobot();
agentName = robot->getName();
std::string frame = root->getRoot()->getName();
Eigen::Vector3f pos;
pos << 100, 0, 0;
armarx::FramedPositionPtr position = new armarx::FramedPosition(pos, frame, agentName);
 
position->changeFrame(robot, "TCP L");

Variable Documentation

GlobalFrame

std::string const GlobalFrame = "Global"

#include <RobotAPI/libraries/core/FramedPose.h>

Variable of the global coordinate system.

use this if you are specifying a global pose.

Definition at line 65 of file FramedPose.h.