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Cartesian point-to-point motion

Cartesian point-to-point motions are introduced at this point because their use is similar to other Cartesian motion instructions. However, Cartesian PTPs are (despite their name) not Cartesian motions at all, as they do not represent a motion along a defined Cartesian path. Their character is equal to the joint level PTPs introduced in section 2.1. In contrast to those PTPs, Cartesian PTPs are defined as motion of the MCP to a given target Frame, starting from the current position of the MCP. In contrast to joint level PTPs, the exact goal axis configuration is not specified by Cartesian PTPs and will be chosen deliberately by the robot control, unless specified otherwise (see 2.3.5).

In the Robotics API, Cartesian PTP motions are accessible through the robot’s PtpInterface. It provides overloads of the ptp() method that expect a Frame as motion goal. Those methods create RtActivities that perform Cartesian PTPs, considering the configured MCP.

The following example illustrates the usage of Cartesian PTP motions:

// lwr is a robot of type LWR 
PtpInterface ptpInterface = lwr.use(PtpInterface.class); 
 
// (re-)set MCP to lwr flange (optional) 
Frame flange = lwr.getFlange(); 
ptpInterface.addDefaultParameters(new MotionCenterParameters(flange)); 
 
// create a motion goal frame 
Frame goal = flange.plus(0, 0, 0.2); 
 
// fix the goal to lwr base, otherwise motion will try to track a moving target 
Frame fixedGoal = goal.snapshot(lwr.getBase()); 
 
// cartesian ptp motion 
ptpInterface.ptp(fixedGoal).execute();

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Robotics API support for: Cartesian Point-To-Point motion
Provided by:

PtpInterface

Also available in:

MotionInterface

Method(s):

ptp(Frame, DeviceParameters...)
ptp(Frame, double[], DeviceParameters...)

Valid DeviceParameters:

OverrideParameter, MotionCenterParameter, JointDeviceParameters, ControllerParameter, RedundancyDeviceParameter, RobotToolParameter, AlphaParameter

Robotics API support for: Cartesian HoldMotion
Provided by:

HoldMotionInterface

Also available in:
Method(s):

o holdCartesianPosition(Frame, DeviceParameters...)

Valid DeviceParameters:

OverrideParameter, MotionCenterParameter, JointDeviceParameters, ControllerParameter, RedundancyDeviceParameter, RobotToolParameter, AlphaParameter

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