LBR iiwa - start/resume application by gesture control

robotneuling · May 2nd 2017

Hello,

I am new to this forum and hope to obtain some good ideas and suggestions here. I am currently working with a KUKA LBR iiwa and I am learning the ropes of operating and programming the robot. I already use the manual to look up information and examples .

I would like to program the following program sequence:
The robot should detect a collision (e.g. hand) and stop. Then the application should be resumed by a gesture.

This is what I have tried so far:

Code

//Trigger
ICallbackAction ica = new ICallbackAction() {
	@Override
	public void onTriggerFired(IFiredTriggerInfo triggerInformation)
	{
	getLogger().info("TriggerTime: "+ triggerInformation.getTriggerTime().toString());
	getLogger().info("TriggerCondition: "+ triggerInformation.getFiredCondition().toString());
	getApplicationControl().pause();

	};
}; //End ICallbackAction ica


//Condition for Cartesian force from all directions (Frame below the robot flange)
ForceCondition flangecollision = ForceCondition.createSpatialForceCondition(lbr.getFlange(), 15);
lbr.move(ptp(getApplicationData().getFrame("/Frame_Z2")).triggerWhen(flangecollision, ica));

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In case of collision the method triggerWhen(...) is called and the action is programmed in onTriggerFired(…).
The problem here is that the paused motion can only be resumed via the Start key on the smartPAD. I would like to resume the application by gesture control (see Video 1). Another questions is how can the application be started in general by a gesture (see video 2)?

1) https://youtu.be/90sS-sxEZm8?t=2m45s at 2:45
2) https://youtu.be/sJBgEk96igk?t=20s at 0:20

Thanks and regards
robotneuling

kiiwa · May 3rd 2017

Hi,

Here are the steps:
- Start your motion:
- Use "Breakwhen" when you detect a force
- Get into "PosHold" and wait until there's an external force.

I'd like to post the code, but I don't have time, check the keys words in bold in the doc

good luck

robotneuling · May 4th 2017

edit2: How can I check if a certain frame ("/Frame_Z2") has been reached in order to terminate the while loop?

This is what I have programmed so far:

Code

ForceCondition collision = ForceCondition.createSpatialForceCondition(lbr.getFlange(), 15);
		//CartesianImpedanceControl
		CartesianImpedanceControlMode controlMode = new CartesianImpedanceControlMode();
		controlMode.parametrize(CartDOF.TRANSL).setStiffness(5000);
		controlMode.parametrize(CartDOF.ALL).setDamping(1.0);

		boolean frame_reached = true;

		while (frame_reached){
		IMotionContainer positionContainer = lbr.move(ptp(getApplicationData().getFrame("/Frame_Z2")).breakWhen(collision));		
		lbr.moveAsync(positionHold(controlMode, 3, TimeUnit.SECONDS));		
		lbr.moveAsync(positionHold(controlMode, -1, TimeUnit.SECONDS).breakWhen(collision));		
		}

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edit: I think it works now but not perfect . I'll keep you posted

Hi kiiwa,

how do you proceed once you are in positionHold?
How can the motion be resumed by an external force?

Thank you!

Quote from kiiwa

Hi,

Here are the steps:
- Start your motion:
- Use "Breakwhen" when you detect a force
- Get into "PosHold" and wait until there's an external force.

I'd like to post the code, but I don't have time, check the keys words in bold in the doc

good luck

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kiwi8 · May 5th 2017

Hi Robotneuling,

For checking if you have reached a certain Frame (assuming you know the Frame the Robot should reach) you can use Frame1.isCloseTo(Frame2, maxDist, maxRot). You just get the current cartesian Position, save it in Frame1 and save your Destination in Frame2.MaxDist is the Maximum Deviation you want to allow.

For the second part, what you have should work already, because you just want to terminate the Position hold with a breakWhen(externalForce) like you have. However, I wouldn't execute the PositionHold asynchronous because you want those to be blocking statements and in your case the execution of the program goes on after the Position hold is called.

Hope this helps, kiwi

robotneuling · May 6th 2017

edit:
It works now.
I used moveAsync instead of move ....

Code

lbr.moveAsync(positionHold(controlMode, -1, TimeUnit.SECONDS).breakWhen(collision));

Hi kiwi8,

thanks for your help.

I don't get the loop stopped by using "Frame1.isCloseTo(Frame2, maxDist, maxRot)".

The code:

Code

while (true){
			lbr.move(ptp(getApplicationData().getFrame("/Frame_Z2")).breakWhen(collision));		
			lbr.move(positionHold(controlMode, 3, TimeUnit.SECONDS));		
			lbr.move(positionHold(controlMode, -1, TimeUnit.SECONDS).breakWhen(collision));

			Frame Frame1 = lbr.getCurrentCartesianPosition(lbr.getFlange());
			if (Frame1.isCloseTo(getApplicationData().getFrame("/Frame_Z2"), 2, 2))
			{ break; }
		}

The loop doesn't stop once I have reached the specified frame (/Frame_Z2) ...
Any idea how to fix this?

greengrape83 · May 6th 2017

If you stop a motion by 'breakwhen', you need to handle trivial details to resume the motion because there are several kinds of motions with different parameters.
But by the following pair of methods you can actually freeze and unfreeze the robot.

Code

getApplicationControl().setApplicationOverride(0)
getApplicationControl().setApplicationOverride(1)

robotneuling · May 6th 2017

Hi greengrape83,

So you would integrate that pair of methods into the while loop?
For what reason?
I haven't really used setApplicationOverride so far that's why I am asking.

Quote from greengrape83
If you stop a motion by 'breakwhen', you need to handle trivial details to resume the motion because there are several kinds of motions with different parameters.
But by the following pair of methods you can actually freeze and unfreeze the robot.
Code
getApplicationControl().setApplicationOverride(0)
getApplicationControl().setApplicationOverride(1)

greengrape83 · May 7th 2017

The 'while' loop is a good idea for the application containing only one motion.
But I'm not sure it can handle a normal robot application case.
A normal robot application always contains a set of motions. And collision pause/resume should be applied to most of the motions.

The following is the way that I have used to handle the similar situation. I wish it be helpful.

Code

// Some impedance mode may be necessary...
        //TODO: 
        // Collision condition
        ICondition collisionCondition = ForceCondition.createSpatialForceCondition(lbr.getFlange(), 15.0d);
        // Collision observer
        ConditionObserver collisionObserver = getObserverManager().createAndEnableConditionObserver(collisionCondition, NotificationType.OnEnable, new IAnyEdgeListener()
        {


            @Override
            public void onAnyEdge(ConditionObserver conditionObserver, Date time, int missedEvents, boolean conditionValue)
            {
                if (conditionValue)
                {
                    // Here a collision is detected and try to freeze the robot
                    getApplicationControl().setApplicationOverride(0.0d);
                }
                else
                {
                    // Some extra judgements may be necessary for force wobble when motion paused...
                    // TODO
                    // Here a collision is removed and try to unfreeze the robot
                    getApplicationControl().setApplicationOverride(1.0d);
                }
            }


        });
        // A set of motions to go with the supposed the path. If collision detected, the current motion freezed. If collision removed, the motion continue.
        lbr.move(ptp(getApplicationData().getFrame("/P1")));
        lbr.move(lin(getApplicationData().getFrame("/P2")));
        lbr.move(circ(getApplicationData().getFrame("/P3"), getApplicationData().getFrame("/P4")));
        lbr.move(ptp(getApplicationData().getFrame("/PTarget")));
        // Disable and remove the observers.
        collisionObserver.disable();
        getObserverManager().removeConditionObserver(collisionObserver);

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Quote from robotneuling

Hi greengrape83,

So you would integrate that pair of methods into the while loop?
For what reason?
I haven't really used setApplicationOverride so far that's why I am asking.

robotneuling · Jun 30th 2017

Hi,

I know it's a while ago but I don't get the robot stopped and resumed smoothly.
I tried to use a collisionObserver as explained by greengrape83.
I don't get the application resumed once the robot is freezed and the ApplicationOverride stays at 0.
The robot should detect a collision (e.g. hand) and stop. Then the application should be resumed by a gesture (like in this video:

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at 2:45).

Any idea how to fix this or is there another way?

Thank you .

greengrape83 · Jul 5th 2017

Hi robotneuling,

I've tested the code snippet on my iiwa.
The robot motions are frozen when I press on the robot and the motions are resumed when I remove the press.
Maybe you can provide the task log about your app running for analysis.

robotneuling · Jul 5th 2017

Hi greengrape83,

I want to stop/freeze the robot once a collision is detected and the robot should stay in that position [like motion.breakWhen(condition...);].
The robot should resume its motion as soon as a "new" collision is deteced (e.g. hand gesture like in the video).

Thank you.

Quote from greengrape83

Hi robotneuling,

I've tested the code snippet on my iiwa.
The robot motions are frozen when I press on the robot and the motions are resumed when I remove the press.
Maybe you can provide the task log about your app running for analysis.

greengrape83 · Jul 6th 2017

It is easy to simply realize the function that first collision to freeze, second to resume, third to freeze... by changing several code lines as following.
However, if the force wobble and user friendliness is considered, much more is needed to make a precise judgement when collision happens and when resume collision happens.

Code

// Some impedance mode may be necessary...
        //TODO:
        // Collision condition
        ICondition collisionCondition = ForceCondition.createSpatialForceCondition(lbr.getFlange(), 15.0d);
        // Collision observer
        // A class member to keep the state
        bCollision = true;
        ConditionObserver collisionObserver = getObserverManager().createAndEnableConditionObserver(collisionCondition, NotificationType.OnEnable, new IAnyEdgeListener()
        {


            @Override
            public void onAnyEdge(ConditionObserver conditionObserver, Date time, int missedEvents, boolean conditionValue)
            {
                if (conditionValue)
                {
                    logger.info("force exceed");
                    // Here a collision or resume is detected and try to freeze/resume the robot
                    if (bCollision)
                    {
                        logger.info("Collision");
                        getApplicationControl().setApplicationOverride(0.0d);
                    }
                    else
                    {
                        logger.info("resume");
                        getApplicationControl().setApplicationOverride(1.0d);
                    }
                    bCollision = !bCollision;
                }
                else
                {
                    logger.info("force reduced");
                    // Some extra judgements may be necessary for force wobble when motion paused...
                    // TODO
                    // Here a collision is removed and try to unfreeze the robot
                    //getApplicationControl().setApplicationOverride(1.0d);
                }
            }


        });
        // A set of motions to go with the supposed the path. If collision detected, the current motion freezed. If collision removed, the motion continue.
        lbr.move(ptp(getApplicationData().getFrame("/P1")));
        lbr.move(lin(getApplicationData().getFrame("/P2")));
        lbr.move(circ(getApplicationData().getFrame("/P3"), getApplicationData().getFrame("/P4")));
        lbr.move(ptp(getApplicationData().getFrame("/P5")));
        // Disable and remove the observers.
        collisionObserver.disable();
        getObserverManager().removeConditionObserver(collisionObserver);

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LBR iiwa - start/resume application by gesture control

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