How can I stop an object with deceleration ?

[fabio_g10]

[ FlexSim 22.1.3 ]

Hi everbody.

I have a crane that is travelling to a location in a warehouse. How can I perform a 'real' stop of that crane in the middle of travel, with deceleration to zero speed ?

I've tried Object.stop() but is stops immediately (no-deceleration) and I need the crane to decelerates to zero speed.

Thanks

Fabio

[jason_lightfootVL7B4 · Accepted solution]

Pretty sure this is not possible unless you control all the kinematics of travel yourself. You could post it as an Idea, to have a change in speed affect current travel, here on the forum on which people can vote.

[moehlmann_fe]

As Jason said, you would have to interrupt the current travel with a preempting task sequence and 'manually' add kinematics to decelerate to a stop.

The attached model shows how this can be done. The stop is triggered by sending a message to the crane (msgparam1 = 0). The process flow reacts to this and interrupts the travel. In the custom code activity, the current velocity of the crane is read from the kinematics. From that the stopping distance is calculated and new kinematics are added.

Another message (msgparam1 = 1) will resume the crane.

crane_decelerationtostop.fsm.pdf

(Rightclick on the file attachment -> Save Link/Target As (might be called differently depending on the browser) -> Set "Save as type" to All Types -> Save with a name ends with .fsm)

[fabio_g10]

Excellent Felix ! This approach in your attached model worked for me !

Thank you very much !.

Fabio

[fabio_g10]

Thank you Jason !

[boris_m6]

This answer was very helpful. but can i preemt it as a task, so i can stop it properly and the start a travel task directed to the other way directly from this code?

To create a task that has all this steps, the stop, then the travel to the opposite direction

[moehlmann_fe]

You can set the preemption setting to abort the active taks. Then, if you know where the crane should travel to next, you can add that travel activity to the process flow.

[boris_m6]

I get what you are trying to do but i cannot make it work

i'll put the images of my model

I preemot and abort all, then i ionsert the kinematics of deacceleration and then i'm tryng to add the travel task there but it gets stucked there where the image shows and the crane doesn't travel anywhere

[moehlmann_fe]

Could you upload a screenshot of the settings of the travel activity (where the token is stuck) and the "Run Sub Flow"?

[boris_m6]

is this ok?

[moehlmann_fe]

Yes, thank you for the extra screenshots.

The value in the "Executer/Task Sequence" field of the travel activity should be 'token.taskSequence' (the "Assign to"-value from the Create TS activity). That way the task will be added to the preempting task sequence.

Otherwise, by using 'token.crane', the task is treated as its own separate task sequence which gets queued up behind the preempting sequence. As a result both sequences wait for the other to finish which blocks the simulation from advancing.