Solved: AGV Travel with EndSpeed > 0 finishes before the destination is reached

sastanin · ‎02-15-2024

[ FlexSim 24.0.1 ]

How to reproduce:

FlexSim 24.0.2

AGV Network with Speeds = 3.0 m/s, Acceleration/Deceleration = 0.4 m/s².

Create a Task Sequence in Process Flow using AGV Travel. Set End Speed = 3.0 m/s, and any Control Point as a destination.

Expected behavior: the token should released from AGV Travel only when the travel is completed.

Observered behavior: the token may be released earlier, before the destination is reached. The task executer finishes its travel task before the destination is reached and enters "allocated idle" state.

I've created a model that reproduces this bug. It seems to depend both on End Speed option (doesn't happen with End Speed = 0), and a particular AGV speed (doesn't happen with Speed = 1). Accelerations and decelerations do not seem important.

AGV_Travel_Wait_for_Finish_24_0.fsm

moehlmann_fe · ‎02-15-2024

This is by design and speed and acceleration determine how premature the task will be completed.

The assumption when using an endspeed > 0 is that another travel task will be appended to the task sequence and the AGV will continue at that speed. However, in order to continue past the current destination it would have to allocate further control points. This allocation would only happen when the next travel task starts. Since its possible that this allocation will fail, the tasks ends prematurely so if the (expected) next task can't allocate the next point, the AGV still has enough distance to the CP to decelerate to a stop.

If you want the AGV to drive to the CP at max speed and then stop on a dime, set the deceleration value very high.

sastanin · ‎02-16-2024

Thank you for explanation. It's very clear now. Decelertion = 0 does work for me.

AGV Travel with EndSpeed > 0 finishes before the destination is reached

AGV Travel with EndSpeed > 0 finishes before the destination is reached

Photos