How does the blend move work when the constant velocity profile is not reached?

[barata]

Hi,

In my application I have to blend several moves with the same velocity and acceleration on only one axis.

In the LabView help it is said that  "A blend factor of –1 causes the pending move to start when the existing move finishes its constant velocity segment and starts to decelerate, as shown in the following figure. "

However, if the trajectory parameters are such that the constant velocity segment is never reached (for instance, because during the acceleration segment the target positon is reached), how does the blend motion vi behave? I have looked everywhere and could not find an answer.

Can anyone help me on this?

 Thank you in advance,

João Barata

[Jochen · Accepted solution]

Hi,

the blending starts as soon as the deceleration ramp starts. In the case that the constant  velocity is never reached, the deceleration ramp starts exactly in the middle of the move (assuming that the values for acceleration and deceleration are the same), so you end up with a triangular velocity profile instead of a trpezoidal velocity profile. That means, it could never happen, that the target position is reached during the acceleration ramp.

I hope that helps,

Jochen Klier

National Instruments

[barata]

Thank you, Jochen, for your answer. 

I thought the trajectory profile was imposed in a different way, but with your answer it became clear how it works.

My best regards,

João Barata