Speed limitation close to software limit by traj planner

Hi all,
I just want to confirm that the traj planner decreases the speed before reaching a software limit defined in the .ini file as Max or Min limits of a joint or axis. So if you jog manually towards a soft limit, it ramp down the vel cmd instead of going from the jog speed to 0 at the software limit location.

I did some test and it seems to be the case, the traj planner ramping down the speed, but I cannot remember why I use to think it was not the case. Maybe it was not the case in the past.

If someone could confirm this, that would be great.

Thank you

Nicolas

My speeds are about 110 or 120ipm in the ini and it always stops at .01 past the software limit's.

I haven't really tested it thoroughly, but I would assume it will use your acceleration setting to slow down at the limit

Leon82 wrote:

My speeds are about 110 or 120ipm in the ini and it always stops at .01 past the software limit's.

I experienced that on some machines. If I remember correctly they were all closed loop. Are you running servos? A slight overshoot might be the culprit.

Steppers.

There is probably a parameter for acceptable overshoot. It has never gone past it.

Even in a fanuc you can set the distance past

Hi,
I am using servos in position control so I would expect the machine to decelerate smoothly then get bang on the soft limit.

Thank you for your answers.
Nicolas

Hi all,
regarding this topic,I obverse a different behaviour regarding if the motor is homed or not.
If it is homed, the axis min position limits the motion. If it is not homed, the joint min position does not seem to be effective.
Any idea why?

Thank you,
Nicolas

Hi,
ok, that sounds perfectly normal. I am just wondering then why do you define min and max limit for the joints in the ini file?
Is it if the hard limit switch is triggered to get a value for the machine position, or is it for display reason of the machine limits in gremlin or axis?
Thank you,
Nicolas

The hard limits are to prevent machine damage from a faulty encoder or a large amount of lost steps or slippage of the coupling.

Ideally you would set them a little after home and min limit.

so in a perfect world you will never hit your hard limit switches only software limit