Re: [ros-users] base_local_planner

Eric,

That ticket didn't include the linear case originally, but it does now.
Thanks for pointing it out. The PR2 has such high acceleration limits that
its easy for me to overlook this stuff, but it really matters for robots
with lower acceleration limits.

Hope all is well,

Eitan

On Thu, May 27, 2010 at 11:09 AM, Eric Perko <wisesage5001@gmail.com> wrote:

> Eitan,
>
> Does that ticket also include taking into account linear decelerations
> as well as rotational limits? I've been using the TrajectoryPlanner
> with reasonable acceleration limits for my differential drive robot
> (say 0.25 m/s^2 for acc_limit_x) and, while we seem to accelerate
> smoothly, upon reaching a goal within tolerance the system sends
> abrupt halt commands. Does the TrajectoryPlanner expect another piece
> of software to modulate the speeds to account for safe deceleration or
> should I be seeing smooth deceleration as the robot approaches the
> goal?
>
> - Eric
>
> On Thu, May 27, 2010 at 2:00 PM, Eitan Marder-Eppstein
> <eitan@willowgarage.com> wrote:
> > Andreas,
> >
> > This could be due to the fact that the rotate to goal code doesn't take
> the
> > robot's acceleration limits into account. There's actually a ticket open
> > against it here: https://code.ros.org/trac/ros-pkg/ticket/3127 that got
> a
> > bit lost in the pile. I'm going to change the priority on it to make sure
> > that I get to it in the next week or so since it seems to be affecting
> you.
> >
> > Hope all is well,
> >
> > Eitan
> >
> >
> > On Thu, May 27, 2010 at 12:13 AM, Andreas Vogt <andreas.vogt@dfki.de>
> wrote:
> >>
> >> Hi,
> >> I am running my planner with this parameters:
> >>
> >> TrajectoryPlannerROS:
> >> max_vel_x: 0.2
> >> min_vel_x: 0.01
> >> max_rotational_vel: 0.23
> >> min_in_place_rotational_vel: 0.01
> >>
> >> acc_limit_th: 0.05
> >> acc_limit_x: 0.05
> >> acc_limit_y: 0.05
> >>
> >> holonomic_robot: false
> >>
> >> but sometimes it seems that the velocity (angular.z here omega) jumps
> >> without account for the acceleration. In my case from zero to
> >> max_rotational_vel.
> >>
> >>
> >> Any ideas ?
> >>
> >> Andreas
> >>
> >>
> >>
> >>
> >>
> >> [ERROR] 170.700000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.230000
> >> 0.000000
> >> [ERROR] 170.754000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.230000
> >> 0.000000
> >> [ERROR] 170.805000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.173355
> >> 0.000000
> >> [ERROR] 170.855000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.173355
> >> 0.000000
> >> [ERROR] 170.902000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.173355
> >> 0.000000
> >> [ERROR] 170.952000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.173355
> >> 0.000000
> >> [ERROR] 171.003000000: ICP: 0.000000 VEL: 0.000000 OMEGA: 0.140928
> >> 0.000000
> >> [ERROR] 171.053000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.118000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.152000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.201000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.250000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.302000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.353000000: ICP: 10.000000 VEL: 0.105000 OMEGA: 0.000000
> >> 0.000000
> >> [ERROR] 171.401000000: ICP: 0.000000 VEL: 0.010000 OMEGA: -0.230000
> >> 0.000000
> >> [ERROR] 171.450000000: ICP: 0.000000 VEL: 0.010000 OMEGA: -0.230000
> >> 0.000000
> >> [ERROR] 171.501000000: ICP: 0.000000 VEL: 0.010000 OMEGA: -0.230000
> >> 0.000000
> >> [ERROR] 171.550000000: ICP: 0.000000 VEL: 0.010000 OMEGA: -0.230000
> >> 0.000000
> >> [ERROR] 171.609000000: ICP: 0.000000 VEL: 0.010000 OMEGA: -0.230000
> >> 0.000000
> >>
> >>
> >>
> >>
> >> _______________________________________________
> >> ros-users mailing list
> >> ros-users@code.ros.org
> >> https://code.ros.org/mailman/listinfo/ros-users
> >
> >
> > _______________________________________________
> > ros-users mailing list
> > ros-users@code.ros.org
> > https://code.ros.org/mailman/listinfo/ros-users
> >
> >
> _______________________________________________
> ros-users mailing list
> ros-users@code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>