Re: [ros-users] base_local_planner

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Author: Andreas Vogt
Date:  
To: ros-users
Subject: Re: [ros-users] base_local_planner

Hi,

thanks for the code but the velocity are still jumps.

Andreas

Eitan Marder-Eppstein schrieb:
> 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 <
> <mailto: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
>     < <mailto: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
>     < <mailto: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
>     >>  <mailto:ros-users@code.ros.org>
>     >> https://code.ros.org/mailman/listinfo/ros-users

>     >

>     >
>     > _______________________________________________
>     > ros-users mailing list
>     >  <mailto:ros-users@code.ros.org>
>     > https://code.ros.org/mailman/listinfo/ros-users

>     >

>     >
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>
>
> ------------------------------------------------------------------------
>
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>



--

Andreas Vogt
Logistics and Production Robotics

DFKI Bremen
Robotics Innovation Center
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28359 Bremen, Germany

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