[ros-users] base_local_planner

Andreas Vogt andreas.vogt at dfki.de
Fri May 28 12:22:17 UTC 2010


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 <wisesage5001 at gmail.com 
> <mailto:wisesage5001 at 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 at willowgarage.com <mailto:eitan at 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 at dfki.de <mailto:andreas.vogt at 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
>     >>
>     >>
>     >>
>     >>
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-- 

 Andreas Vogt 
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