[ros-users] base_local_planner

[Eric Perko]

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> 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> 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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