[ros-users] Pioneer 3dx in ROS

Dan Lazewatsky lazewatskyd at cse.wustl.edu
Tue May 18 17:59:52 UTC 2010 

Tucker,
I'm at rev 54. Changing pulse from 1.0 to 0.5 didn't have any effect  
other than playing the startup sound more often. My launch file is  
attached.

-Dan
On May 18, 2010, at 12:19 PM, Tucker Hermans wrote:

> Dan,
>
> Are you using the latest version (rev 52 or newer)?  David updated  
> some things to make the timing switch to using ros time instead of  
> the standard system time.  After this change I had to change to  
> explicitly sending pulses, whereas I did not before.  Now setting  
> pulse to 0.5 works and I have no issue with the use_sonar  parameter  
> responding correctly.
>
> If this doesn't work, then can you attach your launch file?
>
> -Tucker
>
> On Tue, May 18, 2010 at 1:11 PM, Dan Lazewatsky <lazewatskyd at cse.wustl.edu 
> > wrote:
> I finally had a chance to play around with this some more. Setting  
> pulse to 1.0 does indeed make the motors respond sensibly, but also  
> seems to cause the robot to constantly make the startup beeps and  
> turn on the sonar regardless of what use_sonar is set to.
>
> -Dan
>
> On Apr 27, 2010, at 6:01 PM, Tucker Hermans wrote:
>
>> Dan,
>>
>> There is a pulse parameter on the ros parameter server for the p2os  
>> node (see p2osnode.cc line 49 for where it is defined).
>>
>> If you set this value to something other than -1.0 it should send  
>> the pulse (see p2osnode.cc line 725).
>>
>> Adding the following line to the p2os node in your launch file  
>> should do the trick:
>>
>> <param name="pulse" value="1.0"/>
>>
>> -Tucker
>>
>> On Tue, Apr 27, 2010 at 6:35 PM, Dan Lazewatsky <lazewatskyd at cse.wustl.edu 
>> > wrote:
>> No luck setting pulse to 1 (I'm assuming you're referring to the  
>> PULSE
>> parameter in robot_params.h)
>>
>> -Dan
>>
>> On 4/23/10 2:39 PM, David Feil-Seifer wrote:
>> > I wrote the node, but a while ago, so I can't be sure, but Ithink  
>> that
>> > I sent a "pulse" message every 1s to keep that watchdog from  
>> kicking
>> > in. However, by default it is turned off. Try setting the "pulse"
>> > parameter to 1.
>> >
>> > -Dave
>> >
>> > On Fri, Apr 23, 2010 at 8:24 AM, Brian Gerkey<gerkey at willowgarage.com 
>> >  wrote:
>> >
>> >> It's been a long time since I used a Pioneer, and I haven't  
>> looked at
>> >> the node that you're using, so this is shooting in the dark:
>> >>
>> >> If I recall correctly, the microcontroller implements a watchdog  
>> that
>> >> will stop the motors if it hasn't heard a velocity command over  
>> the
>> >> serial line after a certain amount of time.  If you send  
>> commands too
>> >> slowly, the watchdog would kick in between commands, causing the  
>> robot
>> >> to move a bit, halt, move a bit, halt, etc. I believe that the
>> >> watchdog is configurable, or at least can be turned on or off,  
>> which
>> >> might account for the different in behavior between your robots.
>> >>
>> >> Something to try is to make the node resend the last received  
>> velocity
>> >> to the robot at a relatively high rate (10Hz should be enough).   
>> Of
>> >> course, the node should then implement its own watchdog, which  
>> would
>> >> send zero velocities if it hasn't received a command via ROS after
>> >> some time.
>> >>
>> >>         brian.
>> >>
>> >> On Fri, Apr 23, 2010 at 6:56 AM, Tucker Hermans<thermans at cc.gatech.edu 
>> >  wrote:
>> >>
>> >>> Dan,
>> >>> Without being able to investigate your setup further, the only  
>> thing I can
>> >>> think is that the commands being sent over the serial  
>> connection are either
>> >>> experiencing high latency or are being sent to infrequently, so  
>> that the
>> >>> velocity commands sent to the microcontroller are far enough  
>> apart that you
>> >>> get the stuttering effect.
>> >>> I tried reproducing this by setting a very high time (30s as  
>> opposed to 2s)
>> >>> to resend velocity commands but this had no effect.  Are you  
>> seeing
>> >>> statements from the p2os node of the form "new speed [0.25, 0.0]
>> >>> (timestamp)" and "setting vel: [0.25,0.0]".  If not what kind  
>> of debug
>> >>> output are you seeing on the node?
>> >>> -Tucker
>> >>>
>> >>> On Thu, Apr 22, 2010 at 12:31 PM, Dan Lazewatsky<lazewatskyd at cse.wustl.edu 
>> >
>> >>> wrote:
>> >>>
>> >>>> I just tried out a few things from your pioneer_control  
>> package and I get
>> >>>> the same behavior I was seeing before.
>> >>>>
>> >>>> -Dan
>> >>>>
>> >>>> On 4/21/10 7:13 PM, Dan Lazewatsky wrote:
>> >>>>
>> >>>> Hi Tucker,
>> >>>> I think that should be enough to get me going.
>> >>>>
>> >>>> Thanks!
>> >>>> -Dan
>> >>>>
>> >>>> On 4/21/10 6:57 PM, Tucker Hermans wrote:
>> >>>>
>> >>>> Hi Dan,
>> >>>> I send the MotorState command of 4 and have no problems.
>> >>>> I have a teleop keyboard port which I use for communicating  
>> with the p3dx
>> >>>> that you can find
>> >>>> here: github.com/trhermans/AffLearning/tree/master/ 
>> pioneer_control/
>> >>>> Note: the launch file is setup for a p3dx with a PTZ connected  
>> to an
>> >>>> onboard computer and uses the probe camera driver to get the  
>> video stream.
>> >>>> I have only been testing the changes to the p2os package on a  
>> p3dx with an
>> >>>> onboard computer, I don't think this should have any issues,  
>> but it could.
>> >>>> Let me know if the keyboard operation gives the same problems  
>> you have now
>> >>>> and I'll try and help debug it.
>> >>>> -Tucker
>> >>>>
>> >>>> On Wed, Apr 21, 2010 at 7:49 PM, Dan Lazewatsky
>> >>>> <lazewatskyd at cse.wustl.edu>  wrote:
>> >>>>
>> >>>>> Hi all -
>> >>>>> I know this has been discussed here a bit, but not in much  
>> detail.
>> >>>>> We have a Pioneer3dx that we'd like to get up and running  
>> again. I
>> >>>>> downloaded and compiled the p2os package which seems to be  
>> able to
>> >>>>> successfully connect and communicate with the robot using a  
>> serial to
>> >>>>> USB adapter. However, I'm having trouble getting the motors  
>> to do
>> >>>>> anything sensible. The robot's motor self-test looks like it  
>> works fine,
>> >>>>> but sending cmd_vel, all I can get is extremely slow, jerky  
>> movement
>> >>>>> forward or backwards (no turning). I enabled the motors with:
>> >>>>>
>> >>>>> rostopic pub cmd_motor_state -1 p2os/MotorState 1 (I also  
>> tried 4
>> >>>>> instead of 1 which was mentioned in a previous discussion)
>> >>>>>
>> >>>>> This feels like a communication problem between the motor  
>> commands p2os
>> >>>>> is sending and the robot, but I don't know what's going on.  
>> Any ideas?
>> >>>>>
>> >>>>> Thanks,
>> >>>>> -Dan
>> >>>>> _______________________________________________
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