java-player-users

[Java-player-users] =?ISO-8859-1?Q?VFH?=

[Steffen J. <Ste...@gm...>]

Hi,

Problem 1:

I'm using the vfh driver with the PositionInterface. How do I determine when
the robot has reached its goal?

I've already tried to use getXSpeed and getYSpeed of the PositionInterface
and to do busy waiting until the robot stops. However, this doesn't work
satisfactorily, because it needs a very long delay (around one second)
before I can use the speed information without taking the risk that it is
not updated. Furthermore, busy waiting blocks my system unnecessarily.  


Problem 2:

My player config file defines two position devices:

driver
(
  name "vfh"
  provides ["position:3"]
  requires ["position:0" "laser:0"]
  
   max_speed 0.15
   max_turnrate 40
   safety_dist 0.10
   distance_epsilon 0.2
   angle_epsilon 360
   free_space_cutoff 100000000.0
)

driver
(
  name "stage"
  provides ["position:0" "laser:0"] 
  samples 181
  model "robot"
)

In order to get access to the position device at index 0 I simply do: 
ppd     = playerClient.requestInterfacePosition(0, 'a');

To get access to vfh which runs at index 3, however, it does not suffice to
request the PositionInterface at index 3, but I have to do the request three
times. The first call returns position:1 (which does not exist), the second
returns position:2 and finally the third call returns the desired
PositionInterface for vfh. This is independend of what indices I speficy in
the request method.
 
vfh     = playerClient.requestInterfacePosition(3, 'a'); 
vfh     = playerClient.requestInterfacePosition(3, 'a');
vfh     = playerClient.requestInterfacePosition(3, 'a');

Is it a bug or do I do something wrong?

Many thanks,
Steffen.

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Re: [Java-player-users] VFH

[Radu B. R. <ru...@in...>]

Hello Steffen,

On Tue, Aug 30, 2005 at 07:40:38AM +0200, Steffen Jaensch wrote:
> Hi,
> 
> Problem 1:
> 
> I'm using the vfh driver with the PositionInterface. How do I determine when
> the robot has reached its goal?
> 
> I've already tried to use getXSpeed and getYSpeed of the PositionInterface
> and to do busy waiting until the robot stops. However, this doesn't work
> satisfactorily, because it needs a very long delay (around one second)
> before I can use the speed information without taking the risk that it is
> not updated. Furthermore, busy waiting blocks my system unnecessarily.  

One second sounds a bit too much. Are you using the threaded mode?

> In order to get access to the position device at index 0 I simply do: 
> ppd     = playerClient.requestInterfacePosition(0, 'a');
> 
> To get access to vfh which runs at index 3, however, it does not suffice to
> request the PositionInterface at index 3, but I have to do the request three
> times. The first call returns position:1 (which does not exist), the second
> returns position:2 and finally the third call returns the desired
> PositionInterface for vfh. This is independend of what indices I speficy in
> the request method.
>  
> vfh     = playerClient.requestInterfacePosition(3, 'a'); 
> vfh     = playerClient.requestInterfacePosition(3, 'a');
> vfh     = playerClient.requestInterfacePosition(3, 'a');
> 
> Is it a bug or do I do something wrong?

Unfortunately, it is a bug. It has been on my "to fix" list for too long
now. I will do it asap.

> Many thanks,
> Steffen.

Cheers,
Radu.
--
| Radu Bogdan Rusu | http://www.rbrusu.com
| Intelligent Autonomous Systems Group
| Technische Universitaet Muenchen

Re: [Java-player-users] VFH

[Radu B. R. <ru...@in...>]

Hellos,

Steffen, I just commited a patched PlayerClient.java to the CVS SF
repository. Please download/CVS it and see if it solves your (or anyone
else's) problem with the interface index.

Now calls like requestInterface... (X , 'a'); should work (X=1..10).

Sorry it took so long.

Cheers,
Radu.

Radu Bogdan Rusu wrote:

>Hello Steffen,
>
>On Tue, Aug 30, 2005 at 07:40:38AM +0200, Steffen Jaensch wrote:
>  
>
>>In order to get access to the position device at index 0 I simply do: 
>>ppd     = playerClient.requestInterfacePosition(0, 'a');
>>
>>To get access to vfh which runs at index 3, however, it does not suffice to
>>request the PositionInterface at index 3, but I have to do the request three
>>times. The first call returns position:1 (which does not exist), the second
>>returns position:2 and finally the third call returns the desired
>>PositionInterface for vfh. This is independend of what indices I speficy in
>>the request method.
>> 
>>vfh     = playerClient.requestInterfacePosition(3, 'a'); 
>>vfh     = playerClient.requestInterfacePosition(3, 'a');
>>vfh     = playerClient.requestInterfacePosition(3, 'a');
>>
>>Is it a bug or do I do something wrong?
>>    
>>
>
>Unfortunately, it is a bug. It has been on my "to fix" list for too long
>now. I will do it asap.
>
>  
>
>>Many thanks,
>>Steffen.
>>    
>>
>
>Cheers,
>Radu.
>--
>| Radu Bogdan Rusu | http://www.rbrusu.com
>| Intelligent Autonomous Systems Group
>| Technische Universitaet Muenchen
>
>  
>

Yours sincerely,
Radu Bogdan Rusu
--
| Radu Bogdan Rusu | http://www.rbrusu.com
| Intelligent Autonomous Systems Group
| Technische Universitaet Muenchen