Re: [Playerstage-users] position2d 'GoTo' not working under player-2.0?

[Solly B. <so...@cs...>]

Hi Geoffrey, Toby,

Thanks for the suggestions.

I've tried using SetMotorEnable but I get a NACK from player: "playerc 
error : got NACK from request". Not sure whether the vfh driver supports 
SetMotorEnable... I guess it should, in which case I'm not sure what's 
going on.

Interestingly, if you try SetSpeed(1,0) it works exactly as expected... 
robot sets off on its merry way. That's *without* changing any of the 
code in Position2dProxy. As Geoffrey pointed out the SetSpeed member 
function also sends a 0 for the motor state:

void
Position2dProxy::SetSpeed(double aXSpeed, double aYSpeed, double aYawSpeed)
{
   scoped_lock_t lock(mPc->mMutex);
   playerc_position2d_set_cmd_vel(mDevice,aXSpeed,aYSpeed,aYawSpeed,0);
}

but this actually works.

I've just tried editing the code in Position2dProxy::GoTo and setting 
the 0 parameter to a 1 as Geoffrey suggested. This time the robot moves 
(some sort of message is getting through!) but it doesn't behave as 
expected.
eg. GoTo(5,0,0) => robot does nothing
eg. GoTo(0,5,0) => robot rotates in a circle continuously

Very odd, but perhaps I'm missing something.

Solly

Geoffrey Biggs wrote:
> Looking at the Position2dProxy code, it looks like it should be sending 
> 1 for the state in both Goto() and SetSpeed(). Try changing the 0 in 
> Goto() to a 1 and see if that works.
> 
> Geoff
> 
> Solly Brown wrote:
> 
>> Hi all,
>>
>> Does the GoTo command work in the position2d proxy under player 2.0?
>>
>> I've set up the vfh driver to provide a position2d interface, and I 
>> know the cfg file is correct since I'm able to successfully use vfh 
>> through the playerv utility.
>>
>> However, I haven't been able to get vfh to work in my own code. There 
>> are no error messages -- it just doesn't appear to do anything. That 
>> led me to suspect that the motors weren't enabled, and looking at the 
>> source code I found this function call in the position2d proxy:
>>
>> void
>> Position2dProxy::GoTo(double aX, double aY, double aYaw)
>> {
>>   scoped_lock_t lock(mPc->mMutex);
>>   playerc_position2d_set_cmd_pose(mDevice,aX,aY,aYaw,0);
>> }
>>
>> The last parameter in playerc_position2d_set_cmd_pose is 0, and this 
>> appears to correspond to the motor state being set to disabled. 
>> Checking the playerv code I find the opposite call:
>>
>> playerc_position2d_set_cmd_pose(self->proxy, self->goal_px, 
>> self->goal_py, self->goal_pa, 1);
>>
>> ie. the last parameter is 1 not a 0. So it seems that the motors in 
>> the position2d proxy GoTo command are switched off, whereas the 
>> playerv utility sets them to enabled... which perhaps explains why one 
>> works and the other one doesn't?
>>
>> So what's going on here? How do I use the GoTo/vfh in my own code? 
>> Below is the simplest example of my own code that I expected to work 
>> but did nothing.
>>
>> Thanks for your help...
>>
>> Solly
>>
>> -------------------------------------
>> #include <iostream>
>> #include <libplayerc++/playerc++.h>
>>
>> int
>> main(int argc, char *argv[])
>> {
>>   using namespace PlayerCc;
>>
>>   PlayerClient    robot("localhost");
>>   Position2dProxy pp(&robot,1); //vfh position2d proxy
>>
>>   pp.GoTo( 5, 0, 0);
>>
>> }
>>
>> ---------------------------------------
>> Here's my .cfg file (I'm using gazebo)
>>
>> driver
>> (
>>   name "gazebo"
>>   provides ["simulation:0"]
>>   plugin "libgazeboplugin"
>>   server_id "default"
>> )
>>
>> driver
>> (
>>   name "gazebo"
>>   provides ["position2d:0"]
>>   gz_id "robot1"
>> )
>>
>> driver
>> (
>>   name "gazebo"
>>   provides ["laser:0"]
>>   gz_id "laser1"
>> )
>>
>> driver
>> (
>>   name "vfh"
>>   provides ["position2d:1"]
>>   requires ["position2d:0" "laser:0"]
>>   safety_dist 0.10
>>   distance_epsilon 0.3
>>   angle_epsilon 5
>> )
>>
>> driver
>> (
>>   name "gazebo"
>>   provides ["camera:0"]
>>   gz_id "camera1"
>>   save 1
>> )
>>
>> driver
>> (
>>   name "gazebo"
>>   provides ["power:0"]
>>   gz_id "robot1"
>> )
>>
> 
> 
> 
> 
>