delay in Player-Stage

[Aslund]

Hey Everyone

I am implementing a Extended Kalman Filter in Player-Stage, my prior estimation of the position is based on the velocity model. Because I use the velocity model, then I need a small delay before I can do feature extraction of the environment, here I use clock() from the time.h to measure the difference in time. The new problem is that when my program enters the loop, the robot in my Stage simulation stops moving, so when the loop finished, the robot is far from the position the velocity model estimated. Is it possible to make a delay with a while-loop or something else while keeping the robot moving?
Ps. a short code piece is shown below 

        begin = clock();
        ......
        PriorEstimate();
        ......
        do
        {
            end = clock();
        }
        while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
        ....
        FeatureExtraction();

Thanks for your help

Regards

Sebastian

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[Richard Vaughan-4]

On Thu, Nov 5, 2009 at 9:06 AM, Aslund <sebastian.aslund@...> wrote:
> Hey Everyone
>
> I am implementing a Extended Kalman Filter in Player-Stage, my prior
> estimation of the position is based on the velocity model. Because I use the
> velocity model, then I need a small delay before I can do feature extraction
> of the environment, here I use clock() from the time.h to measure the
> difference in time. The new problem is that when my program enters the loop,
> the robot in my Stage simulation stops moving,

Can you explain what's happening here? Why does the robot stop moving?

- rtv


so when the loop finished,

> the robot is far from the position the velocity model estimated. Is it
> possible to make a delay with a while-loop or something else while keeping
> the robot moving?
> Ps. a short code piece is shown below
>
>         begin = clock();
>         ......
>         PriorEstimate();
>         ......
>         do
>         {
>             end = clock();
>         }
>         while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
>         ....
>         FeatureExtraction();
>
> Thanks for your help
>
> Regards
>
> Sebastian
>
> ------------------------------------------------------------------------------
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> trial. Simplify your report design, integration and deployment - and focus
> on
> what you do best, core application coding. Discover what's new with
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> _______________________________________________
> Playerstage-users mailing list
> Playerstage-users@...
> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>

--
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Autonomy Lab / Computing Science / Simon Fraser University

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[Aslund]

Hey Richard

Why it stops moving is exactly my problem and I don't know why.
What happens is that I predict my future position based on a translational and rational velocity, and a time step delta_t.
Before I can do a laser scan and make a feature extraction on the enviroment, then I have to wait delta_t before I preform the scan. In the short moment it takes to make the prior position estimat, the robot moves, but as soon it hits the loop where the program waits for delta_t to have passed, the robot does'nt move and I have no idea why.
Hope this distribution clarifies the problem and hope a solution can be found.

Regards

Sebastian

ps.
I have added my main file if that have any interest.
  

2009/11/5 Richard Vaughan <rtvaughan@...>

On Thu, Nov 5, 2009 at 9:06 AM, Aslund <sebastian.aslund@...> wrote:
> Hey Everyone
>
> I am implementing a Extended Kalman Filter in Player-Stage, my prior
> estimation of the position is based on the velocity model. Because I use the
> velocity model, then I need a small delay before I can do feature extraction
> of the environment, here I use clock() from the time.h to measure the
> difference in time. The new problem is that when my program enters the loop,
> the robot in my Stage simulation stops moving,

Can you explain what's happening here? Why does the robot stop moving?

- rtv

so when the loop finished,
> the robot is far from the position the velocity model estimated. Is it
> possible to make a delay with a while-loop or something else while keeping
> the robot moving?
> Ps. a short code piece is shown below
>
>         begin = clock();
>         ......
>         PriorEstimate();
>         ......
>         do
>         {
>             end = clock();
>         }
>         while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
>         ....
>         FeatureExtraction();
>
> Thanks for your help
>
> Regards
>
> Sebastian
>

> ------------------------------------------------------------------------------
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> trial. Simplify your report design, integration and deployment - and focus
> on
> what you do best, core application coding. Discover what's new with
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> _______________________________________________
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> Playerstage-users@...
> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>



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Autonomy Lab / Computing Science / Simon Fraser University

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[main.cpp]

---

#include <iostream>
#include <time.h>
#include <math.h>
#include "libplayerc++/playerc++.h"
#include "MathTools.h"
#include "MathStruct.h"
#include "FeatureExtraction.h"
#include "ExtendedKalman.h"
#include "gnuplot_i.hpp"



using namespace std;
using namespace PlayerCc;

typedef pair<double,double> Pair;

///Get our algoritmes
MathTools MathTool;

void initGlobVar(double& GlobVarX, double& GlobVarY, double& GlobVarYaw)
{
    ///Request an initial value for the global position
    cout << "Enter the robots position, defined in meters and degree\n" <<
            "X: ";
    cin  >> GlobVarX;

    cout << "Y: ";
    cin  >> GlobVarY;

    cout << "Yaw: ";
    cin  >> GlobVarYaw;

    MathTool.convToRad(GlobVarYaw);
}

///---------------- Main ----------------------------------------------------------------------

int main(int argc, char *argv[])
{
///Setting up the robot and its proxies
    PlayerClient    robot("localhost");
    LaserProxy      sp(&robot,0);
    Position2dProxy pp(&robot,0);

///Vectors and matrixes.
    vector<double> dataX, dataY, x_k(3);
    vector<Pair> Z;
    matrix<double> x_cov(3,3);

///Defines
    double GlobX, GlobY, GlobYaw = 0;
    double speed = 1.0, turnrate = -1.0 * double(2.0/9.0);
    int count;

///Time
    clock_t start, end;

///Map
    vector<Pair> Map;
    Map.push_back( make_pair(7.86992, MathTool.getPi()/2.0 ));
    Map.push_back( make_pair(7.86992, MathTool.getPi() ));
    Map.push_back( make_pair(7.86992, -1*MathTool.getPi()/2.0 ));
    Map.push_back( make_pair(2.8, -0.527 ));

    cout << "--- Map ----" << endl;
    MathTool.printPairs(Map);
    cout << "------------" << endl;
///First read, initilize the proxies
    robot.Read();

///Set global positioning
    initGlobVar(GlobX, GlobY, GlobYaw);
    pp.SetOdometry(GlobX, GlobY, GlobYaw);
    pp.SetSpeed(speed, turnrate);

///Set initial position
    x_k[0] = GlobX; x_k[1] = GlobY; x_k[2] = GlobYaw;

///Set intial covariance matrix
    for(int row = 0; row < 3; row++)
        for(int col = 0; col < 3; col++)
            x_cov[row][col] = 0;

///Initialize extended kalman filter
    ExtendedKalman Kalman(x_k, x_cov);

///Set first time
    start = clock();

   // for(;;)
   // {

    ///Set robot speed
        pp.SetSpeed(speed, turnrate);

    ///Set speed in the kalman filter
        Kalman.setMotion(speed, turnrate);

    ///Set motion error
        Kalman.setMotionError(0.05, 0.10);

///-------------------- Prior Estimate --------------------------------------------------------------------
        x_k = Kalman.getX_Prior();

///--------------------------------------------------------------------------------------------------------

        end = clock();

    ///Wait until 2.086s have passed
    ///No motion while loop is running???
        do
        {
            end = clock();
        }
        while((double)(end-start)/CLOCKS_PER_SEC < 2.086);

    /// read from the proxies
        robot.Read();
       // pp.SetSpeed(speed, turnrate);

    ///Update time
        start = end;

    ///Get number of laser samples
        count = sp.GetCount();

    ///Store the laser data in cartesian coordinates
        for(int i = 0; i < count; i++)
        {
            if(sp.GetRange(i) < 7.9)
            {
                dataX.push_back( sp.GetRange(i) * cos(sp.GetBearing(i)) );
                dataY.push_back( sp.GetRange(i) * sin(sp.GetBearing(i)) );
            }
        }

///-------------------- Feature Extraction ------------------------------------------------------------------

    ///Pass laser scans to the algoritmen
        FeatureExtraction Feature(false, dataX, dataY);

    ///Preform feature extration according to DACSAC2
        Feature.DACSAC2();
///----------------------------------------------------------------------------------------------------------

    ///Get result of feature extraction
        Z = Feature.getMeasurement();

        cout << "Feature Extraction result: " << endl;
        MathTool.printPairs(Z);

///-------------------- Post Estimate -----------------------------------------------------------------------
        x_k = Kalman.getX_Post(Map, Z);
///----------------------------------------------------------------------------------------------------------

 // }
}

---

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[Richard Vaughan-4]

On Thu, Nov 5, 2009 at 10:39 AM, Aslund <sebastian.aslund@...> wrote:

> Hey Richard
>
> Why it stops moving is exactly my problem and I don't know why.
> What happens is that I predict my future position based on a translational
> and rational velocity, and a time step delta_t.
> Before I can do a laser scan and make a feature extraction on the
> enviroment, then I have to wait delta_t before I preform the scan. In the
> short moment it takes to make the prior position estimat, the robot moves,
> but as soon it hits the loop where the program waits for delta_t to have
> passed, the robot does'nt move and I have no idea why.

That's because Stage runs in Player's main thread. If your work is
happening there too, no simulated time can pass.

- rtv

> Hope this distribution clarifies the problem and hope a solution can be
> found.
>
> Regards
>
> Sebastian
>
> ps.
> I have added my main file if that have any interest.
>
>
> 2009/11/5 Richard Vaughan <rtvaughan@...>
>>
>> On Thu, Nov 5, 2009 at 9:06 AM, Aslund <sebastian.aslund@...> wrote:
>> > Hey Everyone
>> >
>> > I am implementing a Extended Kalman Filter in Player-Stage, my prior
>> > estimation of the position is based on the velocity model. Because I use
>> > the
>> > velocity model, then I need a small delay before I can do feature
>> > extraction
>> > of the environment, here I use clock() from the time.h to measure the
>> > difference in time. The new problem is that when my program enters the
>> > loop,
>> > the robot in my Stage simulation stops moving,
>>
>> Can you explain what's happening here? Why does the robot stop moving?
>>
>> - rtv
>>
>>
>> so when the loop finished,
>> > the robot is far from the position the velocity model estimated. Is it
>> > possible to make a delay with a while-loop or something else while
>> > keeping
>> > the robot moving?
>> > Ps. a short code piece is shown below
>> >
>> >         begin = clock();
>> >         ......
>> >         PriorEstimate();
>> >         ......
>> >         do
>> >         {
>> >             end = clock();
>> >         }
>> >         while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
>> >         ....
>> >         FeatureExtraction();
>> >
>> > Thanks for your help
>> >
>> > Regards
>> >
>> > Sebastian
>> >
>> >
>> > ------------------------------------------------------------------------------
>> > Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> > 30-Day
>> > trial. Simplify your report design, integration and deployment - and
>> > focus
>> > on
>> > what you do best, core application coding. Discover what's new with
>> > Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> > _______________________________________________
>> > Playerstage-users mailing list
>> > Playerstage-users@...
>> > https://lists.sourceforge.net/lists/listinfo/playerstage-users
>> >
>> >
>>
>>
>>
>> --
>> Richard Vaughan
>> Autonomy Lab / Computing Science / Simon Fraser University
>>
>>
>> ------------------------------------------------------------------------------
>> Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> 30-Day
>> trial. Simplify your report design, integration and deployment - and focus
>> on
>> what you do best, core application coding. Discover what's new with
>> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> _______________________________________________
>> Playerstage-users mailing list
>> Playerstage-users@...
>> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>
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> on
> what you do best, core application coding. Discover what's new with
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> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>

--
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Autonomy Lab / Computing Science / Simon Fraser University

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[Aslund]

I see, quite a problem.
Is there a way to count the time without blocking for stage?

Regards

Sebastian
 

2009/11/5 Richard Vaughan <rtvaughan@...>

On Thu, Nov 5, 2009 at 10:39 AM, Aslund <sebastian.aslund@...> wrote:
> Hey Richard
>
> Why it stops moving is exactly my problem and I don't know why.
> What happens is that I predict my future position based on a translational
> and rational velocity, and a time step delta_t.
> Before I can do a laser scan and make a feature extraction on the
> enviroment, then I have to wait delta_t before I preform the scan. In the
> short moment it takes to make the prior position estimat, the robot moves,
> but as soon it hits the loop where the program waits for delta_t to have
> passed, the robot does'nt move and I have no idea why.

That's because Stage runs in Player's main thread. If your work is
happening there too, no simulated time can pass.

- rtv

> Hope this distribution clarifies the problem and hope a solution can be
> found.
>
> Regards
>
> Sebastian
>
> ps.
> I have added my main file if that have any interest.
>
>
> 2009/11/5 Richard Vaughan <rtvaughan@...>
>>
>> On Thu, Nov 5, 2009 at 9:06 AM, Aslund <sebastian.aslund@...> wrote:
>> > Hey Everyone
>> >
>> > I am implementing a Extended Kalman Filter in Player-Stage, my prior
>> > estimation of the position is based on the velocity model. Because I use
>> > the
>> > velocity model, then I need a small delay before I can do feature
>> > extraction
>> > of the environment, here I use clock() from the time.h to measure the
>> > difference in time. The new problem is that when my program enters the
>> > loop,
>> > the robot in my Stage simulation stops moving,
>>
>> Can you explain what's happening here? Why does the robot stop moving?
>>
>> - rtv
>>
>>
>> so when the loop finished,
>> > the robot is far from the position the velocity model estimated. Is it
>> > possible to make a delay with a while-loop or something else while
>> > keeping
>> > the robot moving?
>> > Ps. a short code piece is shown below
>> >
>> >         begin = clock();
>> >         ......
>> >         PriorEstimate();
>> >         ......
>> >         do
>> >         {
>> >             end = clock();
>> >         }
>> >         while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
>> >         ....
>> >         FeatureExtraction();
>> >
>> > Thanks for your help
>> >
>> > Regards
>> >
>> > Sebastian
>> >
>> >
>> > ------------------------------------------------------------------------------
>> > Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> > 30-Day
>> > trial. Simplify your report design, integration and deployment - and
>> > focus
>> > on
>> > what you do best, core application coding. Discover what's new with
>> > Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> > _______________________________________________
>> > Playerstage-users mailing list
>> > Playerstage-users@...
>> > https://lists.sourceforge.net/lists/listinfo/playerstage-users
>> >
>> >
>>
>>
>>
>> --
>> Richard Vaughan
>> Autonomy Lab / Computing Science / Simon Fraser University
>>
>>
>> ------------------------------------------------------------------------------
>> Let Crystal Reports handle the reporting - Free Crystal Reports 2008
>> 30-Day
>> trial. Simplify your report design, integration and deployment - and focus
>> on
>> what you do best, core application coding. Discover what's new with
>> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>> _______________________________________________
>> Playerstage-users mailing list
>> Playerstage-users@...
>> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>
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> Playerstage-users@...
> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>



--
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Autonomy Lab / Computing Science / Simon Fraser University

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[Rich Mattes-2]

Some parts of this message have been removed. Learn more about Nabble's security policy.

Is it possible that the simulation is just slowing down a lot because your client program is hammering your CPU during the while loop?  Try adding a small delay, like calling usleep(100000); [100 ms] inside of the while loop to free up system resources for everything else that’s trying to run.  It looks like your update interval is somewhere around 2 seconds, so pausing for 100ms should make your delay time between about 2 and 2.1 seconds.  Cut the usleep by an order of magnitude (i.e. remove a 0) and you should get a delay time between about 2 and 2.01 seconds.

 

I don’t think it has anything to do with you actually stopping Player or Stage, since your program is running on its own and just using the client libraries to tie in to Player via the network.  It sounds more like a system-wide resource issue to me.

 

Rich

 

From: Aslund [mailto:sebastian.aslund@...]
Sent: Thursday, November 05, 2009 1:40 PM
To: playerstage-users@...
Subject: Re: [Playerstage-users] delay in Player-Stage

 

Hey Richard

Why it stops moving is exactly my problem and I don't know why.
What happens is that I predict my future position based on a translational and rational velocity, and a time step delta_t.
Before I can do a laser scan and make a feature extraction on the enviroment, then I have to wait delta_t before I preform the scan. In the short moment it takes to make the prior position estimat, the robot moves, but as soon it hits the loop where the program waits for delta_t to have passed, the robot does'nt move and I have no idea why.
Hope this distribution clarifies the problem and hope a solution can be found.

Regards

Sebastian

ps.
I have added my main file if that have any interest.
  

2009/11/5 Richard Vaughan <rtvaughan@...>

On Thu, Nov 5, 2009 at 9:06 AM, Aslund <sebastian.aslund@...> wrote:
> Hey Everyone
>
> I am implementing a Extended Kalman Filter in Player-Stage, my prior
> estimation of the position is based on the velocity model. Because I use the
> velocity model, then I need a small delay before I can do feature extraction
> of the environment, here I use clock() from the time.h to measure the
> difference in time. The new problem is that when my program enters the loop,
> the robot in my Stage simulation stops moving,

Can you explain what's happening here? Why does the robot stop moving?

- rtv

so when the loop finished,
> the robot is far from the position the velocity model estimated. Is it
> possible to make a delay with a while-loop or something else while keeping
> the robot moving?
> Ps. a short code piece is shown below
>
>         begin = clock();
>         ......
>         PriorEstimate();
>         ......
>         do
>         {
>             end = clock();
>         }
>         while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
>         ....
>         FeatureExtraction();
>
> Thanks for your help
>
> Regards
>
> Sebastian
>

> ------------------------------------------------------------------------------
> Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
> trial. Simplify your report design, integration and deployment - and focus
> on
> what you do best, core application coding. Discover what's new with
> Crystal Reports now.  http://p.sf.net/sfu/bobj-july
> _______________________________________________
> Playerstage-users mailing list
> Playerstage-users@...
> https://lists.sourceforge.net/lists/listinfo/playerstage-users
>
>



--
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Autonomy Lab / Computing Science / Simon Fraser University

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[Aslund]

Thanks for all the help.
usleep did the trick and it works, nealy.
Got some timming issues with the laser scanning, seems to come to early, but I am hoping that I can overcome it soon :)

Regards

Sebastian

2009/11/5 Rich Mattes <jpgr87@...>

Is it possible that the simulation is just slowing down a lot because your client program is hammering your CPU during the while loop?  Try adding a small delay, like calling usleep(100000); [100 ms] inside of the while loop to free up system resources for everything else that’s trying to run.  It looks like your update interval is somewhere around 2 seconds, so pausing for 100ms should make your delay time between about 2 and 2.1 seconds.  Cut the usleep by an order of magnitude (i.e. remove a 0) and you should get a delay time between about 2 and 2.01 seconds.

 

I don’t think it has anything to do with you actually stopping Player or Stage, since your program is running on its own and just using the client libraries to tie in to Player via the network.  It sounds more like a system-wide resource issue to me.

 

Rich

 

From: Aslund [mailto:sebastian.aslund@...]
Sent: Thursday, November 05, 2009 1:40 PM

To: playerstage-users@...

Subject: Re: [Playerstage-users] delay in Player-Stage

 

Hey Richard

Why it stops moving is exactly my problem and I don't know why.
What happens is that I predict my future position based on a translational and rational velocity, and a time step delta_t.
Before I can do a laser scan and make a feature extraction on the enviroment, then I have to wait delta_t before I preform the scan. In the short moment it takes to make the prior position estimat, the robot moves, but as soon it hits the loop where the program waits for delta_t to have passed, the robot does'nt move and I have no idea why.
Hope this distribution clarifies the problem and hope a solution can be found.

Regards

Sebastian

ps.
I have added my main file if that have any interest.
  

2009/11/5 Richard Vaughan <rtvaughan@...>

On Thu, Nov 5, 2009 at 9:06 AM, Aslund <sebastian.aslund@...> wrote:
> Hey Everyone
>
> I am implementing a Extended Kalman Filter in Player-Stage, my prior
> estimation of the position is based on the velocity model. Because I use the
> velocity model, then I need a small delay before I can do feature extraction
> of the environment, here I use clock() from the time.h to measure the
> difference in time. The new problem is that when my program enters the loop,
> the robot in my Stage simulation stops moving,

Can you explain what's happening here? Why does the robot stop moving?

- rtv

so when the loop finished,
> the robot is far from the position the velocity model estimated. Is it
> possible to make a delay with a while-loop or something else while keeping
> the robot moving?
> Ps. a short code piece is shown below
>
>         begin = clock();
>         ......
>         PriorEstimate();
>         ......
>         do
>         {
>             end = clock();
>         }
>         while((double)(end-start)/CLOCKS_PER_SEC < delta_t);
>         ....
>         FeatureExtraction();
>
> Thanks for your help
>
> Regards
>
> Sebastian
>

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>



--
Richard Vaughan
Autonomy Lab / Computing Science / Simon Fraser University

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