The ARGoS Forum

Posted: **Wed Sep 17, 2014 11:09 pm**

Are there any pathfinding implementations (dijkstra, A*, etc) for ARGoS or shall I write my own?

Any code I'll produce I'll put on Github/BitBucket when I've completed my project.

Nick

Posted: **Wed Sep 17, 2014 11:14 pm**

Hi Nick,

I don't have any ready-made implementation, but if you feel like contributing your own, go ahead! That would be really nice

Cheers,
Carlo

Posted: **Fri Oct 10, 2014 11:01 am**

Will do

Posted: **Fri Nov 21, 2014 4:44 pm**

Hi,

I ended up using boost's graph and astar implementation in the end (not enough time to implement my own, although I'd like to as a programming challenge).

However, I seem to be having troubles with my robot's movement towards a specified point. This is more than likely and issue with my own maths but was wondering if you might be able to help.

Here's the function: https://gist.github.com/squiddon/ab9aab96e812421687dc

When robot starts at origin and the goal point is directly behind it the robot does a little shuffle (alternating velocity to left and right wheels) motion forward and never turns around. Wondering if you've encountered this behaviour before?

Nick

Posted: **Fri Nov 21, 2014 5:04 pm**

I think I've cracked it already, needed to play about with the min/max angle range.

Posted: **Fri Nov 21, 2014 5:08 pm**

If I understood correctly, you want to go to a specific point in the environment stored in the variable m_sCurrentGoal.

The untested code, just out of my head, could be:

Code: Select all

void CSingleRobot::SetWheelSpeeds(const CCI_PositioningSensor::SReading& s_me_inworld,
                                  const CVector2& c_target_inworld) {
   // Get my rotation in the world
   CRadians cZAngle, cYAngle, cXAngle;
   s_me_inworld.Orientation.ToEulerAngles(cZAngle, cYAngle, cXAngle);
   // Get position of target wrt robot
   CVector2 cMeToTarget(
      c_target_inworld.GetX() - s_me_inworld.Position.GetX(),
      c_target_inworld.GetY() - s_me_inworld.Position.GetY());
   cMeToTarget.Rotate(-cZAngle);
   // Get direction angle
   CRadians cAngle = cMeToTarget.Angle();
   // Set wheel speed depending on angle
   if(m_cGoStraightAngleRange.WithinMinBoundIncludedMaxBoundIncluded(cAngle)) {
      // straight
      m_pcWheels->SetLinearVelocity(m_fWheelVelocity, m_fWheelVelocity);
   } else {
      if(cAngle.GetValue() >= 0.0) {
         // go left
         m_pcWheels->SetLinearVelocity(0.0, m_fWheelVelocity);
      } else {
         // go right
         m_pcWheels->SetLinearVelocity(m_fWheelVelocity, 0.0);
      }
   }
}

Posted: **Fri Nov 21, 2014 5:09 pm**

NOTE: Your original code has a bug in wheel actuation (you rotate left when you should rotate right, and viceversa).

Posted: **Fri Nov 21, 2014 7:58 pm**

Good spot, although the behaviour seemed to work my end. My maths were definitely wrong.

Your function works perfectly, thanks very much

Posted: **Fri Nov 21, 2014 8:16 pm**

Cool!

Posted: **Fri Nov 21, 2014 8:42 pm**

Hello!
I am trying to increase the length of rays shot by proximity sensor using Argos 2 Simulator.
Special thanks to all of you.

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