Hi, I am using hukuyo sensor on polaris and I am using Tutorials/1.2/control robot/mobile base laser. The code is given below

public: void OnUpdate()

{

if(key is pressed)

{

joint1->SetForce(0,15);

joint2->SetForce(0,15);

}

unsigned int n = this->laser->GetRangeCount();

double min_dist = 1e6;

for(unsigned int i = 0; i < n; i++)

      {

        if(this->sicksensor->GetRange(i) < min_dist)

          min_dist = this->sicksensor->GetRange(i);
      }

      if(min_dist < this->sicksensor->GetRangeMax())
      {
        printf("obstacle is detected");
        this->joint1->SetForce(0,0);
        this->joint2->SetForce(0,0);
      }

}

whenever the obstacle is placed it is printing obstacle is detected but it is not setting the force 0. I also tried giving it reverse force then set to 0 , but then also it is not working.It is going in reverse direction but not stoping .

        this->joint1->SetForce(0,-20);
        this->joint2->SetForce(0,-20);
        this->joint1->SetForce(0,0);
        this->joint2->SetForce(0,0);

I want that when it detects the object it should stop at certain distance and hukuyo range is 10. Please help .Basically how can we apply brake on polaris. i think brake is not working of Polaris ranger. Thanks!

Comments

Take a look at this example vehicle control plugin. It should have a good solution for you.

Comments

Hi, Thanks for the tutorial. It helped me a lot but still now the problem has not been resolved , it stops the polaris immediately when obstacle is detected but when i remove the obstacle and give it negative force it doesnt move reverse. And also sometimes it is changing the steering angle hence the polaris stops with tiltd tires , which is I thnk wrong. plz suggest what should i do . Thanks!

Asked by anonymous on 2014-11-26 04:13:19 UTC

You'll have to control the angle of the front wheels, in addition to the rotational velocity. I think the two steering joints are front_left_steering_joint and front_right_steering_joint.

Asked by nkoenig on 2014-11-26 11:46:34 UTC

Hi, Here in my code joint1 is front_left_wheel and joint2 is front_right_wheel. I am able to control the steering joints angle as in if suppose I am giving 45 degrees angle then it will move 45 degrees,. But I am not able to understand controlling the angle of front wheels. can you please give some guidance realted to it. If you want I can mail you my whole code . Thanks!

Asked by anonymous on 2014-11-27 07:47:04 UTC

I just want it to be lyk a real simulation, that when it detects it should apply brake and stops , and then it should take a reverse and then decide the direction accordingly whether to move right or left. By using vehicle control plugin I am able to stop the vehicle because of wheel angle but I am not able to take reverse when key2 is pressed.

Asked by anonymous on 2014-11-27 07:51:08 UTC

here is my code:

int min_dist = 1e6;

if(key1 pressed)

       {
           joint1->SetForce(0,15);
           joint2->SetForce(0,15);
        }

        else if(key2 pressed)
        {
            joint1->SetForce(0,-40);
            joint2->SetForce(0,-40);
        }

         for(unsigned int i = 0; i < n; i++)
            {
              if(this->sicksensor->GetRange(i) < min_dist)
                min_dist = this->sicksensor->GetRange(i);

            }

            if(min_dist < this->sicksensor->GetRangeMax())
            {
              printf("object is detected");
              double velocity=this->joint1->GetForce(0);
              int t=1;
              double acceleration=(velocity/t);
              double target_dist=((velocity*velocity)/(2*acceleration));

              if(min_dist<=target_dist)
              {

double steeringRange=this->steering_joint->GetHighStop(0).Radian()-this->steering_joint->GetLowStop(0).Radian();

                  double steeringRatio= steeringRange / tireAngleRange;

                  double steeringAngle=this->steering_joint->GetAngle(0).Radian();

                  double wheelAngle=steeringAngle/steeringRatio;


                  this->joint1->SetLowStop(0,wheelAngle);
                  this->joint1->SetHighStop(0,wheelAngle);
                  this->joint1->SetLowStop(0,wheelAngle);
                  this->joint1->SetHighStop(0,wheelAngle);

                  this->joint2->SetHighStop(0,wheelAngle);
                  this->joint2->SetLowStop(0,wheelAngle);
                  this->joint2->SetHighStop(0,wheelAngle);
                  this->joint2->SetLowStop(0,wheelAngle);

              }
            }

Comments

Here is code that can control the polaris ranger. Please refer to the aforementioned for moving and stopping the polaris.

Comments

ohk .. Thanks a lot.

Asked by anonymous on 2014-12-02 00:12:18 UTC