Chief Delphi - Turning problems in Vex autonomous.

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Turning problems in Vex autonomous. [Solved]

I wrote the following code using easyC for Vex.
It's a function, it's supposed to take the angle I give it and turn in that direction. If I give it a positive angle, it turns to the right. I'm trying to make it turn to the left if I give it a negative angle, but it ain't happening. For some reason it simply turns to the right again. Any ideas?

Code:

#include "Main.h"

 

void turn ( int angle )

{ // Turns the robot a set number of degrees

      int done = 0; 

      int abs; 

 

      angle = angle/4 ; //For the optical sensors, one turn is 90 pulses.

      if ( angle < 0 )

      {

            abs = -angle ;

      }

      else

      {

            abs = angle ;

      }

      PresetEncoder ( L_OPTICAL_SENSOR_CHANNEL , Left_Optical_Sensor ) ;

      PresetEncoder ( R_OPTICAL_SENSOR_CHANNEL , Right_Optical_Sensor ) ;

      StartEncoder ( L_OPTICAL_SENSOR_CHANNEL ) ;

      StartEncoder ( R_OPTICAL_SENSOR_CHANNEL ) ;

      while ( done != 2 )

      {

            Left_Optical_Sensor = GetEncoder ( L_OPTICAL_SENSOR_CHANNEL ) ;

            Right_Optical_Sensor = GetEncoder ( R_OPTICAL_SENSOR_CHANNEL ) ;

            if ( Left_Optical_Sensor < abs )

            {

                  if ( angle > 0 & angle <= 90 )

                  {

                        SetMotor ( L_MOTOR , 255 ) ;

                  }

                  if ( angle >= -90 & angle < 0 )

                  {

                        SetMotor ( L_MOTOR , 0 ) ;

                  }

            }

            else

            {

                  SetMotor ( L_MOTOR , 127 ) ;

                  done = done + 1 ;

                  StopEncoder ( L_OPTICAL_SENSOR_CHANNEL ) ;

            }

            if ( Right_Optical_Sensor < abs )

            {

                  if ( angle > 0 & angle <= 90 )

                  {

                        SetMotor ( R_MOTOR , 255 ) ;

                  }

                  if ( angle >= -90 & angle < 0 )

                  {

                        SetMotor ( R_MOTOR , 0 ) ;

                  }

            }

            else

            {

                  SetMotor ( R_MOTOR , 127 ) ;

                  done = done + 1 ;

                  StopEncoder ( R_OPTICAL_SENSOR_CHANNEL ) ;

            }

      }

      return  ;

}

Re: Turning problems in Vex autonomous.

Code:

if ( angle > 0 & angle <= 90 )

This should be the logical operator &&, not the bit operator &.

Personally, I always write multiple expressions in the following form. It is more readable and forces the precedence I want. I have to type a few more keystrokes but it is worth the correctness and clarity.

Code:

if ( (angle > 0) && (angle <= 90) )

Otherwise someone who knows the functions you are calling will have to help you.

Re: Turning problems in Vex autonomous.

Since the wheels are mounted on opposite sides of the robot, they need to be operated opposite from each other. For example: To drive straight you would use:
SetMotor ( L_MOTOR , 255 ) ;
SetMotor ( R_MOTOR , 0 ) ;

Try swapping the SetMotor ( R_MOTOR , 255 ) ; and SetMotor ( R_MOTOR , 0 ) ; calls.

Re: Turning problems in Vex autonomous.

Thanks, Keith. It works great now.

koenig3456: But I want the robot to turn... ;-)