## Revision 985

ticket #159:
main() is just for testing
no working code yet just comments, still need to figure out the math

View differences:

branches/simulator/projects/simulator/core/test_motors.c
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```#include <stdio.h>
```
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```#define	FORWARD	  1
```
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```#define	BACKWARD  0
```
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```#define CUTOFF	  120
```
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```/* move will move a robot from its initial position, (x,y), and theta (in degree) to a new position given dir, and speed.
```
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``` * (x,y) will be updated by the move function instead of returning a value
```
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``` * (x,y) is some kind of absolute position in the "world", let's make (0,0) the top left of the "world"
```
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``` * theta will an angle be between 0 - 359 (0 degree being faces east)
```
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``` * dir is either FORWARD or BACKWARD
```
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``` * speed is between 0 - 255, there is some magical cutoff point before the motors actually starts running
```
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``` * 2 pairs of dir and speed, one for each motor
```
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``` * move will return 0 if successful
```
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``` */
```
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```int move (int *x, int *y, int theta, int dir1, int speed1, int dir2, int speed2) {
```
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```  if (theta < 0 || theta > 359) return 1;
```
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```  if (dir1 != FORWARD && dir1 != BACKWARD) return 1;
```
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```  if (dir2 != FORWARD && dir2 != BACKWARD) return 1;
```
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```  if (speed1 < 0 || speed1 > 255) return 1;
```
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```  if (speed2 < 0 || speed2 > 255) return 1;
```
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```  /* if speed is lower than the cut off, don't move */
```
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```  if (speed1 < CUTOFF) {
```
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```    speed1 = 0;
```
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```  }
```
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```  if (speed2 < CUTOFF) {
```
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```    speed2 = 0;
```
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```  }
```
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```  /* FAKE VALUES */
```
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```  (*x) += speed1-CUTOFF;
```
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```  (*y) += speed1-CUTOFF;
```
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```  /* d = distance between the two wheels = 12 cm
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```   * v1 = speed of the first wheel
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```   * v2 = speed of the second wheel
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```   *
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```   * Unless v1 = v2, if left at that point, the robot will go in a circle at some radius.
```
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```   *
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```   * This radius is = dv1/(v1-v2).
```
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```   * Since we could measure the displacement of a wheel, we could figure out what the overall angular displacement is using r(theta) = arc length  and then use trig after that to figure out x, y coordinate displacement.
```
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```   */
```
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```  return 0;
```
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```}
```
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```int main () {
```
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```  int x = 0;
```
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```  int y = 0;
```
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```  printf("%d %d\n",x,y);
```
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```  move(&x,&y,0,FORWARD,150,FORWARD,150);
```
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```  printf("%d %d\n",x,y);
```
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```  return 0;
```
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```}
```

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