Colony

#include <stdio.h>

#include <math.h>

#include "motion.h"

#include "robot.h"

#define CUTOFF                120

#define ABS(x) (x<0?-x:x)

#define TIME                        1 /*sec*/

#define ROBOT_WIDTH 131 /*mm*/

/** move will move a robot from its initial position, (x,y), and theta (in radians) to a new position given speed.

 * (x,y) and theta will be updated by the move function instead of returning a value

 * (x,y) is some kind of absolute position in the "world", let's make (0,0) the top left of the "world"

 * theta will an angle be between 0 - 2*Pi (0 being faces east)

 * speed is between 0 - 255, there is some magical cutoff point before the motors actually starts running

 * move will return 0 if successful

 **/

int move_robot(Robot* r)

{

        short speed1 = r->shared->motor1;

        short speed2 = r->shared->motor2;

        float theta = r->pose.theta;

        if (theta < 0 || theta > 2*M_PI) return 1;

        if (speed1 < 0 || speed1 > 255) return 1;

        if (speed2 < 0 || speed2 > 255) return 1;

        /* if speed is lower than the cut off, don't move */

        if (ABS(speed1) < CUTOFF) {

                speed1 = 0;

        }

        if (ABS(speed2) < CUTOFF) {

                speed2 = 0;

        }

        double radius;

        if (speed1 == speed2) {

                /* go straight */

        r->pose.x += cos(theta) * speed1;

        r->pose.y += sin(theta) * speed1;

                return 0;

        }

        radius = ROBOT_WIDTH * speed1 / (speed1 - speed2);

        double t = speed1 / radius;

        double newx = radius * sin(t);

        double newy = radius - radius * cos(t);

        r->pose.x += newx * cos(theta);

        r->pose.y += newx * sin(theta);

        r->pose.x += newy * - sin(theta);

        r->pose.y += newy * cos(theta);

        r->pose.theta = fmod((t + theta), (2 * M_PI));

        if (r->pose.theta<0) r->pose.theta += 2 * M_PI;

        return 0;

}