Programming the iRobot Create
iRobot Create ProgrammingI'm currently taking an Embedded Systems class at my university in which we get to program microcontrollers. In our lab we use the iRobot Create platform with the Cerebot II board, which looks a lot like one of those autonomous vacuum cleaners. We have 9 different structured labs in which we have to program the iRobot to do something. Then we have our final project, in which we have to program the robot to be FULLY autonomous and navigate through a course. It has to be able to get from the starting point to the finish, while traversing through many obstacles and staying within the borders of the course.
This thread will be kind of like a blog in the sense that I'll be posting my various labs so you can check out the code if you're interested in getting into iRobots or microcontroller. They are a lot of fun. I'll try my best to get a video of the robot doing each project, but can't promise anything. You can download the libraries that are used in my code here: libraries.
Here's a photo that I snapped of the iRobot Create that we use in lab. We've got an additional LCD and sonar/range finder attached to a servo.
Collision Detection:
Objective: The robot is to travel a total of 2 meters in the forward direction and react to collisions.
- Go forward. If the robot bumps into something it will backup 15 cm
- Next it will turn left is the right bumper is hit, or right if the left bumper is hit (if both bumpers are hit it will turn right)
- Then the robot will move 25cm forward and turn 90 degrees in the opposite direction relative to the first turn so that it's traveling in the same heading it was originally on
- Then it will resume traveling the original 2 meters and stop
Code:
Code:#include "open_interface.h" #include "util.h" #include <stdlib.h> /* required for randomize() and random() */ #include "lcd.h" #include <stdio.h> int goForward(); void correctDirection(char previousTurn); void turn(char direction); void printCrap(int which); int forwardDistance = 0; oi_t *sensor_status; //Declare a pointer to the data type oi_t defined in open_interface.h int main (void) { sensor_status = oi_alloc(); //Allocate memory appropriate for a oi_t type data structure and assign the returned address of the structure to the variable sensor_status oi_init(sensor_status); // Initialize the Open Interface oi_clear_distance(sensor_status); while (forwardDistance <= (2 * 100) ) { int bumperStatus = goForward(); switch (bumperStatus) { case 9: printCrap(2); break; case 1: printCrap(2); turn('L'); correctDirection('L'); break; case 2: printCrap(2); turn('R'); correctDirection('R'); break; case 3: printCrap(2); turn('R'); correctDirection('R'); break; } } return 0; } //Go straight until collision detected, then back up and return bumper states int goForward() { //keep going straight until conllision (or stop if the entire 2m is clear) int currentBumperStatus = oi_bump_status(sensor_status); while ((currentBumperStatus == 0) && ((oi_current_distance(sensor_status) + forwardDistance) <= (2 * 100))) { oi_set_wheels(250,250); currentBumperStatus = oi_bump_status(sensor_status); } oi_set_wheels(0,0); //STOP forwardDistance += oi_current_distance(sensor_status); // copy over distance as it's about to be cleared oi_clear_distance(sensor_status); //Are 2m up? If so exit function & we're done! if ((oi_current_distance(sensor_status) + forwardDistance) >= (2 * 100)) { return 9; } //Now back that ass up for 15 cm while (oi_current_distance(sensor_status) >= -15){ oi_set_wheels(-250,-250); } oi_set_wheels(0,0); oi_clear_distance(sensor_status); //Return which bumpber was hit to take appropriate action return currentBumperStatus; } //Move 25cm forward & resume opposite direcion relative to original direction void correctDirection(char previousTurn) { oi_clear_distance(sensor_status); while (oi_current_distance(sensor_status) <= 25) { oi_set_wheels(250,250); } oi_set_wheels(0,0); oi_clear_distance(sensor_status); if (previousTurn == 'L'){ turn('R'); } if (previousTurn == 'R') { turn('L'); } } void turn(char direction) { oi_clear_angle(sensor_status); int angle = oi_current_angle(sensor_status); //Turn left if (direction == 'L') { while ((angle >=0 && angle <= 90) || (angle >=270 && angle <= 360)) { oi_set_wheels(250,0); wait_ms(20); angle = oi_current_angle(sensor_status); } } //Turn right if (direction == 'R') { while ((angle >=0 && angle <= 90) || (angle >=270 && angle <= 360)) { oi_set_wheels(0,250); wait_ms(20); angle = oi_current_angle(sensor_status); } } oi_set_wheels(0,0); oi_clear_distance(sensor_status); } //Print the distance, angle, or bumper status on the LCD for debugging purposes void printCrap(int which) { lcd_init(); if (which == 0 ) { lcd_home_line1(); char str[10]; int distanceTraveled = oi_current_distance(sensor_status); //distance returned is in cm sprintf(str, "Distance: %dcm", distanceTraveled); lcd_puts(str); } if (which == 1 ) { lcd_home_line1(); char str[10]; int distanceTraveled = oi_current_angle(sensor_status); //distance returned is in cm sprintf(str, "Angle: %d deg", distanceTraveled); lcd_puts(str); } if (which == 2 ) { lcd_home_line1(); int bumperStatus = oi_bump_status(sensor_status); //distance returned is in cm; char str[22]; sprintf(str,"%s %d", "Bumper status:", bumperStatus); sprintf(str,"%s %s", str, "."); lcd_puts(str); } }
 |
or Register
|
Reply With Quote
