scoutos / scout / libscout / src / behaviors / smart_runaround.cpp @ 2fd5122a
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/**
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* Copyright (c) 2011 Colony Project
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include "maze_solve.h" |
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using namespace std; |
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// want to have a minimal working thing, use a big enough
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// static array and start in the middle
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// we assume we are facing right, that affects where we store
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// wall information
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// -1 for wall, 0 for unseen, 1 for traveled, 2 for critical
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#define WALL -1 |
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#define UNSEEN 0 |
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#define SEEN 1 |
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#define CRITICAL 2 |
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// facings on map, NOT on robot
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#define UP 0 |
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#define RIGHT 1 |
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#define DOWN 2 |
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#define LEFT 3 |
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// number of pixels on one row/column of map block
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#define BLOCK_LENGTH 13 |
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// robot control variables
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#define BASESPEED 50 |
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// robots row and column on map, starting at center
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int row = MAP_LENGTH/2+1; // add 1 because we know MAP_LENGTH is odd |
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int col = MAP_LENGTH/2+1; |
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// utility functions
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// pixels to meters
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float pix_to_m(int pixels) |
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{ |
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return pixels/200.0; |
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} |
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// meters to pixels
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int m_to_idx(float meters) |
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{ |
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float pixels = meters*200.0; |
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float idx = pixels/BLOCK_LENGTH;
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return floor(idx+0.5); |
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} |
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/* return a direction (if any) where adjacent block
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* is labeled "info" on map. Searches clockwise
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* starting at up. Returns -1 if no direction valid.
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*/
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int maze_solve::choose_direc(int row, int col, int info) |
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{ |
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if (map[row-1][col] == info) |
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return UP;
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else if (map[row][col+1] == info) |
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return RIGHT;
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else if (map[row+1][col] == info) |
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return DOWN;
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else if (map[row][col-1] == info) |
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return LEFT;
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return -1; |
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} |
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Duration sonar_update_time(1.5); |
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// THIS VERSION MODIFIED BY ZANE
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void maze_solve::run(){
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ROS_INFO("Starting to solve the maze");
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// Go up to the first line.
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//follow_line();
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// Turn the sonar on.
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sonar->set_on(); |
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sonar->set_range(0, 23); |
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// initialize map to all UNSEEN
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for(int r = 0; r < MAP_LENGTH; r++) { |
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for(int c = 0; c < MAP_LENGTH; c++) |
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map[r][c] = UNSEEN; |
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} |
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// Wait for the sonar to initialize.
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while(!look_around(25, 25, RIGHT) && ok()) |
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{ |
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spinOnce(); |
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} |
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/* Assumptions:
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* Grid has a fixed size
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* Start location unknown
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* When robot moves forward, it moves to exact center
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* of the block in front.
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*/
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int dir = RIGHT; // current direction |
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int new_dir = RIGHT; // direction in which to turn after a scan |
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bool success = false; // true when maze solved |
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while(ok())
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{ |
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// Look left, right, and forward
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look_around(row, col, dir); |
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// Try moving in each direction
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new_dir = choose_direc(row, col, UNSEEN); |
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if(new_dir < 0) |
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new_dir = choose_direc(row, col, SEEN); |
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if(new_dir >= 0) { |
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turn_from_to(dir, new_dir); |
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dir = new_dir; |
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} |
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} |
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// Check and report final condition.
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if (success)
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ROS_INFO("YAY! I have solved the maze");
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else
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ROS_INFO("NO! The maze is unsolvable");
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} |
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// NOT CURRENTLY USED!!!
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bool maze_solve::solve(int row, int col, int dir) |
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{ |
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int initial_dir = dir;
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ROS_INFO("I am at direction %d", dir);
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// use backtracking to solve the maze
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if (at_destination())
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return true; |
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// Wait for sonar to update.
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sonar_update_time.sleep(); |
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// this function should fill the adjacent cells around me with
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// wall's or paths
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while(!look_around(row, col, dir) && ok())
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{ |
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spinOnce(); |
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} |
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/* try go up */
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if (map[row-1][col] != WALL && initial_dir != UP) |
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{ |
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ROS_INFO("GOING UP!");
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// Turn up.
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turn_from_to(dir, UP); |
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follow_line(); |
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// Solve recursively.
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bool solved = solve(row-1, col, DOWN); |
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if (solved)
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{ |
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return solved;
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} |
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else
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{ |
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//Update where we are.
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dir = UP; |
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} |
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} |
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/* try right */
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if (map[row][col+1] != WALL && initial_dir != RIGHT) |
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{ |
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ROS_INFO("GOING RIGHT!");
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// Turn right.
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turn_from_to(dir, RIGHT); |
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follow_line(); |
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// Solve recursively.
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bool solved = solve(row, col+1, LEFT); |
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if (solved)
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{ |
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return solved;
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} |
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else
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{ |
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//Update where we are.
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dir = RIGHT; |
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} |
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} |
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/* try down */
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if (map[row+1][col] != WALL && initial_dir != DOWN) |
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{ |
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ROS_INFO("GOING DOWN!");
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// Turn down.
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turn_from_to(dir, DOWN); |
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follow_line(); |
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// Solve recursively.
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bool solved = solve(row+1, col, UP); |
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if (solved)
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{ |
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return solved;
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} |
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else
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{ |
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//Update where we are.
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dir = DOWN; |
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} |
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} |
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/* try left */
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if (map[row][col-1] != WALL && initial_dir != LEFT) |
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{ |
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ROS_INFO("GOING LEFT!");
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// Turn down.
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turn_from_to(dir, LEFT); |
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follow_line(); |
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// Solve recursively.
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bool solved = solve(row, col-1, RIGHT); |
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if (solved)
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{ |
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return solved;
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} |
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else
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{ |
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//Update where we are.
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dir = LEFT; |
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} |
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} |
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ROS_INFO("DEAD END FOUND, TURNING BACK.");
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// we have exhausted all the options. This path is clearly a
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// dead end. go back to where we come from and return false.
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turn_from_to(dir, initial_dir); |
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follow_line(); |
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return false; |
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} |
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/* this function takes in the current direction,
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* and turns the scout to the intended direction
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*/
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void maze_solve::turn_from_to(int current_dir, int intended_dir) { |
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switch ((4 + intended_dir - current_dir) % 4) // TODO: Try without "4 +" at start |
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{ |
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case 0: |
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turn_straight(intended_dir); |
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break;
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case 1: |
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turn_right(); |
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break;
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case 2: |
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spot_turn(); |
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break;
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case 3: |
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turn_left(); |
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break;
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} |
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} |
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bool maze_solve::look_around(int row, int col, int dir) |
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{ |
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// look around current place using sonar
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// store whether or not
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// there is a wall into the map
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// stores at row col 2 if point is critical, 1 otherwise
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int* readings = sonar->get_sonar_readings();
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spinOnce(); |
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// Assumption: readings are given in millimeters - Zane
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// distances with respect to robot, NOT map
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// Look to the left.
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float left_distance = readings[0]/1000.0; |
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int left_idx = m_to_idx(left_distance);
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// Look to the front.
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float front_distance = readings[36]/1000.0; |
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int front_idx = m_to_idx(front_distance);
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// Look to the right.
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float right_distance = readings[24]/1000.0; |
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int right_idx = m_to_idx(right_distance);
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ROS_INFO("front: %d left: %d right: %d", front_distance, left_distance, right_distance);
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if (right_distance == 0 || front_distance == 0 || left_distance == 0) |
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return false; |
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// determine relative distances on map, based on robot position
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int up_d, right_d, down_d, left_d;
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// determine upward distance
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switch (dir)
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{ |
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case UP:
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up_d = front_idx; |
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right_d = right_idx; |
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down_d = 0; // unknown |
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left_d = left_idx; |
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break;
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case RIGHT:
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up_d = left_idx; |
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right_d = front_idx; |
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down_d = right_idx; |
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left_d = 0; // unknown |
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break;
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case DOWN:
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up_d = 0; // unknown |
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right_d = left_idx; |
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down_d = front_idx; |
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left_d = right_idx; |
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break;
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case LEFT:
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up_d = right_idx; |
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right_d = 0; // unknown |
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down_d = left_idx; |
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left_d = front_idx; |
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break;
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} |
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// change map until wall index, or until reading < 500
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// reading < 500 <=> left_idx < 8 (approx.)
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// map blocks above robot (on map)
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for(int u = 0; u < 8; u++) |
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{ |
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if(u = up_d) {
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map[row-u][col] = (up_d)?WALL:SEEN; |
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break;
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} |
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map[row-u][col] = SEEN; |
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} |
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// map blocks to right of robot
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for(int r = 0; r < 8; r++) |
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{ |
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if(r = right_d) {
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map[row][col+r] = (right_d)?WALL:SEEN; |
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break;
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} |
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map[row][col+r] = SEEN; |
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} |
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// map blocks under robot (on map)
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for(int d = 0; d < 8; d++) |
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{ |
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if(d = down_d) {
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map[row+d][col] = (down_d)?WALL:SEEN; |
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break;
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} |
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map[row+d][col] = SEEN; |
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} |
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// map blocks to left of robot
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for(int l = 0; l < 8; l++) |
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{ |
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if(l = left_d) {
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map[row][col-l] = (left_d)?WALL:SEEN; |
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break;
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} |
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map[row][col-l] = SEEN; |
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} |
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return true; |
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} |
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// TODO: test this function
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// return true iff the map has been completely explored
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// and only true if it "returned" to home destination after solving
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bool maze_solve::at_destination()
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{ |
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// check whether there is a square portion with
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// only SEEN or WALL blocks, of the size of the map.
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int start_row = -1; |
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int start_col = -1; |
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int seen_width = 0; |
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int seen_height = 0; |
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for(int r = 0; r < MAP_LENGTH; r++) { |
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for(int c = 0; c < MAP_LENGTH; c++) { |
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if(map[r][c] == UNSEEN) {
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start_row = -1;
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start_col = -1;
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seen_width = 0;
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seen_height = 0;
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} |
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else {
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start_row = r; |
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start_col = c; |
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seen_width++; |
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seen_height++; |
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} |
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if(seen_width >= 15) |
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return true; |
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} |
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} |
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return false; |
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} |
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// TODO: test these functions to make sure robot moves well
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// move forward one block in direction "dir"
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void maze_solve::turn_straight(int dir) |
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{ |
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// TODO: try to use motor encoder values to move forward enough
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motors->set_sides(BASESPEED, BASESPEED, MOTOR_ABSOLUTE); |
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spinOnce(); |
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Duration moveTime(1.0); |
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moveTime.sleep(); |
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// update robot's position on map
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switch(dir)
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{ |
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case UP:
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row--; |
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break;
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case RIGHT:
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col++; |
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break;
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case DOWN:
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row++; |
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break;
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case LEFT:
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col--; |
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break;
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} |
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} |
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// turn clockwise (right)
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void maze_solve::turn_right()
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{ |
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motors->set_sides(BASESPEED, -BASESPEED, MOTOR_ABSOLUTE); |
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spinOnce(); |
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Duration moveTime(3.3); |
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moveTime.sleep(); |
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} |
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// do a 180 deg turn, NOT a barrel roll
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void maze_solve::spot_turn()
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{ |
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motors->set_sides(BASESPEED, -BASESPEED, MOTOR_ABSOLUTE); |
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spinOnce(); |
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Duration moveTime(6.6); |
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moveTime.sleep(); |
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} |
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// turn counter-clockwise (left)
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void maze_solve::turn_left()
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{ |
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motors->set_sides(-BASESPEED, BASESPEED, MOTOR_ABSOLUTE); |
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spinOnce(); |
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Duration moveTime(3.3); |
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moveTime.sleep(); |
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} |