root / scout / libscout / src / LinesensorControl.cpp @ c9638ad1
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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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/**
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* @file LinesensorControl.cpp
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* @brief Contains line following function implementation
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*
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* @author Colony Project, CMU Robotics Club
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* @author Alex Zirbel
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*/
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#include "LinesensorControl.h" |
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using namespace std; |
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static double last_ret; |
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/**
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* @brief Initialize the line following module of libscout.
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*/
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LinesensorControl::LinesensorControl(const ros::NodeHandle& libscout_node,
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string scoutname)
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: node(libscout_node) |
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{ |
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query_client = |
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node.serviceClient<linesensor::query_linesensor>(scoutname+"/query_linesensor");
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} |
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/**
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* @brief Returns the current readings of the line follwing sensor.
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*/
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vector<uint32_t> LinesensorControl::query() |
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{ |
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// Set scan range
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linesensor::query_linesensor srv; |
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if (!query_client.call(srv))
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{ |
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ROS_ERROR("LinesensorControl query failed.");
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} |
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if (srv.response.readings.size() != 8) |
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{ |
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ROS_WARN("Linesensor reading vector has %d readings, 8 expected.",
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int(srv.response.readings.size()));
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} |
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return srv.response.readings;
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} |
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/**
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* @brief Returns the average readings of the line following sensors.
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*/
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double LinesensorControl::readline()
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{ |
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unsigned int total_read = 0; |
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unsigned int weighted_total = 0; |
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vector<uint32_t> readings = query(); |
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if (readings.size() < 8) |
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{ |
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return last_ret;
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} |
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for (int i = 0; i < 8; i++) |
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{ |
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total_read += readings[i]; |
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weighted_total += i * readings[i]; |
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} |
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if (total_read == 0) |
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{ |
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return last_ret;
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} |
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double ret_val = last_ret = ((double) weighted_total / total_read) - 3.5; |
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return ret_val;
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} |
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bool LinesensorControl::fullline(vector<uint32_t> readings)
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{ |
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if (readings.size() < 8) |
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{ |
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return false; |
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} |
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for(int i=0; i<8; i++) |
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{ |
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if(readings[i] < 200) |
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return false; |
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} |
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return true; |
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} |
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/**
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* We define a destination as two gaps of white between the line and patches
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* of 95-shade color (dark grey) on either side.
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* I use 95-shade color in an attempt to not throw off the line localization.
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*/
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bool LinesensorControl::destination(vector<uint32_t> readings)
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{ |
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if (readings.size() < 8) |
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{ |
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return false; |
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} |
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// Try to match this pattern to what we see
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int expected_pattern[] = {95, 0, 255, 0, 95}; |
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int pat_idx = 0; |
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for (int i = 0; i < 8; i++) |
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{ |
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// If the difference between what we have and expect is less than 5
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if (abs(readings[i] - expected_pattern[pat_idx]) < 5) |
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{ |
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// Check. Keep looking for the rest of the pattern.
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pat_idx++; |
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} |
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// The whole pattern was found
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if (pat_idx > 4) |
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{ |
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return true; |
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} |
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} |
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return false; |
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} |