Create WheeledRobot.hpp

cpp/WheeledRobot.hpp

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+/**
+* 
+* BreezySLAM: Simple, efficient SLAM in C++
+*
+* WheeledRobot.hpp - C++ header for WheeledRobot class
+*
+* Copyright (C) 2014 Simon D. Levy
+
+* This code is free software: you can redistribute it and/or modify
+* it under the terms of the GNU Lesser General Public License as 
+* published by the Free Software Foundation, either version 3 of the 
+* License, or (at your option) any later version.
+* 
+* This code is distributed in the hope that it will be useful,     
+* but WITHOUT ANY WARRANTY without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+* 
+* You should have received a copy of the GNU Lesser General Public License 
+* along with this code.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <math.h>
+
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Velocities;
+
+/**
+* An abstract class for wheeled robots.  Supports computation of forward and angular 
+* velocities based on odometry. Your subclass should should implement the
+* extractOdometry method.
+*/
+class WheeledRobot 
+{
+    
+protected:
+    
+/**
+* Builds a WheeledRobot object. Parameters should be based on the specifications for
+* your robot.
+* @param wheel_radius_mm radius of each odometry wheel, in meters        
+* @param half_axle_length_mm half the length of the axle between the odometry wheels, in meters  
+* @return a new WheeledRobot object
+*/
+WheeledRobot(double wheel_radius_mm, double half_axle_length_mm)
+{
+    this->wheel_radius_mm = wheel_radius_mm;     
+    this->half_axle_length_mm = half_axle_length_mm;
+    
+    this->timestamp_seconds_prev = 0;
+    this->left_wheel_degrees_prev = 0;
+    this->right_wheel_degrees_prev = 0;
+}
+
+/**
+* Computes forward and angular velocities based on odometry.
+* @param timestamp time stamp, in whatever units your robot uses       
+* @param left_wheel_odometry odometry for left wheel, in whatever units your robot uses       
+* @param right_wheel_odometry odometry for right wheel, in whatever units your robot uses
+* @return velocities object representing velocities for these odometry values
+*/
+
+Velocities
+computeVelocities(
+    double timestamp, 
+    double left_wheel_odometry, 
+    double right_wheel_odometry);
+
+/**
+* Extracts usable odometry values from your robot's odometry.
+* @param timestamp time stamp, in whatever units your robot uses       
+* @param left_wheel_odometry odometry for left wheel, in whatever units your robot uses       
+* @param right_wheel_odometry odometry for right wheel, in whatever units your robot uses
+* @param timestamp_seconds gets time stamp in seconds
+* @param left_wheel_degrees gets left wheel rotation in degrees
+* @param right_wheel_degrees gets right wheel rotation in degrees
+*/
+virtual void extractOdometry(
+    double timestamp, 
+    double left_wheel_odometry, 
+    double right_wheel_odometry, 
+    double & timestamp_seconds, 
+    double & left_wheel_degrees, 
+    double & right_wheel_degrees) = 0;
+
+friend ostream& operator<< (ostream & out, WheeledRobot & robot)
+{
+    
+    char subclassStr[100];
+    robot.descriptorString(subclassStr);
+    
+    char str[200];
+    sprintf(str, "<Wheel radius=%f m Half axle Length=%f m | %s>",
+        robot.wheel_radius_mm, robot.half_axle_length_mm, subclassStr);
+    
+    out << str;
+    
+    return out;
+}
+
+
+/**
+* Gets a descriptor string for your robot.
+* @param str gets the descriptor string    
+*/
+virtual void descriptorString(char * str) = 0;
+
+private:
+    
+    double wheel_radius_mm;
+    double half_axle_length_mm;
+    
+    double timestamp_seconds_prev;
+    double left_wheel_degrees_prev;
+    double right_wheel_degrees_prev;    
+    
+    static double radians(double degrees)
+    {
+        return degrees * M_PI / 180;
+    }
+    
+    
+};