scoutos / scout / encoders / src / encoders.cpp @ 14241f84
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1 | 14241f84 | Lalitha Ganesan | /**
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2 | * Copyright (c) 2011 Colony Project
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3 | *
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4 | * Permission is hereby granted, free of charge, to any person
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5 | * obtaining a copy of this software and associated documentation
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6 | * files (the "Software"), to deal in the Software without
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7 | * restriction, including without limitation the rights to use,
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8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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9 | * copies of the Software, and to permit persons to whom the
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10 | * Software is furnished to do so, subject to the following
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11 | * conditions:
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12 | *
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13 | * The above copyright notice and this permission notice shall be
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14 | * included in all copies or substantial portions of the Software.
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15 | *
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16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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23 | * OTHER DEALINGS IN THE SOFTWARE.
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24 | **/
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25 | |||
26 | |||
27 | /**
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28 | * @file encoders.cpp
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29 | * @brief Encoders
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30 | *
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31 | * Implementation of functions for encoder use.
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32 | *
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33 | * @author Colony Project, CMU Robotics Club
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34 | * @author Benjamin Wasserman
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35 | **/
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36 | |||
37 | #include "ros/ros.h" |
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38 | #include "encoders.h" |
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39 | //#include "libscout/src/constants.h"
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40 | #include <cstdlib> |
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41 | |||
42 | /**
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43 | * @defgroup encoders Encoders
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44 | * @brief Functions for using the encoders
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45 | *
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46 | **/
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47 | |||
48 | /* Encoder state variables */
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49 | /** \todo Fix types: static */
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50 | int encoder_fl; /**< The current state of the front left encoder. */ |
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51 | int encoder_fr; /**< The current state of the front right encoder. */ |
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52 | int encoder_bl; /**< The current state of the back left encoder. */ |
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53 | int encoder_br; /**< The current state of the back right encoder. */ |
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54 | |||
55 | /*!
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56 | * \brief Encoders driver. This is a ROS node that controls encoders.
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57 | *
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58 | * This is the main function for the encoders node. It is run when the node
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59 | * starts and initializes the encoders. It then publishes to the
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60 | * encoder_state topic and advertises the query_encoders service.
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61 | *
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62 | * \param argc The number of command line arguments (should be 1)
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63 | * \param argv The array of command line arguments
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64 | **/
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65 | int main(int argc, char **argv){ |
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66 | /* Initialize in ROS the encoders driver node */
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67 | ros::init(argc, argv, "encoders_driver");
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68 | |||
69 | /* Advertise that this serves the query_encoders service */
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70 | ros::NodeHandle n; |
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71 | ros::ServiceServer service = n.advertiseService("query_encoders", encoders_query);
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72 | |||
73 | /* Subscribe to the encoder_state topic */
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74 | ros::Subscriber sub0 = n.subscribe("encoder_state", 4, encoder_state); |
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75 | |||
76 | /* Initialize hardware for motors */
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77 | // Hardware init functions here
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78 | |||
79 | ROS_INFO("Ready to set encoders.");
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80 | ros::spin(); |
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81 | |||
82 | return 0; |
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83 | } |
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84 | |||
85 | /*!
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86 | * \brief Gets encoder state
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87 | *
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88 | * Sets the encoder state based on subscription to the encoder_state topic.
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89 | *
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90 | * \param msg The message from the encoder_state topic, containing encoder
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91 | * configuration settings.
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92 | */
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93 | void encoder_state(const encoders::encoder_state::ConstPtr& msg){ |
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94 | encoder_fl = msg->fl_encoder; |
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95 | encoder_fr = msg->fr_encoder; |
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96 | encoder_bl = msg->bl_encoder; |
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97 | encoder_br = msg->br_encoder; |
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98 | } |
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99 | |||
100 | /*!
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101 | * \brief Outputs current encoder data
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102 | *
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103 | * Serves the service query_encoders by responding to service requests with the
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104 | * encoder values.
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105 | * \param req The request. Should be empty.
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106 | * \param res The response. The fields will be filled with values.
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107 | */
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108 | bool encoders_query(encoders::query_encoders::Request &req,
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109 | encoders::query_encoders::Response &res){ |
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110 | |||
111 | res.fl_encoder = encoder_fl; |
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112 | res.fr_encoder = encoder_fr; |
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113 | res.bl_encoder = encoder_bl; |
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114 | res.br_encoder = encoder_br; |
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115 | |||
116 | ROS_DEBUG("Encoder values queried");
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117 | return true; |
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118 | } |