Publish the topic "/range" using a "sensor_msgs/Range"

[jabrena]

It is necessary to add support for a RangeFinder on EV3.

Currently, exist 2 alternatives on EV3 to use a RangeFinder:

• EV3 IR Sensor
• EV3 Ultrasonic Sensor

Tasks:

• [x] Develop node for EV3IRSensor
• [x] Develop node for EV3UltrasonicSensor
• [x] Execute tests for IRSensor
• [x] Execute tests for Ultrasonic Sensor
• [x] Review EV3 Sensor units vs ROS Range Units

Examples: The following examples could be useful to publish a Range message on ROS using both sensors. https://sourceforge.net/p/lejos/nxt/code/HEAD/tree/trunk/ros/nxt_lejos/nxt_lejos_proxy/src/org/lejos/ros/sensors/ https://sourceforge.net/p/lejos/nxt/code/HEAD/tree/trunk/ros/nxt_lejos/nxt_lejos_proxy/src/org/lejos/ros/sensors/UltrasonicSensor.java https://github.com/Hacks4ROS/h4r_ev3_ctrl/blob/develop/h4r_ev3_control/src/h4r_ev3_control/ev3_ultrasonic_controller.cpp https://github.com/Hacks4ROS/h4r_ev3_ctrl/blob/develop/h4r_ev3_control/src/h4r_ev3_control/ev3_infrared_controller.cpp https://github.com/srmanikandasriram/ev3-ros/blob/master/src/ultrasonic_sensor.cpp https://github.com/NCharabaruk/maxsonar_arduino_ros/blob/master/maxsonar_arduino_ros.ino

[jabrena]

Implemented both sensors. Pending tests.

[jabrena]

Related issue: https://github.com/rctoris/jrosbridge/issues/24

[jabrena]

Initial tests with a IR Sensor:

header: 
  seq: 428
  stamp: 
    secs: 1505425774
    nsecs:  51000064
  frame_id: base_link
radiation_type: 1
field_of_view: 0.0500000007451
min_range: 0.0500000007451
max_range: 0.800000011921
range: 43.0

[jabrena]

Initial tests with a US Sensor:

header: 
  seq: 264
  stamp: 
    secs: 1505426295
    nsecs: 107000064
  frame_id: base_link
radiation_type: 0
field_of_view: 0.0500000007451
min_range: 0.0500000007451
max_range: 2.5
range: 73.5

[jabrena]

vagrant@vagrant:~$ rostopic hz /range
subscribed to [/range]
average rate: 30.048
    min: 0.007s max: 0.076s std dev: 0.01353s window: 29
average rate: 30.519
    min: 0.001s max: 0.076s std dev: 0.01385s window: 60
average rate: 30.362
    min: 0.001s max: 0.080s std dev: 0.01423s window: 89
average rate: 30.326
    min: 0.001s max: 0.080s std dev: 0.01389s window: 120
average rate: 29.754
    min: 0.001s max: 0.173s std dev: 0.01793s window: 148
average rate: 29.825
    min: 0.001s max: 0.173s std dev: 0.01778s window: 160

[jabrena]

It is necessary to review the min_range & max_range of both EV3 Sensors.

IR Sensor:

https://shop.lego.com/en-US/EV3-Infrared-Sensor-45509 Proximity measurement of approximately 50-70 cm

Ultrasonic Sensor:

https://shop.lego.com/es-ES/EV3-Ultrasonic-Sensor-45504 Measures distances between one and 250 cm

ROS Range Definition:

    public static final String DEFINITION =
            "# Single range reading from an active ranger that emits energy and reports\n" +
            "# one range reading that is valid along an arc at the distance measured. \n" +
            "# This message is  not appropriate for laser scanners. See the LaserScan\n" +
            "# message if you are working with a laser scanner.\n\n" +
            "# This message also can represent a fixed-distance (binary) ranger.  This\n" +
            "# sensor will have min_range===max_range===distance of detection.\n" +
            "# These sensors follow REP 117 and will output -Inf if the object is detected\n" +
            "# and +Inf if the object is outside of the detection range.\n\n" +
            "Header header           " +
            "# timestamp in the header is the time the ranger\n                        " +
            "# returned the distance reading\n\n" +
            "# Radiation type enums\n" +
            "# If you want a value added to this list, send an email to the ros-users list\n" +
            "uint8 ULTRASOUND=0\n" +
            "uint8 INFRARED=1\n\n" +
            "uint8 radiation_type    " +
            "# the type of radiation used by the sensor\n                        " +
            "# (sound, IR, etc) [enum]\n\n" +
            "float32 field_of_view   " +
            "# the size of the arc that the distance reading is\n                        " +
            "# valid for [rad]\n                        " +
            "# the object causing the range reading may have\n                        " +
            "# been anywhere within -field_of_view/2 and\n                        " +
            "# field_of_view/2 at the measured range. \n                        " +
            "# 0 angle corresponds to the x-axis of the sensor.\n\nfloat32 min_range       " +
            "# minimum range value [m]\n" +
            "float32 max_range       " +
            "# maximum range value [m]\n                        " +
            "# Fixed distance rangers require min_range==max_range\n\n" +
            "float32 range           " +
            "# range data [m]\n                        " +
            "# (Note: values < range_min or > range_max\n                        " +
            "# should be discarded)\n                        " +
            "# Fixed distance rangers only output -Inf or +Inf.\n                        " +
            "# -Inf represents a detection within fixed distance.\n                        " +
            "# (Detection too close to the sensor to quantify)\n                        " +
            "# +Inf represents no detection within the fixed distance.\n                        " +
            "# (Object out of range)";

[jabrena]

ROS Units:

float32 field_of_view valid for [rad] float32 min_range minimum range value [m] float32 max_range maximum range value [m] float32 range range data [m]

EV3 Units:

range: cm