dynamixel » dxsim-gazebo

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h2. = Introduction

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This repository contains a @Gazebo@ plugin that allows simulating a chain of @Dynamixel@ motors connected together to the same serial bus.

It provides the same interface as the real one, i.e. a @pty@ port connection you can connect to, and it emulates completely the @Dynamixel Protocol 2.0@.

*However*, not all the functionalities have been implemented yet.

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h3. Working functionalities

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* Motor models implemented are @MX28T@, @MX64T@.

** A template for other motors is provided (@libdynamixel/src/motors/MOTOR.h@).

* Set position and velocities of the motor.

* Multiple instances of @dxsim-gazebo@ can be instantiated (*NB:* specify a different pty port for each!).

* Emulate @RAM@ and @EEPROM@ of each motor's Control Table (see online documentation).

** The number of entries is fully customizable through the motors' header files.

* Debug mode can be enabled from the @sdf@ file, independently for each motor.

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h3. Not implemented functionalities

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* Set effort.

* You can send PID gains, but they are not used.

h3. Assumptions

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* The dynamics of the motor has been neglected.

h2. = Installation

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* You need first to clone and install "libydnamixel":https://redmine.laas.fr/projects/libdynamixel

** Follow instructions reported in "readme.md":https://redmine.laas.fr/projects/libdynamixel/repository/libdynamixel/revisions/master/entry/readme.md file.

* Then clone @dxsim-gazebo@ repository.

** To install it, use the following commands:

<pre><code class="shell">

$ autoreconf -if

$ ./configure [--prefix=<installation_path>]

$ make && make install

</code></pre>

** Make sure that the folder @lib/gazebo@ at the installation location is contained in the environment variable @GAZEBO_PLUGIN_PATH@ in your @.bashrc@.

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h2. = How to use

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In the @sdf@ file of your model, you have to insert the following lines for each instance you want to create:

<pre><code class="XML">

  <plugin name="dxsim" filename="dxsim-gazebo.so">

    <pty>/tmp/pty-dynamixel</pty>

    <period>1e-3</period>

    <motors>

      <motor>

        <joint spin="ccw">joint_1</joint>

        <eeprom>/home/gcorsini/dx_eeprom_id1</eeprom>

        <model>MX64T</model>

        <p0>0.0</p0>

        <v0>0.0</v0>

        <id>1</id>

        <noise>0</noise>

        <debug>0</debug>

      </motor>

      <motor>

        <joint spin="ccw">joint_2</joint>

        <eeprom>$HOME/dx_eeprom_id2</eeprom>

        <model>MX28T</model>

        <p0>0.0</p0>

        <v0>0.0</v0>

        <id>2</id>

        <noise>0</noise>

        <debug>0</debug>

      </motor>

    </motors>

  </plugin>

</code></pre>

* @<eeprom>@: path where the EEPROM file is saved. Environment variables can be specified, e.g. @$HOME@.

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If a @eeprom@ path has been specified, then at that location you should have a file looking like the following:

<pre>

model_number 311

model_info 0

firmware_ver 0

id 1

return_delay_time 0

operating_mode 1

secondary_id 255

homing_offset 0

temperature_limit 80

max_voltage_limit 160

min_voltage_limit 95

pwm_limit 885

current_limit 1941

acceleration_limit 32767

velocity_limit 1023

</pre>

+This file is an example of the @eeprom@ of a @MX64T@ motor.+

Changes to this file will lead to a runtime error in @dynamixel-gazebo@ if not performed properly; the EEPROM file should contain all the memory entries specified in the motor model's header file related to the EEPROM.

> For more details please visit the "online Dynamixel documentation":https://emanual.robotis.com/.

>> "MX Series documentation":https://emanual.robotis.com/docs/en/dxl/mx/.

h2. = Todo

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