rox_argo_kinematics
===================

This node translates the command velocties from cartesian space to the joint space and sends it to the motors through the relayboardV3 node.
The kinematics node, inturn subscribes to the joint states from the relayboard in order to calculate, updates and publishes odometry.

*Location:* https://github.com/neobotix/rox_argo_kinematics/

Parameters
**********

:control_rate:

  ============== =======
  Type           Default
  -------------- -------
  double         50.0
  ============== =======

  Description
    Frequency at which motor commands are sent. (Hz)

:wheel_radius:

  ============== =======
  Type           Default
  -------------- -------
  double         0.50
  ============== =======

  Description
    Radius of the wheel. (m)

:cmd_timeout:

  ============== =======
  Type           Default
  -------------- -------
  double         0.1
  ============== =======

  Description
    Maximum interval between 2 consecutive velocity commands. (s)

:zero_vel_threshold:

  ============== =======
  Type           Default
  -------------- -------
  double         0.001
  ============== =======

  Description
    Velocity below which the steering for a wheel is disabled. [m/s]

:broadcast_tf:

  ============== =======
  Type           Default
  -------------- -------
  bool           true
  ============== =======

  Description
    Broadcasts Transformation frame between the `base_link` and `odom`.

:small_vel_threshold:

  ============== =======
  Type           Default
  -------------- -------
  double         0.02
  ============== =======

  Description
    Velocity below which it is allowed to move a wheel into the outward position. [m/s]

:num_wheels:

  ============== =======
  Type           Default
  -------------- -------
  int            4
  ============== =======

  Description
    number of drive modules (need at least 2).

:wheel[i].center_pos_x:

  ============== =======
  Type           Default
  -------------- -------
  double         1.0
  ============== =======

  Description
    X position of the steering axis. [m]

:wheel[i].center_pos_y:

  ============== =======
  Type           Default
  -------------- -------
  double         1.0
  ============== =======

  Description
    Y position of the steering axis. [m]

:wheel[i].drive_joint_name:

  ============== =======
  Type           Default
  -------------- -------
  std::string    "rand"
  ============== =======

  Description
    ROS joint name for this motor.

:wheel[i].steer_joint_name:

  ============== =======
  Type           Default
  -------------- -------
  std::string    "rand"
  ============== =======

  Description
    ROS joint name for this motor.


Published Topics
****************

* odom(nav_msgs/Odometry): Gives the position of the robot in the cartesian space.
* tf: Publishes the required transforms that maps odom and the base_footprint.
* drives/joint_trajectory(trajectory_msgs/JointTrajectory): Publishes the joint commands that is later subscribed and converted to motor commands by the argo_drive_node.

Subscribed Topics
*****************

* cmd_vel(geometry_msgs/Twist): Subscribes to the cartesian velocity commands(m/s) published by Teleop, nav2_controller and so on.

Example
*******

::

  /**:
    ros__parameters:
      num_wheels: 3
      control_rate: 50.0
      wheel_radius: 0.050
      wheel_lever_arm: 0.0
      zero_vel_threshold: 0.005
      small_vel_threshold: 0.02
      broadcast_tf: true
      cmd_timeout: 0.2
      trajectory_timeout: 0.1

      wheel0:
        drive_joint_name: "wheel_front_left_joint"
        steer_joint_name: "caster_front_left_joint"
        center_pos_x: 0.265
        center_pos_y: 0.215

      wheel1:
        drive_joint_name: "wheel_back_left_joint"
        steer_joint_name: "caster_back_left_joint"
        center_pos_x: -0.265
        center_pos_y: 0.215

      wheel3:
        drive_joint_name: "wheel_back_right_joint"
        steer_joint_name: "caster_back_right_joint"
        center_pos_x: -0.265
        center_pos_y: -0.215

      wheel2:
        drive_joint_name: "wheel_front_right_joint"
        steer_joint_name: "caster_front_right_joint"
        center_pos_x: 0.265
        center_pos_y: -0.215