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Convention for kinematics calculations:

We are using a direct coordiante system (x,y,z) where the origin is the center of rotation of the system.

                ^
                | Z axis
                |
    X axis      |
      <----------
               /
              /
             / Y axis
            /
            v

The calculated axes are named rx, ry around respectively the X and Y axis with counter-clockwize positive value and tz vertical translation.

All parameters relative to legs are following the same convention and are given in meters:

- coordinates of "lega" are named: "ax", "ay"
- coordinates of "legb" are named: "bx", "by"
- coordinates of "legc" are named: "cx", "cy"

The calculation takes into account the unit defined for each real or calculated motors. If the unit field is missing, the universal units are used: meters (m) for distance, radians (rad) for angles.

The rotation center of the system can be changed using: 

fjsz.controller.center = <center_id>

Configuration Example

Configuration with two centers of rotation:

- plugin: emotion
  module: tripod
  class: tripod
  name: fjs_tripod
  centers:
    ### Si111
    - center_id: hall
      ax: -0.140
      ay: -0.1525
      bx: -0.140
      by: 0.0675
      cx: 0.140
      cy: -0.0425
    ### Si311
    - center_id: ring
      ax: -0.140
      ay: -0.0675
      bx: -0.140
      by: 0.1525
      cx: 0.140
      cy: 0.0425
  axes:
    - name: $mfjsur
      tags: real lega
    - name: $mfjsuh
      tags: real legb
    - name: $mfjsd
      tags: real legc

    - name: fjsz
      unit: mm
      tags: tz
    - name: fjsrx
      unit: mrad
      tags: rx
    - name: fjsry
      unit: mrad
      tags: ry