Breadcrumbs

Star-Planet

Description

A planet motion command is a special type of connected Group, where a particular XBot is the Star or Sun XBot, and the other XBots (planets) move relative to the Star XBot. The planet XBot’s coordinate system’s origin is the Star XBot’s current position.

An example of a system with 2 M3-06 XBots (120mm x 120mm) is provided below:

Moving the Planet XBot will change the relative position between the Planet and Star XBot.

Planet_XBot_Coordinate_System.png

Note: The feedback position of the Planet XBot does NOT use the Star XBot’s position as the origin. It uses the system origin like any other XBot.

Moving the Star XBot will cause the Planet XBot to follow the Star. 

Planet_XBot_Example2.png

It is possible to move both Planet XBot and Star XBot simultaneously. 

Planet_XBot_Example3.png

In this example, the Planet XBot is in a circular motion around the Star XBot while the Star XBot is moving in a straight line. The result is the Planet XBot will follow a spiral path so that it is revolving in a perfect circle around the Star XBot even during Star XBot motion.

It is possible for all real XBots to be planet XBots, and revolve around a virtual Star XBot of size 0,0.

Virtual XBot ID starts from 100, and end at 127. It can be moved just like a normal XBot.
Virtual_XBot_Movement.png

Performance Limits for Star-Planet Movers

There are kinematic limitations placed on both the Star XBot and the Planet XBots so that the combined motion does not exceed the system limits. 

 

Star XBot 

Planet XBot

 Speed

0.5 x System Speed Limit

0.5 x System Speed Limit

Acceleration 

factor (fs) x Acceleration Limit (As)

  • fs = min(fp)

  • As (for Virtual XBot) = min(Ap)

  • As (for Real XBot) = based on System Acceleration Limit and assigned stereotype

factor (fp) x Acceleration Limit (Ap)

  • fp = Ap / (As + Ap)

  • Ap = based on System Acceleration Limit and assigned stereotype (therefore this value can be different for each Planet XBot)

Jerk 

0.5 x System Jerk Limit

0.5 x System Jerk Limit

Note that the System Jerk Limit can be changed using Set Jerk Limit.

Commands