ROS MoveIt!, virtual joints, planar joints, prismatic joints

Question

I do have a robotic application, where a 7Dof robot arm is mounted on a omnidirectional mobile platform. My overall goal is to get MoveIt! to calculate a sequence of joint movements, such that the robot EEF reaches a desired goal in Cartesian space.

In order to combine a robot platform with a world, the MoveIt! setup assistant lets you assign virtual joints between the "footprint" of the platform and the world it is placed in.

I do have two strategies. Either

• select a planar joint as a virtual joint. (What are the degrees of freedom or respectively the joint information that I can gather from this joint)

or

• select a fixed joint and add a (prismatic-x -> prismatic-y -> revolute-z) chain to the robot model.

Are there any significant differences (advantages/ disadvantages) to either of the approaches?

Answer 1

I am assuming that what you want is to to move the eef to any pose in the workspace by moving the robot's base.

If this is the case please refer to the Inverse Reachability Module by OpenRave like @ben suggested.

You might also want to check out the ROS package move_base.