Mobile Manipulation

MIT 6.421

Robotic Manipulation

Fall 2023, Lecture 13

Follow live at https://slides.com/d/uPcX7cE/live

(or later at https://slides.com/russtedrake/fall23-lec13)

PR2 by Willow Garage

Eve by 1x

Toyota Research Institute Mobile Manipulator

Toyota HSR

Fetch by Fetch Robotics

Spot by Boston Dynamics

Everyday Robot by Google (DeepMind)

What's different about mobile manipulation?

What's different about Perception?
- Partial views + unknown environments
- State estimation (e.g. \({}^W \hat{X}^C.\))
What's different about Kinematics/Motion Planning?
- Mobile base (holonomic vs nonholonomic)
- Continuous rotations require some care
- (often) Better kinematics!
What's different about Simulation?
- Large scale scenes / asset curation
Some new challenges in Navigation

Partial views

Unknown environments

From pose_estimation_icp pset problem

To subtract out the background, we assumed:

known, fixed environment, and
known transforms (e.g. \({}^WX^{C}\))

iiwa14_spheres_collision.urdf

iiwa14_spheres_dense_collision.urdf

What's different about mobile manipulation?

What's different about Perception?
- Partial views + unknown environments
- State estimation (e.g. \({}^W \hat{X}^C.\))
What's different about Kinematics/Motion Planning?
- Mobile base (holonomic vs nonholonomic)
- Continuous rotations require some care
- (often) Better kinematics!
What's different about Simulation?
- Large scale scenes / asset curation
Some new challenges in Navigation

  ...
  <link name="base"/>
  <link name="base_x"/>
  <link name="base_y"/>
  <joint name="iiwa_base_x" type="prismatic">
    <parent link="base"/>
    <child link="base_x"/>
    <axis xyz="1 0 0"/>
  </joint>
  <joint name="iiwa_base_y" type="prismatic">
    <parent link="base_x"/>
    <child link="base_y"/>
    <axis xyz="0 1 0"/>
  </joint>
  <joint name="iiwa_base_z" type="prismatic">
    <parent link="base_y"/>
    <child link="iiwa_link_0"/>
    <axis xyz="0 0 1"/>
    <limit lower="0" upper="0.25"/>
  </joint>
  <link name="iiwa_link_0">
  ...

  ...
  <link name="base"/>
  <joint name="iiwa_base" type="fixed">
    <parent link="base"/>
    <child link="iiwa_link_0"/>
  </joint>
  <link name="iiwa_link_0">
  ...

A small modification to the iiwa14.urdf...

(I've also removed the joint limits on joint 0)

Holonomic mobile bases

Nonholonomic bases

from Handbook of Robotics, Ch 49

from https://arxiv.org/pdf/2206.10533.pdf

What's different about mobile manipulation?

What's different about Perception?
- Partial views + unknown environments
- State estimation (e.g. \({}^W \hat{X}^C.\))
What's different about Kinematics/Motion Planning?
- Mobile base (holonomic vs nonholonomic)
- Continuous rotations require some care
- (often) Better kinematics!
What's different about Simulation?
- Large scale scenes / asset curation
Some new challenges in Navigation