Hello, Elaine!
I’m Elaine Short, newly-minted Associate Professor of Computer Science and I’m spending my sabbatical here at Hello Robot working on making the vision of in-home robotics a reality, especially for people like me who have mobility disabilities that make it hard or impossible to do things around the house. I’ve been working in robotics, human-robot interaction (HRI), and assistive technology for more than 15 years, and doing open-source ROS programming for most of that time. My favorite kind of project goes deep on both the human and robot sides of the equation, and my goal with these blog posts is to show off some fun open-source demos of how Stretch could be used as an assistive device, give you a feel for where the technology is right now, identify some problems that remain to make assistive robotics at home a reality, and talk about how ideas from the disability community can be applied to make sure these technologies are empowering and fun to use for disabled people and everyone else.
Hello, Stretch!
After a few weeks of getting familiar with the Hello Robot codebase, my shiny refurbished Stretch 4 arrived at my apartment. I’ll be doing more with Stretch’s autonomous capabilities later, but as a first activity, I got the gamepad connected to the default teleoperation interface and took the robot for a spin. Starting from my home office, I used the robot to open the door, drove the robot to the kitchen, opened the fridge, took out a drink, put it back, closed the fridge, and took a little detour on the way back to the office to introduce the robot to my (understandably wary) cats. I had to step in once when a careless maneuver put a container of leftover corn on the cob in a precarious position, but other than that I was able to use the robot to do every step of the process. The most difficult thing was opening the door (but not unlatching it) – I might take some inspiration from home customization for service animals and put a rope or piece of cloth on the handle in the future to make it easier for the robot.
The Tech Side
Stretch is a ruthlessly practical mobile manipulator: it has a small footprint, six degrees of freedom in the arm (gripper, lift, telescoping arm, and 3 DOF wrist) that let it reach the floor and up to about 5 feet off the ground, omnidirectional base, and serious onboard sensing with wide field-of-view cameras, LiDAR, and ground line sensors. You can read more about the technical specifications here. I have a decent amount of experience teleoperating robots and playing video games, but I was still impressed that I was able to do relatively complex constrained manipulation (opening doors, managing stuff in a crowded fridge) without much practice. Stretch 4 is also pretty strong – it was able to break the seal on the fridge door and push the door open with just the wrist. Perception and planning remain hard problems for open-ended manipulation, but I think Stretch’s physical capabilities will be enough to make itself useful.
As always, Stretch 4’s code is open-source; you can look over the low level code in the stretch4_body repository, including the built-in gamepad teleoperation functionality.
The Disability View
I like Stretch as an assistive robot for a few reasons. First, you can see the history of work with the disability community in the design – for example, being able to reach the floor. The ability to reach the floor is relatively uncommon in this kind of robot, but if you have a mobility disability, you’ll know that gravity is an enemy that will put all your favorite things (pens, containers, your cell phone) out of reach. Because Stretch 4 is designed with assistive applications in mind, being able to pick things up off the floor was a key design constraint, even when keeping everything else as simple as possible.
Starting with teleoperation is also a disability-informed approach. Nondisabled people often want to hand off their chores entirely, but for people with mobility disabilities, being able to act on the world in meaningful ways is as important as the activity itself getting done. Humans, disabled or not, are also incredible problem-solvers, and teleoperation lets the human-robot team accomplish tasks that neither could do alone.
What’s Left?
There’s a pretty big gap between a one-time demo and daily use, especially for robots. One of my goals for this sabbatical is to use the robot close to every day, and try to figure out some practical uses for this type of mobile manipulator around the house. I’m excited to see how far I can push the robot’s capabilities (washing machine, I’m looking at you next).