At Last, A Simply Useful™ Mobile Manipulator

Historically, versatile mobile manipulators have been large, heavy, and expensive. Stretch changes that. Thanks to its unprecedented design, it performs a wide range of tasks in a simple, intuitive manner. We call it ‘Simply Useful™’.

Ready for Autonomy

We designed Stretch for autonomous operation. It comes with a calibrated robot model (URDF) that is well-aligned to 3D camera images, and open source calibration code in Python that you can customize. ROS integration simplifies the use of existing ROS packages for autonomy, including the ROS navigation stack. We also provide demo code to help you get started.

The Python demo code gives examples of

• 3D mapping, localization, and navigation

• Fast planning to reach locations in a 3D map

• Surface segmentation and object grasping

• Contact detection for surface cleaning, drawer opening, and writing

• Holding out objects to people using deep neural networks for body pose estimation

Sense What Matters

A sensor suite designed specifically for navigation and manipulation in human environments.

Contact Sensitive

Stretch has torque sensing in all its joints, which enables it to detect contact. Low gear ratios, low mass, and low friction enable Stretch to move until contact, such as when reaching out to write on a whiteboard or lowering down to clean a surface.

IMUs and Accelerometers

IMUs and an accelerometer help Stretch detect bumps and sense its orientation. The 9 DOF IMU in the base can be used for odometry, detecting bumps, and sensing tilt. The 3 DOF accelerometer in the wrist can detect contact and support human-robot interaction. An IMU in the head supports high-frequency head pose estimation synchronized with 3D camera images.

Microphone Array

The ReSpeaker V2 microphone array in the head supports speech recognition and sound source localization through ROS. There’s also a programmable light ring.

Reach What Matters

Reaches important places in human environments and around the human body.

From Floors to Countertops

With 109cm vertical range of motion, Stretch can place its wrist from just above the floor to well above a countertop. Its telescoping arm can extend 52cm beyond the base and the wrist extends the reach, enabling the gripper to touch the back of a countertop or reach over clutter.

Navigate Tight Spaces

Given what it can reach, Stretch has a remarkably small footprint. It’s just 34cm wide and 33cm long. Retracting the arm and stowing the tool makes everything fit over the base, simplifying navigation through the clutter of human environments.

Comfortable Interactions

Stretch reaches ergonomic locations around people who are standing, seated, in a wheelchair, or in bed. It’s ready to reach out with intuitive motions.

Researcher Friendly

We’ve been there, spending our weekends calibrating a robot’s camera or reverse engineering a closed-source motor controller. Stretch comes calibrated out of the box with open source code from the low-level motor controllers to high-level autonomy demos. It also uses community favorites like Ubuntu, ROS, and Python.

Open Source from Top to Bottom

Stretch’s code is open source and available on GitHub. We use OSI-approved licenses wherever possible. Our custom code is written almost entirely in Python and its firmware is based on open source Arduino sketches.

Extensible Hardware

We want you to explore. If you’d like to attach a camera to the wrist, add a tablet to the head, or create a custom tool, we’ve got you covered. Stretch includes:

• Threaded mounting points on the base, shoulder, head, and wrist

• 7 x USB-3 and 12VDC (5A) in the base

• 1x USB-2 and 12VDC (3A) in the head

• 1x USB-2 and 12VDC (3A) in the shoulder

• 1x USB-2 and a 10 pin Arduino break-out in the wrist

• A wrist that supports a Dynamixel X-Series Frame and Dynamixel X-Series servos

A Workhorse for Everyday Grasping

Robust, adaptive, and ready to grasp a variety of everyday objects

The Stretch Compliant Gripper comes standard with Stretch. It is remarkably good at grasping objects, often succeeding with only coarse alignment. The springs conform to the object while rubber fingertips achieve high-friction contact, capturing even small pills.

The gripper’s Python interface provides motor current and position feedback as approximations of grip pose and grip force. We also provide a ROS interface and URDF model for the gripper.

A Tool for Every Occasion

In manipulation, your robot is only as good as your end-of-arm tool. We’ve developed a range of tools to attach to Stretch. The Stretch Tool Share has open-hardware designs that you can download, including tools that you can 3D print for Stretch.

Stretch 2 Specification