@ -34,7 +34,7 @@ The provided battery charger can be plugged and unplugged at any time during ope
| SUPPLY | 1) Power the robot during tethered use<br/>2) Repair damaged batteries. |
| REPAIR | Repair damaged batteries. |
Please review the [Battery Maintenance Guide](https://docs.hello-robot.com/0.2/stretch-hardware-guides/battery_maintenance_guide_re1/) for proper care and charging of Stretch batteries.
Please review the [Battery Maintenance Guide](https://docs.hello-robot.com/0.2/stretch-hardware-guides/docs/battery_maintenance_guide_re1//) for proper care and charging of Stretch batteries.
@ -18,13 +18,7 @@ A few items you'll want to know about before getting started.
The entire robot powers up and down with the On/Off switch. When powering down, we recommend selecting 'Power Off' from the Ubuntu Desktop prior to hitting the Off switch
### LED Lightbar
The LED lightbar on the base indicates the battery voltage according to its color. It should be green, indicating a full charge. If it is orange or red the batteries require charging.
### Charging the Battery
@ -37,7 +31,7 @@ The provided battery charger can be plugged and unplugged at any time during ope
| SUPPLY | 1) Power the robot during tethered use<br/>2) Repair damaged batteries. |
| REPAIR | Repair damaged batteries. |
Please review the [Battery Maintenance Guide](https://docs.hello-robot.com/0.2/stretch-hardware-guides/battery_maintenance_guide_re1/) for proper care and charging of Stretch batteries.
Please review the [Battery Maintenance Guide](https://docs.hello-robot.com/0.2/stretch-hardware-guides/docs/battery_maintenance_guide_re2/) for proper care and charging of Stretch batteries.
@ -49,6 +43,26 @@ To allow motion once again, hold the button down for two seconds. After the beep
### LED Lightbar
The LED lightbar in the base provides a simple way to quickly ascertain the robot state. At all times its color indicates the battery voltage.
More information on the voltage display is available in the [Battery Maintenance Guide](https://docs.hello-robot.com/0.2/stretch-hardware-guides/docs/battery_maintenance_guide_re2/#state-of-battery-charge)
The lightbar will also flash as follows:
| Mode | Flashing |
|--------------------|-----------------------|
| Normal Operation | None |
| Runstopped | Rapid flash at 1 Hz |
| Charger plugged in | Slow strobe at 0.5 Hz |
Try runstopping the robot and plugging in the charger to become familiar with these modes.
### Safe Handling
Like any robot, it is possible to break Stretch if you're not careful. Use common sense when applying forces to its joints, transporting it, etc.
@ -65,7 +79,12 @@ The [Stretch Unpowered Best Practices Video](https://youtu.be/mQdOGEksdYM) provi
**Things to be mindful of**:
* Manually moving the head and wrist. They will move but they want to go at their own speed.
* The arm will slowly descend when the robot is powered off. If the arm is retracted it may rest the tool on the base. If desired to hold the arm up when un-powered, the provided 'clip-clamp' can be clipped onto the mast below the shoulder to support it.
* The lift will slowly descend when the robot is powered off. If the arm is retracted it may come to rest the tool on the base. If desired to hold the arm up when un-powered, the provided 'clip-clamp' can be clipped onto the mast below the shoulder to support it.
**NOTE**: The RE2 lift descends faster than the RE1. For the RE2 we recommend always attaching the clip-clamp as shown below prior to powering down the NUC computer
Now let's move the robot around using the [Stretch Body Robot API](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/robot.py). Try typing in these interactive commands at the iPython prompt:
NOTE: ROS2 support for Stretch is currently under active development and is considered 'beta'.
This tutorial track is for users looking to become familiar with programming the Stretch RE1 and RE2 via ROS2. We recommend going through the tutorials in the following order:
@ -15,12 +17,12 @@ This tutorial track is for users looking to become familiar with programming the
**NOTE**: ROS 2 tutorials are still under active development.
The aim of example 3 is to combine the two previous examples and have Stretch utilize its laser scan data to avoid collision with objects as it drives forward.
**NOTE**: ROS 2 tutorials are still under active development.
Stretch driver offers a [`FollowJointTrajectory`](http://docs.ros.org/en/api/control_msgs/html/action/FollowJointTrajectory.html) action service for its arm. Within this tutorial we will have a simple FollowJointTrajectory command sent to a Stretch robot to execute.
**NOTE**: ROS 2 tutorials are still under active development.
### NOTE
Simulation support for Stretch in ROS 2 is under active development. Please reach out to us if you want to work with Stretch in a simulated environment like Gazebo/Ignition in ROS 2.
**NOTE**: ROS 2 tutorials are still under active development.
## Installing Ubuntu 20.04 with ROS 2 Galactic on Stretch
Hello Robot utilizes Ubuntu, an open source Linux operating system, for the Stretch RE1 platform. If you are unfamiliar with the operating system, we encourage you to review a [tutorial](https://ubuntu.com/tutorials/command-line-for-beginners#1-overview) provided by Ubuntu. Additionally, the Linux command line, BASH, is used to execute commands and is needed to run ROS on the Stretch robot. Here is a [tutorial](https://ryanstutorials.net/linuxtutorial/) on getting started with BASH.
This will runs all of the planning capabilities, but without the setup, simulation and interface that the above demo provides. In order to create plans for the robot with the same interface as the offline demo, you can run
@ -48,16 +48,19 @@ You should see that the arm stops on contact when it extends, however it doesn't
The four stepper joints (base, arm, and lift) all support guarded contact settings when executing motion. This is evident in their `move_to` and `move_by` methods. For example, we see in the Arm's base class of [PrismaticJoint](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/prismatic_joint.py):
In this method you can optionally specify a contact threshold in the positive direction (`contact_thresh_pos`) and the negative direction `contact_thresh_neg`, as well a contact model (`contact_model` - which we'll learn about below). Note that these optional parameters will default to `None`, in which case the motion will adopt the default settings as defined the robot's parameters:
In this method you can optionally specify a contact threshold in the positive direction (`contact_thresh_pos`) and the negative direction `contact_thresh_neg`.
**NOTE**: these optional parameters will default to `None`, in which case the motion will adopt the default settings as defined the robot's parameters
**NOTE**: The parameters `contact_thresh_pos_N` and `contact_thresh_neg_N` are deprecate and no-longer supported.
@ -68,17 +71,13 @@ A contact model is simply a function that, given a user specified contact thresh
### The Effort-Pct Contact Model
[Effort-Pct](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/prismatic_joint.py#L142) is the default contact model for Stretch RE2. It simply scales the maximum range of motor currents into the range of [-100,100]. Thus, if you desire to have the robot arm extend but stop at 50% of its maximum current, you would write:
[Effort-Pct](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/prismatic_joint.py) is the default contact model for Stretch RE2. It simply scales the maximum range of motor currents into the range of [-100,100]. Thus, if you desire to have the robot arm extend but stop at 50% of its maximum current, you would write:
[Pseudo-N](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/prismatic_joint.py#L122) was the original contact model for Stretch RE1. We call it 'pseudo-N' as its contact thresholds are very rough approximations of Newtons. This simple model simply scales the motor current by the actuator parameter `force_N_per_A`.
Pseudo-N remains the default contact model for RE1 models. However, we recommend that newly developed RE1 code use the Effort-Pct model.
@ -5,7 +5,7 @@ In this tutorial we explore how to add additional degrees of freedom to the Stre
Stretch exposes a Dynamixel X-Series TTL control bus at the end of its arm. It uses the [Dynamixel XL430-W250](https://emanual.robotis.com/docs/en/dxl/x/xl430-w250/) for the [WristYaw](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/wrist_yaw.py) and the [StretchGripper](https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/stretch_gripper.py) degrees of freedom that come standard with the robot.
See the [Hardware User Guide](https://docs.hello-robot.com/hardware_user_guide/#wrist) to learn how to mechanically attach additional DOFs to the robot.
See the [Hardware User Guide](https://docs.hello-robot.com/0.2/stretch-hardware-guides/docs/hardware_guide_re2/#wrist-tool-plate) to learn how to mechanically attach additional DOFs to the robot.
**Note: Stretch is compatible with [any Dynamixel X Series servo](https://emanual.robotis.com/docs/en/dxl/x/) that utilizes the TTL level Multidrop Bus.**
@ -100,7 +100,8 @@ Sometimes the robot motion isn't quite what is expected when executing a splined
For example, the arm trajectory below has a large excursion outside of the joints range of motion (white). This is because the second waypoint expects a non-zero velocity when the arm reaches full extension.
<imgsrc="./images/bad_trajectory.png"/>
Often the trajectory waypoints will be generated from a motion planner. It is important that this planner incorporates the position, velocity, and acceleration constraints of the joint. These can be found by, for example
Stretch Body is the Python interface to working with the Stretch RE1. This page serves as a reference of the interfaces defined in the `stretch_body` library.
See the [Stretch Body Tutorials](shttps://docs.hello-robot.com/0.2/stretch-tutorials/stretch_body/) for additional information on working with this library.
See the [Stretch Body Tutorials](https://docs.hello-robot.com/0.2/stretch-tutorials/stretch_body/) for additional information on working with this library.
hello-chintan
2 years ago