URX API Server

This project is a Python application that uses Flask to create a REST API for controlling a UR5e robot. The API lets users send URScript commands to the robot and get feedback. The project also has two features for observing the robot’s data: a Socket Listener and a Proxy with a Socket Server. The Socket Listener can passively monitor the data sent between the robot and the REST server. The Proxy can act as an intermediary between the REST server and the robot, and forward every message to the Socket Server for real-time observability. This way, users can watch the robot’s status and actions without affecting its operation.

Note: Even though there are Linux configurations, the project was only tested on Windows and MacOS.

Prerequisites

• Python 3.8.0
  • Note: Python 3.8.0 is required because of the urx library. For proper operation it is not possible to use a different version of Python.
• pip 20.2.4
• If going to use Proxy:
  • For Windows: Ncap 1.75 (https://npcap.com/#download)
  • For Linux: libpcap-dev (sudo apt-get install libpcap-dev)
  • For Mac: libpcap (brew install libpcap)

Installation

pip install -r requirements.txt
python setup.py 

Environment variables

There are 12 environment variables that need to be set:

• FLASK_HOST
• FLASK_PORT
• URX_HOST
• URX_PORT
• BOT_NAME
• PROXY
• PROXY_HOST
• PROXY_PORT
• WEBSOCKET_HOST
• WEBSOCKET_PORT
• LISTENER
• LISTENER_SLEEP_TIME

Their default values are on the .env file and are:

• FLASK_HOST = 127.0.0.1
• FLASK_PORT = 8080
• URX_HOST = 192.168.0.16
• URX_PORT = 30002
• BOT_NAME = ur5e
• PROXY=False
• PROXY_HOST=127.0.0.1
• PROXY_PORT=9090
• WEBSOCKET_HOST=127.0.0.1
• WEBSOCKET_PORT=5000
• LISTENER=False
• LISTENER_SLEEP_TIME=1

Note: There is also an ENVIRONMENT environment variable that is used to set the environment to dev or bot. The default value is bot. If the value is dev the server will not try to connect to the robot.

Starting venv and server

If running on Windows:

venv/Scripts/activate.bat
python start.py

Otherwise:

source venv/bin/activate
python start.py

API

Health check

/health

This endpoint is used to check if the server is running.

curl -X GET http://<FLASK_HOST>:<FLASK_PORT>/health

Health connection

/<BOT_NAME>/health-connection

This endpoint is used to check if the server is connected to the robot.

curl -X GET http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/health-connection

Partial gripper

/<BOT_NAME>/gripper/partial

This endpoint is used to partially open or close the gripper.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/gripper/partial -d '{"amount": 0.0}'

Body:

{
    "amount": 0.0
}

Open gripper

/<BOT_NAME>/gripper/open

This endpoint is used to open the gripper.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/gripper/open

Close gripper

/<BOT_NAME>/gripper/close

This endpoint is used to close the gripper.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/gripper/close

Movej

/<BOT_NAME>/movej

This endpoint is used to move the robot to a joint position.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/movej -d '{"joint_positions": [0.0, 0.0, 0.0, 0.0, 0.0, 0.0,] "acceleration": 0.0, "velocity": 0.0, "pose_object" : true, "relative": false}'

Body:

{
    "joint_positions": [0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
    "acceleration": 0.0,
    "velocity": 0.0,
    "pose_object" : true,
    "relative": false
}

Movel

/<BOT_NAME>/movel

This endpoint is used to move the robot to a cartesian position.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/movel -d '{"coordinates_and_angles": [0.0, 0.0, 0.0, 0.0, 0.0, 0.0,], "acceleration": 0.0, "velocity": 0.0, "pose_object" : true, "relative": false}'

Body:

{
    "coordinates_and_angles": [0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
    "acceleration": 0.0,
    "velocity": 0.0,
    "pose_object" : true,
    "relative": false
}

Movels

/<BOT_NAME>/movels

This endpoint is used to move the robot to a cartesian position for a series of coordinates.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/movels -d '{"coordinates_list": [[0.0, 0.0, 0.0, 0.0, 0.0, 0.0]], "acceleration": 0.0, "velocity": 0.0}'

Body:

{
    "coordinates_list": [[0.0, 0.0, 0.0, 0.0, 0.0, 0.0]],
    "acceleration": 0.0,
    "velocity": 0.0
}

Move

/<BOT_NAME>/move

This endpoint is used to move the robot to a cartesian position.

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/move -d '{"direction": "up", "distance": 0.0, "acceleration": 0.0, "velocity": 0.0}'

Body:

{
    "direction": "up",
    "distance": 0.0,
    "acceleration": 0.0,
    "velocity": 0.0
}

Note: The direction can be any of the following: up, down, left, right, forward, backward, roll, pitch, yaw

Config

/<BOT_NAME>/config

This endpoint is used to get or set the configuration of the robot.

curl -X GET http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/config

curl -X POST http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/config -d '{"velocity": 0.0, "acceleration": 0.0, "wait_timeout_limit": 0.0, "program_running_timeout_limit": 0., "amount_movement": 0.0, "amount_rotation": 0.0}'

Body:

{
    "velocity": 0.0,
    "acceleration": 0.0,
    "wait_timeout_limit": 0.0,
    "program_running_timeout_limit": 0.0,
    "amount_movement": 0.0,
    "amount_rotation": 0.0
}

Current pose

/<BOT_NAME>/current-pose

This endpoint is used to get the current pose of the robot.

curl -X GET http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/current-pose

Current joint positions

/<BOT_NAME>/current-joint-positions

This endpoint is used to get the current joint positions of the robot.

curl -X GET http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/current-joint-positions

Current tool position

/<BOT_NAME>/current-tool-position

This endpoint is used to get the current tool position of the robot.

curl -X GET http://<FLASK_HOST>:<FLASK_PORT>/<BOT_NAME>/current-tool-position