A high-level framework for programming robotic arms using TCP/IP connection.

# Description

The arm-lightweight-controller is a very lightweight robotic arm controller for a real robot that is based on sending commands via tcp/ip (e.g. URScript commands in case of Universal Robots arms). It can be used as a standalone module - ROS is not required. Module is written in Python2.7 (ROS compatibility).

## Difference between existing drivers (UR)

In ur_modern_driver the MoveIt is used to plan a path. In order to be usable in simulation, MoveIt planner computes many points between points specified in a trajectory. In arm-lightweight-controller there is no possibility to do that - path planning is performed entirely in the robot's controller. We cannot efficiently simulate the robot behavior, but it's fast and usable when it comes to the real robot.

## TCP/IP communication details

Universal Robots provide the description of TCP/IP packages that are sent from robot's controller via sockets. The current communication schema in arm-lightweight-controller is based on that. In order to add more functionalities from this interface - see attached file under provided link.

# Installation

A module arm-lightweight-controller can be installed using PyPi:

pip2 install robot_controller


Here is how to start. See examples/run.py file for an example of use.

import robot_controller
robot = robot_controller.Ur3("150.254.47.150", 30003, 30002)
...
...


In order to configure your Python environment just run the setup.py script.

## Functionality

Short description of available methods in the Manipulator class. For more details please refer to the method descriptions in the code.

• def move(self, trajectory, is_movej=True, is_pose=True, a=1, v=1, use_mapping=False) - send a move command to the specified robot. User can specify if it is a linear move / points are specified in a joint space or as poses / if the trajectory is in a robot's coordinate system or some external (see: set_mapping() method).
• def get_pose(self) - reads current pose from a byte stream.
• def get_joints(self) - reads current joint coordinates from a byte stream.
• def set_mapping(self, matrix) - sets a mapping between a robot coordinate system and some external one. While this method is invoked, user can pass trajectory in some external coordinate system (see: move() command).
• def execute_in_force_mode(self, trajectory_commands, task_frame, selection_vector, wrench, type=1, limits) - Executes constructed commands in the specified force mode. Please see URScript API reference doc - force_mode()

# Contribution

All questions to: michal.bednarek@put.poznan.pl

## Project details

Uploaded source