clamp_controller

Python-based high-level controller to monitor and command a network of distributed clamps.

This repo is part of the Robotic Assembled Timber Structures with Integral Timber Joints project.

Repo folder structure

/src/clamp_controller - Contains all the import-able class and functions.

/src/controller_instances - Contains instances of customized controllers for different projects.

/src/serial_radio_transport_driver - A light weight library for transporting Serial Message to the USB Dongle, the message format is described in the radio firmware.

Design Goals

ClampModel

Digital twin of a clamp. Contains all the properties (e.g. step/mm conversion, soft limit, address) of a clamp and the telemetry reading.

Also contain functions to:

• Decode received telemetry

• Conversion between linear position and step position.

SerialCommander

The main model of the application. Contains:

• Instance of all available ClampModel
• Instance of the SerialPort that connects to the USBRadioDongle
• Instance of the RosClampCommandListener that connects to a ROS core via roslibpy

Functions to:

• Accept high-level synchronized move command for multiple clamps.
• Create low level move, home, speed-set and stop command.
• Send low level command to clamp with resend-on-Nack option.

RosClampCommandListener

A class that maintains the connection with ROS via roslibpy and listens-for (and replies-to) commands received as a rostopic.

CommanderGUI

A long function that create the tkinter UI for monitoring and control. This UI

Alternatively, it is possible to run the SerialCommander directly without UI, all the connections and settings can be accessed by code.

RemoteClampFunctionCall

A class for calling the clamp function from a remote process via roslibpy and ROS.

Installation

1. Clone the this repository.
2. Change directory cd to the local location of this repository.
3. Activate your virtual environment (optional).
4. Install the packages in the /src folder and the dependencies:

pip install -r requirements-dev.txt

Network Setup

Multiple devices need to cooperate with each other during robotic execution. A number of networks are present to connect the devices to the control computer (which is my Laptop) running the Process Execution Controller. Below is a typical network configuration for the devices on the network.

Laptop (Ethernet Port) - connection to RFL ethernet network (192.168.0.0/24 subnet)

• Linux Virtual Machine running ROS Master, ROS Bridge and ROS RRC_Driver (192.168.0.117)
• ABB Robot Controller running RRC
• Routable Internet via ETH guest network

Laptop (Wireless Adapter) - connection to ESP32 camera network (192.168.1.0/24 subnet)

• 4 (or more) ESP32 cameras (192.168.1.100 to 192.168.1.103)

Laptop (USB COM Port) - connection to USB Radio Dongle (proprietary network)

• 4 Clamps (address 1-4)
• 4 Screwdrivers (address 5-8)

(there are alternative network setup possible, for example using USB-Ethernet Adapter for connecting to the Wireless AP)

(the ROS instances can also be run from my Laptop's VMware Workstation Ubuntu 16 Virtual Machine bridged to the RFL network)

Usage

Controller with front end user interface:

1. To start the controller UI. Change directory to where you want the log files to be placed.
2. Run one of the controller UI instance, for example:

cd local_directory_for_log_files
python local_path_to_repo\src\controller_instances\08_TokyoCommander_UI+ROS.py
python -m controller_instances.10_Commander4Clamps4Screws

UI like this should appear:

Remote calling clamp functions

To remotely call clamp functions from a separate python execution/process (e.g. itj_process controllers), you need to import RemoteClampFunctionCall. The following things should be started before making calls:

• ros and ros_bridge is started on the linux machine, for example: roslaunch rosbridge_server rosbridge_websocket.launch
• the calling machine and the ros machine is on the same local network.
• a clamp_controller Controller Instance has started and is already connected to ROS

Example code:

# Connect to ROS via roslibpy
   hostip = '192.168.43.141'
   clamps_connection = RemoteClampFunctionCall(hostip)

# Command to send clamp to target (non-blocking)
   clamps_connection.sendD(ROS_VEL_GOTO_COMMAND)
# Command to send clamp to target (blocking)
   success = clamps_connection.send_and_wait(ROS_VEL_GOTO_COMMAND, 1000)
# Command to stop clamps (non-blocking)
self.
   clamps_connection.send(ROS_STOP_COMMAND(['1','2']))

Read the RemoteClampFunctionCall.py for available functions.

Addresses

In the latest use case, 4 Clamps and 4 Screwdrivers are used, also including 4 cameras on Clamps and 1 camera on Toolcanger. The addresses are as follows:

Type	id	radio address	camera address
CL3	c1	1	192.168.1.101
CL3	c2	2	192.168.1.102
CL3M	c3	3	192.168.1.103
CL3M	c4	4	192.168.1.104
SL1	s1	5
SL1	s2	6
SL1	s3	7
SL1_G200	s4	8
TC4_Camera			192.168.1.100

Credits

This repository was created by Pok Yin Victor Leung leung@arch.ethz.ch @yck011522 at @gramaziokohler