mmWave Radar ROS Node

This is a radar ROS node for TI’s mmWave devices. The ROS node sets up a ROS service as an interface to configure the mmWave Evaluation Module and publishes a ROS PointCloud2 message with the objects detected when the sensor is activated.

NOTE: This ROS node, running on TDA4, currently is tested only with TI’s IWR6843ISK.

Setup

Re-flash the the TI mmWave EVM with Out-of-Box firmware

If you are using a brand new TI mmWave EVM, it may come pre-flashed with an older version of the Out-of-Box Demo. The EVM should be re-flashed with the Out-of-Box demo from the compatible version of the mmWave SDK.

On a PC, download Uniflash, TI’s flashing software

Install libraries required for Uniflash to work:

sudo apt install libusb-0.1-4 libgconf-2-4

Make sure the file /lib/x86_64-linux-gnu/libudev.so.0 exists. If it does not exist execute the following command to generate a symbolic link necessary for Uniflash to work:
```
sudo ln -sf /lib/x86_64-linux-gnu/libudev.so.1 /lib/x86_64-linux-gnu/libudev.so.0
```
Navigate to the download directory, make the file executable and run the Uniflash installer:
```
cd ~/Downloads
```
```
chmod +x uniflash_sl.7.1.0.3796.run
```
```
./uniflash_sl.7.1.0.3796.run
```
Download the linux version of the mmWave SDK. MmWave SDK version:
- Compatible with TI mmWave SDK v3.5 out-of-box demo when using IWR6843AOPEVM
- Compatible with TI mmWave SDK v3.5 out-of-box demo when using IWR6843 ES2.0 EVM
Install the following mmWave SDK dependency:
```
sudo apt-get install libc6:i386
```
Navigate to the download directory, make the file executable and run the mmWave SDK installer (change <ver> to the appropriate version):
```
cd ~/Downloads
```
```
chmod +x mmwave_sdk_<ver>-Linux-x86-Install.bin
```
```
./mmwave_sdk_<ver>-Linux-x86-Install.bin
```
Follow the EVM Operational Modes Setup Guide to confirgure the device for flashing mode. Once configured for flashing mode, power cycle the device by toggling the NRST switch or unplugging then reconnecting the micro usb cable.
Follow the Using Uniflash with mmWave Guide to flash the device with the apropriate binary.

Ensure the device is connected to the PC, then serial port names can be found with:
```
ls /dev | grep 'ttyUSB'  # for standalone EVMs

ls /dev | grep 'ttyACM'  # for EVM + ICBOOST carrier board
```
Two serial ports should appear e.g.: ttyUSB0 and ttyUSB1, in this example, /dev/ttyUSB0 should be entered as the COM port in the Settings & Utilities tab in Uniflash.

The .bin file can be found at <MMWAVE_SDK_INSTALL_DIR>/packages/ti/demo/xwr68xx/mmw/xwr68xx_mmw_demo.bin
Follow the EVM Operational Modes Setup Guide to confirgure the device for functional mode. Once configured for functional mode, power cycle the device by toggling the NRST switch or unplugging then reconnecting the micro usb cable.

Select Chirp Configuration

This ROS node will, by default, use a chirp configuration that optimizes range resolution. The configuration file is located at /cfg/6843_3d.cfg. If you wish to use the default chirp configuration, no further action is required.

If you wish to use a custom chirp configuration, the mmWave Sensing Estimator can be used to estimate the chirp configuration based on scene parameters. For more information on how to select the right chirp parameters in a FMCW Radar device, please see Programming Chirp Parameters in TI Radar Devices. To modify the parameters, edit 6843_3d.cfg and save the file using a text editor or specify an alternate configuration file in the mmWaveQuickConfig node section of 6843_3d_TDA4VM.launch.

NOTE: This ROS node currently is tested only with the chirp configuration provided. Modifying the chirp configuration may have an adverse effect on the performance.

Setup Symbolic Links

This section is necessary for those using multiple sensors. Users with a single sensor can skip this step.

When the standalone sensors are connected to the TDA4, the device appears as /dev/ttyUSBx (Command Port) and /dev/ttyUSBy (Data Port). These names are then used in the launch files to comunicate with the sensor. When using multiple sensors and hardcoding these ttyUSB names, the devices must then be connected to the TDA4 in a specific order. Furthermore, other devices may also appear as /dev/ttyUSBx. Therefore, creating a symbolic link will be extremely useful. Below are the steps to setting up symbolic links.

NOTE: The following steps are for standalone EVMs and will not work with the ICBOOST carrier board.

On the TDA4 host linux, create a file named 99-usb-serial.rules in the directory /etc/udev/rules.d/ with super user:
```
root@tda4vm-sk:~$ sudo vi /etc/udev/rules.d/99-usb-serial.rules
```

Press ‘i’, then type or paste the following:

SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea70", SYMLINK+="mmWave_%s{serial}_%E{ID_USB_INTERFACE_NUM}"

Close and save the file by hitting ‘Esc’, typing ‘:’, then ‘wq’, and finally pressing ‘Enter’.
Plug in the first sensor to the TDA4 and type the following in the command line:
```
root@tda4vm-sk:~$ ls -1 /dev/ | grep mmWave
```
Two symbolic links should appear. Example: “mmWave_00CE0FCA_00”, typically the command port, and “mmWave_00E0FCA_01”, typically the data port.
Repeat steps 4-5 for any additional sensors that are being used. Be sure to note the names of each serial port as you go.
In the file, /launch/6843_quad_3d_TDA4VM.launch, update the com_user and com_data parameters for each sensor to match the new serial port names.

Setup Static Transform

This section is necessary for those using multiple sensors. Users with a single sensor can skip this step.

The launch files for the radar driver also create a static transofrm. If the position or angle of the sensors on the robot is different, the arguments in the static transorm must be changed. Find more information on static transorms here: http://wiki.ros.org/tf#static_transform_publisher

For example, one can use the center of the robot as a baseline. In the file, /launch/6843_quad_3d_TDA4VM.launch, update tf_args (X Y Z Yaw Pitch Roll) for each sensor to describe the position of the sensor relative to the center of the robot.

Synchronization

For details regarding time synchronization of frames from multiple mmWave devices click here.

Usage

Build the mmWave radar ROS node

cd $ROS_WS
# ROS1
catkin_make --source /opt/robotics_sdk/ros1 --force-cmake
source devel/setup.bash

Launch the mmWave radar ROS node

# ROS1
roslaunch ti_mmwave_rospkg 6843_3d_TDA4VM.launch # for single sensor

roslaunch ti_mmwave_rospkg 6843_quad_3d_TDA4VM.launch # for multiple sensors

Visualization on Remote Ubuntu PC

In the PC Docker container,

roslaunch ti_mmwave_rospkg viz_remote_pc.launch # for single sensor

roslaunch ti_mmwave_rospkg viz_remote_pc_quad.launch # for multiple sensor

Launch File Parameters

Parameter	Description	Value
max_allowed_elevation_angle_deg	Maximum allowed elevation angle in degrees for detected object data [0 > value >= 90]	int
max_allowed_azimuth_angle_deg	Maximum allowed azimuth angle in degrees for detected object data [0 > value >= 90]	int
device_num	The device number for this sensor	int
com_user	Serial port used for configuring mmWave radar device	string
com_data	Serial port used for receiving data from mmWave radar device	string
tf_args	Values to be used for tf transformation	string