V2X_SJTU

Introduction

A repository of basic codes and usage instructions for Mokar V2X devices. The project is sponsored by Shanghai Jiaotong University.

Here are some introductions and tutorials for the V2X device. Honestly speaking, I 'm just a beginner in this field. My document and tutorial contain only some basic ways to code & run programs on the V2X device.

Instruction about Symbols
In this instruction, all the linux commands with "$" should be run on your own computer, and the orders with "#" should be run on device.

Content

1. Description
2. Installation
3. Hardware Connection
4. Before Communication
5. Samples
6. Coding
7. TCP Communication
8. Other Problems
9. Contact

1.Description

Folder tree:
.
├── lidar_ros --ros package for message sending
│   ├── include
│   ├── msg
│   └── src
├── mde --SDK provided by Mokar Technology
│   └── mocar
│   ├── bin --Compiled files here
│   ├── build --Make file here
│   ├── docs --Documents by Mocar
│   ├── libs --Library
│   ├── license --License
│   └── samples --Some sample codes by Mokar, except Lidar_send and Lidar_recv generated by Fantasticos
├── NTP --Clock Synchronization Software
│   └── ntpclient-2015
└── TCP_Scripts --TCP communication code
├── test_tcp_1 --Old version 1
├── test_tcp_2 --Old version 2
├── test_tcp_3 --Latest version
└── test_tcp_3 (copy) --Copy of old version 3

mde is a developing kit provided and copyrighted by Mokar Technology.
TCP_Scripts contains some simple programs and their codes for socket TCP communication between computer and Mokar V2X devices.
lidar_ros is a ros package sending messages to road side devices
NTP is a software for clock synchronization

2. Installation

To clone the codes from Github
$ cd /your_own_work_space
$ git clone https://github.com/Fantasticos/V2X_SJTU.git

Install some essential libraries
$ sudo apt-get install libc6:i386
$ sudo apt-get install lib32stdc++6
$ sudo apt-get install lib32z1

Install arm-linux-gnueabihf cross compiler

Download compiler

Move .tar to /opt $ sudo mv gcc-linaro-arm-linux-gnueabihf-4.9-2014.07_linux/ /opt

Extract
$ tar -xvf gcc-linaro-arm-linux-gnueabihf-4.9-2014.07_linux.tar

Modify profile
$ cd /etc
$ sudo gedit profile
add export PATH=$PATH:/opt/gcc-linaro-arm-linux-gnueabihf-4.9-2014.07_linux/bin
$ sudo gedit ~/.bashrc
add source /etc/profile

reboot the terminal

3. Hardware Connection

Refer to the handbook provided by Huali for hardware wire connection instruction

If you want to connect your computer and v2x device by Wifi, search for Wifi AP named "IMASTERXXXX", default device ip address 192.168.10.1

If you want to connect through Ethernet, change your local ip address to be 192.168.253.1 and wire-connect directly to the Mokar device, or through a switch. Default device ip address 192.168.253.10

4. Before Communication

Suppose you connect through a wire, the ip address of V2X device will be 192.168.253.10. If you connect wirelessly, just replace the ip with 192.168.10.1

IMPORTANT
You should change your ip address according to your target address. For example, if you want to connect to 192.168.253.10 with Ethernet, you have to change your own ipv4 address to be 192.168.253.x, x can be replaced by any integer from 0 to 255 except 10 (you cannot set your ip to be identical with your device's)

Before you test the communicaiton, you have to upload the essential libraries.

$ cd mde/mocar/libs  
$ scp libmocarv2x.so [email protected]:/usr/lib/  
$ scp base/libasnhl.so [email protected]:/usr/lib/  
$ scp base/libosstoed.so [email protected]:/usr/lib/  
$ scp base/libLLC.so [email protected]:/usr/lib/  
$ scp base/libstack.so [email protected]:/usr/lib/  
$ scp base/libsmartway.so [email protected]:/usr/lib/  
$ scp ../samples/mocar_log.conf  [email protected]:/usr/local  

PASSWORD: hL2017.moKar

5. Run Samples

The sample codes are in mocar/samples, you can compile the sample under mocar/build

$ cd mde/mocar/build
$ make

Upload the sample app to the v2x device, take bsm for example

$ cd ../bin
$ scp bsm [email protected]:/var

Open a new terminal, log into the device through SSH

$ ssh -l root 192.168.253.10
PASSWORD: hL2017.moKar

Enter /var and run the sample app

# cd /var
# ./bsm

If warn undefined symbol: mde_stack_init, just remove usr/local and upload the .conf file again. # rm -rf /usr/local/*
$ scp ../samples/mocar_log.conf [email protected]:/usr/local

Now you can see the device sending bsm message at 10 HZ.

You can repeat this process and upload program to another Mokar device, run the same ./bsm, you can definitely see the two device communicating!!!

If you want to change the IP of device
# vi /etc/network/interfaces
change the address

6. Coding

The coding work now takes place in mocar/samples
Two example are provided, lidar_send and lidar_recv. I wrote these two program for my graduation project. They combine both TCP communication and BSM message.
To generate your own code, I suggest you to copy one sample, like bsm, copy the folder and rename the folder. Also remember to replace the code file name and the name in makefile.

Now you can write any funcion in c++ you like!!!

7. TCP Communicaiton

The communication between computer and V2X device is done by TCP.
In TCP_Scripts, programs include client and server, client runs on the computer and server runs on the device.

In my project, the tcp server is merged into samples/lidar_send and samples/lidar_recv. lidar_send is for the Road Side Device, while lidar_recv is for the On Board device

To test, you can upload lidar_send or lidar_recv to the device, these two are both tcp servers. lidar_send is for road side unit while lidar_recv is for on board unit.
I wrote 2 clients for this project, one is road side client. It subscribe messages from rostopic and publish them through tcp to the road side v2x device.
Another client is TCP_Scripts/test_tcp_3/TCP_Client2.c or its executable client2
I also wrote a talker.cpp to simulate the message published by the lidar.

To fully function the communication chain, follow the steps carefully:

1. Move /lidar_ros to your own workspace i.e. catkin_ws

$ cd catkin_ws
$ catkin_make
$ roscore

2. Start the 2 tcp servers on the devices, take the road side device for example, you can repeat it again with OBU.
   use ssh login 192.168.10.1 # cd /var
# ./lidar_send open another terminal and ssh login again, use the ntp to synchronize the two clock # cd /var
# ./ntpclient -s -d -c 1 -i 5 -h 192.168.10.101

you can refer to 8.　Other Problems for instruction on ntpclient

ATTENTION
Some times when you run lidar_send or lidar_recv you will meet the segment fault. This is because the time should be changed to 01/01/2010 before running the program. (I'm also confused why, but this is what the engineer told me)
To fix this problem
open another terminal, ssh login
# date 0101000010

3. Start the clients for road side unit, open the client to send messages
   $ rosrun lidar_ros talker
$ rosrun lidar_ros listener 192.168.10.1
   for on board unit
   $ cd TCP_Scripts/test_tcp_3
$ ./client2 192.168.253.10

Now you can see the two device communicating messages generated by talker.

8. Other Problems

Synchronization of clock

To make sure that the clock are at the same pace, I use NTP to synchronize it.

The NTP server should be installed on your own computer, you can google it yourself, there are plenty of tutorials.

The problem is that the compilation of NTP client in the device is extremely trouble some because it use gcc-linaro-arm-linux-gnueabihf. To make it easy, I compiled the client on my computer and just share the executable.

$ cd NTP/ntpclient-2015
$ scp ntpclient [email protected]:/var

If you have established NTP server on your own computer, you can run the following code on the device, and you can see your clock synchronized.
# ./ntpclient -s -d -c 1 -i 5 -h 192.168.253.1
IP address can be changed with that of your own PC

9. Contact

If you have any questions, feel free to email me. My email address is [email protected]