LiDAR_Inertial_Visual_Handhold

News

• 15 July 2024: Fix the bug related to LiDAR (IMU) timestamp compensation in the livox_ros_driver, remove the dynamic library dependency from mvs_ros_driver, and enable this synchronization scheme to use the official livox_sdk.
• 28 June 2024: Update reproduction videos and some important notes.
• 27 May 2024: Fix a bug in the calculation of the synthetic GPRMC timestamp, which could cause timestamp rollback. Additionally, we add checksum verification for GPRMC.
• 20 May 2024: According to Livox Avia's pin requirements, we convert PPS TTL level to RS485 level and supplement it with more detailed electronic connection and material list.

1. Introduction

This repository provides the CAD files (with suffix “*.SLDPRT and *.SLDASM”) for our handheld device, which can be opened and edited with Solidworks. All of the modules are suitable for printing with FDM (Fused Deposition Modeling). In addition, we have also open-sourced our hardware synchronization scheme, as well as the STM32 source code and hardware wiring configuration instructions.

2. Relevant guidance video

Thanks to the Bilibili uploader GundaSmart for making a detailed reproduction video. Everyone can follow the video to reproduce it. His sensor configuration includes a MID360 and a Hikvision pinhole camera.

FAST-LIVO Reproduction (Part 1)

FAST-LIVO Reproduction (Part 2)

FAST-LIVO Reproduction (Part 3)

FAST-LIVO Reproduction (Part 4)

FAST-LIVO Reproduction (Part 5)

3. Guide to installation

3.1 Root directory

├── handhold_cad/ - CAD source files
│   ├── ...
├── livox_ros_driver/ - Livox LiDAR ROS driver
│   ├── ...
├── mvs_ros_pkg/ - Camera driver
│   ├── ...
└── stm32_timersync-open/ - Embedded engineering folder
│   ├── USER/ - Main functionality folder
│   ├── ...
└── README.md - Project homepage document
└── ...

3.2 Assembly instruction

The assembly instructions are demonstrated in the GIFs below. Each module is clearly labeled corresponding to the name of its STL file.

3.3 Electronic connection

The guide for the electronic connections is presented as follows:

Livox AVIA LiDAR M12	Peripheral Function	Diagram
PIN 1	Power: +	AVIA 12-Pin Interface, top: female bottom: male
PIN 2	Ground
PIN 7	Ethernet: RX-
PIN 6	Ethernet: RX+
PIN 5	Ethernet: TX-
PIN 4	Ethernet: TX+
PIN 11 (Sync-)	RS485_Output B-
PIN 12 (Sync+)	RS485_Output A+

MVS Camera 6PIN	Name	I/O Type	Description	Peripheral Function	Diagram
PIN 1	DC_PWR	--	Power Supply		MVS Camera 6-Pin Interface
PIN 2	OPTO_IN	Line 0+	Optical Isolation Input	STM32 PA1
PIN 3	GPIO	Line 2+	General Purpose Input/Output
PIN 4	OPTO_OUT	Line 1+	Optical Isolation Output
PIN 5	OPTO_GND	Line 0- / 1-	Optical Isolation Ground	STM32 GND
PIN 6	GND	Line 2-	Ground

STM32	Peripheral Function
PA1	MVS camera PIN2 (OPTO_IN)
PB5	RS485_Input (TXD)
PA9	TTL2USB (RXD)
VCC	RS485_Input (VCC) | TTL2USB (VCC)
GND	RS485_Input (GND) | TTL2USB (GND) | MVS camera PIN5 (GND)

RS485	Peripheral Function
RS485_Output A+	LiDAR M12 PIN12 (Sync+)
RS485_Output B-	LiDAR M12 PIN11 (Sync-)
RS485_Output (GND)	LiDAR M12 PIN2 (GND)

🔴🔥 IMPORTANT:

• STM32 PB5 (PPS signal) is converted from TTL to RS-485, resulting in RS485_Output A+ and RS485_Output B-;
• STM32 TXD (GPRMC) is converted from TTL to USB and sent to the PC;
• If you are using the Mid360, you can directly connect STM32 PB5 to LiDAR M12 pps interface;
• Before you roslaunch livox_ros_driver livox_lidar_msg.launch, you can use sudo chmod a+rw /dev/ttyUSB0 grant permissions to the USB serial port;
• The default connection method in this repository directly connects to M12 without using the Livox converter. If you use the converter, you can connect STM32 PB5 (PPS signal) to the Livox converter Sync Port without converting TTL to 485 level. Refer to Issue 19 for details.

4. How to run the driver

roslaunch mvs_ros_pkg mvs_camera_trigger.launch
roslaunch livox_ros_driver livox_lidar_msg.launch
rosbag record /livox/lidar /livox/imu left_camera/image

5. Main material lists (only for reference)

Item	Pics	Purchasing list
Livox Avia LiDAR		Livox Avia
CMOS		MV-CA013-21UC
Camera Len		MVL-HF0628M-6MPE
STM32		STM32F103C8T6
Screen		IPS Screen 10''
Battery		4800mah
TTL to USB		TTL to USB
TTL to 485		TTL to 485

6. License

The source code is released under GPLv3 license.

If you use any code of this repo in your academic research, it will be very appreciated if you can cite any of our following papers:

[1] Zheng, Chunran, et al. "FAST-LIVO: Fast and Tightly-coupled Sparse-Direct LiDAR-Inertial-Visual Odometry." 
[2] Hong, Sheng, et al. "Rollvox: real-time and high-quality LiDAR colorization with rolling shutter camera."