Cruiser-Documentation

Documentation for Cruiser Project.

Documentation maintainer: @hanzheteng

1. Introduction

The aim of Cruiser Project is to establish An Intelligent Aerial Security System.

Based on a Matrice 100 and the SDK from DJI, we developed an intelligent security guard system with utilitarian functions, including automatically flying along predetermined paths, identifying and categorizing objects, pedestrian tracking, etc. The onboard computer is responsible for real-time algorithms running on a robot operating system, and the ground station is mainly responsible for extra computing. The drone can be commanded by a mobile app, which is developed by our android engineers.

By the system we designed, the campus police could save their labor and surveil the campus in a more efficient and thorough way, providing a safer environment for students.

This project originated from a National-level College Students' Innovative Entrepreneurial Training Plan Program, and then also participated in the 15th Challenge Cup National College Students’ Extracurricular Academic Science and Technology Works Contest.

2. Repositories

Repositories	Description ( Functions )	Platform	Collaborators
OnboardROS	Movement control Object detection and tracking Autonomous landing by Hough circle detection Executing command from mobile terminal	DJI Matrice100 Manifold ( Ubuntu 14.04 ) Robot Operating System ( indigo ) Onboard-SDK-ROS	@Cuijie12358 @hanzheteng @XiangqianMa @ShoupingShan
GroundStation	Object detection and classification Abnormal behavior detection	Ubuntu 14.04 OpenCV ( 2.4.10 ) CUDA ( 8.0 ) Darknet YOLO CNN	@finaldong @ShoupingShan
MobileController	Autonomous cruising mission Object detection and tracking	Android 5.1 or above	@TrafalgarZZZ @hwding

3. CDT Protocol

Cruiser Data Transmission(CDT) Protocol.

3.1 Protocol Introduction

DJI Onboard SDK OPEN Protocol provide a method for communication between Mobile and Onboard device called Data Transparent Transmission.

Under this mechanism, we could send message to Autopilot first and Autopilot will transfer this message to Mobile or Onboard device.

CMD Frame
CMD SET	CMD ID	CMD VAL ( CDT DATA )

DJI Onboard SDK OPEN Protocol is only used between Onboard and Autopilot. With CMD SET 0x00 CMD ID 0xFE we could send message from Onboard to Mobile. With CMD SET 0x02 CMD ID 0x02 Onboard device could get message from Mobile.

So we define a new set of command and acknowledge messages within CMD VAL called Cruiser Data Transmission (CDT).

3.2 CDT Frame

CDT DATA
CDT SET	CDT ID	CDT VAL

Field	Offset(byte)	Size(byte)
CDT SET	0	1
CDT ID	1	1
CDT VAL	2	vary by CDTs

3.3 Function List

• Data type : unsigned char[ ]
• M-O : from Mobile to Onboard -- CDT ID is an odd number
• O-M : from Onboard to Mobile -- CDT ID is an even number
• CMD : command
• ACK : acknowledge

 

CDT SET	CDT ID	CDT VAL Size(byte)	Direction	Description
0x00	---	---	---	--- ( reserved )
0x01 Visual Landing	0x01	---	M-O	Start - CMD
	0x02	---	O-M	Start - ACK
	0x03	---	M-O	Stop visual detection - CMD
	0x04	---	O-M	Stop - ACK
	0x06	---	O-M	Land vertically
	0x08	---	O-M	Land successfully
	0x42	2 + 2	O-M	Delta X and Y position (meter) ( 2 bytes char instead of 1 float )
	0x44	2 + 1	O-M	Circle center and radius ( 1 point and 1 length )
0x02 Object Tracking	0x01	---	M-O	Start - CMD
	0x02	---	O-M	Start - ACK
	0x03	---	M-O	Stop - CMD
	0x04	---	O-M	Stop - ACK
	0x11	2 + 2	M-O	Object position to be tracking ( 2 diagonal points of a rectangle )
	0x12	---	O-M	Position - ACK
	0x42	2 + 2	O-M	Delta X and Y position (meter) ( 2 bytes char instead of 1 float )
	0x44	2 + 2	O-M	Current position of object ( 2 diagonal points of a rectangle )

4. Robot Operating System

4.1 ROS Node Info

Node name	Sub topic	Pub topic	Description	Collaborators
dji-sdk/...	( many )	( many ) /dji_sdk/local_position	Official SDK	DJI
dji_sdk_read_cam	---	/dji_sdk/image_raw /dji_sdk/camera_info	Get camera image and publish	DJI
mobile_msg	/dji_sdk/data_received_from_remote_device cruiser/landing_move cruiser/tracking_move cruiser/tracking_position_now	cruiser/landing_flag cruiser/tracking_flag cruiser/tracking_position	Read message from Mobile and pub	@Cuijie12358 @hanzheteng
landing_alg_node	/dji_sdk/image_raw /dji_sdk/local_position cruiser/landing_flag	cruiser/landing_move	Hough circle detection	@ShoupingShan @XiangqianMa
landing_move_node	/dji_sdk/local_position cruiser/landing_move	---	Movement control	@Cuijie12358 @hanzheteng
tracking_alg_node	/dji_sdk/image_raw /dji_sdk/local_position cruiser/tracking_flag cruiser/tracking_position	cruiser/tracking_move cruiser/tracking_position_now	Object tracking algorithm	@ShoupingShan @XiangqianMa
tracking_move_node	/dji_sdk/local_position cruiser/tracking_flag cruiser/tracking_move	---	Movement control	@Cuijie12358 @hanzheteng

4.2 ROS Topic Format

Topic name	Format	Message file	Description
dji-sdk/ ...	( many )	( many )	Official SDK
cruiser/landing_flag	bool flag	Flag.msg	Start or stop landing flag
cruiser/landing_move	bool state float32 delta_X_meter float32 delta_Y_meter	DeltaPosition.msg	Delta X and Y distance in ground coordinate system
cruiser/tracking_flag	bool flag	Flag.msg	Start or stop tracking flag
cruiser/tracking_move	bool state float32 delta_X_meter float32 delta_Y_meter	DeltaPosition.msg	Delta X and Y distance in ground coordinate system
cruiser/tracking_position	float32 a_width_percent float32 a_height_percent float32 b_width_percent float32 b_height_percent	TrackingPosition.msg	Two points on screen in percentage
cruiser/tracking_position_now	float32 a_width_percent float32 a_height_percent float32 b_width_percent float32 b_height_percent	TrackingPosition.msg	Two points on screen in percentage

5. Update Log

Activate Error problem solving on DJI FORUM: http://forum.dev.dji.com/thread-26936-1-1.html (Please switch to Chinese forum first, otherwise the link would lead to another wrong page.)