Obstacle Avoidance Sensors used in Ardupilot based Spraying Drones
obstacle avoidance sensors are used to navigate and to avoid collisions during their operation. A drone with these sensors is more likely to be safe, prevent equipment damage, and avoid harming people or objects around it. Following are some obstacle avoidance sensors can be used in Ardupilot based spraying drones:
RADAR and LiDAR can be used for collision avoidance or as an altimeter. To use these kind of sensors Ardupilot required the basic parameter settings which I have explained it briefly. I took an example of two sensors to explain and for the better understanding of the readers. Our RND engineer Mr. Aniket Avati took successful field test using these sensors.
I). LiDAR (Light Detection and Ranging) sensors use laser beams to measure distances. TF02-PRO
Above mentioned diagram give brief about the connection of TF02 Pro to Ardupilot Boards. But to set the parameter user will have to use the ground control station. Here I will explain it using indigenous made in India ground control station that is AeroGCS KEA
Configurations Through AeroGCS KEA:
1. RNGFND1_TYPE = 27 (TF02-Pro) (Need to reboot the flight controller after setting the parameter)
2. RNGFND1_MIN_CM = 25 (Minimum distance in centimeters that rangefinder can reliably read)
3. RNGFND1_MAX_CM = 1200 (Maximum distance in centimeters that rangefinder can reliably read) (This value is to be set 10 to 15% less than the sensor’s range. Also please test this parameter in outdoor environment)
4. RNGFND1_GNDCLEAR = 10 (More accurately the distance in centimeters from the range finder to the ground when the vehicle is landed. This value depends on how you have mounted the rangefinder)
5. RNGFND1_ORIENT = 25 (Defines the orientation of rangefinder)
6. TERRAIN_ENABLE = 0 (This parameter is to be set if sensor is placed downward facing. The sensor will act as terrain following sensor and plan should be given in terrain mode to follow the terrain).
Set the altitude mode to terrain from AeroGCS GREEN.
If Telem2 port is used then the serial parameters should be set to:
1. SERIAL2_PROTOCOL = 9 (Rangefinder)
2. SERIAL2_BAUD = 115 (Baud rate)
If GPS1 port is used then the serial parameters should be set to:
1. SERIAL3_PROTOCOL = 9 (Rangefinder)
2. SERIAL3_BAUD = 115 (Baud rate)
Note: Please reboot the vehicle/flight controller after setting all the parameters.
Please check the output of sensor in AeroGCS GREEN on flight view window.
II). RADAR, Radar technology is indeed used in many drones for collision avoidance and navigation purposes. Radar stands for “radio detection and ranging,” and it uses radio waves to detect objects and measure their distance, speed, and direction. In the context of drones, radar systems can help detect obstacles, including other aircraft, buildings, trees, or any other objects that may pose a collision risk. Here I will explain the connectionas and configurations using MR72.
Here configuration settings will different for Automatic mode and Manual mode as explained below.
A) Configurations Through AeroGCS KEA For Manual Mode:
1. PRX1_TYPE = 6 (TeraRangerEvoPro) (Need to reboot the flight controller after setting the parameter)
2. SERIAL2_BAUD = 115 (Baud rate)
3. SERIAL2_PROTOCOL = 11 (Lidar360) (Set this parameter if sensor is connected in telem2 port)
4. AVOID_ANGLE_MAX = 10
5. AVOID_BEHAVE = 1 (0:Slide 1:Stop) (Avoidance behavior)
6. AVOID_DIST_MAX = 10m (Distance from object at which obstacle avoidance will begin)
7. AVOID_ENABLE = 2 (Use Proximity Sensor)
8. AVOID_MARGIN = 5m (Vehicle will attempt to stay at least this distance (in meters) from objects)
B) Configurations Through AeroGCS KEA For Auto Mode:
1. PRX1_TYPE = 6 (TeraRangerEvoPro) (Need to reboot the flight controller after setting the parameter)
2. SERIAL2_BAUD = 115 (Baud rate)
3. SERIAL2_PROTOCOL = 11 (Lidar360) (Set this parameter if sensor is connected in telem2 port)
4. OA_TYPE = 1 (Bendyruler) (Need to reboot the flight controller after setting the parameter)
5. OA_BR_LOOKAHEAD = 5m typical (It is the distance (in meters) ahead of the vehicle that should be probed)
6. OA_MARGIN_MAX = 2–3m typical (the distance (in meters) that the vehicle should stay away from obstacles)
Note: Please reboot the vehicle/flight controller after setting all the parameters.
III) Conclusion: Ardupilot provides a robust and flexible framework for configuring the RADAR and LiDAR sensors. Ardupilot based Spraying drones can be configure in plug and play mode using AeroGCS KEA and AeroGCS GREEN.
