Mirrors_Framework/PX4-Autopilot
1
0
Fork 0
mirror of https://github.com/PX4/PX4-Autopilot.git synced 2025-12-07 18:59:29 +08:00
Code Issues Actions 5 Packages Projects Releases Wiki Activity

Collision mode only works with mpc_pos_mode that is acceleration based

Browse Source
This commit is contained in:
Hamish Willee
2025-06-18 16:19:21 +10:00
parent f35b92a487
commit ef252481a8
1 changed files with 5 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
docs/en/computer_vision/collision_prevention.md
View File

@@ -3,7 +3,7 @@
_Collision Prevention_ may be used to automatically slow and stop a vehicle before it can crash into an obstacle.
It can be enabled for multicopter vehicles when using acceleration-based [Position mode](../flight_modes_mc/position.md) (or VTOL vehicles in MC mode).
It can be enabled for multicopter vehicles in [Position mode](../flight_modes_mc/position.md), and can use sensor data from an offboard companion computer, offboard rangefinders over MAVLink, a rangefinder attached to the flight controller, or any combination of the above.
It can be enabled for multicopter vehicles in [Position mode](../flight_modes_mc/position.md) (with [MPC_POS_MODE](#MPC_POS_MODE) set to `Acceleration based`), and can use sensor data from an offboard companion computer, offboard rangefinders over MAVLink, a rangefinder attached to the flight controller, or any combination of the above.
Collision prevention may restrict vehicle maximum speed if the sensor range isn't large enough!
It also prevents motion in directions where no sensor data is available (i.e. if you have no rear-sensor data, you will not be able to fly backwards).
@@ -26,15 +26,14 @@ Users are notified through _QGroundControl_ while _Collision Prevention_ is acti
PX4 software setup is covered in the next section.
If you are using a distance sensor attached to your flight controller for collision prevention, it will need to be attached and configured as described in [PX4 Distance Sensor](#rangefinder).
If you are using a companion computer to provide obstacle information see [companion setup](#companion
If you are using a companion computer to provide obstacle information see [companion setup](#companion) below.
## Supported Rangefinders {#rangefinder}
## Supported Rangefinders {#rangefinder}
### Lanbao PSK-CM8JL65-CC5 [Discontinued]
At time of writing PX4 allows you to use the [Lanbao PSK-CM8JL65-CC5](../sensor/cm8jl65_ir_distance_sensor.md) IR distance sensor for collision prevention “out of the box”, with minimal additional configuration:
- First [attach and configure the sensor](../sensor/cm8jl65_ir_distance_sensor.md), and enable collision prevention (as described above, using [CP_DIST](#CP_DIST)).
- Set the sensor orientation using [SENS_CM8JL65_R_0](../advanced_config/parameter_reference.md#SENS_CM8JL65_R_0).
@@ -51,7 +50,6 @@ Other sensors may be enabled, but this requires modification of driver code to s
This should be done by mimicking the `SENS_CM8JL65_R_0` parameter (though you might also hard-code the orientation in the sensor _module.yaml_ file to something like `sf0x start -d ${SERIAL_DEV} -R 25` - where 25 is equivalent to `ROTATION_DOWNWARD_FACING`).
- Modify the driver to set the _field of view_ in the distance sensor UORB topic (`distance_sensor_s.h_fov`).
## PX4 (Software) Setup
Configure collision prevention by [setting the following parameters](../advanced_config/parameters.md) in _QGroundControl_:
@@ -62,7 +60,7 @@ Configure collision prevention by [setting the following parameters](../advanced
| <a id="CP_DELAY"></a>[CP_DELAY](../advanced_config/parameter_reference.md#CP_DELAY) | Set the sensor and velocity setpoint tracking delay. See [Delay Tuning](#delay_tuning) below. |
| <a id="CP_GUIDE_ANG"></a>[CP_GUIDE_ANG](../advanced_config/parameter_reference.md#CP_GUIDE_ANG) | Set the angle (to both sides of the commanded direction) within which the vehicle may deviate if it finds fewer obstacles in that direction. See [Guidance Tuning](#angle_change_tuning) below. |
| <a id="CP_GO_NO_DATA"></a>[CP_GO_NO_DATA](../advanced_config/parameter_reference.md#CP_GO_NO_DATA) | Set to 1 to allow the vehicle to move in directions where there is no sensor coverage (default is 0/`False`). |
| <a id="MPC_POS_MODE"></a>[MPC_POS_MODE](../advanced_config/parameter_reference.md#MPC_POS_MODE) | Set to `Direct velocity` or `Smoothed velocity` to enable Collision Prevention in Position Mode (default is `Acceleration based`). |
| <a id="MPC_POS_MODE"></a>[MPC_POS_MODE](../advanced_config/parameter_reference.md#MPC_POS_MODE) | Must be set to `Acceleration based`. |
## Algorithm Description
@@ -131,7 +129,6 @@ The guidance feature will never direct the vehicle in a direction without sensor
If the vehicle feels stuck with only a single distance sensor pointing forwards, this is probably because the guidance cannot safely adapt the direction due to lack of information.
:::
## Algorithm Description
The data from all sensors are fused into an internal representation of 72 sectors around the vehicle, each containing either the sensor data and information about when it was last observed, or an indication that no data for the sector was available.
@@ -212,7 +209,7 @@ The steps are:
type: px4_msgs::msg::ObstacleDistance
```
For more information see [DDS Topics YAML](../middleware/uxrce_dds.md#dds-topics-yaml) in [uXRCE-DDS](../middleware/uxrce_dds.md) (PX4-ROS 2/DDS Bridge)_.
For more information see [DDS Topics YAML](../middleware/uxrce_dds.md#dds-topics-yaml) in [uXRCE-DDS](../middleware/uxrce_dds.md) (PX4-ROS 2/DDS Bridge)\_.
3. Open PlotJuggler and navigate to the **Tools > Reactive Script Editor** section.
In the **Script Editor** tab, add following scripts in the appropriate sections: