/dvs/git/dirty/gitlab-master_av/dw/sdk/samples/safetyforcefield/README.md

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# Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.

@page dwx_safetyforcefield_sample Safety Force Field Sample
@tableofcontents

@note SW Release Applicability: This sample is available in **NVIDIA DRIVE Software** releases.

@section dwx_safetyforcefield_description Description

The Safety Force Field sample checks whether a desired control (i.e., a choice of steering angle and longitudinal acceleration)
is safe when all actors (ego-vehicle and other obstacles) execute a safety procedure. Safety is with respect to the obstacles in a given
obstacle array, or egomotion/vehicleIO state. If the control is deemed unsafe, it is corrected to a safe one.

In this sample, only the ego-vehicle executes a corrected control. Other vehicles do not apply any control correction.
A lane graph can optionally be specified and will make the safety procedure line up parallel to the given lane.

@section dwx_safetyforcefield_running Running the Sample

The command line for the sample is:

    ./sample_safetyforcefield --testcase=[0|1]
                              --useRoadStructure=[0|1]
                              --expandClaimedSets=[0|1]

where

    --testcase=[0|1]
        Specifies a predefined synthetic scenario.
        Scenario 0 has an ego-vehicle with two other vehicles that are cutting in the ego-vehicle's driving direction.
        Scenario 1 has an ego-vehicle following another slow vehicle.
        Default value: 0
    --useRoadStructure=[0|1]
        1 for safety procedure to line up with a road
        Default value: 0
    --expandClaimedSets=[0|1]
        1 for claimed sets to expand by possible reaction time uncertainty
        Default value: 0

@subsection dwx_safetyforcefield_examples Examples

#### Running the sample with default arguments

    ./sample_safetyforcefield

#### Running the sample using a expanding claimed set that lines up with the road structure

    ./sample_safetyforcefield --useRoadStructure=1 --expandClaimedSets=1

@section dwx_safetyforcefield_output Output

The output is composed of two images:
- The left image is a top down view of the claimed sets, i.e., the likely trajectories of the actors executing their safety procedures.
- The right image is a control constraint image of the ego-vehicle.

In the top down view of claimed sets:

- The ego-vehicle's claimed set is magenta.
- Other vehicles claimed sets are cyan.
- Rendering hovers over the ego-vehicle, where the claimed set remains stationary.

In the control constraint image:

- The X-axis indicates the front wheel steering angle. Any pixel on the left half of the image has a positive steering angle.
On the X-axis there is one gray marking per degree.
- The Y-axis indicates acceleration. Any pixel on the top half of the image has positive acceleration.
On the Y-axis there is one gray marking per meter per second squared.
- The white unfilled box indicates the steering angle and acceleration limits.
- A green pixel indicates a safe control, which meets all control constraints.
- A red pixel indicates an unsafe control, which violates at least one of the control constraints.
- The black circle is the ego-vehicle's control before actuation.
- The blue circle is the ego-vehicle's control after actuation.
- The dark green circle is the initial control on the ego-vehicle's safety procedure.

![](safetyforcefield/sample_safetyforcefield.png)

@section dwx_safetyforcefield_more Additional Information

For more details, please refer to @ref safetyforcefield_mainsection.