关于$OpenCDA$

有关$OpenCDA$的内容请参考以下2篇博客：
1.　详解自动驾驶仿真框架OpenCDA；
2.　OpenCDA学习。

$OpenCDA$优势

1. $SUMO$和$Carla$这两个软件本身是比较成熟的，在各自的软件上不用担心；
2. 开源，$SUMO$开源，$Carla$开源，成本对企业很重要，花小钱办大事谁会拒绝，市场的商业软件太贵，$Prescan$、$Carmaker/Truckmaker$、$VTD$的价格对小公司来说价格太高了，做$HIL$更贵了，开源是趋势，$51simone$也宣布开源(部分开源，核心模块不开源)了；
3. 感知、规划和控制的仿真，规划被认为是最适合用来做仿真的模块，控制依赖车辆模型，感知依赖传感器，这些模拟的保真度相对难以把控，但是规划对他们的依赖相对较低，有地图定位还是可以做的；$SUMO$能提供交通流，符合规划的需求,很多工程师做强化学习就用它；
4. $Carla$已经打通和$Carsim$的数据流，这个架构具备可扩展性,规划和控制的仿真验证应该不成问题；
5. $OpenCDA$团队称希望能做$HIL$，还会继续开发。

$OpenCDA$缺点

1. 集成$Carla$的版本不是最新的，按文档里说得是$0.9.11$和$0.9.12$；
2. 车辆动力学部分，$Carla$本身不是最新，我还不清楚能不能集成$Carsim$版本（这一点确认了来更新）。

运行$OpenCDA$

1. 在一个终端下启动$Carla$模拟器

./carla/CARLA_0.9.11/CarlaUE4.sh

2. 在另一个终端下启动$OpenCDA$

conda activate opencda
cd ~/OpenCDA
python opencda.py -t single_2lanefree_carla -v 0.9.11

The logic flow of conducting a scenario test in $OpenCDA$

1. Define the yaml file

description: |-
  Copyright 2021 <UCLA Mobility Lab>
  Author: Runsheng Xu <rxx3386@ucla.edu>
  Content: This is the scenario testing configuration file for platooning joining and cooperative merge
           at the customized 2lanefree simple version.

# define carla simulation setting
world:
  sync_mode: true
  client_port: 2000
  fixed_delta_seconds: &delta 0.05
  seed: 25
  weather:
    sun_altitude_angle: 15 # 90 is the midday and -90 is the midnight
    cloudiness: 0 # 0 is the clean sky and 100 is the thickest cloud
    precipitation: 0 # rain, 100 is the heaviest rain
    precipitation_deposits: 0 # Determines the creation of puddles. Values range from 0 to 100, being 0 none at all and 100 a road completely capped with water.
    wind_intensity: 0 # it will influence the rain
    fog_density: 0 # fog thickness, 100 is the largest
    fog_distance: 0  # Fog start distance. Values range from 0 to infinite.
    fog_falloff: 0 # Density of the fog (as in specific mass) from 0 to infinity. The bigger the value, the more dense and heavy it will be, and the fog will reach smaller heights
    wetness: 0


# First define the basic parameters of the vehicles
vehicle_base: &vehicle_base
  sensing: &base_sensing
    perception: &base_perception
      activate: false # when not activated, objects positions will be retrieved from server directly
      camera_visualize: 0 # how many camera images need to be visualized. 0 means no visualization for camera
      camera_num: 0 # how many cameras are mounted on the vehicle. Maximum 3(frontal, left and right cameras)
      lidar_visualize: false # whether to visualize lidar points using open3d
      lidar: # lidar sensor configuration, check CARLA sensor reference for more details
        channels: 32
        range: 50
        points_per_second: 100000
        rotation_frequency: 20 # the simulation is 20 fps
        upper_fov: 10.0
        lower_fov: -30.0
        dropoff_general_rate: 0.0
        dropoff_intensity_limit: 1.0
        dropoff_zero_intensity: 0.0
        noise_stddev: 0.0
    localization: &base_localize
      activate: true # when not activated, ego position will be retrieved from server directly
      dt: *delta # used for kalman filter
      gnss: # gnss sensor configuration
        noise_alt_stddev: 0.005
        noise_lat_stddev: 2e-6
        noise_lon_stddev: 2e-6
        heading_direction_stddev: 0.1 # degree
        speed_stddev: 0.2
      debug_helper: &loc_debug_helper
        show_animation: false # whether to show real-time trajectory plotting
        x_scale: 10.0 # used to multiply with the x coordinate to make the error on x axis clearer
        y_scale: 10.0 # used to multiply with the y coordinate to make the error on y axis clearer
  behavior: &base_behavior
    max_speed: 95 # maximum speed, km/h
    tailgate_speed: 105 # when a vehicles needs to be close to another vehicle asap
    speed_lim_dist: 3 # max_speed - speed_lim_dist = target speed
    speed_decrease: 15 # used in car following mode to decrease speed for distance keeping
    safety_time: 4 # ttc safety thresholding for decreasing speed
    emergency_param: 0.4 # used to identify whether a emergency stop needed
    ignore_traffic_light: true # whether to ignore traffic light
    overtake_allowed: false # whether overtake allowed, typically false for platoon leader
    collision_time_ahead: 1.3 # used for collision checking
    sample_resolution: 4.5 # the unit distance between two adjacent waypoints in meter
    overtake_counter_recover: 35 # the vehicle can not do another overtake during next certain steps
    local_planner: &base_local_planner # trajectory planning related
      buffer_size: 12 # waypoint buffer size
      trajectory_update_freq: 15 # used to control trajectory points updating frequency
      waypoint_update_freq: 9 # used to control waypoint updating frequency
      min_dist: 3 # used to pop out the waypoints too close to current location
      trajectory_dt: 0.25 # for every dt seconds, we sample a trajectory point from the trajectory path as next goal state
      debug: false # whether to draw future/history waypoints
      debug_trajectory: false # whether to draw the trajectory points and path

  controller: &base_controller
    type: pid_controller # this has to be exactly the same name as the controller py file
    args: &control_args
      lat:
        k_p: 0.75
        k_d: 0.02
        k_i: 0.4
      lon:
        k_p: 0.37
        k_d: 0.024
        k_i: 0.032
      dynamic: false # whether use dynamic pid setting
      dt: *delta # this should be equal to your simulation time-step
      max_brake: 1.0
      max_throttle: 1.0
      max_steering: 0.3

  v2x: &base_v2x # comminuation related
    enabled: true
    communication_range: 35
    loc_noise: 0.0
    yaw_noise: 0.0
    speed_noise: 0.0
    lag: 0

# define the platoon basic characteristics
platoon_base: &platoon_base
  max_capacity: 10
  inter_gap: 0.6 # desired time gap
  open_gap: 1.5 # open gap
  warm_up_speed: 55 # required speed before cooperative merging

# define the background traffic control by carla
carla_traffic_manager:
  sync_mode: true # has to be same as the world setting
  global_distance: 4.0 # the minimum distance in meters that vehicles have to keep with the rest
  # Sets the difference the vehicle's intended speed and its current speed limit.
  #  Carla default speed is 30 km/h, so -100 represents 60 km/h,
  # and 20 represents 24 km/h
  global_speed_perc: -300
  set_osm_mode: true # Enables or disables the OSM mode.
  auto_lane_change: false
  random: false # whether to random select vehicles' color and model
  vehicle_list:
    - spawn_position: [-285, 8.3, 0.3, 0, 0, 0]
    - spawn_position: [-310, 8.3, 0.3, 0, 0, 0]
    - spawn_position: [-390, 8.3, 0.3, 0, 0, 0]
    - spawn_position: [-320, 4.8, 0.3, 0, 0, 0]
      vehicle_speed_perc: -200
    - spawn_position: [-335, 4.8, 0.3, 0, 0, 0]
    - spawn_position: [-360, 4.8, 0.3, 0, 0, 0]
    - spawn_position: [-400, 4.8, 0.3, 0, 0, 0]
    - spawn_position: [-410, 4.8, 0.3, 0, 0, 0]

# define scenario. In this scenario, a 4-vehicle platoon already exists.
scenario:
  platoon_list:
    - <<: *platoon_base
      destination: [1000.372955, 8.3, 0.3]
      members: # the first one is regarded as leader by default
        - <<: *vehicle_base
          spawn_position: [-350, 8.3, 0.3, 0, 0, 0] # x, y, z, roll, yaw, pitch
          sensing:
            <<: *base_sensing
            perception:
              <<: *base_perception
              activate: false
              camera_visualize: 1
              camera_num: 1
              lidar_visualize: true
          platoon: # we need to add platoon specific params
            <<: *platoon_base
          behavior:
            <<: *base_behavior
            local_planner:
              <<: *base_local_planner
              debug_trajectory: true
              debug: false
        - <<: *vehicle_base
          spawn_position: [-360, 8.3, 0.3, 0, 0, 0]
          platoon: # we need to add platoon specific params
            <<: *platoon_base
          controller:
            <<: *base_controller
            args:
              <<: *control_args
              max_throttle: 1.0
        - <<: *vehicle_base
          spawn_position: [-370, 8.3, 0.3, 0, 0, 0]
          platoon: # we need to add platoon specific params
            <<: *platoon_base
            args:
              <<: *control_args
              max_throttle: 1.0
        - <<: *vehicle_base
          spawn_position: [-380, 8.3, 0.3, 0, 0, 0]
          platoon: # we need to add platoon specific params
            <<: *platoon_base
            args:
              <<: *control_args
              max_throttle: 1.0
  single_cav_list: # this is for merging vehicle or single cav without v2x
    - <<: *vehicle_base
      spawn_position: [-380, 4.8, 0.3, 0, 0, 0]
      # when this is defined, the above parameter will be ignored, and a special map function will
      # be used to define the spawn position based on the argument
      spawn_special: [0.625]
      destination: [300, 12.0, 0]
      sensing:
        <<: *base_sensing
        perception:
          <<: *base_perception
          activate: false
          camera_visualize: 1
          camera_num: 1
          lidar_visualize: true
        localization:
          <<: *base_localize
          debug_helper:
            <<: *loc_debug_helper
      v2x:
        <<: *base_v2x
        communication_range: 35
      platoon: # we need to add platoon specific params
        <<: *platoon_base
      behavior:
        <<: *base_behavior
        overtake_allowed: true
        local_planner:
          <<: *base_local_planner
          debug_trajectory: true
          debug: false

2. Construct scenario (Co-Simulation)／Construct scenario (CARLA only)
3. Execute a single step
4. Keep the simulation loop running
5. Evaluation