1       Functions 2       Reference Model 3       I/O Data
4       Functions of AI Modules 5       I/O Data of AI Modules 6       AIW, AIMs, and JSON
7       AI Modules 8       Data Types

1        Functions

The functions of the Autonomous Motion Subsystem (AMS) are:

  1. Receive a request to reach a destination from the Human-CAV Interaction Subsystem  (HCI).
  2. Request current Pose to Environment Sensing Subsystem (ESS).
  3. Converse with HCI and settle on final Route.
  4. Respond/request to specific Remote AMS requests.
  5. Produce Full Environment Representation.
  6. Generate Paths (Plath Planner).
  7. Generate Goal and Trajectory (Motion Planner).
  8. Check whether Trajectory can be implemented (Obstacle Avoider).
  9. Issue Command to Motion Actuation Subsystem.
  10. Process Message from Motion Actuation Subsystem (MAS).
  11. If required, AMS Command Issuer forwards information back to the chain’s AIM.

2        Reference Model

Figure 1 gives the Autonomous Motion Subsystem Reference Model.

 

Figure 1 – Autonomous Motion Subsystem Reference Model

The operation of the Autonomous Motion Subsystem unfolds as follows:

  1. A human requests the Human-CAV Interaction to take them to a destination.
  2. HCI interprets request and passes interpretation to the AMS.
  3. The AMS activates the Route Planner to generate a set of Waypoints starting from the current Pose (obtained from the ESS) up to the destination.
  4. The Waypoints enter the Path Planner which generates a set of Poses to reach the next Waypoint.
  5. For each Path, the Motion Planner generates a Trajectory to reach the next Pose.
  6. Obstacle Avoider receives the Trajectory and checks if an Alert was received.
  7. If an Alert was received, Obstacle Avoider detects whether the Trajectory created a collision.
    1. If a collision is detected, Obstacle Avoider requests a new Trajectory from Motion Planner.
    2. If no collision is detected, Obstacle Avoider issues an AMS-MAS Message to MAS.
  8. The MAS sends MAS-AMS Message about the execution of the Command.
  9. The AMS, based on the MAS-AMS Messages received conveying Environment information, may discontinue the execution of the earlier MS-MAS Message and issue a new AMS-MAS Message.
  10. The decision of each element of the said chain may be recorded in the Decision Recorder (“black box”).

3        I/O Data

Table 1 gives the input/output data of Autonomous Motion Subsystem.

Table 1 – I/O data of Autonomous Motion Subsystem

Input data From Comment
Basic Environment Descriptors Environment Sensing Subsystem CAV’s Environment representation.
Alert Environment Sensing Subsystem Critical information from an EST in ESS.
HCI-AMS Message Human-CAV Interaction Human commands, e.g., “take me home”
Environment Descriptors Remote AMSs Other CAVs and vehicles, and roadside units.
MAS-AMS Message Motion Actuation Subsystem Message sent by the AMS to the MAS.
Remote-Ego AMS Message Remote AMS Remote AMS to Ego AMS message
Output data To Comment
AMS-HCI Message Human-CAV Interaction AMS’s message to HCI-AMS.
AMS-MAS Message Motion Actuation Subsystem Message to MAS, e.g., “in 5s assume a given Spatial Attitude”.
Environment Descriptors Remote AMSs For information to other CAVs
Ego-Remote AMS Message Remote AMSs Ego AMS to Remote AMS message

4        Functions of AI Modules

Table 2 gives the AI Modules of the Autonomous Motion Subsystem.

Table 2 – Functions of Autonomous Motion Subsystem’s AI Modules

AIM Function
Full Environment Description Creates an internal representation of the Environment by fusing infor­mation from itself, Remote AMSs, and other CAV-aware entities.
Route Selection Planner Computes a set of possible Routes, through a road network, from the current to the target destination.
Path Selection Planner Generates a set of Paths, considering:

1.      Route.
2.      Spatial Attitude.
3.      Full Environment Representation.
4.      Traffic Rules.
Motion Selection Planner Defines a Trajectory to reach a Goal using the Spatial Attitude:

1.      Satisfying the CAV’s kinematic and dynamic constraints
2.      Considering passengers’ comfort.
Traffic Obstacle Avoider Checks whether Trajectory is compatible with Alert information:

  1. If it is, it passes the Trajectory to the Command Issuer.
  2. If it is not, it requests a new Trajectory.

If AMS Command Issuer informs Obstacle Avoider that AMS-MAS Message cannot be implemented, Traffic Obstacle Avoider may issue a “discontinue previous Command” and forward the Road State to the appropriate upstream AIM, possibly up to the Route Planner. This may decide to communicate the Road State to the Human-CAV Interaction Subsystem.
AMS Command Issuer Instructs the MAS to execute the Trajectory considering the Environment conditions and receives MAS-AMS Messages about the execution. Based on a Message, the Road State may be communicated to the Obstacle Avoider.
AMS Decision Recorder Records decisions by Route Planner, Path Planner, Motion Planner, Obstacle Avoider, and Command Issuer.

5        I/O Data of AI Modules

Table 3 gives, for each AIM (1st column), the input data (2nd column) and the output data (3rd column) of Autonomous Motion Subsystem.

Table 3 – Autonomous Motion Subsystem’s data

AIM Input Output
Full Environment Description – Basic Environment Descriptors
– Other data from Remote AMSs		 – Full Environment Descriptors
Route Selection Planner – Poses
– Full Environment Descriptors
– Offline Map Data
– Road State
– Selected Route		 – Route
Path Selection Planner – Route
– Full Environment Descriptors
– Offline Maps
– Road State		 – Set of Paths
Motion Selection Planner – Set of Paths
– Full Environment Descriptors
– Road State		 – Trajectory
Traffic Obstacle Avoider – Trajectory
– Full Environment Descriptors
– Alert
– Road State		 – Trajectory
AMS Command Issuer – Trajectory
– MAS-AMS Message		 – AMS-MAS Message
AMS Decision Recorder – Route
– Path
– Trajectory
– AMS-MAS Message
– MAS-AMS Message		 – File of Recorded Data

6     AIW, AIMs, and JSON Metadata

7       AI Modules

Initial versions of AIMs are available.

8       Data Types

Initial versions of  Data Types are available.