1       Functions 2       Reference Model 3       I/O Data
4       Functions of AI Modules 5       I/O Data of AI Modules 6      AUW, AIMs, and JSON
7       Reference Software 8       Conformance Testing 9     Performance Assessment

1        Functions of Motion Actuation Subsystem

The Motion Actuation Subsystem (MAS):

  1. Transmits spatial and environmental information gathered from its sensors and mechanical subsystems to the Environment Sensing Subsystem (ESS).
  2. Receives AMS-MAS Message from the Autonomous Motion Subsystem (AMS).
  3. Translates AMS-MAS Message into specific Commands to its own mechanical subsystems, e.g., Brakes, Steering, and Motors.
  4. Receives Responses from its mechanical subsystems.
  5. Packages Responses into MAS-AMS Messages.
  6. Sends AMS-MAS Messages to Autonomous Motion Subsystem, possibly containing an updated Road State.

2        Reference Architecture of Motion Actuation Subsystem

Figure 1 represents the Motion Actuation Subsystem Reference Model.

Figure 1 – Motion Actuation Subsystem Reference Model

The operation of the Motion Actuation Subsystem unfolds as follows:

  1. “Other Environment Data” are transferred to the ESS.
  2. MAS Spatial Attitude Generation computes the Ego CAV Spatial Attitude Attitude using Spatial Data (Odometer, Speedometer, and Accelerometer) Data and sends it to the ESS.
  3. AMS Command Interpretation interprets AMS-MAS Messages received from AMS and issues commands to Motors, Wheel, and Brakes.
  4. MAS Response Analysis interprets the responses received from Motors, Wheel, and Brakes and sends AMS-MAS Messages to to AMS.

3        I/O Data of Motion Actuation Subsystem

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

Table 1 – I/O data of Motion Actuation Subsystem

Input Comments
Spatial Data Provides distance data.
Weather Data Data such as humidity, pressure, temperat­ure.
AMS-MAS Message High-level motion command.
Motor Response Forces wheel rotation, Motor gives gives feedback.
Wheel Response Moves wheel by an angle, Wheel gives feedback.
Brake Response Acts on brake, Brake gives feedback.
Output Comments
Spatial Attitude Position, Orientation and their velocity and acceleration vectors.
Weather Data Data such as humidity, pressure, temperat­ure, and ice.
Motor Command Forces wheels rotation, gives feedback.
Wheel Command Moves wheels by an angle, gives feedback.
Brake Command Acts on brakes, gives feedback.
AMS-MAS Message Feedback from MAS Response Analysis during and after AMS-MAS Message ex­ecution.

4        Functions of Motion Actuation Subsystem’s AI Modules

Table 2 gives the AI Modules of Autonomous Motion Subsystem.

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

AIM Function
Spatial Attitude Generation Computes Ego CAV’s Spatial Attitude using odometer, speedometer, and accelerometer data.
AMS Command Interpretation Receives, analyses, and actuates AMS-MAS Message into specific commands to Brakes, Steering Wheels, and Wheel Motors.
MAS Response Analysis Receives and analyses responses from Brakes, Steering Wheel, and Wheel Motors.
Assembles and forwards the MAS-AMS Response to AMS.
Ice Condition Analysis Adds ice condition information to input Weather Data.

5        I/O Data of Motion Actuation Subsystem’s AI Modules

Table 3 gives, for each AIM (1st column), the input data (2nd column) from which AIM (column) and the output data (3rd column).

Table 3 – I/O Data of Motion Actuation Subsystem’s AI Modules

AIM Input Output
Spatial Attitude Generation Spatial Data Spatial Attitude
AMS Command Interpretation AMS-MAS Message Brake Command
Motor Command
Wheel Command
MAS Response Analysis Brake Response
Motor Response
Wheel Response
AMS-MAS Message
Ice Condition Analysis Brake Response
Motor Response
Wheel Response
Weather Data
Weather Data

6     AIW, AIMs, and JSON

AIW AIMs  AIM Names JSON
CAV-MAS Motion Actuation Subsystem X
  CAV-MSG Spatial Attitude Generation X
  CAV-ACI AMS Command Interpretation X
  CAV-MRA MAS Response Analysis X
  CAV-ICA Ice Condition Analysis X

7     Reference Software

 

8      Conformance Testing

 

9     Performance Assessment