Go to CAV-TEC V1.1 Data Types

Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment

1    Definition

Wheel States is a Data Type enumerating the operational states of a wheel steering actuator of the Connected Autonomous Vehicle.

2    Functional Requirements

Wheel States shall represent the following actuator states:

  1. Normal – steering actuator operating normally and following commands within expected tolerance.
  2. Hold – actuator holding the wheel at its current angle.
  3. ActiveSteering – actuator actively controlling the wheel angle in response to commands.
  4. Released – wheel released with minimal assistive torque applied.
  5. Stuck – wheel cannot move as commanded; mechanical or servo obstruction.
  6. MechanicalStopReached – wheel angle reached mechanical end-stop; no further movement allowed.
  7. Overheated – actuator temperature exceeds rated thermal limits; performance derated.
  8. Degraded – reduced operational capability due to subsystem constraints or partial fault.
  9. Fault – general actuator or sensor fault requiring inspection or fallback mode.
  10. Unavailable – steering actuator unavailable (offline, in maintenance, or non-responsive).
  11. Calibration – actuator performing calibration or alignment procedures.
  12. SelfTest – actuator performing startup or periodic diagnostics.
  13. DeratedThermal – thermal derating active due to excessive actuator temperature.
  14. DeratedLoad – derating active due to high mechanical or steering rack load.
  15. SensorFault – fault detected in wheel angle, encoder, or feedback sensors.
  16. CommunicationFault – communication between steering controller and actuator is impaired.
  17. LowPower – insufficient power supply to support nominal steering behavior.
  18. EmergencyOverride – emergency logic temporarily overrides actuator control for safety.

3    Syntax

https://schemas.mpai.community/CAV2/V1.1/data/WheelStates.json

4    Semantics

Table 1 – Semantics of the Wheel States Data Type

Value Description
Normal Steering actuator operating normally and following commands within expected tolerance.
Hold Actuator holding the wheel at its current angle (e.g., hill-hold stabilisation).
ActiveSteering Actuator actively controlling the wheel angle in response to commands.
Released Wheel released with minimal assistive torque applied.
Stuck Wheel cannot move as commanded; mechanical or servo obstruction.
MechanicalStopReached Wheel angle reached mechanical end-stop; no further movement allowed.
Overheated Actuator temperature exceeds rated thermal limits; performance derated.
Degraded Reduced operational capability due to subsystem constraints or partial fault.
Fault General actuator or sensor fault requiring inspection or fallback mode.
Unavailable Steering actuator unavailable (offline, in maintenance, or non-responsive).
Calibration Actuator performing calibration or alignment procedures.
SelfTest Actuator performing startup or periodic diagnostics.
DeratedThermal Thermal derating active due to excessive actuator temperature.
DeratedLoad Derating active due to high mechanical or steering rack load.
SensorFault Fault detected in wheel angle, encoder, or feedback sensors.
CommunicationFault Communication between steering controller and actuator is impaired.
LowPower Insufficient power supply to support nominal steering behavior.
EmergencyOverride Emergency logic temporarily overrides actuator control for safety.

5    Conformance Testing

A Data instance conforms with Wheel States (CAV-WHS) if:

  1. The Data validates against the Wheel States JSON Schema.
  2. All Data in the Wheel States JSON Schema:
    1. Have the specified type.
    2. Validate against their JSON Schemas.
    3. Conform with their Data Qualifiers.

6    Performance Assessment

Not part of this specification.

Go to CAV-TEC V1.1 Data Types