Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment
1 Definition
Wheel Command is a Data Type representing a steering command directed to a specific wheel of the Connected Autonomous Vehicle, including the desired angle, steering mode, rate limits, control profile, safety limits, and health awareness information.
2 Functional Requirements
A Wheel Command instance shall include:
- The identifier of the wheel being commanded.
- The desired steering angle.
A Wheel Command instance may include:
- The steering mode.
- The maximum allowed steering rate.
- A multi-phase steering control profile.
- Safety limits including maximum torque, current, and mechanical stop warning.
- Health awareness information including thermal derating, load estimate, and calibration status.
3 Syntax
https://schemas.mpai.community/CAV2/V1.1/data/WheelCommand.json
4 Semantics
| Label | Description |
| Header | Wheel Command Header – Standard “CAV-WHC-Vx.y”. |
| MInstanceID | Identifier of the M-Instance (Virtual Space) associated with this Wheel Command instance. |
| UEnvironmentID | Identifier of the U-Environment (Real Space) associated with this Wheel Command instance. |
| WheelCommandID | Unique identifier of this Wheel Command instance. |
| WheelID | Identifier of the wheel being commanded. |
| WheelCommandTime | Time this Wheel Command instance was produced. |
| WheelCommand | Set of steering command parameters. |
| – Angle | Desired steering angle in degrees (–90 to +90). |
| – SteeringMode | Steering mode: one of ManualAssist, SteerByWire, ActiveSteering, EmergencyOverride, Calibration. |
| – SteeringRateLimit | Maximum allowed steering rate in degrees per second. |
| – ControlProfile | Optional multi-phase steering envelope. |
| – Phase | Phase of the steering envelope: one of ramp-up, hold, ramp-down. |
| – Duration | Phase duration in seconds. |
| – Angle | Target steering angle for this phase in degrees. |
| – SteeringRate | Steering rate for this phase in degrees per second. |
| – SafetyLimits | Safety constraints for the steering actuator. |
| – MaxTorque | Maximum allowed actuator torque. |
| – MaxCurrent | Maximum allowed actuator current. |
| – MechanicalStopWarning | Indicates proximity to the mechanical steering stop. |
| – HealthAwareness | Health and condition information of the steering actuator. |
| – ThermalDerating | Indicates whether thermal derating is active. |
| – LoadEstimate | Estimated load on the steering actuator. |
| – CalibrationRequired | Indicates whether calibration of the steering actuator is required. |
| DataXMData | MPAI-PTF Data Exchange Metadata providing provenance, authorisation, legal, security, and confidence information associated with this Wheel Command instance in a trusted data exchange context. |
| DescrMetadata | Human-readable descriptive metadata of the Wheel Command instance (plain text, max 2048 characters). |
5 Conformance Testing
A Data instance conforms with Wheel Command (CAV-WHC) if:
- The Data validates against the Wheel Command JSON Schema.
- All Data in the Wheel Command JSON Schema:
- Have the specified type.
- Validate against their JSON Schemas.
- Conform with their Data Qualifiers.
6 Performance Assessment
Not part of this specification.
