Definition
Functional Requirements
Syntax
Semantics
Conformance Testing
Performance Assessment
1 Definition
Motor States define the set of operational and fault‑related conditions that a Motor may report to the Motion Actuation Subsystem (MAS). They describe the real, physical and control‑level behaviour of traction and drive motors used for propulsion and, where applicable, regenerative braking. These states enable the MAS to interpret torque delivery, detect degradation or faults, coordinate traction control, and enforce safety‑critical reactions such as derating or emergency stop.
2 Functional Requirements
Motor States shall enable the CAV’s Motion Actuation Subsystem (MAS) to:
- Interpret the motor’s current operational condition, including inactive, transient, active, and limited‑output behaviour.
- Distinguish between commanded inactivity (Idle, Offline) and active torque production (Active, Starting, Stopping).
- Identify traction loss conditions to support stability, ESC, and traction control coordination.
- Monitor derating conditions due to thermal, voltage, or current constraints.
- Detect controller saturation where requested torque or speed cannot be met.
- Detect and react to electrical, thermal, sensor, and communication faults.
- Support calibration and commissioning workflows.
- Identify emergency stop behaviour triggered by safety logic or external emergency controls.
- Provide sufficient semantic detail to trigger safe fallback behaviour, limp‑home modes, or controlled stops.
3 Syntax
https://schemas.mpai.community/CAV2/V1.1/data/MotorStates.json
4 Semantics
Motor States is a string enumeration. Table 1 gives the set of valid values and their descriptions.
| Normal | Nominal operation; motor is within all electrical, thermal, and control limits and meeting requested setpoints. |
| LossOfTraction | Motor/wheel is spinning with insufficient tractive force; slip or loss of grip detected by control logic. |
| Idle | Motor enabled and available but producing negligible torque or velocity. |
| Active | Motor actively producing commanded torque, velocity, or position. |
| Starting | Transient state while ramping from idle or standstill to active operation. |
| Stopping | Transient state while ramping down torque or speed toward idle or stop. |
| DeratedThermal | Motor output is intentionally limited due to temperature thresholds being approached or exceeded. |
| DeratedVoltage | Motor output is limited due to DC bus or supply voltage constraints. |
| DeratedCurrent | Motor output is limited to enforce current limits or protect power electronics. |
| Saturated | Motor controller has reached its output limit and cannot increase torque or speed to meet the requested setpoint. |
| OvertemperatureFault | Fault triggered due to exceeding motor or inverter thermal protection thresholds. |
| OvercurrentFault | Fault triggered due to exceeding current protection limits. |
| UndervoltageFault | Fault triggered due to DC bus or supply voltage falling below safe operating levels. |
| SensorFault | Fault in encoder, resolver, temperature, current, or similar sensing components. |
| CommunicationFault | Loss, timeout, or corruption of communication with the motor controller or drive. |
| Calibration | Motor is undergoing calibration or zeroing procedures; output may be constrained or unavailable. |
| Offline | Motor or controller is powered down, not initialised, or administratively disabled. |
| EmergencyStop | Emergency stop engaged; torque generation is forcibly disabled by safety logic. |
5 Conformance Testing
A Data instance conforms with Motor States (CAV‑MTS) if:
- The Data validates against the Motor States’ JSON Schema.
- The value is one of the strings defined in the Motor States enumeration.
6 Performance Assessment
Not part of this specification.
