VTOL PMU DroneCAN application

Developers docs: DroneCAN template application.

1. BRIEF HARDWARE INFO

View	STM32CubeMX	Pinout
		pinout

2. APPLICATION DESCRIPTION AND DESIGN

The PMU node does 3 things:

1. Battery. This module estimates the battery info based on ADC voltage and current measurements and publishes BatteryInfo message.
2. Gate monitor. This module estimates the internal state of the PMU based on ADC voltage of gates. It publishes the LogMessage and set CRITICAL state once an error is detected.
3. Buzzer. This module notifies with sound if the internal state of the board is bad. If the internal state is fine, it repeats the BeepCommand from an autopilot.

From the software side, the high level node design can be illustrated with the following UML diagramm:

More details about each module:

2.1. Battery

The battery module sends BatteryInfo message with 1 Hz rate.

Here:

• voltage and current are measured values,
• full_charge_capacity_wh, battery_id, model_instance_id are configured via parameters,
• average_power_10_sec, remaining_capacity_wh,state_of_charge_pct are calculated based on the above values.

2.2. Gate monitor checks the gates

If at least one gate is broken, it starts to notify with LogMessage each 10 seconds until the node is rebooted. The LogMessage has a number of broken gates.

The node ignores all broken states first 5 seconds to prevent false positive failures.

DMA Rank	Periphery	Pin	Meaning	Note
1	ADC_IN2	PA2	ADC_GATE_2	If voltage < 1.4 V, so it is broken.
3	ADC_IN4	PA4	ADC_GATE_3	If voltage < 1.4 V, so it is broken.
4	ADC_IN6	PA6	ADC_GATE_4	If voltage < 1.4 V, so it is broken.

2.3. Buzzer

The buzzer notifies with sound about dead gates.

3. PARAMETERS

Here is a list of parameters.

More details you can find in the parameters auto-generated documentation Src/dronecan_application/README.md.

4. TEST CASES

1. TestBatteryInfo
   • TC1. Publish rate must be 1 Hz (plus minus 50 ms is acceptable)
   • TC2. Votlage should be within [4.5, 60.0] Volts
   • TC3. Set a random value between [0, 100] battery.soc_pct, so msg.state_of_charge_pct should be the same
   • TC4. The same for battery.battery_id
   • TC5. The same for battery.model_instance_id
   • TC6. Similar for pair battery.capacity_mah and battery.full_voltage, but check msg.full_charge_capacity_wh value according to a formula
   • TC7. We should also check msg.remaining_capacity_wh. Well, it seems to be we should check it manually.
2. TestBuzzer
   • I don't know how to automatically test it...
3. TestGateMonitor
   • TC1. Test good gate Reboot the node. Set gate.threshold to 4095 (that means gates are always ok). Wait for 15 seconds. Debug message should not appear. The NodeStatus should have good health.
   • TC2. Test bad gates Reboot the node. Set gate.threshold to 0 (that means gates are always bad). Verify, that the node publish LogMessage with 0.1 Hz rate (burst publishing are not allowed, first 5 second node publish nothing) The NodeStatus should have CRITICAL health.

5. CONNECTION

SWD connector Upload a firmware	JST GH 4 pin connector CAN-bus bench test

6. NOTES

Current ADC

1. Accuracy

ADC_RESOLUTION = 12 bit
ADC_RAW_MAX = 4095
MAX_CURRENT = 200 A
CURRENT_SENSETIVITY = 146.5 mA

2. Frequency

MCU_FREQUENCY = 72 000 000
ADC_FREQUENCY = 12 000 000
NUMBER_OF_CONVERSION = 7
SAMPLING_TIME = 55.5 Cycles
THEORY_GROUP_FREQUENCY = 30 888 Measurements/sec
ACTUATL_GROUP_FREQUENCY = 22 175 Measurements/sec