actuators[ ] array of structs with pprz units and driver units

[dewagter]

In simulation / NPS, we would like to simulate all actuators. The actuators[ ] array can not be used because it has different units: e.g. PWM 1100 - 1900.

With the new system of sending actuators to different actuator drivers, the conversion to actuator_driver units is best done when sending to the actuator_driver.

• this means the separate copy of actuators_pprz is not needed.
• this allows to simulate actuators directly and remove dependencies on control allocation.

[gautierhattenberger]

The issue with this (actuators in pprz_t) is that the actuators message is now also in pprz_t. So if you need to read the actuators position to adjust the trim (which should be in "driver" unit), you will have a good chance to make errors doing the conversion or just forgetting to convert it to the correct scale.
An actuator structure could hold the two values, that could be used with proper format when needed...

[dewagter]

Agreed

[dewagter]

Changed to actuator struct. If you have naming recommendations let me know.

This should allow us to simulate actuators directly now in nps_autopilot_rotorcraft.c ->
nps_autopilot.commands[i] = (double)actuators[i].pprz_val / MAX_PPRZ;

I didn't change it yet because the actuator indexes often do not match and requires some harmonization (see #3203)

[EwoudSmeur]

Great development!

[dewagter]

Sample generatle airframe.h

#define Set_AIL_LEFT_Servo(actuator_value_pprz) { \
  actuators[SERVO_AIL_LEFT_IDX].pprz_val = ClipAbs( actuator_value_pprz, MAX_PPRZ); \
  command_value = actuator_value_pprz * (actuator_value_pprz>0 ? SERVO_AIL_LEFT_TRAVEL_UP_NUM : SERVO_AIL_LEFT_TRAVEL_DOWN_NUM); \
  command_value /= actuator_value_pprz>0 ? SERVO_AIL_LEFT_TRAVEL_UP_DEN : SERVO_AIL_LEFT_TRAVEL_DOWN_DEN; \
  servo_value = SERVO_AIL_LEFT_NEUTRAL + command_value; \
  actuators[SERVO_AIL_LEFT_IDX].driver_val = Clip(servo_value, SERVO_AIL_LEFT_MIN, SERVO_AIL_LEFT_MAX); \
  ActuatorUavcan2CmdSet(SERVO_AIL_LEFT_DRIVER_NO, actuators[SERVO_AIL_LEFT_IDX].driver_val); \
}

[dewagter]

The issue with this (actuators in pprz_t) is that the actuators message is now also in pprz_t. So if you need to read the actuators position to adjust the trim (which should be in "driver" unit), you will have a good chance to make errors doing the conversion or just forgetting to convert it to the correct scale. An actuator structure could hold the two values, that could be used with proper format when needed...

This is now sent in driver_val.

[Fabien-B]

Hi @dewagter, following this PR, I have this error when building the CobraV2 aircraft from ENAC/conf_enac.xml.
Can you look into it please ?

In file included from modules/switching/switch_servo.h:27,
from modules/switching/switch_servo.c:22:
modules/switching/switch_servo.c: In function 'switch_servo_periodic':
/home/fabien/paparazzi/var/aircrafts/CobraV2/ap/generated/airframe.h:162:3: error: 'command_value' undeclared (first use in this function)
162 | command_value = actuator_value_pprz * (actuator_value_pprz>0 ? SERVO_SWITCH_TRAVEL_UP_NUM : SERVO_SWITCH_TRAVEL_DOWN_NUM); \
| ^~~~~~~~~~~~~

[dewagter]

Should be solved in #3280 ...
if someone accepts it, you can merge