Plane: added systemID as an aux function #29237
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allows for systemID to reduce XY gains in pos controlled modes
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I'm struggling to understand why this is called "System ID". It doesn't seem to have anything to do with identifying the system - which is what we have SYSID_THISMAV for no? |
"system identification" is a control systems term that refers to characterising the dynamics of a system (a vehicle in this case). In copter it is a flight mode called SYSTEMID flight mode. |
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| // @DisplayName: System identification axis | ||
| // @Description: Controls which axis are being excited. Set to non-zero to see more parameters | ||
| // @User: Standard | ||
| // @Values: 0:None, 1:Input Roll Angle, 2:Input Pitch Angle, 3:Input Yaw Angle, 4:Recovery Roll Angle, 5:Recovery Pitch Angle, 6:Recovery Yaw Angle, 7:Rate Roll, 8:Rate Pitch, 9:Rate Yaw, 10:Mixer Roll, 11:Mixer Pitch, 12:Mixer Yaw, 13:Mixer Thrust, 14:Measured Lateral Position, 15:Measured Longitudinal Position, 16:Measured Lateral Velocity, 17:Measured Longitudinal Velocity, 18:Input Lateral Velocity, 19:Input Longitudinal Velocity |
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Should add "VTOL" to these, would be good to support in FW flight in the future.
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I was planning to re-use the same axes (where relevant, can't do lateral vel and pos).
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remove values 14-19. I did not implement them in my version of sysid. it doesn't look like you did either. Lets keep it to the attitude controller. We can expand to the position controller later.
| gcs().send_text(MAV_SEVERITY_WARNING, "SystemID: must be armed"); | ||
| return; | ||
| } | ||
| if (!plane.quadplane.enabled()) { |
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This case should be handled by plane.control_mode->supports_systemid()
I'm aware of this problem hence bringing it up. I've found it helps to provide some way to differentiate overloaded terms. Could the new (user facing) name be something like "Dynamic System Identification" or "System Model Identification" or DSMI (Dynamic System Model Identification)? |
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| auto *attitude_control = plane.quadplane.attitude_control; | ||
| attitude_control->bf_feedforward(restore.att_bf_feedforward); | ||
| attitude_control->rate_bf_roll_sysid(0); |
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Setting these to zero is not necessary. These are set to zero in the attitude controller at the end of every loop.
https://github.com/ArduPilot/ardupilot/blob/master/ArduPlane/quadplane.cpp#L1948
| // @Field: Az: Delta velocity, Z-Axis | ||
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| // log system id | ||
| void AP_SystemID::log_data() const |
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I see you removed the logging of RATE and ANG from this function. It is imperative that these all be logged at the same rate. Why don't you use the same technique as copter to allow logging at multiples of the fast loop rate. this is important to allow users to choose an appropriate rate for their use case.
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It is imperative that these all be logged at the same rate.
unlike copter, the default setup in plane is to log all these at the full loop rate, so they are all logged at the same rate. We could force the LOG_BITMASK in case a user has changed that, or we could just document that the defaults should be used.
Why don't you use the same technique as copter to allow logging at multiples of the fast loop rate. this is important to allow users to choose an appropriate rate for their use case.
it would be good to discuss why this is needed. Is it to make logs smaller? The sysid runs for a short time (usually) and the extra complexity to support down sampling didn't seem worthwhile, but let's discuss when you have a chance
enable as an AUX switch
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This adds VTOL systemID as an AUX function to quadplanes. It works in QSTABILIZE, QHOVER and QLOITER modes.
In QLOITER it multiplies the XY position and velocity gains by SID_XY_CTRL_MUL to reduce the impact of the XY controller on the systemID result
The AP_SystemID class is structured in a way to make it fairly easy to move this to a common library in the future if copter wants to adopt the same approach