Improved the rx frame rate detection/training by delaying calculation to avoid loop time jitter during flight controller initialization.
For auto cutoffs calculate a value appropriate for BIQUAD or PT1 depending on the configuration.
Added a new rc_smoothing_info cli command to display internal details about its operation.
Adds options to select the filter type for both input and derivative.
rc_smoothing_input_type = PT1 | BIQUAD (default is BIQUAD)
rc_smoothing_derivative_type = OFF | PT1 | BIQUAD (default is OFF)
Adds an additional rc channel smoothing algorithm that can be used in place of the default rc interpolation. Utilizing a filter-based approach the smoothing has lower latency and is immune to loop time jitter that can introduce artifacts. Additionally a smoothing filter is added to the setpoint derivative used to produce D-term setpoint weight resulting in a smoother effect on D.
The default setting is to use the previous interpolation logic and there are no changes unless the optional method is selected.
Configuration:
rc_smoothing_type: (INTERPOLATION | FILTER) - defaults to INTERPOLATION
rc_smoothing_input_hz: (0-255) - sets the rc channel input filter cutoff in Hz. Default value of 0 will enable auto calculation based on received RX frame rate.
rc_smoothing_derivative_hz: (0-255) - sets the setpoint weight derivative filter cutoff in Hz. Default value of 0 will enable auto calculation based on received RX frame rate.
rc_smoothing_debug_axis: (ROLL | PITCH | YAW | THROTTLE) - determines which axis is logged in the debug fields
Debug logging:
set debug_mode = RC_SMOOTHING
debug(0) = raw un-smoothed rc channel data
debug(1) = raw un-smoothed setpoint derivative
debug(2) = filtered setpoint derivative before applied to setpoint weight
debug(3) = auto-calculated filter cutoff frequency base after sampling the rx frame rate
Notes:
Currently only enabled for F4/F7 due to flash size limitations
Uses the rc_inter_ch parameter to determine which channels are smoothed (same as default interpolation logic)
The auto filter cutoff calculation will set a cutoff frequency of 30Hz for typical SBUS frames (9ms). 11ms Spektrum will calculate to approximately 25Hz. The user can manually enter the filter cutoffs to be used instead of the auto calculation. The current default calculation was chosen as a good starting point but may be adjusted in the future.
Setting a lower cutoff frequency will result in more smoothing, but also more delay.
There currently isn't any support for receivers that change their rx frame rate dynamically. So for CRSF users wishing to use this alternate smoothing method should change their settings to lock the rx frame rate for now. Support for auto-adjusting to new frame rates in flight will likely be added.
Updates for finalize the flight performance.
Disable if GPS Rescue is active
Constrain the max setpoint calculated by the angle correction logic. To catch border cases where the user activates the feature while inverted and has a high gain which could result in excessively high setpoint rates.
Make sure internal states are reset when feature is activated via mode switch.
Adds a new angle limiting mode for pilots who are learning to fly in acro mode. Primarily targeted at new LOS acro pilots, but can be used with FPV as well.
The feature is activated with a new mode named "ACRO TRAINER". When the feature is active, the craft will fly in normal acro mode but will limit roll/pitch axes so that they don't exceed the configured angle limit. New pilots can start with a small angle limit and progressively increase as their skills improve.
The accelerometer must be enabled for the feature to be configured and function.
Also the feature will only be active while in acro flight and will disable if ANGLE or HORIZON modes are selected.
For most users all they need to do is simply configure the new mode to be active as desired on the "Modes" tab in the configurator and configure the desired angle limit in the cli.
Configuration parameters:
acro_trainer_angle_limit: (range 10-80) Angle limit in degrees.
acro_trainer_lookahead_ms: (range 10-200) Time in milliseconds that the logic will "look ahead" to help minimize overshoot and bounce-back if the limit is approached at high gyro rates. The default value of 50 should be good for most users. For low powered or unresponsive craft (micros or brushed) it may be helpful to increase this setting if you're seeing substantial overshoot.
acro_trainer_debug_axis: (ROLL, PITCH) The axis that will log information if debugging is active.
To enable debugging:
set debug_mode = ACRO_TRAINER
debug(0) - Current angle
debug(1) - The internal logic state
debug(2) - Modified setpoint
debug(3) - Projected angle based gyro rate and lookahead period
* through extensive testing prior to the beginning of the RC cycle, we have
discovered that the simplest combination of filters appears to be up to four
PT1 filters: two for gyro, and two for d-term.
* non-cascaded biquad filter plumbing is retained for noisy setups and the
dynamic notch bandpass, although gyro and d-term variants of the filtering may
eventually be removed in favor of pt1
* update all related unit tests
