Add motor mixing library and demo #81
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libs/motor_control/mixer/mixer.h
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| typedef struct { | ||
| ESC_Inst_Type motor_arr[MAX_MOTOR_INSTANCES]; | ||
| uint8_t motor_instances; |
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I don't see a check that the number of motor matches the expected configuration anywhere. Perhaps we could add a motor config as a discriminated union to the init function and avoid the headaches like this.
libs/motor_control/mixer/mixer.c
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| // TODO: Add checks here for edge-cases like R=P=0 and Y>T | ||
| switch (mixer->uav_config) { | ||
| case MIXER_UAV_CFG_QUADROTOR_X: | ||
| m1 = limit_min_thrust_values(mixer_mapped.thrust - mixer_mapped.roll + |
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Local saturation is a problem, if it happens our thrust vector will be oriented wrongly. @nikolaptr can provide some more insight but I believe thrust should be (dynamically?) capped so that no motor is saturated and we always have control of the vector direction. That way we lose power but gain controlability.
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I understand the issue here, thanks for pointing this. I think that @nikolaptr mentioned somewhere that this issue could be solved statically, and that it could be simpler solution.
@nikolaptr Can you point me to some materials or prior implementations related to this issue so I can be sure I approach this correctly?
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I implemented some solution for saturation based on the way Ardupilot does it. Please check it out @DNedic
libs/motor_control/mixer/mixer.c
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| int32_t min_receiver_val, max_receiver_val, neutral_receiver_val; | ||
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| #ifdef CONFIG_MIXER_MINIMAL_RECEIVER_DATA_OFFSET | ||
| min_receiver_val = CONFIG_MIXER_MINIMAL_RECEIVER_DATA_VALUE; |
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AFAIK zephyr will ALWAYS define numerical CONFIG_s
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That makes sense, thanks a lot!
- Changed input type from int32_t raw SBUS to normalized floats - Thrust: 0.0-1.0, Roll/Pitch/Yaw: -1.0 to 1.0 - Implemented matrix-based motor mixing using factor coefficients - Single mixing algorithm works for all frame types - Easy to add new configurations (hex, octo, etc.) - Added proper output normalization to handle saturation - Maintains control ratios when limits are exceeded - Improved initialization: MIXER_Init() must be called before MIXER_AddMotor() - Updated demos to use new float-based API with SBUS normalization - Removed receiver value normalization from mixer (belongs in input layer)
This PR adds motor mixing library for quadcopters and demo that showcases the usage of the library.