Plane follow lua applet #30654
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Plane follow lua applet #30654
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IamPete1
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tridge
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libraries/AP_Follow/AP_Follow.h
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| //========================================================================== | ||
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| uint32_t _last_location_update_ms; // Time of last target position update (ms) | ||
| uint64_t _last_location_update_us; // Time of last target position update (ms) |
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I'd make this uint64_t _last_location_update_ms;
libraries/AP_Follow/AP_Follow.cpp
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| } | ||
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| // apply jitter-corrected timestamp to this update unless the update is older than the most recently received message or FOLL_TIMEOUT seconds | ||
| uint64_t location_update_us = _jitter.correct_offboard_timestamp_usec((uint64_t)packet.time_boot_ms * 1000, AP_HAL::micros()); |
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uint64_t location_update_ms = uint64_div1000(_jitter.correct_offboard_timestamp_usec((uint64_t)packet.time_boot_ms * 1000, AP_HAL::micros()));
libraries/AP_Follow/AP_Follow.cpp
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| // apply jitter-corrected timestamp to this update unless the update is older than the most recently received message or FOLL_TIMEOUT seconds | ||
| uint64_t location_update_us = _jitter.correct_offboard_timestamp_usec((uint64_t)packet.time_boot_ms * 1000, AP_HAL::micros()); | ||
| if (location_update_us < _last_location_update_us || (location_update_us - _last_location_update_us) > _timeout.cast_to_float() * 1000000 ) { |
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I would do something like:
float tdelta = int32_t(location_update_ms - _last_location_update_ms) * 0.001;
if (tdelta < 0 && tdelta > -10) {
xxx;
}
libraries/AP_Follow/AP_Follow.cpp
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| /// Altitude comes in AMSL | ||
| _target_location.set_alt_cm(packet.alt * 0.1, Location::AltFrame::ABSOLUTE); | ||
| // convert the incoming altitude to terrain altitude | ||
| _target_location.change_alt_frame(Location::AltFrame::ABOVE_TERRAIN); |
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what happens if this fails?
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This creates a new Lua Script applet that implements "plane follow" - a fixed wing follow/chase functionality that runs in guided mode. The code uses the core AP_Follow library functionality and therefore uses most of the documented FOLL_ parameters that are used in Copter and Rover FOLLOW mode.
The kinematic extrapolation improvements made by @lthall significantly improved the quality and smoothness of the follow.
I've made one small enhancement to make the follow Altitude sensitive as this was required by the partner who I worked with through this process. If FOLL_ALT_TYPE = 3:terrain then the follow altitude will be terrain relative. There is also a scripted FOLLP_OVR_ALT that forces the follow vehicle to use a specific altitude overriding the altitude it receives from the lead plane and the follow library.
I've also included a Lua module that is used by the script but might also be useful to others.
pid.lua - A PID controller extracted/generalized from plane_aerobatics