ardupilot/ArduCopter/surface_tracking.cpp

91 lines
3.5 KiB
C++

#include "Copter.h"
// adjust_climb_rate - hold copter at the desired distance above the
// ground; returns climb rate (in cm/s) which should be passed to
// the position controller
float Copter::SurfaceTracking::adjust_climb_rate(float target_rate)
{
#if RANGEFINDER_ENABLED == ENABLED
if (!copter.rangefinder_alt_ok()) {
// if rangefinder is not ok, do not use surface tracking
return target_rate;
}
const float current_alt = copter.inertial_nav.get_altitude();
const float current_alt_target = copter.pos_control->get_alt_target();
float distance_error;
float velocity_correction;
uint32_t now = millis();
valid_for_logging = true;
// reset target altitude if this controller has just been engaged
if (now - last_update_ms > SURFACE_TRACKING_TIMEOUT_MS) {
target_alt_cm = copter.rangefinder_state.alt_cm + current_alt_target - current_alt;
}
last_update_ms = now;
// adjust rangefinder target alt if motors have not hit their limits
if ((target_rate<0 && !copter.motors->limit.throttle_lower) || (target_rate>0 && !copter.motors->limit.throttle_upper)) {
target_alt_cm += target_rate * copter.G_Dt;
}
/*
handle rangefinder glitches. When we get a rangefinder reading
more than RANGEFINDER_GLITCH_ALT_CM different from the current
rangefinder reading then we consider it a glitch and reject
until we get RANGEFINDER_GLITCH_NUM_SAMPLES samples in a
row. When that happens we reset the target altitude to the new
reading
*/
int32_t glitch_cm = copter.rangefinder_state.alt_cm - target_alt_cm;
if (glitch_cm >= RANGEFINDER_GLITCH_ALT_CM) {
copter.rangefinder_state.glitch_count = MAX(copter.rangefinder_state.glitch_count+1,1);
} else if (glitch_cm <= -RANGEFINDER_GLITCH_ALT_CM) {
copter.rangefinder_state.glitch_count = MIN(copter.rangefinder_state.glitch_count-1,-1);
} else {
copter.rangefinder_state.glitch_count = 0;
}
if (abs(copter.rangefinder_state.glitch_count) >= RANGEFINDER_GLITCH_NUM_SAMPLES) {
// shift to the new rangefinder reading
target_alt_cm = copter.rangefinder_state.alt_cm;
copter.rangefinder_state.glitch_count = 0;
}
if (copter.rangefinder_state.glitch_count != 0) {
// we are currently glitching, just use the target rate
return target_rate;
}
// calc desired velocity correction from target rangefinder alt vs actual rangefinder alt (remove the error already passed to Altitude controller to avoid oscillations)
distance_error = (target_alt_cm - copter.rangefinder_state.alt_cm) - (current_alt_target - current_alt);
velocity_correction = distance_error * copter.g.rangefinder_gain;
velocity_correction = constrain_float(velocity_correction, -SURFACE_TRACKING_VELZ_MAX, SURFACE_TRACKING_VELZ_MAX);
// return combined pilot climb rate + rate to correct rangefinder alt error
return (target_rate + velocity_correction);
#else
return target_rate;
#endif
}
// get surfacing tracking alt
// returns true if there is a valid target
bool Copter::SurfaceTracking::get_target_alt_cm(float &_target_alt_cm) const
{
// check target has been updated recently
if (AP_HAL::millis() - last_update_ms > SURFACE_TRACKING_TIMEOUT_MS) {
return false;
}
_target_alt_cm = target_alt_cm;
return true;
}
// set surface tracking target altitude
void Copter::SurfaceTracking::set_target_alt_cm(float _target_alt_cm)
{
target_alt_cm = _target_alt_cm;
last_update_ms = AP_HAL::millis();
}