path: root/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c

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/**
 * @file fw_pos_control_l1_params.c
 *
 * Parameters defined by the L1 position control task
 *
 * @author Lorenz Meier <lm@inf.ethz.ch>
 */

#include <nuttx/config.h>
#include <systemlib/param/param.h>

/*
 * Controller parameters, accessible via MAVLink
 */

/**
 * L1 period
 *
 * This is the L1 distance and defines the tracking
 * point ahead of the aircraft its following.
 * A value of 25 meters works for most aircraft. Shorten
 * slowly during tuning until response is sharp without oscillation.
 *
 * @min 1.0
 * @max 100.0
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_L1_PERIOD, 25.0f);

/**
 * L1 damping
 *
 * Damping factor for L1 control.
 *
 * @min 0.6
 * @max 0.9
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_L1_DAMPING, 0.75f);

/**
 * Default Loiter Radius
 *
 * This radius is used when no other loiter radius is set.
 *
 * @min 10.0
 * @max 100.0
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_LOITER_R, 50.0f);

/**
 * Cruise throttle
 *
 * This is the throttle setting required to achieve the desired cruise speed. Most airframes have a value of 0.5-0.7.
 *
 * @min 0.0
 * @max 1.0
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_THR_CRUISE, 0.7f);

/**
 * Negative pitch limit
 *
 * The minimum negative pitch the controller will output.
 *
 * @unit degrees
 * @min -60.0
 * @max 0.0
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_P_LIM_MIN, -45.0f);

/**
 * Positive pitch limit
 *
 * The maximum positive pitch the controller will output.
 *
 * @unit degrees
 * @min 0.0
 * @max 60.0
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_P_LIM_MAX, 45.0f);

/**
 * Controller roll limit
 *
 * The maximum roll the controller will output.
 *
 * @unit degrees
 * @min 0.0
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_R_LIM, 45.0f);

/**
 * Throttle limit max
 *
 * This is the maximum throttle % that can be used by the controller. 
 * For overpowered aircraft, this should be reduced to a value that 
 * provides sufficient thrust to climb at the maximum pitch angle PTCH_MAX.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_THR_MAX, 1.0f);

/**
 * Throttle limit min
 *
 * This is the minimum throttle % that can be used by the controller. 
 * For electric aircraft this will normally be set to zero, but can be set 
 * to a small non-zero value if a folding prop is fitted to prevent the 
 * prop from folding and unfolding repeatedly in-flight or to provide 
 * some aerodynamic drag from a turning prop to improve the descent rate.
 *
 * For aircraft with internal combustion engine this parameter should be set
 * for desired idle rpm.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_THR_MIN, 0.0f);

/**
 * Throttle limit value before flare
 *
 * This throttle value will be set as throttle limit at FW_LND_TLALT, 
 * before arcraft will flare.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_THR_LND_MAX, 1.0f);

/**
 * Maximum climb rate
 *
 * This is the best climb rate that the aircraft can achieve with 
 * the throttle set to THR_MAX and the airspeed set to the 
 * default value. For electric aircraft make sure this number can be 
 * achieved towards the end of flight when the battery voltage has reduced. 
 * The setting of this parameter can be checked by commanding a positive 
 * altitude change of 100m in loiter, RTL or guided mode. If the throttle 
 * required to climb is close to THR_MAX and the aircraft is maintaining 
 * airspeed, then this parameter is set correctly. If the airspeed starts 
 * to reduce, then the parameter is set to high, and if the throttle 
 * demand required to climb and maintain speed is noticeably less than 
 * FW_THR_MAX, then either FW_T_CLMB_MAX should be increased or 
 * FW_THR_MAX reduced.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_CLMB_MAX, 5.0f);

/**
 * Minimum descent rate
 *
 * This is the sink rate of the aircraft with the throttle 
 * set to THR_MIN and flown at the same airspeed as used 
 * to measure FW_T_CLMB_MAX.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_SINK_MIN, 2.0f);

/**
 * Maximum descent rate
 *
 * This sets the maximum descent rate that the controller will use. 
 * If this value is too large, the aircraft can over-speed on descent. 
 * This should be set to a value that can be achieved without 
 * exceeding the lower pitch angle limit and without over-speeding 
 * the aircraft.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_SINK_MAX, 5.0f);

/**
 * TECS time constant
 *
 * This is the time constant of the TECS control algorithm (in seconds). 
 * Smaller values make it faster to respond, larger values make it slower
 * to respond.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_TIME_CONST, 5.0f);

/**
 * Throttle damping factor
 *
 * This is the damping gain for the throttle demand loop. 
 * Increase to add damping to correct for oscillations in speed and height.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_THR_DAMP, 0.5f);

/**
 * Integrator gain
 *
 * This is the integrator gain on the control loop. 
 * Increasing this gain increases the speed at which speed 
 * and height offsets are trimmed out, but reduces damping and 
 * increases overshoot.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_INTEG_GAIN, 0.1f);

/**
 * Maximum vertical acceleration
 *
 * This is the maximum vertical acceleration (in metres/second square)
 * either up or down that the controller will use to correct speed 
 * or height errors. The default value of 7 m/s/s (equivalent to +- 0.7 g) 
 * allows for reasonably aggressive pitch changes if required to recover 
 * from under-speed conditions.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_VERT_ACC, 7.0f);

/**
 * Complementary filter "omega" parameter for height
 *
 * This is the cross-over frequency (in radians/second) of the complementary 
 * filter used to fuse vertical acceleration and barometric height to obtain 
 * an estimate of height rate and height. Increasing this frequency weights 
 * the solution more towards use of the barometer, whilst reducing it weights 
 * the solution more towards use of the accelerometer data.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_HGT_OMEGA, 3.0f);

/**
 * Complementary filter "omega" parameter for speed
 *
 * This is the cross-over frequency (in radians/second) of the complementary 
 * filter used to fuse longitudinal acceleration and airspeed to obtain an 
 * improved airspeed estimate. Increasing this frequency weights the solution
 * more towards use of the arispeed sensor, whilst reducing it weights the 
 * solution more towards use of the accelerometer data.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_SPD_OMEGA, 2.0f);

/**
 * Roll -> Throttle feedforward
 *
 * Increasing this gain turn increases the amount of throttle that will 
 * be used to compensate for the additional drag created by turning. 
 * Ideally this should be set to  approximately 10 x the extra sink rate 
 * in m/s created by a 45 degree bank turn. Increase this gain if 
 * the aircraft initially loses energy in turns and reduce if the 
 * aircraft initially gains energy in turns. Efficient high aspect-ratio 
 * aircraft (eg powered sailplanes) can use a lower value, whereas 
 * inefficient low aspect-ratio models (eg delta wings) can use a higher value.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_RLL2THR, 10.0f);

/**
 * Speed <--> Altitude priority
 *
 * This parameter adjusts the amount of weighting that the pitch control 
 * applies to speed vs height errors. Setting it to 0.0 will cause the 
 * pitch control to control height and ignore speed errors. This will 
 * normally improve height accuracy but give larger airspeed errors. 
 * Setting it to 2.0 will cause the pitch control loop to control speed 
 * and ignore height errors. This will normally reduce airspeed errors, 
 * but give larger height errors. The default value of 1.0 allows the pitch 
 * control to simultaneously control height and speed. 
 * Note to Glider Pilots - set this parameter to 2.0 (The glider will 
 * adjust its pitch angle to maintain airspeed, ignoring changes in height).
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_SPDWEIGHT, 1.0f);

/**
 * Pitch damping factor
 *
 * This is the damping gain for the pitch demand loop. Increase to add 
 * damping to correct for oscillations in height. The default value of 0.0 
 * will work well provided the pitch to servo controller has been tuned 
 * properly.
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_PTCH_DAMP, 0.0f);

/**
 * Height rate P factor
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_HRATE_P, 0.05f);

/**
 * Speed rate P factor
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_T_SRATE_P, 0.05f);

/**
 * Landing slope angle
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_LND_ANG, 5.0f);

/**
 *
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_LND_HVIRT, 10.0f);

/**
 * Landing flare altitude (relative)
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_LND_FLALT, 15.0f);

/**
 * Landing throttle limit altitude (relative)
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_LND_TLALT, 5.0f);

/**
 * Landing heading hold horizontal distance
 *
 * @group L1 Control
 */
PARAM_DEFINE_FLOAT(FW_LND_HHDIST, 15.0f);