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Copter: restructure hybrid into more states

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Randy Mackay 2014-04-11 17:16:40 +09:00
parent f467d7bc20
commit e48c93d93c
1 changed files with 413 additions and 274 deletions
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687
ArduCopter/control_hybrid.pde
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@ -5,52 +5,68 @@
* hybrid tries to improve upon regular loiter by mixing the pilot input with the loiter controller
*/
#define HYBRID_SPEED_0 10 //
#define HYBRID_SPEED_0 10 // speed below which it is always safe to switch to loiter
#define HYBRID_LOITER_STAB_TIMER 300 // Must be higher than HYBRID_BRAKE_LOITER_MIX_TIMER (twice is a good deal) set it from 100 to 500, the number of centiseconds between loiter engage and getting wind_comp (once loiter stabilized)
#define HYBRID_BRAKE_LOITER_MIX_TIMER 150 // Number of cycles to transition from brake mode to loiter mode. Must be lower than HYBRID_LOITER_STAB_TIMER
#define HYBRID_LOITER_MAN_MIX_TIMER 50 // Set it from 100 to 200, the number of centiseconds loiter and manual commands are mixed to make a smooth transition.
#define HYBRID_SMOOTH_RATE_FACTOR 0.04f // controls the smoothness of the transition from ?? to ??. 0.04 = longer smoother transitions, 0.07 means faster transitions
#define HYBRID_BRAKE_TIME_ESTIMATE_MAX 600 // max number of cycles the brake will be applied before we switch to loiter
#define HYBRID_BRAKE_TO_LOITER_TIMER 150 // Number of cycles to transition from brake mode to loiter mode. Must be lower than HYBRID_LOITER_STAB_TIMER
#define HYBRID_LOITER_TO_PILOT_MIX_TIMER 50 // Set it from 100 to 200, the number of centiseconds loiter and manual commands are mixed to make a smooth transition.
#define HYBRID_SMOOTH_RATE_FACTOR 0.04f // filter applied to pilot's roll/pitch input as it returns to center. A lower number will cause the roll/pitch to return to zero more slowly if the brake_rate is also low.
#define HYBRID_STICK_RELEASE_SMOOTH_ANGLE 1800 // max angle required (in centi-degrees) after which the smooth stick release effect is applied
#define HYBRID_WIND_COMP_ESTIMATE_SPEED_MAX 10 // wind compensation estimates will only run when velocity is at or below this speed in cm/s
// declare some function to keep compiler happy
static void hybrid_update_pilot_lean_angle(int16_t &lean_angle_filtered, int16_t &lean_angle_raw);
static void hybrid_update_brake_angle_from_velocity(int16_t &brake_angle, float velocity);
static void hybrid_update_wind_comp_estimate();
static void hybrid_get_wind_comp_lean_angles(int16_t &roll_angle, int16_t &pitch_angle);
// mission state enumeration
enum hybrid_rp_mode {
HYBRID_PILOT_OVERRIDE=0,
HYBRID_BRAKE=1,
HYBRID_BRAKE_TO_LOITER=2,
HYBRID_LOITER=3,
HYBRID_LOITER_TO_PILOT_OVERRIDE=4
HYBRID_PILOT_OVERRIDE=0, // pilot is controlling this axis (i.e. roll or pitch)
HYBRID_BRAKE, // this axis is braking towards zero
HYBRID_BRAKE_READY_TO_LOITER, // this axis has completed braking and is ready to enter loiter mode (both modes must be this value before moving to next stage)
HYBRID_BRAKE_TO_LOITER, // both vehicle's axis (roll and pitch) are transitioning from braking to loiter mode (braking and loiter controls are mixed)
HYBRID_LOITER, // both vehicle axis are holding position
HYBRID_LOITER_TO_PILOT_OVERRIDE // pilot has input controls on this axis and this axis is transitioning to pilot override (other axis will transition to brake if no pilot input)
};
static struct {
hybrid_rp_mode roll_mode : 2; // roll mode: pilot override, brake or loiter
hybrid_rp_mode pitch_mode : 2; // pitch mode: pilot override, brake or loiter
uint8_t loiter_engaged : 1; // 1 if loiter target has been set and loiter controller is running
hybrid_rp_mode roll_mode : 3; // roll mode: pilot override, brake or loiter
hybrid_rp_mode pitch_mode : 3; // pitch mode: pilot override, brake or loiter
uint8_t braking_time_updated_roll : 1; // true once we have re-estimated the braking time. This is done once as the vehicle begins to flatten out after braking
uint8_t braking_time_updated_pitch : 1; // true once we have re-estimated the braking time. This is done once as the vehicle begins to flatten out after braking
// pilot input related variables
int16_t pilot_roll; // pilot requested roll angle (filtered to slow returns to zero)
int16_t pilot_pitch; // pilot requested roll angle (filtered to slow returns to zero)
// braking related variables
float brake_gain; // gain used during conversion of vehicle's velocity to lean angle during braking (calculated from brake_rate)
int16_t brake_roll; // target roll angle during braking periods
int16_t brake_pitch; // target pitch angle during braking periods
int16_t brake_timeout_roll; // number of cycles allowed for the braking to complete, this timeout will be updated at half-braking
int16_t brake_timeout_pitch; // number of cycles allowed for the braking to complete, this timeout will be updated at half-braking
int16_t brake_angle_max_roll; // maximum lean angle achieved during braking. Used to determine when the vehicle has begun to flatten out so that we can re-estimate the braking time
int16_t brake_angle_max_pitch; // maximum lean angle achieved during braking Used to determine when the vehicle has begun to flatten out so that we can re-estimate the braking time
int16_t brake_to_loiter_timer; // cycles to mix brake and loiter controls in HYBRID_BRAKE_TO_LOITER
// loiter related variables
int16_t loiter_to_pilot_timer_roll; // cycles to mix loiter and pilot controls in HYBRID_LOITER_TO_PILOT
int16_t loiter_to_pilot_timer_pitch; // cycles to mix loiter and pilot controls in HYBRID_LOITER_TO_PILOT
int16_t loiter_final_roll; // final roll angle from loiter controller as we exit loiter mode (used for mixing with pilot input)
int16_t loiter_final_pitch; // final pitch angle from loiter controller as we exit loiter mode (used for mixing with pilot input)
// wind compensation related variables
Vector2f wind_comp_ef; // wind compensation in earth frame, filtered lean angles from position controller
int16_t wind_comp_roll; // roll angle to compensate for wind
int16_t wind_comp_pitch; // pitch angle to compensate for wind
int8_t wind_comp_timer; // counter to reduce wind_offset calcs to 10hz
// final output
int16_t roll; // final roll angle sent to attitude controller
int16_t pitch; // final pitch angle sent to attitude controller
} hybrid;
// wind compensation related variables
static Vector2f wind_comp_ef; // wind compensation in earth frame, filtered lean angles from position controller
static int16_t wind_offset_roll, wind_offset_pitch; // wind offsets for pitch/roll
static int8_t wind_offset_timer; // counter to reduce wind_offset calcs to 10hz
static int16_t wind_comp_start_timer; // counter to delay start of wind compensation calcs until loiter has settled
// breaking related variables
static float brake_gain; // gain used during conversion of vehicle's velocity to lean angle during braking (calculated from brake_rate)
static int16_t brake_roll = 0, brake_pitch = 0; // target roll and pitch angles during both pilot-override and braking periods. Updated during pilot override to match pilot's input
static int16_t brake_timeout_roll, brake_timeout_pitch; // time in seconds allowed for the braking to complete, this timeout will be updated at half-braking
static int16_t brake_roll_max, brake_pitch_max; // used to detect half braking
static float brake_loiter_mix; // varies from 0 to 1, allows a smooth loiter engage
static bool brake_timeout_roll_updated, brake_timeout_pitch_updated; // Allow the timeout to be updated only once per braking.
// loiter related variables
static float loiter_man_mix; // varies from 0 to 1, allow a smooth loiter to manual transition
static int16_t loiter_man_timer;
static int16_t loiter_roll, loiter_pitch; // store pitch/roll at loiter exit
// hybrid_init - initialise hybrid controller
static bool hybrid_init(bool ignore_checks)
{
@ -68,46 +84,43 @@ static bool hybrid_init(bool ignore_checks)
// initialise altitude target to stopping point
pos_control.set_target_to_stopping_point_z();
// initialise lean angles to current attitude
hybrid.pilot_roll = 0;
hybrid.pilot_pitch = 0;
hybrid.roll = constrain_int16(ahrs.roll_sensor, -g.hybrid_brake_angle_max, g.hybrid_brake_angle_max);
hybrid.pitch = constrain_int16(ahrs.pitch_sensor, -g.hybrid_brake_angle_max, g.hybrid_brake_angle_max);
// compute brake_gain
brake_gain = (15.0f * (float)wp_nav._brake_rate + 95.0f) / 100.0f;
hybrid.brake_gain = (15.0f * (float)g.hybrid_brake_rate + 95.0f) / 100.0f;
if (ap.land_complete) {
// Loiter start
// if landed begin in loiter mode
hybrid.roll_mode = HYBRID_LOITER;
hybrid.pitch_mode = HYBRID_LOITER;
}else{
// Alt_hold like to avoid hard twitch if hybrid enabled in flight
// if not landed start in pilot override to avoid hard twitch
hybrid.roll_mode = HYBRID_PILOT_OVERRIDE;
hybrid.pitch_mode = HYBRID_PILOT_OVERRIDE;
}
// initialise wind_comp (ef) each time hybrid is switched on
wind_comp_ef.zero();
// initialise offset angles
wind_offset_roll = wind_offset_pitch = 0;
// initialise wind offset computation and loiter-stab transition timer
wind_offset_timer = 0;
loiter_stab_timer = HYBRID_LOITER_STAB_TIMER;
// initialise wind_comp each time hybrid is switched on
hybrid.wind_comp_ef.zero();
hybrid.wind_comp_roll = 0;
hybrid.wind_comp_pitch = 0;
hybrid.wind_comp_timer = 0;
return true;
}
// hybrid_exit - restore position controller
static void hybrid_exit()
{
pos_control.init_I = true; // restore reset I for normal behaviour
}
// hybrid_run - runs the hybrid controller
// should be called at 100hz or more
static void hybrid_run()
{
int16_t target_roll, target_pitch; // pilot's roll and pitch angle inputs
int16_t pilot_throttle_scaled = 0; // pilot's throttle input
float target_yaw_rate = 0; // pilot desired yaw rate in centi-degrees/sec
float target_climb_rate = 0; // pilot desired climb rate in centimeters/sec
float brake_to_loiter_mix; // mix of brake and loiter controls. 0 = fully brake controls, 1 = fully loiter controls
float loiter_to_pilot_mix; // mix of loiter and pilot controls. 0 = fully loiter controls, 1 = fully pilot controls
float vel_fw, vel_right; // vehicle's current velocity in body-frame forward and right directions
const Vector3f& vel = inertial_nav.get_velocity();
@ -154,240 +167,317 @@ static void hybrid_run()
vel_fw = vel.x*ahrs.cos_yaw() + vel.y*ahrs.sin_yaw();
vel_right = -vel.x*ahrs.sin_yaw() + vel.y*ahrs.cos_yaw();
// get roll stick input
if (target_roll != 0) {
// roll stick input detected, set roll mode to pilot override
hybrid.roll_mode = HYBRID_PILOT_OVERRIDE;
// Roll state machine
// Each state (aka mode) is responsible for:
// 1. dealing with pilot input
// 2. calculating the final roll output to the attitude controller
// 3. checking if the state (aka mode) should be changed and if 'yes' perform any required initialisation for the new state
switch (hybrid.roll_mode) {
} else {
// roll stick is centered
// if still in pilot override mode and breaking will complete within 0.5seconds switch to braking mode
if ((hybrid.roll_mode == HYBRID_PILOT_OVERRIDE) && (abs(brake_roll) < 2*wp_nav._brake_rate)) {
hybrid.roll_mode = HYBRID_BRAKE; // Set brake roll mode
brake_roll = 0; // this avoid false brake_timeout computing
brake_timeout_roll = 600; // seconds*0.01 - time allowed for the braking to complete, updated at half-braking
brake_timeout_roll_updated = false; // Allow the timeout to be updated only once
brake_roll_max = 0; // used to detect half braking
} else { // manage brake-to-loiter transition
// brake timeout
if (brake_timeout_roll > 0) {
brake_timeout_roll--;
}
// Changed loiter engage : not once HYBRID_SPEED_0 is reached but after a little delay that let the copter stabilize if it remains some rate. (maybe compare omega.x/y rather)
if ((fabs(vel_right) < HYBRID_SPEED_0) && (brake_timeout_roll>50)) {
brake_timeout_roll = 50; // let 0.5s between brake reaches HYBRID_SPEED_0 and loiter engage
}
if ((hybrid.roll_mode == HYBRID_BRAKE) && (brake_timeout_roll==0)){ //stick released and transition finished (speed 0) or brake timeout => loiter mode
hybrid.roll_mode = HYBRID_LOITER; // Set loiter roll mode
}
}
}
case HYBRID_PILOT_OVERRIDE:
// update pilot desired roll angle using latest radio input
// this filters the input so that it returns to zero no faster than the brake-rate
hybrid_update_pilot_lean_angle(hybrid.pilot_roll, target_roll);
// get pitch stick input
if (target_pitch != 0) {
// pitch stick input detected set pitch mode to pilot override
hybrid.pitch_mode = HYBRID_PILOT_OVERRIDE; // Set stab pitch mode
}else{
if((hybrid.pitch_mode == HYBRID_PILOT_OVERRIDE) && (abs(brake_pitch) < 2*wp_nav._brake_rate)){ // stick released from stab and copter horizontal (at wind_comp) => transition mode
hybrid.pitch_mode = HYBRID_BRAKE; // Set brake pitch mode
brake_pitch = 0; // this avoid false brake_timeout computing
brake_timeout_pitch = 600; // seconds*0.01 - time allowed for the braking to complete, updated at half-braking
brake_timeout_pitch_updated = false;// Allow the timeout to be updated only once
brake_pitch_max = 0; // used to detect half braking
}else{ // manage brake-to-loiter transition
// brake timeout
if (brake_timeout_pitch > 0) {
brake_timeout_pitch--;
// switch to BRAKE mode for next iteration if no pilot input
if ((target_roll == 0) && (abs(hybrid.pilot_roll) < 2 * g.hybrid_brake_rate)) {
// initialise BRAKE mode
hybrid.roll_mode = HYBRID_BRAKE; // Set brake roll mode
hybrid.brake_roll = 0; // initialise braking angle to zero
hybrid.brake_angle_max_roll = 0; // reset brake_angle_max so we can detect when vehicle begins to flatten out during braking
hybrid.brake_timeout_roll = HYBRID_BRAKE_TIME_ESTIMATE_MAX; // number of cycles the brake will be applied, updated during braking mode. To-Do: this must be adjusted based on loop rate
hybrid.braking_time_updated_roll = false; // flag the braking time can be re-estimated
}
// Changed loiter engage : not once HYBRID_SPEED_0 is reached but after a little delay that let the copter stabilize if it remains some rate. (maybe compare omega.x/y rather)
if ((fabs(vel_fw) < HYBRID_SPEED_0) && (brake_timeout_pitch > 50)) {
brake_timeout_pitch = 50; // let 0.5s between brake reaches HYBRID_SPEED_0 and loiter engage
}
if ((hybrid.pitch_mode == HYBRID_BRAKE) && (brake_timeout_pitch == 0)) {
hybrid.pitch_mode = HYBRID_LOITER; // Set loiter pitch mode
}
}
}
// manual roll with smooth decrease filter
if (hybrid.roll_mode == HYBRID_PILOT_OVERRIDE) {
if (((int32_t)brake_roll * (int32_t)target_roll >= 0) && (abs(target_roll) < HYBRID_STICK_RELEASE_SMOOTH_ANGLE)) {
// Smooth decrease only when we want to stop, not if we have to quickly change direction
if (brake_roll > 0){ // we use brake_roll to save mem usage and also because it will be natural transition with brake mode.
// rate decrease
brake_roll -= max((float)brake_roll * HYBRID_SMOOTH_RATE_FACTOR, wp_nav._brake_rate);
// use the max value if we increase and because we could have a smoother manual decrease than this computed value
brake_roll = max(brake_roll,target_roll);
}else{
brake_roll += max(-(float)brake_roll * HYBRID_SMOOTH_RATE_FACTOR, wp_nav._brake_rate);
brake_roll = min(brake_roll,target_roll);
}
} else {
brake_roll = target_roll;
}
}
// final lean angle should be pilot input plus wind compensation
hybrid.roll = hybrid.pilot_roll + hybrid.wind_comp_roll;
break;
// manual pitch with smooth decrease filter
if (hybrid.pitch_mode == HYBRID_PILOT_OVERRIDE) {
if (((int32_t)brake_pitch * (int32_t)target_pitch >= 0) && (abs(target_pitch) < HYBRID_STICK_RELEASE_SMOOTH_ANGLE)) { //Smooth decrease only when we want to stop, not if we have to quickly change direction
if (brake_pitch > 0) { // we use brake_pitch to save mem usage and also because it will be natural transition with brake mode.
brake_pitch -= max((float)brake_pitch * HYBRID_SMOOTH_RATE_FACTOR, wp_nav._brake_rate); //rate decrease
brake_pitch = max(brake_pitch,target_pitch); // use the max value because we could have a smoother manual decrease than this computed value
case HYBRID_BRAKE:
case HYBRID_BRAKE_READY_TO_LOITER:
// calculate brake_roll angle to counter-act velocity
hybrid_update_brake_angle_from_velocity(hybrid.brake_roll, vel_right);
// update braking time estimate
if (!hybrid.braking_time_updated_roll) {
// check if brake angle is increasing
if (abs(hybrid.brake_roll) >= hybrid.brake_angle_max_roll) {
hybrid.brake_angle_max_roll = abs(hybrid.brake_roll);
} else {
// braking angle has started decreasing so re-estimate braking time
hybrid.brake_timeout_roll = 1+(uint16_t)(15L*(int32_t)(abs(hybrid.brake_roll))/(10L*(int32_t)g.hybrid_brake_rate)); // the 1.2 (12/10) factor has to be tuned in flight, here it means 120% of the "normal" time.
hybrid.braking_time_updated_roll = true;
}
}
// if velocity is very low reduce braking time to 0.5seconds
// Note: this speed is extremely low (only 10cm/s) meaning this case is likely never executed
if ((fabs(vel_right) <= HYBRID_SPEED_0) && (hybrid.brake_timeout_roll > 50)) {
hybrid.brake_timeout_roll = 50;
}
// reduce braking timer
if (hybrid.brake_timeout_roll > 0) {
hybrid.brake_timeout_roll--;
} else {
brake_pitch += max(-(float)brake_pitch * HYBRID_SMOOTH_RATE_FACTOR, wp_nav._brake_rate);
brake_pitch = min(brake_pitch,target_pitch);
// indicate that we are ready to move to Loiter.
// Loiter will only actually be engaged once both roll_mode and pitch_mode are changed to HYBRID_BRAKE_READY_TO_LOITER
// logic for engaging loiter is handled below the roll and pitch mode switch statements
hybrid.roll_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
} else {
brake_pitch = target_pitch;
}
// check for pilot input
if (target_roll != 0) {
hybrid.roll_mode = HYBRID_PILOT_OVERRIDE;
}
// final lean angle is braking angle + wind compensation angle
hybrid.roll = hybrid.brake_roll + hybrid.wind_comp_roll;
break;
case HYBRID_BRAKE_TO_LOITER:
case HYBRID_LOITER:
// these modes are combined roll-pitch modes and are handled below
break;
case HYBRID_LOITER_TO_PILOT_OVERRIDE:
// update pilot desired roll angle using latest radio input
// this filters the input so that it returns to zero no faster than the brake-rate
hybrid_update_pilot_lean_angle(hybrid.pilot_roll, target_roll);
// count-down loiter to pilot timer
if (hybrid.loiter_to_pilot_timer_roll > 0) {
hybrid.loiter_to_pilot_timer_roll--;
} else {
// when timer runs out switch to full pilot override for next iteration
hybrid.roll_mode = HYBRID_PILOT_OVERRIDE;
}
// calculate loiter_to_pilot mix ratio
loiter_to_pilot_mix = (float)hybrid.loiter_to_pilot_timer_roll / (float)HYBRID_LOITER_TO_PILOT_MIX_TIMER;
loiter_to_pilot_mix = constrain_float(loiter_to_pilot_mix, 0.0f, 1.0f);
// Loiter-Manual mix at loiter exit
hybrid.roll = loiter_to_pilot_mix*(float)hybrid.loiter_final_roll+(1.0f-loiter_to_pilot_mix)*(float)(hybrid.brake_roll+hybrid.wind_comp_roll);
break;
}
// braking update: roll
if (hybrid.roll_mode >= HYBRID_BRAKE) { // Roll: allow braking update to run also during loiter
if (vel_right >= 0) { // negative roll = go left, positive roll = go right
brake_roll = max(brake_roll-wp_nav._brake_rate, max((-brake_gain*vel_right*(1.0f+500.0f/(vel_right+60.0f))),-wp_nav._max_braking_angle));
}else{
brake_roll = min(brake_roll+wp_nav._brake_rate, min((-brake_gain*vel_right*(1.0f+500.0f/(-vel_right+60.0f))),wp_nav._max_braking_angle));
}
if (abs(brake_roll) > brake_roll_max) { // detect half braking and update timeout
brake_roll_max = abs(brake_roll);
} else if (!brake_timeout_roll_updated) {
brake_timeout_roll = 1+(uint16_t)(15L*(int32_t)(abs(brake_roll))/(10L*(int32_t)wp_nav._brake_rate)); // the 1.2 (12/10) factor has to be tuned in flight, here it means 120% of the "normal" time.
brake_timeout_roll_updated = true;
}
}
// braking update: pitch
if (hybrid.pitch_mode >= HYBRID_BRAKE) { // Pitch: allow braking update to run also during loiter
if (vel_fw >= 0) { // positive pitch = go backward, negative pitch = go forward
brake_pitch = min(brake_pitch+wp_nav._brake_rate,min((brake_gain*vel_fw*(1.0f+(500.0f/(vel_fw+60.0f)))),wp_nav._max_braking_angle)); // centidegrees
} else {
brake_pitch = max(brake_pitch-wp_nav._brake_rate,max((brake_gain*vel_fw*(1.0f-(500.0f/(vel_fw-60.0f)))),-wp_nav._max_braking_angle)); // centidegrees
}
if (abs(brake_pitch)>brake_pitch_max){ // detect half braking and update timeout
brake_pitch_max = abs(brake_pitch);
} else if (!brake_timeout_pitch_updated){
// Changes 12 by 15 to let the brake=>loiter 0.5s happens before this timeout ends
brake_timeout_pitch = 1+(int16_t)(15L*(int32_t)(abs(brake_pitch))/(10L*(int32_t)wp_nav._brake_rate)); // the 1.2 (12/10) factor has to be tuned in flight, here it means 120% of the "normal" time.
brake_timeout_pitch_updated = true;
}
}
// loiter to manual mix
if ((hybrid.pitch_mode==HYBRID_PILOT_OVERRIDE)||(hybrid.roll_mode==HYBRID_PILOT_OVERRIDE)) {
if (loiter_man_timer !=0 ) {
loiter_man_mix = constrain_float((float)(loiter_man_timer)/(float)HYBRID_LOITER_MAN_MIX_TIMER, 0, 1.0);
loiter_man_timer--;
}
}
// loitering/moving:
if (hybrid.pitch_mode == HYBRID_LOITER && hybrid.roll_mode == HYBRID_LOITER) {
// while loitering, updates average lat/lon wind offset angles from I terms
if (hybrid.loiter_engaged) {
if (loiter_stab_timer != 0) {
loiter_stab_timer--;
// Pitch state machine
// Each state (aka mode) is responsible for:
// 1. dealing with pilot input
// 2. calculating the final pitch output to the attitude contpitcher
// 3. checking if the state (aka mode) should be changed and if 'yes' perform any required initialisation for the new state
switch (hybrid.pitch_mode) {
case HYBRID_PILOT_OVERRIDE:
// update pilot desired pitch angle using latest radio input
// this filters the input so that it returns to zero no faster than the brake-rate
hybrid_update_pilot_lean_angle(hybrid.pilot_pitch, target_pitch);
// switch to BRAKE mode for next iteration if no pilot input
if ((target_pitch == 0) && (abs(hybrid.pilot_pitch) < 2 * g.hybrid_brake_rate)) {
// initialise BRAKE mode
hybrid.pitch_mode = HYBRID_BRAKE; // set brake pitch mode
hybrid.brake_pitch = 0; // initialise braking angle to zero
hybrid.brake_angle_max_pitch = 0; // reset brake_angle_max so we can detect when vehicle begins to flatten out during braking
hybrid.brake_timeout_pitch = HYBRID_BRAKE_TIME_ESTIMATE_MAX; // number of cycles the brake will be applied, updated during braking mode. To-Do: this must be adjusted based on loop rate
hybrid.braking_time_updated_pitch = false; // flag the braking time can be re-estimated
}
// final lean angle should be pilot input plus wind compensation
hybrid.pitch = hybrid.pilot_pitch + hybrid.wind_comp_pitch;
break;
case HYBRID_BRAKE:
case HYBRID_BRAKE_READY_TO_LOITER:
// calculate brake_pitch angle to counter-act velocity
hybrid_update_brake_angle_from_velocity(hybrid.brake_pitch, -vel_fw);
// update braking time estimate
if (!hybrid.braking_time_updated_pitch) {
// check if brake angle is increasing
if (abs(hybrid.brake_pitch) >= hybrid.brake_angle_max_pitch) {
hybrid.brake_angle_max_pitch = abs(hybrid.brake_pitch);
} else {
// braking angle has started decreasing so re-estimate braking time
hybrid.brake_timeout_pitch = 1+(uint16_t)(15L*(int32_t)(abs(hybrid.brake_pitch))/(10L*(int32_t)g.hybrid_brake_rate)); // the 1.2 (12/10) factor has to be tuned in flight, here it means 120% of the "normal" time.
hybrid.braking_time_updated_pitch = true;
}
}
// if velocity is very low reduce braking time to 0.5seconds
// Note: this speed is extremely low (only 10cm/s) meaning this case is likely never executed
if ((fabs(vel_right) <= HYBRID_SPEED_0) && (hybrid.brake_timeout_pitch > 50)) {
hybrid.brake_timeout_pitch = 50;
}
// reduce braking timer
if (hybrid.brake_timeout_pitch > 0) {
hybrid.brake_timeout_pitch--;
} else {
// indicate that we are ready to move to Loiter.
// Loiter will only actually be engaged once both pitch_mode and pitch_mode are changed to HYBRID_BRAKE_READY_TO_LOITER
// logic for engaging loiter is handled below the pitch and pitch mode switch statements
hybrid.pitch_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
// check for pilot input
if (target_pitch != 0) {
hybrid.pitch_mode = HYBRID_PILOT_OVERRIDE;
}
// final lean angle is braking angle + wind compensation angle
hybrid.pitch = hybrid.brake_pitch + hybrid.wind_comp_pitch;
break;
case HYBRID_BRAKE_TO_LOITER:
case HYBRID_LOITER:
// these modes are combined pitch-pitch modes and are handled below
break;
case HYBRID_LOITER_TO_PILOT_OVERRIDE:
// update pilot desired pitch angle using latest radio input
// this filters the input so that it returns to zero no faster than the brake-rate
hybrid_update_pilot_lean_angle(hybrid.pilot_pitch, target_pitch);
// count-down loiter to pilot timer
if (hybrid.loiter_to_pilot_timer_pitch > 0) {
hybrid.loiter_to_pilot_timer_pitch--;
} else {
// when timer runs out switch to full pilot override for next iteration
hybrid.pitch_mode = HYBRID_PILOT_OVERRIDE;
}
// calculate loiter_to_pilot mix ratio
loiter_to_pilot_mix = (float)hybrid.loiter_to_pilot_timer_pitch / (float)HYBRID_LOITER_TO_PILOT_MIX_TIMER;
loiter_to_pilot_mix = constrain_float(loiter_to_pilot_mix, 0.0f, 1.0f);
// Loiter-Manual mix at loiter exit
hybrid.pitch = loiter_to_pilot_mix*(float)hybrid.loiter_final_pitch+(1.0f-loiter_to_pilot_mix)*(float)(hybrid.brake_pitch+hybrid.wind_comp_pitch);
break;
}
//
// Shared roll & pitch states (HYBRID_BRAKE_TO_LOITER and HYBRID_LOITER)
//
// switch into LOITER mode when both roll and pitch are ready
if (hybrid.roll_mode == HYBRID_BRAKE_READY_TO_LOITER && hybrid.pitch_mode == HYBRID_BRAKE_READY_TO_LOITER) {
hybrid.roll_mode = HYBRID_BRAKE_TO_LOITER;
hybrid.pitch_mode = HYBRID_BRAKE_TO_LOITER;
hybrid.brake_to_loiter_timer = HYBRID_BRAKE_TO_LOITER_TIMER;
// init loiter controller
wp_nav.init_loiter_target();
// move wind compensation back into loiter I term
g.pid_loiter_rate_lat.set_integrator(hybrid.wind_comp_ef.x);
g.pid_loiter_rate_lon.set_integrator(hybrid.wind_comp_ef.y);
}
// roll-mode is used as the combined roll+pitch mode when in BRAKE_TO_LOITER or LOITER modes
if (hybrid.roll_mode == HYBRID_BRAKE_TO_LOITER || hybrid.roll_mode == HYBRID_LOITER) {
// force pitch mode to be same as roll_mode just to keep it consistent (it's not actually used in these states)
hybrid.pitch_mode = hybrid.roll_mode;
// handle combined roll+pitch mode
switch (hybrid.roll_mode) {
case HYBRID_BRAKE_TO_LOITER:
// reduce brake_to_loiter timer
if (hybrid.brake_to_loiter_timer > 0) {
hybrid.brake_to_loiter_timer--;
} else {
// progress to full loiter on next iteration
hybrid.roll_mode = HYBRID_LOITER;
hybrid.pitch_mode = HYBRID_LOITER;
}
// calculate percentage mix of loiter and brake control
brake_to_loiter_mix = (float)hybrid.brake_to_loiter_timer / (float)HYBRID_BRAKE_TO_LOITER_TIMER;
brake_to_loiter_mix = constrain_float(brake_to_loiter_mix, 0.0f, 1.0f);
// calculate brake_roll and pitch angles to counter-act velocity
hybrid_update_brake_angle_from_velocity(hybrid.brake_roll, vel_right);
hybrid_update_brake_angle_from_velocity(hybrid.brake_pitch, -vel_fw);
// run loiter controller
wp_nav.update_loiter();
// calculate final roll and pitch output by mixing loiter and brake controls
hybrid.roll = ((1.0f-brake_to_loiter_mix) * (float)wp_nav.get_roll()) + (brake_to_loiter_mix * (float)(hybrid.brake_roll + hybrid.wind_comp_pitch));
hybrid.pitch = ((1.0f-brake_to_loiter_mix) * (float)wp_nav.get_pitch()) + (brake_to_loiter_mix * (float)(hybrid.brake_pitch + hybrid.wind_comp_pitch));
// check for pilot input
if (target_roll != 0 || target_pitch != 0) {
// if roll input switch to pilot override for roll
if (target_roll != 0) {
hybrid.roll_mode = HYBRID_PILOT_OVERRIDE;
// switch pitch-mode to brake (but ready to go back to loiter anytime)
hybrid.pitch_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
// if pitch input switch to pilot override for pitch
if (target_pitch != 0) {
hybrid.pitch_mode = HYBRID_PILOT_OVERRIDE;
if (target_roll == 0) {
// switch roll-mode to brake (but ready to go back to loiter anytime)
hybrid.roll_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
}
}
break;
case HYBRID_LOITER:
// run loiter controller
wp_nav.update_loiter();
// set roll angle based on loiter controller outputs
hybrid.roll = wp_nav.get_roll();
hybrid.pitch = wp_nav.get_pitch();
// update wind compensation estimate
hybrid_update_wind_comp_estimate();
}
// Brake_Loiter commands mix factor
brake_loiter_mix = constrain_float((float)(HYBRID_LOITER_STAB_TIMER-loiter_stab_timer)/(float)HYBRID_BRAKE_LOITER_MIX_TIMER, 0, 1.0);
} else {
hybrid.loiter_engaged = true; // turns on NAV_HYBRID if both sticks are at rest
pos_control.init_I = false; // stop I terms from being cleared when init_loiter_target is called. avoids the stop_and_go effect
wp_nav.init_loiter_target(); // init loiter controller and sets XY stopping point
pos_control.set_target_to_stopping_point_z(); // init altitude
loiter_stab_timer = HYBRID_LOITER_STAB_TIMER; // starts a 3 seconds timer
brake_roll = 1; // required for next mode_1 smooth stick release and to avoid twitch
brake_pitch = 1; // required for next mode_1 smooth stick release and to avoid twitch
// check for pilot input
if (target_roll != 0 || target_pitch != 0) {
// if roll input switch to pilot override for roll
if (target_roll != 0) {
hybrid.roll_mode = HYBRID_LOITER_TO_PILOT_OVERRIDE;
hybrid.loiter_to_pilot_timer_roll = HYBRID_LOITER_TO_PILOT_MIX_TIMER;
// initialise pilot_roll
hybrid.pilot_roll = target_roll;
// switch pitch-mode to brake (but ready to go back to loiter anytime)
hybrid.pitch_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
// if pitch input switch to pilot override for pitch
if (target_pitch != 0) {
hybrid.pitch_mode = HYBRID_LOITER_TO_PILOT_OVERRIDE;
hybrid.loiter_to_pilot_timer_pitch = HYBRID_LOITER_TO_PILOT_MIX_TIMER;
// initialise pilot_pitch
hybrid.pilot_pitch = target_pitch;
// if roll not overriden switch roll-mode to brake (but be ready to go back to loiter any time)
if (target_roll == 0) {
hybrid.roll_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
}
// store final loiter outputs for mixing with pilot input
hybrid.loiter_final_roll = wp_nav.get_roll();
hybrid.loiter_final_pitch = wp_nav.get_pitch();
// retrieve latest wind compensation lean angles
hybrid_get_wind_comp_lean_angles(hybrid.wind_comp_roll, hybrid.wind_comp_pitch);
}
break;
default:
// do nothing for uncombined roll and pitch modes
break;
}
} else {
// transition from Loiter to Manual
if (hybrid.loiter_engaged) {
hybrid.loiter_engaged = false;
loiter_man_timer = HYBRID_LOITER_MAN_MIX_TIMER;
// save pitch/roll at loiter exit
loiter_roll = wp_nav.get_roll();
loiter_pitch = wp_nav.get_pitch();
}
if (wind_offset_timer == 0) { // reduce update frequency of wind_offset to 10Hz
// retrieve latest wind compensation lean angles
hybrid_get_wind_comp_lean_angles(wind_offset_roll, wind_offset_pitch);
wind_offset_timer = 10;
} else {
wind_offset_timer--;
}
}
// if required, update loiter controller
if(hybrid.loiter_engaged) {
wp_nav.update_loiter();
}
// select output to stabilize controllers
switch (hybrid.roll_mode) {
// To-Do: try to mix loiter->manual using brake_loiter_mix variable as we are doing on loiter engage
case HYBRID_PILOT_OVERRIDE:
// Loiter-Manual mix at loiter exit
target_roll = loiter_man_mix*(float)loiter_roll+(1.0f-loiter_man_mix)*(float)(brake_roll+wind_offset_roll);
break;
case HYBRID_BRAKE:
target_roll = brake_roll + wind_offset_roll;
break;
case HYBRID_BRAKE_TO_LOITER:
break;
case HYBRID_LOITER:
if (hybrid.loiter_engaged) {
// Brake_Loiter mix at loiter engage
target_roll = brake_loiter_mix*(float)wp_nav.get_roll()+(1.0f-brake_loiter_mix)*(float)(brake_roll+wind_offset_roll);
}else {
target_roll = brake_roll + wind_offset_roll;
}
break;
case HYBRID_LOITER_TO_PILOT_OVERRIDE:
// Loiter-Manual mix at loiter exit
target_roll = loiter_man_mix*(float)loiter_roll+(1.0f-loiter_man_mix)*(float)(brake_roll+wind_offset_roll);
// To-Do: add handling of exiting this mode far far above
break;
}
switch (hybrid.pitch_mode){
case HYBRID_PILOT_OVERRIDE:
//Loiter-Manual mix at loiter exit
target_pitch = loiter_man_mix*(float)loiter_pitch+(1.0f-loiter_man_mix)*(float)(brake_pitch+wind_offset_pitch);
break;
case HYBRID_BRAKE:
target_pitch = brake_pitch+wind_offset_pitch;
break;
case HYBRID_BRAKE_TO_LOITER:
break;
case HYBRID_LOITER:
if(hybrid.loiter_engaged) {
// mix brake and loiter outputs
target_pitch = brake_loiter_mix*(float)wp_nav.get_pitch()+(1.0f-brake_loiter_mix)*(float)(brake_pitch+wind_offset_pitch);
} else {
// only wind-compensate pitch (roll is likely under manual control)
target_pitch = brake_pitch+wind_offset_pitch;
}
break;
case HYBRID_LOITER_TO_PILOT_OVERRIDE:
// mix brake and loiter outputs
target_pitch = brake_loiter_mix*(float)wp_nav.get_pitch()+(1.0f-brake_loiter_mix)*(float)(brake_pitch+wind_offset_pitch);
// To-Do: add handling of exiting this mode far far above
break;
}
// constrain target pitch/roll angles
target_roll = constrain_int16(target_roll,-aparm.angle_max,aparm.angle_max);
target_pitch = constrain_int16(target_pitch,-aparm.angle_max,aparm.angle_max);
hybrid.roll = constrain_int16(hybrid.roll, -aparm.angle_max, aparm.angle_max);
hybrid.pitch = constrain_int16(hybrid.pitch, -aparm.angle_max, aparm.angle_max);
// update attitude controller targets
attitude_control.angle_ef_roll_pitch_rate_ef_yaw(target_roll, target_pitch, target_yaw_rate);
attitude_control.angle_ef_roll_pitch_rate_ef_yaw(hybrid.roll, hybrid.pitch, target_yaw_rate);
// throttle control
if (sonar_alt_health >= SONAR_ALT_HEALTH_MAX) {
@ -400,6 +490,51 @@ static void hybrid_run()
}
}
// hybrid_update_pilot_lean_angle - update the pilot's filtered lean angle with the latest raw input received
static void hybrid_update_pilot_lean_angle(int16_t &lean_angle_filtered, int16_t &lean_angle_raw)
{
// if raw input is large or reversing the vehicle's lean angle immediately set the fitlered angle to the new raw angle
if ((lean_angle_filtered > 0 && lean_angle_raw < 0) || (lean_angle_filtered < 0 && lean_angle_raw > 0) || (abs(lean_angle_raw) > HYBRID_STICK_RELEASE_SMOOTH_ANGLE)) {
lean_angle_filtered = lean_angle_raw;
} else {
// lean_angle_raw must be pulling lean_angle_filtered towards zero, smooth the decrease
if (lean_angle_filtered > 0) {
// reduce the filtered lean angle at 4% or the brake rate (whichever is faster).
// To-Do: the HYBRID_SMOOTH_RATE_FACTOR must be adjusted based on update rate
lean_angle_filtered -= max((float)lean_angle_filtered * HYBRID_SMOOTH_RATE_FACTOR, g.hybrid_brake_rate);
// do not let the filtered angle fall below the pilot's input lean angle.
// the above line pulls the filtered angle down and the below line acts as a catch
lean_angle_filtered = max(lean_angle_filtered, lean_angle_raw);
}else{
// To-Do: the HYBRID_SMOOTH_RATE_FACTOR must be adjusted based on update rate
lean_angle_filtered += max(-(float)lean_angle_filtered * HYBRID_SMOOTH_RATE_FACTOR, g.hybrid_brake_rate);
lean_angle_filtered = min(lean_angle_filtered, lean_angle_raw);
}
}
}
// hybrid_update_brake_angle_from_velocity - updates the brake_angle based on the vehicle's velocity and brake_gain
// brake_angle is slewed with the wpnav.hybrid_brake_rate and constrained by the wpnav.hybrid_braking_angle_max
// velocity is assumed to be in the same direction as lean angle so for pitch you should provide the velocity backwards (i.e. -ve forward velocity)
static void hybrid_update_brake_angle_from_velocity(int16_t &brake_angle, float velocity)
{
float lean_angle;
// calculate velocity-only based lean angle
if (velocity >= 0) {
lean_angle = -hybrid.brake_gain * velocity * (1.0f+500.0f/(velocity+60.0f));
} else {
lean_angle = -hybrid.brake_gain * velocity * (1.0f+500.0f/(-velocity+60.0f));
}
// do not let lean_angle be too far from brake_angle
// To-Do: this constraint needs to account for loop update rate
brake_angle = constrain_int16((int16_t)lean_angle, brake_angle - g.hybrid_brake_rate, brake_angle + g.hybrid_brake_rate);
// constrain final brake_angle
brake_angle = constrain_int16(brake_angle, -g.hybrid_brake_angle_max, g.hybrid_brake_angle_max);
}
// hybrid_update_wind_comp_estimate - updates wind compensation estimate
// should be called at the maximum loop rate when loiter is engaged
// To-Do: adjust the filtering for 100hz and 400hz update rates
@ -409,20 +544,24 @@ static void hybrid_update_wind_comp_estimate()
return;
}
// get position controller accel target
// To-Do: clean this up by using accessor in loiter controller (or move entire hybrid controller to a library shared with loiter)
const Vector3f& accel_target = pos_control.get_accel_target();
// update wind compensation in earth-frame lean angles
if (wind_comp_ef.x == 0) {
if (hybrid.wind_comp_ef.x == 0) {
// if wind compensation has not been initialised set it immediately to the pos controller's desired accel in north direction
wind_comp_ef.x = pos_control.get_desired_acc_x();
hybrid.wind_comp_ef.x = accel_target.x;
} else {
// low pass filter the position controller's lean angle output
wind_comp_ef.x = (0.97f*wind_comp_ef.x+0.03f*pos_control.get_desired_acc_x());
hybrid.wind_comp_ef.x = (0.97f*hybrid.wind_comp_ef.x+0.03f*accel_target.x);
}
if (wind_comp_ef.y == 0) {
if (hybrid.wind_comp_ef.y == 0) {
// if wind compensation has not been initialised set it immediately to the pos controller's desired accel in north direction
wind_comp_ef.y = pos_control.get_desired_acc_y();
hybrid.wind_comp_ef.y = accel_target.y;
} else {
// low pass filter the position controller's lean angle output
wind_comp_ef.y = (0.97f*wind_comp_ef.y+0.03f*pos_control.get_desired_acc_y());
hybrid.wind_comp_ef.y = (0.97f*hybrid.wind_comp_ef.y+0.03f*accel_target.y);
}
}
@ -430,6 +569,6 @@ static void hybrid_update_wind_comp_estimate()
static void hybrid_get_wind_comp_lean_angles(int16_t &roll_angle, int16_t &pitch_angle)
{
// convert earth frame desired accelerations to body frame roll and pitch lean angles
roll_angle = (float)fast_atan((-wind_comp_ef.x*ahrs.sin_yaw() + wind_comp_ef.y*ahrs.cos_yaw())/981)*(18000/M_PI);
pitch_angle = (float)fast_atan(-(wind_comp_ef.x*ahrs.cos_yaw() + wind_comp_ef.y*ahrs.sin_yaw())/981)*(18000/M_PI);
roll_angle = (float)fast_atan((-hybrid.wind_comp_ef.x*ahrs.sin_yaw() + hybrid.wind_comp_ef.y*ahrs.cos_yaw())/981)*(18000/M_PI);
pitch_angle = (float)fast_atan(-(hybrid.wind_comp_ef.x*ahrs.cos_yaw() + hybrid.wind_comp_ef.y*ahrs.sin_yaw())/981)*(18000/M_PI);
}