/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- #if POSHOLD_ENABLED == ENABLED /* * control_poshold.pde - init and run calls for PosHold flight mode * PosHold tries to improve upon regular loiter by mixing the pilot input with the loiter controller */ #define POSHOLD_SPEED_0 10 // speed below which it is always safe to switch to loiter #if MAIN_LOOP_RATE == 100 // definitions for 100hz loop update rate # define POSHOLD_BRAKE_TIME_ESTIMATE_MAX 600 // max number of cycles the brake will be applied before we switch to loiter # define POSHOLD_BRAKE_TO_LOITER_TIMER 150 // Number of cycles to transition from brake mode to loiter mode. # define POSHOLD_WIND_COMP_START_TIMER 150 // Number of cycles to start wind compensation update after loiter is engaged # define POSHOLD_CONTROLLER_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 POSHOLD_SMOOTH_RATE_FACTOR 0.05f // 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 POSHOLD_WIND_COMP_TIMER_10HZ 10 // counter value used to reduce wind compensation to 10hz # define LOOP_RATE_FACTOR 1 // used to adapt PosHold params to loop_rate # define TC_WIND_COMP 0.01f // Time constant for poshold_update_wind_comp_estimate() #else // definitions for 400hz loop update rate # define POSHOLD_BRAKE_TIME_ESTIMATE_MAX (600*4) // max number of cycles the brake will be applied before we switch to loiter # define POSHOLD_BRAKE_TO_LOITER_TIMER (150*4) // Number of cycles to transition from brake mode to loiter mode. Must be lower than POSHOLD_LOITER_STAB_TIMER # define POSHOLD_WIND_COMP_START_TIMER (150*4) // Number of cycles to start wind compensation update after loiter is engaged # define POSHOLD_CONTROLLER_TO_PILOT_MIX_TIMER (50*4) // Set it from 100 to 200, the number of centiseconds loiter and manual commands are mixed to make a smooth transition. # define POSHOLD_SMOOTH_RATE_FACTOR 0.0125f // 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 POSHOLD_WIND_COMP_TIMER_10HZ 40 // counter value used to reduce wind compensation to 10hz # define LOOP_RATE_FACTOR 4 // used to adapt PosHold params to loop_rate # define TC_WIND_COMP 0.0025f // Time constant for poshold_update_wind_comp_estimate() #endif // definitions that are independent of main loop rate #define POSHOLD_STICK_RELEASE_SMOOTH_ANGLE 1800 // max angle required (in centi-degrees) after which the smooth stick release effect is applied #define POSHOLD_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 poshold_update_pilot_lean_angle(int16_t &lean_angle_filtered, int16_t &lean_angle_raw); static int16_t poshold_mix_controls(float mix_ratio, int16_t first_control, int16_t second_control); static void poshold_update_brake_angle_from_velocity(int16_t &brake_angle, float velocity); static void poshold_update_wind_comp_estimate(); static void poshold_get_wind_comp_lean_angles(int16_t &roll_angle, int16_t &pitch_angle); static void poshold_roll_controller_to_pilot_override(); static void poshold_pitch_controller_to_pilot_override(); // mission state enumeration enum poshold_rp_mode { POSHOLD_PILOT_OVERRIDE=0, // pilot is controlling this axis (i.e. roll or pitch) POSHOLD_BRAKE, // this axis is braking towards zero POSHOLD_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) POSHOLD_BRAKE_TO_LOITER, // both vehicle's axis (roll and pitch) are transitioning from braking to loiter mode (braking and loiter controls are mixed) POSHOLD_LOITER, // both vehicle axis are holding position POSHOLD_CONTROLLER_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 { poshold_rp_mode roll_mode : 3; // roll mode: pilot override, brake or loiter poshold_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 uint8_t loiter_reset_I : 1; // true the very first time PosHold enters loiter, thereafter we trust the i terms loiter has // 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 POSHOLD_BRAKE_TO_LOITER // loiter related variables int16_t controller_to_pilot_timer_roll; // cycles to mix controller and pilot controls in POSHOLD_CONTROLLER_TO_PILOT int16_t controller_to_pilot_timer_pitch; // cycles to mix controller and pilot controls in POSHOLD_CONTROLLER_TO_PILOT int16_t controller_final_roll; // final roll angle from controller as we exit brake or loiter mode (used for mixing with pilot input) int16_t controller_final_pitch; // final pitch angle from controller as we exit brake or 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_start_timer; // counter to delay start of wind compensation for a short time after loiter is engaged int8_t wind_comp_timer; // counter to reduce wind comp roll/pitch lean angle 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 } poshold; // poshold_init - initialise PosHold controller static bool poshold_init(bool ignore_checks) { // fail to initialise PosHold mode if no GPS lock if (!GPS_ok() && !ignore_checks) { return false; } // initialize vertical speeds and leash lengths pos_control.set_speed_z(-g.pilot_velocity_z_max, g.pilot_velocity_z_max); pos_control.set_accel_z(g.pilot_accel_z); // initialise altitude target to stopping point pos_control.set_target_to_stopping_point_z(); // initialise lean angles to current attitude poshold.pilot_roll = 0; poshold.pilot_pitch = 0; // compute brake_gain poshold.brake_gain = (15.0f * (float)g.poshold_brake_rate + 95.0f) / 100.0f; if (ap.land_complete) { // if landed begin in loiter mode poshold.roll_mode = POSHOLD_LOITER; poshold.pitch_mode = POSHOLD_LOITER; // set target to current position // only init here as we can switch to PosHold in flight with a velocity <> 0 that will be used as _last_vel in PosControl and never updated again as we inhibit Reset_I wp_nav.init_loiter_target(); }else{ // if not landed start in pilot override to avoid hard twitch poshold.roll_mode = POSHOLD_PILOT_OVERRIDE; poshold.pitch_mode = POSHOLD_PILOT_OVERRIDE; } // loiter's I terms should be reset the first time only poshold.loiter_reset_I = true; // initialise wind_comp each time PosHold is switched on poshold.wind_comp_ef.zero(); poshold.wind_comp_roll = 0; poshold.wind_comp_pitch = 0; poshold.wind_comp_timer = 0; return true; } // poshold_run - runs the PosHold controller // should be called at 100hz or more static void poshold_run() { int16_t target_roll, target_pitch; // pilot's roll and pitch angle inputs float target_yaw_rate = 0; // pilot desired yaw rate in centi-degrees/sec int16_t 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 controller_to_pilot_roll_mix; // mix of controller and pilot controls. 0 = fully last controller controls, 1 = fully pilot controls float controller_to_pilot_pitch_mix; // mix of controller and pilot controls. 0 = fully last controller 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(); // if not auto armed set throttle to zero and exit immediately if(!ap.auto_armed || !inertial_nav.position_ok()) { wp_nav.init_loiter_target(); attitude_control.relax_bf_rate_controller(); attitude_control.set_yaw_target_to_current_heading(); attitude_control.set_throttle_out(0, false); pos_control.set_alt_target_to_current_alt(); return; } // process pilot inputs if (!failsafe.radio) { // apply SIMPLE mode transform to pilot inputs update_simple_mode(); // get pilot's desired yaw rate target_yaw_rate = get_pilot_desired_yaw_rate(g.rc_4.control_in); // get pilot desired climb rate (for alt-hold mode and take-off) target_climb_rate = get_pilot_desired_climb_rate(g.rc_3.control_in); // check for pilot requested take-off if (ap.land_complete && target_climb_rate > 0) { // indicate we are taking off set_land_complete(false); // clear i term when we're taking off set_throttle_takeoff(); } } // if landed initialise loiter targets, set throttle to zero and exit if (ap.land_complete) { wp_nav.init_loiter_target(); attitude_control.relax_bf_rate_controller(); attitude_control.set_yaw_target_to_current_heading(); // move throttle to between minimum and non-takeoff-throttle to keep us on the ground attitude_control.set_throttle_out(get_throttle_pre_takeoff(g.rc_3.control_in), false); pos_control.set_alt_target_to_current_alt(); return; }else{ // convert pilot input to lean angles get_pilot_desired_lean_angles(g.rc_1.control_in, g.rc_2.control_in, target_roll, target_pitch); // convert inertial nav earth-frame velocities to body-frame // To-Do: move this to AP_Math (or perhaps we already have a function to do this) vel_fw = vel.x*ahrs.cos_yaw() + vel.y*ahrs.sin_yaw(); vel_right = -vel.x*ahrs.sin_yaw() + vel.y*ahrs.cos_yaw(); // If not in LOITER, retrieve latest wind compensation lean angles related to current yaw if (poshold.roll_mode != POSHOLD_LOITER || poshold.pitch_mode != POSHOLD_LOITER) poshold_get_wind_comp_lean_angles(poshold.wind_comp_roll, poshold.wind_comp_pitch); // 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 (poshold.roll_mode) { case POSHOLD_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 poshold_update_pilot_lean_angle(poshold.pilot_roll, target_roll); // switch to BRAKE mode for next iteration if no pilot input if ((target_roll == 0) && (abs(poshold.pilot_roll) < 2 * g.poshold_brake_rate)) { // initialise BRAKE mode poshold.roll_mode = POSHOLD_BRAKE; // Set brake roll mode poshold.brake_roll = 0; // initialise braking angle to zero poshold.brake_angle_max_roll = 0; // reset brake_angle_max so we can detect when vehicle begins to flatten out during braking poshold.brake_timeout_roll = POSHOLD_BRAKE_TIME_ESTIMATE_MAX; // number of cycles the brake will be applied, updated during braking mode. poshold.braking_time_updated_roll = false; // flag the braking time can be re-estimated } // final lean angle should be pilot input plus wind compensation poshold.roll = poshold.pilot_roll + poshold.wind_comp_roll; break; case POSHOLD_BRAKE: case POSHOLD_BRAKE_READY_TO_LOITER: // calculate brake_roll angle to counter-act velocity poshold_update_brake_angle_from_velocity(poshold.brake_roll, vel_right); // update braking time estimate if (!poshold.braking_time_updated_roll) { // check if brake angle is increasing if (abs(poshold.brake_roll) >= poshold.brake_angle_max_roll) { poshold.brake_angle_max_roll = abs(poshold.brake_roll); } else { // braking angle has started decreasing so re-estimate braking time poshold.brake_timeout_roll = 1+(uint16_t)(LOOP_RATE_FACTOR*15L*(int32_t)(abs(poshold.brake_roll))/(10L*(int32_t)g.poshold_brake_rate)); // the 1.2 (12/10) factor has to be tuned in flight, here it means 120% of the "normal" time. poshold.braking_time_updated_roll = true; } } // if velocity is very low reduce braking time to 0.5seconds if ((fabs(vel_right) <= POSHOLD_SPEED_0) && (poshold.brake_timeout_roll > 50*LOOP_RATE_FACTOR)) { poshold.brake_timeout_roll = 50*LOOP_RATE_FACTOR; } // reduce braking timer if (poshold.brake_timeout_roll > 0) { poshold.brake_timeout_roll--; } else { // 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 POSHOLD_BRAKE_READY_TO_LOITER // logic for engaging loiter is handled below the roll and pitch mode switch statements poshold.roll_mode = POSHOLD_BRAKE_READY_TO_LOITER; } // final lean angle is braking angle + wind compensation angle poshold.roll = poshold.brake_roll + poshold.wind_comp_roll; // check for pilot input if (target_roll != 0) { // init transition to pilot override poshold_roll_controller_to_pilot_override(); } break; case POSHOLD_BRAKE_TO_LOITER: case POSHOLD_LOITER: // these modes are combined roll-pitch modes and are handled below break; case POSHOLD_CONTROLLER_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 poshold_update_pilot_lean_angle(poshold.pilot_roll, target_roll); // count-down loiter to pilot timer if (poshold.controller_to_pilot_timer_roll > 0) { poshold.controller_to_pilot_timer_roll--; } else { // when timer runs out switch to full pilot override for next iteration poshold.roll_mode = POSHOLD_PILOT_OVERRIDE; } // calculate controller_to_pilot mix ratio controller_to_pilot_roll_mix = (float)poshold.controller_to_pilot_timer_roll / (float)POSHOLD_CONTROLLER_TO_PILOT_MIX_TIMER; // mix final loiter lean angle and pilot desired lean angles poshold.roll = poshold_mix_controls(controller_to_pilot_roll_mix, poshold.controller_final_roll, poshold.pilot_roll + poshold.wind_comp_roll); break; } // 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 (poshold.pitch_mode) { case POSHOLD_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 poshold_update_pilot_lean_angle(poshold.pilot_pitch, target_pitch); // switch to BRAKE mode for next iteration if no pilot input if ((target_pitch == 0) && (abs(poshold.pilot_pitch) < 2 * g.poshold_brake_rate)) { // initialise BRAKE mode poshold.pitch_mode = POSHOLD_BRAKE; // set brake pitch mode poshold.brake_pitch = 0; // initialise braking angle to zero poshold.brake_angle_max_pitch = 0; // reset brake_angle_max so we can detect when vehicle begins to flatten out during braking poshold.brake_timeout_pitch = POSHOLD_BRAKE_TIME_ESTIMATE_MAX; // number of cycles the brake will be applied, updated during braking mode. poshold.braking_time_updated_pitch = false; // flag the braking time can be re-estimated } // final lean angle should be pilot input plus wind compensation poshold.pitch = poshold.pilot_pitch + poshold.wind_comp_pitch; break; case POSHOLD_BRAKE: case POSHOLD_BRAKE_READY_TO_LOITER: // calculate brake_pitch angle to counter-act velocity poshold_update_brake_angle_from_velocity(poshold.brake_pitch, -vel_fw); // update braking time estimate if (!poshold.braking_time_updated_pitch) { // check if brake angle is increasing if (abs(poshold.brake_pitch) >= poshold.brake_angle_max_pitch) { poshold.brake_angle_max_pitch = abs(poshold.brake_pitch); } else { // braking angle has started decreasing so re-estimate braking time poshold.brake_timeout_pitch = 1+(uint16_t)(LOOP_RATE_FACTOR*15L*(int32_t)(abs(poshold.brake_pitch))/(10L*(int32_t)g.poshold_brake_rate)); // the 1.2 (12/10) factor has to be tuned in flight, here it means 120% of the "normal" time. poshold.braking_time_updated_pitch = true; } } // if velocity is very low reduce braking time to 0.5seconds if ((fabs(vel_fw) <= POSHOLD_SPEED_0) && (poshold.brake_timeout_pitch > 50*LOOP_RATE_FACTOR)) { poshold.brake_timeout_pitch = 50*LOOP_RATE_FACTOR; } // reduce braking timer if (poshold.brake_timeout_pitch > 0) { poshold.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 POSHOLD_BRAKE_READY_TO_LOITER // logic for engaging loiter is handled below the pitch and pitch mode switch statements poshold.pitch_mode = POSHOLD_BRAKE_READY_TO_LOITER; } // final lean angle is braking angle + wind compensation angle poshold.pitch = poshold.brake_pitch + poshold.wind_comp_pitch; // check for pilot input if (target_pitch != 0) { // init transition to pilot override poshold_pitch_controller_to_pilot_override(); } break; case POSHOLD_BRAKE_TO_LOITER: case POSHOLD_LOITER: // these modes are combined pitch-pitch modes and are handled below break; case POSHOLD_CONTROLLER_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 poshold_update_pilot_lean_angle(poshold.pilot_pitch, target_pitch); // count-down loiter to pilot timer if (poshold.controller_to_pilot_timer_pitch > 0) { poshold.controller_to_pilot_timer_pitch--; } else { // when timer runs out switch to full pilot override for next iteration poshold.pitch_mode = POSHOLD_PILOT_OVERRIDE; } // calculate controller_to_pilot mix ratio controller_to_pilot_pitch_mix = (float)poshold.controller_to_pilot_timer_pitch / (float)POSHOLD_CONTROLLER_TO_PILOT_MIX_TIMER; // mix final loiter lean angle and pilot desired lean angles poshold.pitch = poshold_mix_controls(controller_to_pilot_pitch_mix, poshold.controller_final_pitch, poshold.pilot_pitch + poshold.wind_comp_pitch); break; } // // Shared roll & pitch states (POSHOLD_BRAKE_TO_LOITER and POSHOLD_LOITER) // // switch into LOITER mode when both roll and pitch are ready if (poshold.roll_mode == POSHOLD_BRAKE_READY_TO_LOITER && poshold.pitch_mode == POSHOLD_BRAKE_READY_TO_LOITER) { poshold.roll_mode = POSHOLD_BRAKE_TO_LOITER; poshold.pitch_mode = POSHOLD_BRAKE_TO_LOITER; poshold.brake_to_loiter_timer = POSHOLD_BRAKE_TO_LOITER_TIMER; // init loiter controller wp_nav.init_loiter_target(inertial_nav.get_position(), poshold.loiter_reset_I); // (false) to avoid I_term reset. In original code, velocity(0,0,0) was used instead of current velocity: wp_nav.init_loiter_target(inertial_nav.get_position(), Vector3f(0,0,0)); // at this stage, we are going to run update_loiter that will reset I_term once. From now, we ensure next time that we will enter loiter and update it, I_term won't be reset anymore poshold.loiter_reset_I = false; // set delay to start of wind compensation estimate updates poshold.wind_comp_start_timer = POSHOLD_WIND_COMP_START_TIMER; } // roll-mode is used as the combined roll+pitch mode when in BRAKE_TO_LOITER or LOITER modes if (poshold.roll_mode == POSHOLD_BRAKE_TO_LOITER || poshold.roll_mode == POSHOLD_LOITER) { // force pitch mode to be same as roll_mode just to keep it consistent (it's not actually used in these states) poshold.pitch_mode = poshold.roll_mode; // handle combined roll+pitch mode switch (poshold.roll_mode) { case POSHOLD_BRAKE_TO_LOITER: // reduce brake_to_loiter timer if (poshold.brake_to_loiter_timer > 0) { poshold.brake_to_loiter_timer--; } else { // progress to full loiter on next iteration poshold.roll_mode = POSHOLD_LOITER; poshold.pitch_mode = POSHOLD_LOITER; } // calculate percentage mix of loiter and brake control brake_to_loiter_mix = (float)poshold.brake_to_loiter_timer / (float)POSHOLD_BRAKE_TO_LOITER_TIMER; // calculate brake_roll and pitch angles to counter-act velocity poshold_update_brake_angle_from_velocity(poshold.brake_roll, vel_right); poshold_update_brake_angle_from_velocity(poshold.brake_pitch, -vel_fw); // run loiter controller wp_nav.update_loiter(); // calculate final roll and pitch output by mixing loiter and brake controls poshold.roll = poshold_mix_controls(brake_to_loiter_mix, poshold.brake_roll + poshold.wind_comp_roll, wp_nav.get_roll()); poshold.pitch = poshold_mix_controls(brake_to_loiter_mix, poshold.brake_pitch + poshold.wind_comp_pitch, wp_nav.get_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) { // init transition to pilot override poshold_roll_controller_to_pilot_override(); // switch pitch-mode to brake (but ready to go back to loiter anytime) // no need to reset poshold.brake_pitch here as wind comp has not been updated since last brake_pitch computation poshold.pitch_mode = POSHOLD_BRAKE_READY_TO_LOITER; } // if pitch input switch to pilot override for pitch if (target_pitch != 0) { // init transition to pilot override poshold_pitch_controller_to_pilot_override(); if (target_roll == 0) { // switch roll-mode to brake (but ready to go back to loiter anytime) // no need to reset poshold.brake_roll here as wind comp has not been updated since last brake_roll computation poshold.roll_mode = POSHOLD_BRAKE_READY_TO_LOITER; } } } break; case POSHOLD_LOITER: // run loiter controller wp_nav.update_loiter(); // set roll angle based on loiter controller outputs poshold.roll = wp_nav.get_roll(); poshold.pitch = wp_nav.get_pitch(); // update wind compensation estimate poshold_update_wind_comp_estimate(); // check for pilot input if (target_roll != 0 || target_pitch != 0) { // if roll input switch to pilot override for roll if (target_roll != 0) { // init transition to pilot override poshold_roll_controller_to_pilot_override(); // switch pitch-mode to brake (but ready to go back to loiter anytime) poshold.pitch_mode = POSHOLD_BRAKE_READY_TO_LOITER; // reset brake_pitch because wind_comp is now different and should give the compensation of the whole previous loiter angle poshold.brake_pitch = 0; } // if pitch input switch to pilot override for pitch if (target_pitch != 0) { // init transition to pilot override poshold_pitch_controller_to_pilot_override(); // if roll not overriden switch roll-mode to brake (but be ready to go back to loiter any time) if (target_roll == 0) { poshold.roll_mode = POSHOLD_BRAKE_READY_TO_LOITER; poshold.brake_roll = 0; } } } break; default: // do nothing for uncombined roll and pitch modes break; } } // constrain target pitch/roll angles poshold.roll = constrain_int16(poshold.roll, -aparm.angle_max, aparm.angle_max); poshold.pitch = constrain_int16(poshold.pitch, -aparm.angle_max, aparm.angle_max); // update attitude controller targets attitude_control.angle_ef_roll_pitch_rate_ef_yaw(poshold.roll, poshold.pitch, target_yaw_rate); // throttle control if (sonar_alt_health >= SONAR_ALT_HEALTH_MAX) { // if sonar is ok, use surface tracking target_climb_rate = get_throttle_surface_tracking(target_climb_rate, pos_control.get_alt_target(), G_Dt); } // update altitude target and call position controller pos_control.set_alt_target_from_climb_rate(target_climb_rate, G_Dt); pos_control.update_z_controller(); } } // poshold_update_pilot_lean_angle - update the pilot's filtered lean angle with the latest raw input received static void poshold_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) > POSHOLD_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 5% or the brake rate (whichever is faster). lean_angle_filtered -= max((float)lean_angle_filtered * POSHOLD_SMOOTH_RATE_FACTOR, max(1, g.poshold_brake_rate/LOOP_RATE_FACTOR)); // 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{ lean_angle_filtered += max(-(float)lean_angle_filtered * POSHOLD_SMOOTH_RATE_FACTOR, max(1, g.poshold_brake_rate/LOOP_RATE_FACTOR)); lean_angle_filtered = min(lean_angle_filtered, lean_angle_raw); } } } // poshold_mix_controls - mixes two controls based on the mix_ratio // mix_ratio of 1 = use first_control completely, 0 = use second_control completely, 0.5 = mix evenly static int16_t poshold_mix_controls(float mix_ratio, int16_t first_control, int16_t second_control) { mix_ratio = constrain_float(mix_ratio, 0.0f, 1.0f); return (int16_t)((mix_ratio * first_control) + ((1.0f-mix_ratio)*second_control)); } // poshold_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.poshold_brake_rate and constrained by the wpnav.poshold_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 poshold_update_brake_angle_from_velocity(int16_t &brake_angle, float velocity) { float lean_angle; int16_t brake_rate = g.poshold_brake_rate; #if MAIN_LOOP_RATE == 400 brake_rate /= 4; if (brake_rate <= 0) { brake_rate = 1; } #endif // calculate velocity-only based lean angle if (velocity >= 0) { lean_angle = -poshold.brake_gain * velocity * (1.0f+500.0f/(velocity+60.0f)); } else { lean_angle = -poshold.brake_gain * velocity * (1.0f+500.0f/(-velocity+60.0f)); } // do not let lean_angle be too far from brake_angle brake_angle = constrain_int16((int16_t)lean_angle, brake_angle - brake_rate, brake_angle + brake_rate); // constrain final brake_angle brake_angle = constrain_int16(brake_angle, -g.poshold_brake_angle_max, g.poshold_brake_angle_max); } // poshold_update_wind_comp_estimate - updates wind compensation estimate // should be called at the maximum loop rate when loiter is engaged static void poshold_update_wind_comp_estimate() { // check wind estimate start has not been delayed if (poshold.wind_comp_start_timer > 0) { poshold.wind_comp_start_timer--; return; } // check horizontal velocity is low if (inertial_nav.get_velocity_xy() > POSHOLD_WIND_COMP_ESTIMATE_SPEED_MAX) { return; } // get position controller accel target // To-Do: clean this up by using accessor in loiter controller (or move entire PosHold 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 (poshold.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 poshold.wind_comp_ef.x = accel_target.x; } else { // low pass filter the position controller's lean angle output poshold.wind_comp_ef.x = (1.0f-TC_WIND_COMP)*poshold.wind_comp_ef.x + TC_WIND_COMP*accel_target.x; } if (poshold.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 poshold.wind_comp_ef.y = accel_target.y; } else { // low pass filter the position controller's lean angle output poshold.wind_comp_ef.y = (1.0f-TC_WIND_COMP)*poshold.wind_comp_ef.y + TC_WIND_COMP*accel_target.y; } } // poshold_get_wind_comp_lean_angles - retrieve wind compensation angles in body frame roll and pitch angles // should be called at the maximum loop rate static void poshold_get_wind_comp_lean_angles(int16_t &roll_angle, int16_t &pitch_angle) { // reduce rate to 10hz poshold.wind_comp_timer++; if (poshold.wind_comp_timer < POSHOLD_WIND_COMP_TIMER_10HZ) { return; } poshold.wind_comp_timer = 0; // convert earth frame desired accelerations to body frame roll and pitch lean angles roll_angle = (float)fast_atan((-poshold.wind_comp_ef.x*ahrs.sin_yaw() + poshold.wind_comp_ef.y*ahrs.cos_yaw())/981)*(18000/M_PI); pitch_angle = (float)fast_atan(-(poshold.wind_comp_ef.x*ahrs.cos_yaw() + poshold.wind_comp_ef.y*ahrs.sin_yaw())/981)*(18000/M_PI); } // poshold_roll_controller_to_pilot_override - initialises transition from a controller submode (brake or loiter) to a pilot override on roll axis static void poshold_roll_controller_to_pilot_override() { poshold.roll_mode = POSHOLD_CONTROLLER_TO_PILOT_OVERRIDE; poshold.controller_to_pilot_timer_roll = POSHOLD_CONTROLLER_TO_PILOT_MIX_TIMER; // initialise pilot_roll to 0, wind_comp will be updated to compensate and poshold_update_pilot_lean_angle function shall not smooth this transition at next iteration. so 0 is the right value poshold.pilot_roll = 0; // store final controller output for mixing with pilot input poshold.controller_final_roll = poshold.roll; } // poshold_pitch_controller_to_pilot_override - initialises transition from a controller submode (brake or loiter) to a pilot override on roll axis static void poshold_pitch_controller_to_pilot_override() { poshold.pitch_mode = POSHOLD_CONTROLLER_TO_PILOT_OVERRIDE; poshold.controller_to_pilot_timer_pitch = POSHOLD_CONTROLLER_TO_PILOT_MIX_TIMER; // initialise pilot_pitch to 0, wind_comp will be updated to compensate and poshold_update_pilot_lean_angle function shall not smooth this transition at next iteration. so 0 is the right value poshold.pilot_pitch = 0; // store final loiter outputs for mixing with pilot input poshold.controller_final_pitch = poshold.pitch; } #endif // POSHOLD_ENABLED == ENABLED