// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*- #include "AC_AttitudeControl.h" #include #include // table of user settable parameters const AP_Param::GroupInfo AC_AttitudeControl::var_info[] PROGMEM = { // 0, 1 were RATE_RP_MAX, RATE_Y_MAX // @Param: SLEW_YAW // @DisplayName: Yaw target slew rate // @Description: Maximum rate the yaw target can be updated in Loiter, RTL, Auto flight modes // @Units: Centi-Degrees/Sec // @Range: 500 18000 // @Increment: 100 // @User: Advanced AP_GROUPINFO("SLEW_YAW", 2, AC_AttitudeControl, _slew_yaw, AC_ATTITUDE_CONTROL_SLEW_YAW_DEFAULT), // 3 was for ACCEL_RP_MAX // @Param: ACCEL_Y_MAX // @DisplayName: Acceleration Max for Yaw // @Description: Maximum acceleration in yaw axis // @Units: Centi-Degrees/Sec/Sec // @Range: 0 72000 // @Values: 0:Disabled, 18000:Slow, 36000:Medium, 54000:Fast // @Increment: 1000 // @User: Advanced AP_GROUPINFO("ACCEL_Y_MAX", 4, AC_AttitudeControl, _accel_yaw_max, AC_ATTITUDE_CONTROL_ACCEL_Y_MAX_DEFAULT), // @Param: RATE_FF_ENAB // @DisplayName: Rate Feedforward Enable // @Description: Controls whether body-frame rate feedfoward is enabled or disabled // @Values: 0:Disabled, 1:Enabled // @User: Advanced AP_GROUPINFO("RATE_FF_ENAB", 5, AC_AttitudeControl, _rate_bf_ff_enabled, AC_ATTITUDE_CONTROL_RATE_BF_FF_DEFAULT), // @Param: ACCEL_R_MAX // @DisplayName: Acceleration Max for Roll // @Description: Maximum acceleration in roll axis // @Units: Centi-Degrees/Sec/Sec // @Range: 0 180000 // @Increment: 1000 // @Values: 0:Disabled, 72000:Slow, 108000:Medium, 162000:Fast // @User: Advanced AP_GROUPINFO("ACCEL_R_MAX", 6, AC_AttitudeControl, _accel_roll_max, AC_ATTITUDE_CONTROL_ACCEL_RP_MAX_DEFAULT), // @Param: ACCEL_P_MAX // @DisplayName: Acceleration Max for Pitch // @Description: Maximum acceleration in pitch axis // @Units: Centi-Degrees/Sec/Sec // @Range: 0 180000 // @Increment: 1000 // @Values: 0:Disabled, 72000:Slow, 108000:Medium, 162000:Fast // @User: Advanced AP_GROUPINFO("ACCEL_P_MAX", 7, AC_AttitudeControl, _accel_pitch_max, AC_ATTITUDE_CONTROL_ACCEL_RP_MAX_DEFAULT), AP_GROUPEND }; // // high level controllers // void AC_AttitudeControl::set_dt(float delta_sec) { _dt = delta_sec; // set attitude controller's D term filters _pid_rate_roll.set_dt(_dt); _pid_rate_pitch.set_dt(_dt); _pid_rate_yaw.set_dt(_dt); } // relax_bf_rate_controller - ensure body-frame rate controller has zero errors to relax rate controller output void AC_AttitudeControl::relax_bf_rate_controller() { // ensure zero error in body frame rate controllers const Vector3f& gyro = _ahrs.get_gyro(); _rate_bf_target = gyro * AC_ATTITUDE_CONTROL_DEGX100; _pid_rate_roll.reset_I(); _pid_rate_pitch.reset_I(); _pid_rate_yaw.reset_I(); } // shifts earth frame yaw target by yaw_shift_cd. yaw_shift_cd should be in centi-degreesa and is added to the current target heading void AC_AttitudeControl::shift_ef_yaw_target(float yaw_shift_cd) { _angle_ef_target.z = wrap_360_cd_float(_angle_ef_target.z + yaw_shift_cd); } // // methods to be called by upper controllers to request and implement a desired attitude // // angle_ef_roll_pitch_rate_ef_yaw_smooth - attempts to maintain a roll and pitch angle and yaw rate (all earth frame) while smoothing the attitude based on the feel parameter // smoothing_gain : a number from 1 to 50 with 1 being sluggish and 50 being very crisp void AC_AttitudeControl::angle_ef_roll_pitch_rate_ef_yaw_smooth(float roll_angle_ef, float pitch_angle_ef, float yaw_rate_ef, float smoothing_gain) { float rate_ef_desired; float rate_change_limit; Vector3f angle_ef_error; // earth frame angle errors // sanity check smoothing gain smoothing_gain = constrain_float(smoothing_gain,1.0f,50.0f); // if accel limiting and feed forward enabled if ((_accel_roll_max > 0.0f) && _rate_bf_ff_enabled) { rate_change_limit = _accel_roll_max * _dt; // calculate earth-frame feed forward roll rate using linear response when close to the target, sqrt response when we're further away rate_ef_desired = sqrt_controller(roll_angle_ef-_angle_ef_target.x, smoothing_gain, _accel_roll_max); // apply acceleration limit to feed forward roll rate _rate_ef_desired.x = constrain_float(rate_ef_desired, _rate_ef_desired.x-rate_change_limit, _rate_ef_desired.x+rate_change_limit); // update earth-frame roll angle target using desired roll rate update_ef_roll_angle_and_error(_rate_ef_desired.x, angle_ef_error, AC_ATTITUDE_RATE_STAB_ROLL_OVERSHOOT_ANGLE_MAX); } else { // target roll and pitch to desired input roll and pitch _angle_ef_target.x = roll_angle_ef; angle_ef_error.x = wrap_180_cd_float(_angle_ef_target.x - _ahrs.roll_sensor); // set roll and pitch feed forward to zero _rate_ef_desired.x = 0; } // constrain earth-frame angle targets _angle_ef_target.x = constrain_float(_angle_ef_target.x, -_aparm.angle_max, _aparm.angle_max); // if accel limiting and feed forward enabled if ((_accel_pitch_max > 0.0f) && _rate_bf_ff_enabled) { rate_change_limit = _accel_pitch_max * _dt; // calculate earth-frame feed forward pitch rate using linear response when close to the target, sqrt response when we're further away rate_ef_desired = sqrt_controller(pitch_angle_ef-_angle_ef_target.y, smoothing_gain, _accel_pitch_max); // apply acceleration limit to feed forward pitch rate _rate_ef_desired.y = constrain_float(rate_ef_desired, _rate_ef_desired.y-rate_change_limit, _rate_ef_desired.y+rate_change_limit); // update earth-frame pitch angle target using desired pitch rate update_ef_pitch_angle_and_error(_rate_ef_desired.y, angle_ef_error, AC_ATTITUDE_RATE_STAB_PITCH_OVERSHOOT_ANGLE_MAX); } else { // target roll and pitch to desired input roll and pitch _angle_ef_target.y = pitch_angle_ef; angle_ef_error.y = wrap_180_cd_float(_angle_ef_target.y - _ahrs.pitch_sensor); // set roll and pitch feed forward to zero _rate_ef_desired.y = 0; } // constrain earth-frame angle targets _angle_ef_target.y = constrain_float(_angle_ef_target.y, -_aparm.angle_max, _aparm.angle_max); if (_accel_yaw_max > 0.0f) { // set earth-frame feed forward rate for yaw rate_change_limit = _accel_yaw_max * _dt; // update yaw rate target with acceleration limit _rate_ef_desired.z += constrain_float(yaw_rate_ef - _rate_ef_desired.z, -rate_change_limit, rate_change_limit); // calculate yaw target angle and angle error update_ef_yaw_angle_and_error(_rate_ef_desired.z, angle_ef_error, AC_ATTITUDE_RATE_STAB_YAW_OVERSHOOT_ANGLE_MAX); } else { // set yaw feed forward to zero _rate_ef_desired.z = yaw_rate_ef; // calculate yaw target angle and angle error update_ef_yaw_angle_and_error(_rate_ef_desired.z, angle_ef_error, AC_ATTITUDE_RATE_STAB_YAW_OVERSHOOT_ANGLE_MAX); } // convert earth-frame angle errors to body-frame angle errors frame_conversion_ef_to_bf(angle_ef_error, _angle_bf_error); // convert body-frame angle errors to body-frame rate targets update_rate_bf_targets(); // add body frame rate feed forward if (_rate_bf_ff_enabled) { // convert earth-frame feed forward rates to body-frame feed forward rates frame_conversion_ef_to_bf(_rate_ef_desired, _rate_bf_desired); _rate_bf_target += _rate_bf_desired; } else { // convert earth-frame feed forward rates to body-frame feed forward rates frame_conversion_ef_to_bf(Vector3f(0,0,_rate_ef_desired.z), _rate_bf_desired); _rate_bf_target += _rate_bf_desired; } // body-frame to motor outputs should be called separately } // // methods to be called by upper controllers to request and implement a desired attitude // // angle_ef_roll_pitch_rate_ef_yaw - attempts to maintain a roll and pitch angle and yaw rate (all earth frame) void AC_AttitudeControl::angle_ef_roll_pitch_rate_ef_yaw(float roll_angle_ef, float pitch_angle_ef, float yaw_rate_ef) { Vector3f angle_ef_error; // earth frame angle errors // set earth-frame angle targets for roll and pitch and calculate angle error _angle_ef_target.x = constrain_float(roll_angle_ef, -_aparm.angle_max, _aparm.angle_max); angle_ef_error.x = wrap_180_cd_float(_angle_ef_target.x - _ahrs.roll_sensor); _angle_ef_target.y = constrain_float(pitch_angle_ef, -_aparm.angle_max, _aparm.angle_max); angle_ef_error.y = wrap_180_cd_float(_angle_ef_target.y - _ahrs.pitch_sensor); if (_accel_yaw_max > 0.0f) { // set earth-frame feed forward rate for yaw float rate_change_limit = _accel_yaw_max * _dt; float rate_change = yaw_rate_ef - _rate_ef_desired.z; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_ef_desired.z += rate_change; // calculate yaw target angle and angle error update_ef_yaw_angle_and_error(_rate_ef_desired.z, angle_ef_error, AC_ATTITUDE_RATE_STAB_YAW_OVERSHOOT_ANGLE_MAX); } else { // set yaw feed forward to zero _rate_ef_desired.z = yaw_rate_ef; // calculate yaw target angle and angle error update_ef_yaw_angle_and_error(_rate_ef_desired.z, angle_ef_error, AC_ATTITUDE_RATE_STAB_YAW_OVERSHOOT_ANGLE_MAX); } // convert earth-frame angle errors to body-frame angle errors frame_conversion_ef_to_bf(angle_ef_error, _angle_bf_error); // convert body-frame angle errors to body-frame rate targets update_rate_bf_targets(); // set roll and pitch feed forward to zero _rate_ef_desired.x = 0; _rate_ef_desired.y = 0; // convert earth-frame feed forward rates to body-frame feed forward rates frame_conversion_ef_to_bf(_rate_ef_desired, _rate_bf_desired); _rate_bf_target += _rate_bf_desired; // body-frame to motor outputs should be called separately } // angle_ef_roll_pitch_yaw - attempts to maintain a roll, pitch and yaw angle (all earth frame) // if yaw_slew is true then target yaw movement will be gradually moved to the new target based on the SLEW_YAW parameter void AC_AttitudeControl::angle_ef_roll_pitch_yaw(float roll_angle_ef, float pitch_angle_ef, float yaw_angle_ef, bool slew_yaw) { Vector3f angle_ef_error; // set earth-frame angle targets _angle_ef_target.x = constrain_float(roll_angle_ef, -_aparm.angle_max, _aparm.angle_max); _angle_ef_target.y = constrain_float(pitch_angle_ef, -_aparm.angle_max, _aparm.angle_max); _angle_ef_target.z = yaw_angle_ef; // calculate earth frame errors angle_ef_error.x = wrap_180_cd_float(_angle_ef_target.x - _ahrs.roll_sensor); angle_ef_error.y = wrap_180_cd_float(_angle_ef_target.y - _ahrs.pitch_sensor); angle_ef_error.z = wrap_180_cd_float(_angle_ef_target.z - _ahrs.yaw_sensor); // constrain the yaw angle error if (slew_yaw) { angle_ef_error.z = constrain_float(angle_ef_error.z,-_slew_yaw,_slew_yaw); } // convert earth-frame angle errors to body-frame angle errors frame_conversion_ef_to_bf(angle_ef_error, _angle_bf_error); // convert body-frame angle errors to body-frame rate targets update_rate_bf_targets(); // body-frame to motor outputs should be called separately } // rate_ef_roll_pitch_yaw - attempts to maintain a roll, pitch and yaw rate (all earth frame) void AC_AttitudeControl::rate_ef_roll_pitch_yaw(float roll_rate_ef, float pitch_rate_ef, float yaw_rate_ef) { Vector3f angle_ef_error; float rate_change_limit, rate_change; if (_accel_roll_max > 0.0f) { rate_change_limit = _accel_roll_max * _dt; // update feed forward roll rate after checking it is within acceleration limits rate_change = roll_rate_ef - _rate_ef_desired.x; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_ef_desired.x += rate_change; } else { _rate_ef_desired.x = roll_rate_ef; } if (_accel_pitch_max > 0.0f) { rate_change_limit = _accel_pitch_max * _dt; // update feed forward pitch rate after checking it is within acceleration limits rate_change = pitch_rate_ef - _rate_ef_desired.y; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_ef_desired.y += rate_change; } else { _rate_ef_desired.y = pitch_rate_ef; } if (_accel_yaw_max > 0.0f) { rate_change_limit = _accel_yaw_max * _dt; // update feed forward yaw rate after checking it is within acceleration limits rate_change = yaw_rate_ef - _rate_ef_desired.z; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_ef_desired.z += rate_change; } else { _rate_ef_desired.z = yaw_rate_ef; } // update earth frame angle targets and errors update_ef_roll_angle_and_error(_rate_ef_desired.x, angle_ef_error, AC_ATTITUDE_RATE_STAB_ROLL_OVERSHOOT_ANGLE_MAX); update_ef_pitch_angle_and_error(_rate_ef_desired.y, angle_ef_error, AC_ATTITUDE_RATE_STAB_PITCH_OVERSHOOT_ANGLE_MAX); update_ef_yaw_angle_and_error(_rate_ef_desired.z, angle_ef_error, AC_ATTITUDE_RATE_STAB_YAW_OVERSHOOT_ANGLE_MAX); // constrain earth-frame angle targets _angle_ef_target.x = constrain_float(_angle_ef_target.x, -_aparm.angle_max, _aparm.angle_max); _angle_ef_target.y = constrain_float(_angle_ef_target.y, -_aparm.angle_max, _aparm.angle_max); // convert earth-frame angle errors to body-frame angle errors frame_conversion_ef_to_bf(angle_ef_error, _angle_bf_error); // convert body-frame angle errors to body-frame rate targets update_rate_bf_targets(); // convert earth-frame rates to body-frame rates frame_conversion_ef_to_bf(_rate_ef_desired, _rate_bf_desired); // add body frame rate feed forward _rate_bf_target += _rate_bf_desired; // body-frame to motor outputs should be called separately } // rate_bf_roll_pitch_yaw - attempts to maintain a roll, pitch and yaw rate (all body frame) void AC_AttitudeControl::rate_bf_roll_pitch_yaw(float roll_rate_bf, float pitch_rate_bf, float yaw_rate_bf) { Vector3f angle_ef_error; float rate_change, rate_change_limit; // update the rate feed forward with angular acceleration limits if (_accel_roll_max > 0.0f) { rate_change_limit = _accel_roll_max * _dt; rate_change = roll_rate_bf - _rate_bf_desired.x; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_bf_desired.x += rate_change; } else { _rate_bf_desired.x = roll_rate_bf; } // update the rate feed forward with angular acceleration limits if (_accel_pitch_max > 0.0f) { rate_change_limit = _accel_pitch_max * _dt; rate_change = pitch_rate_bf - _rate_bf_desired.y; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_bf_desired.y += rate_change; } else { _rate_bf_desired.y = pitch_rate_bf; } if (_accel_yaw_max > 0.0f) { rate_change_limit = _accel_yaw_max * _dt; rate_change = yaw_rate_bf - _rate_bf_desired.z; rate_change = constrain_float(rate_change, -rate_change_limit, rate_change_limit); _rate_bf_desired.z += rate_change; } else { _rate_bf_desired.z = yaw_rate_bf; } // Update angle error if (labs(_ahrs.pitch_sensor)<_acro_angle_switch) { _acro_angle_switch = 6000; // convert body-frame rates to earth-frame rates frame_conversion_bf_to_ef(_rate_bf_desired, _rate_ef_desired); // update earth frame angle targets and errors update_ef_roll_angle_and_error(_rate_ef_desired.x, angle_ef_error, AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX); update_ef_pitch_angle_and_error(_rate_ef_desired.y, angle_ef_error, AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX); update_ef_yaw_angle_and_error(_rate_ef_desired.z, angle_ef_error, AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX); // convert earth-frame angle errors to body-frame angle errors frame_conversion_ef_to_bf(angle_ef_error, _angle_bf_error); } else { _acro_angle_switch = 4500; integrate_bf_rate_error_to_angle_errors(); if (frame_conversion_bf_to_ef(_angle_bf_error, angle_ef_error)) { _angle_ef_target.x = wrap_180_cd_float(angle_ef_error.x + _ahrs.roll_sensor); _angle_ef_target.y = wrap_180_cd_float(angle_ef_error.y + _ahrs.pitch_sensor); _angle_ef_target.z = wrap_360_cd_float(angle_ef_error.z + _ahrs.yaw_sensor); } if (_angle_ef_target.y > 9000.0f) { _angle_ef_target.x = wrap_180_cd_float(_angle_ef_target.x + 18000.0f); _angle_ef_target.y = wrap_180_cd_float(18000.0f - _angle_ef_target.y); _angle_ef_target.z = wrap_360_cd_float(_angle_ef_target.z + 18000.0f); } if (_angle_ef_target.y < -9000.0f) { _angle_ef_target.x = wrap_180_cd_float(_angle_ef_target.x + 18000.0f); _angle_ef_target.y = wrap_180_cd_float(-18000.0f - _angle_ef_target.y); _angle_ef_target.z = wrap_360_cd_float(_angle_ef_target.z + 18000.0f); } } // convert body-frame angle errors to body-frame rate targets update_rate_bf_targets(); // body-frame rate commands added _rate_bf_target += _rate_bf_desired; } // // rate_controller_run - run lowest level body-frame rate controller and send outputs to the motors // should be called at 100hz or more // void AC_AttitudeControl::rate_controller_run() { // call rate controllers and send output to motors object // To-Do: should the outputs from get_rate_roll, pitch, yaw be int16_t which is the input to the motors library? // To-Do: skip this step if the throttle out is zero? _motors.set_roll(rate_bf_to_motor_roll(_rate_bf_target.x)); _motors.set_pitch(rate_bf_to_motor_pitch(_rate_bf_target.y)); _motors.set_yaw(rate_bf_to_motor_yaw(_rate_bf_target.z)); } // // earth-frame <-> body-frame conversion functions // // frame_conversion_ef_to_bf - converts earth frame vector to body frame vector void AC_AttitudeControl::frame_conversion_ef_to_bf(const Vector3f& ef_vector, Vector3f& bf_vector) { // convert earth frame rates to body frame rates bf_vector.x = ef_vector.x - _ahrs.sin_pitch() * ef_vector.z; bf_vector.y = _ahrs.cos_roll() * ef_vector.y + _ahrs.sin_roll() * _ahrs.cos_pitch() * ef_vector.z; bf_vector.z = -_ahrs.sin_roll() * ef_vector.y + _ahrs.cos_pitch() * _ahrs.cos_roll() * ef_vector.z; } // frame_conversion_bf_to_ef - converts body frame vector to earth frame vector bool AC_AttitudeControl::frame_conversion_bf_to_ef(const Vector3f& bf_vector, Vector3f& ef_vector) { // avoid divide by zero if (is_zero(_ahrs.cos_pitch())) { return false; } // convert earth frame angle or rates to body frame ef_vector.x = bf_vector.x + _ahrs.sin_roll() * (_ahrs.sin_pitch()/_ahrs.cos_pitch()) * bf_vector.y + _ahrs.cos_roll() * (_ahrs.sin_pitch()/_ahrs.cos_pitch()) * bf_vector.z; ef_vector.y = _ahrs.cos_roll() * bf_vector.y - _ahrs.sin_roll() * bf_vector.z; ef_vector.z = (_ahrs.sin_roll() / _ahrs.cos_pitch()) * bf_vector.y + (_ahrs.cos_roll() / _ahrs.cos_pitch()) * bf_vector.z; return true; } // // protected methods // // // stabilized rate controller (body-frame) methods // // update_ef_roll_angle_and_error - update _angle_ef_target.x using an earth frame roll rate request void AC_AttitudeControl::update_ef_roll_angle_and_error(float roll_rate_ef, Vector3f &angle_ef_error, float overshoot_max) { // calculate angle error with maximum of +- max angle overshoot angle_ef_error.x = wrap_180_cd(_angle_ef_target.x - _ahrs.roll_sensor); angle_ef_error.x = constrain_float(angle_ef_error.x, -overshoot_max, overshoot_max); // update roll angle target to be within max angle overshoot of our roll angle _angle_ef_target.x = angle_ef_error.x + _ahrs.roll_sensor; // increment the roll angle target _angle_ef_target.x += roll_rate_ef * _dt; _angle_ef_target.x = wrap_180_cd(_angle_ef_target.x); } // update_ef_pitch_angle_and_error - update _angle_ef_target.y using an earth frame pitch rate request void AC_AttitudeControl::update_ef_pitch_angle_and_error(float pitch_rate_ef, Vector3f &angle_ef_error, float overshoot_max) { // calculate angle error with maximum of +- max angle overshoot // To-Do: should we do something better as we cross 90 degrees? angle_ef_error.y = wrap_180_cd(_angle_ef_target.y - _ahrs.pitch_sensor); angle_ef_error.y = constrain_float(angle_ef_error.y, -overshoot_max, overshoot_max); // update pitch angle target to be within max angle overshoot of our pitch angle _angle_ef_target.y = angle_ef_error.y + _ahrs.pitch_sensor; // increment the pitch angle target _angle_ef_target.y += pitch_rate_ef * _dt; _angle_ef_target.y = wrap_180_cd(_angle_ef_target.y); } // update_ef_yaw_angle_and_error - update _angle_ef_target.z using an earth frame yaw rate request void AC_AttitudeControl::update_ef_yaw_angle_and_error(float yaw_rate_ef, Vector3f &angle_ef_error, float overshoot_max) { // calculate angle error with maximum of +- max angle overshoot angle_ef_error.z = wrap_180_cd(_angle_ef_target.z - _ahrs.yaw_sensor); angle_ef_error.z = constrain_float(angle_ef_error.z, -overshoot_max, overshoot_max); // update yaw angle target to be within max angle overshoot of our current heading _angle_ef_target.z = angle_ef_error.z + _ahrs.yaw_sensor; // increment the yaw angle target _angle_ef_target.z += yaw_rate_ef * _dt; _angle_ef_target.z = wrap_360_cd(_angle_ef_target.z); } // update_rate_bf_errors - calculates body frame angle errors // body-frame feed forward rates (centi-degrees / second) taken from _angle_bf_error // angle errors in centi-degrees placed in _angle_bf_error void AC_AttitudeControl::integrate_bf_rate_error_to_angle_errors() { // roll - calculate body-frame angle error by integrating body-frame rate error _angle_bf_error.x += (_rate_bf_desired.x - (_ahrs.get_gyro().x * AC_ATTITUDE_CONTROL_DEGX100)) * _dt; // roll - limit maximum error _angle_bf_error.x = constrain_float(_angle_bf_error.x, -AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX, AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX); // pitch - calculate body-frame angle error by integrating body-frame rate error _angle_bf_error.y += (_rate_bf_desired.y - (_ahrs.get_gyro().y * AC_ATTITUDE_CONTROL_DEGX100)) * _dt; // pitch - limit maximum error _angle_bf_error.y = constrain_float(_angle_bf_error.y, -AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX, AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX); // yaw - calculate body-frame angle error by integrating body-frame rate error _angle_bf_error.z += (_rate_bf_desired.z - (_ahrs.get_gyro().z * AC_ATTITUDE_CONTROL_DEGX100)) * _dt; // yaw - limit maximum error _angle_bf_error.z = constrain_float(_angle_bf_error.z, -AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX, AC_ATTITUDE_RATE_STAB_ACRO_OVERSHOOT_ANGLE_MAX); // To-Do: handle case of motors being disarmed or channel_throttle == 0 and set error to zero } // update_rate_bf_targets - converts body-frame angle error to body-frame rate targets for roll, pitch and yaw axis // targets rates in centi-degrees taken from _angle_bf_error // results in centi-degrees/sec put into _rate_bf_target void AC_AttitudeControl::update_rate_bf_targets() { // stab roll calculation // constrain roll rate request if (_flags.limit_angle_to_rate_request) { _rate_bf_target.x = sqrt_controller(_angle_bf_error.x, _p_angle_roll.kP(), constrain_float(_accel_roll_max/2.0f, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MIN, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MAX)); }else{ _rate_bf_target.x = _p_angle_roll.kP() * _angle_bf_error.x; } // stab pitch calculation // constrain pitch rate request if (_flags.limit_angle_to_rate_request) { _rate_bf_target.y = sqrt_controller(_angle_bf_error.y, _p_angle_pitch.kP(), constrain_float(_accel_pitch_max/2.0f, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MIN, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MAX)); }else{ _rate_bf_target.y = _p_angle_pitch.kP() * _angle_bf_error.y; } // stab yaw calculation // constrain yaw rate request if (_flags.limit_angle_to_rate_request) { _rate_bf_target.z = sqrt_controller(_angle_bf_error.z, _p_angle_yaw.kP(), constrain_float(_accel_yaw_max/2.0f, AC_ATTITUDE_ACCEL_Y_CONTROLLER_MIN, AC_ATTITUDE_ACCEL_Y_CONTROLLER_MAX)); }else{ _rate_bf_target.z = _p_angle_yaw.kP() * _angle_bf_error.z; } // include roll and pitch rate required to account for precession of the desired attitude about the body frame yaw axes _rate_bf_target.x += _angle_bf_error.y * _ahrs.get_gyro().z; _rate_bf_target.y += -_angle_bf_error.x * _ahrs.get_gyro().z; } // // body-frame rate controller // // rate_bf_to_motor_roll - ask the rate controller to calculate the motor outputs to achieve the target rate in centi-degrees / second float AC_AttitudeControl::rate_bf_to_motor_roll(float rate_target_cds) { float p,i,d; // used to capture pid values for logging float current_rate; // this iteration's rate float rate_error; // simply target_rate - current_rate // get current rate // To-Do: make getting gyro rates more efficient? current_rate = (_ahrs.get_gyro().x * AC_ATTITUDE_CONTROL_DEGX100); // calculate error and call pid controller rate_error = rate_target_cds - current_rate; _pid_rate_roll.set_input_filter_d(rate_error); _pid_rate_roll.set_desired_rate(rate_target_cds); // get p value p = _pid_rate_roll.get_p(); // get i term i = _pid_rate_roll.get_integrator(); // update i term as long as we haven't breached the limits or the I term will certainly reduce if (!_motors.limit.roll_pitch || ((i>0&&rate_error<0)||(i<0&&rate_error>0))) { i = _pid_rate_roll.get_i(); } // get d term d = _pid_rate_roll.get_d(); // constrain output and return return constrain_float((p+i+d), -AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX, AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX); } // rate_bf_to_motor_pitch - ask the rate controller to calculate the motor outputs to achieve the target rate in centi-degrees / second float AC_AttitudeControl::rate_bf_to_motor_pitch(float rate_target_cds) { float p,i,d; // used to capture pid values for logging float current_rate; // this iteration's rate float rate_error; // simply target_rate - current_rate // get current rate // To-Do: make getting gyro rates more efficient? current_rate = (_ahrs.get_gyro().y * AC_ATTITUDE_CONTROL_DEGX100); // calculate error and call pid controller rate_error = rate_target_cds - current_rate; _pid_rate_pitch.set_input_filter_d(rate_error); _pid_rate_pitch.set_desired_rate(rate_target_cds); // get p value p = _pid_rate_pitch.get_p(); // get i term i = _pid_rate_pitch.get_integrator(); // update i term as long as we haven't breached the limits or the I term will certainly reduce if (!_motors.limit.roll_pitch || ((i>0&&rate_error<0)||(i<0&&rate_error>0))) { i = _pid_rate_pitch.get_i(); } // get d term d = _pid_rate_pitch.get_d(); // constrain output and return return constrain_float((p+i+d), -AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX, AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX); } // rate_bf_to_motor_yaw - ask the rate controller to calculate the motor outputs to achieve the target rate in centi-degrees / second float AC_AttitudeControl::rate_bf_to_motor_yaw(float rate_target_cds) { float p,i,d; // used to capture pid values for logging float current_rate; // this iteration's rate float rate_error; // simply target_rate - current_rate // get current rate // To-Do: make getting gyro rates more efficient? current_rate = (_ahrs.get_gyro().z * AC_ATTITUDE_CONTROL_DEGX100); // calculate error and call pid controller rate_error = rate_target_cds - current_rate; _pid_rate_yaw.set_input_filter_all(rate_error); _pid_rate_yaw.set_desired_rate(rate_target_cds); // get p value p = _pid_rate_yaw.get_p(); // get i term i = _pid_rate_yaw.get_integrator(); // update i term as long as we haven't breached the limits or the I term will certainly reduce if (!_motors.limit.yaw || ((i>0&&rate_error<0)||(i<0&&rate_error>0))) { i = _pid_rate_yaw.get_i(); } // get d value d = _pid_rate_yaw.get_d(); // constrain output and return return constrain_float((p+i+d), -AC_ATTITUDE_RATE_YAW_CONTROLLER_OUT_MAX, AC_ATTITUDE_RATE_YAW_CONTROLLER_OUT_MAX); } // accel_limiting - enable or disable accel limiting void AC_AttitudeControl::accel_limiting(bool enable_limits) { if (enable_limits) { // if enabling limits, reload from eeprom or set to defaults if (is_zero(_accel_roll_max)) { _accel_roll_max.load(); } // if enabling limits, reload from eeprom or set to defaults if (is_zero(_accel_pitch_max)) { _accel_pitch_max.load(); } if (is_zero(_accel_yaw_max)) { _accel_yaw_max.load(); } } else { // if disabling limits, set to zero _accel_roll_max = 0.0f; _accel_pitch_max = 0.0f; _accel_yaw_max = 0.0f; } } // // throttle functions // // set_throttle_out - to be called by upper throttle controllers when they wish to provide throttle output directly to motors // provide 0 to cut motors void AC_AttitudeControl::set_throttle_out(float throttle_out, bool apply_angle_boost, float filter_cutoff) { _motors.set_stabilizing(true); _motors.set_throttle_filter_cutoff(filter_cutoff); if (apply_angle_boost) { _motors.set_throttle(get_boosted_throttle(throttle_out)); }else{ _motors.set_throttle(throttle_out); // clear angle_boost for logging purposes _angle_boost = 0; } } // outputs a throttle to all motors evenly with no attitude stabilization void AC_AttitudeControl::set_throttle_out_unstabilized(float throttle_in, bool reset_attitude_control, float filter_cutoff) { if (reset_attitude_control) { relax_bf_rate_controller(); set_yaw_target_to_current_heading(); } _motors.set_throttle_filter_cutoff(filter_cutoff); _motors.set_stabilizing(false); _motors.set_throttle(throttle_in); _angle_boost = 0; } // sqrt_controller - response based on the sqrt of the error instead of the more common linear response float AC_AttitudeControl::sqrt_controller(float error, float p, float second_ord_lim) { if (is_zero(second_ord_lim) || is_zero(p)) { return error*p; } float linear_dist = second_ord_lim/sq(p); if (error > linear_dist) { return safe_sqrt(2.0f*second_ord_lim*(error-(linear_dist/2.0f))); } else if (error < -linear_dist) { return -safe_sqrt(2.0f*second_ord_lim*(-error-(linear_dist/2.0f))); } else { return error*p; } } // Maximum roll rate step size that results in maximum output after 4 time steps float AC_AttitudeControl::max_rate_step_bf_roll() { float alpha = _pid_rate_roll.get_filt_alpha(); float alpha_remaining = 1-alpha; return AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX/((alpha_remaining*alpha_remaining*alpha_remaining*alpha*_pid_rate_roll.kD())/_dt + _pid_rate_roll.kP()); } // Maximum pitch rate step size that results in maximum output after 4 time steps float AC_AttitudeControl::max_rate_step_bf_pitch() { float alpha = _pid_rate_pitch.get_filt_alpha(); float alpha_remaining = 1-alpha; return AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX/((alpha_remaining*alpha_remaining*alpha_remaining*alpha*_pid_rate_pitch.kD())/_dt + _pid_rate_pitch.kP()); } // Maximum yaw rate step size that results in maximum output after 4 time steps float AC_AttitudeControl::max_rate_step_bf_yaw() { float alpha = _pid_rate_yaw.get_filt_alpha(); float alpha_remaining = 1-alpha; return AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX/((alpha_remaining*alpha_remaining*alpha_remaining*alpha*_pid_rate_yaw.kD())/_dt + _pid_rate_yaw.kP()); }