#include #include "AC_PosControl.h" #include #include #include // motors library #include extern const AP_HAL::HAL& hal; #if APM_BUILD_TYPE(APM_BUILD_ArduPlane) // default gains for Plane # define POSCONTROL_POS_Z_P 1.0f // vertical position controller P gain default # define POSCONTROL_VEL_Z_P 5.0f // vertical velocity controller P gain default # define POSCONTROL_VEL_Z_IMAX 1000.0f // vertical velocity controller IMAX gain default # define POSCONTROL_VEL_Z_FILT_HZ 5.0f // vertical velocity controller input filter # define POSCONTROL_VEL_Z_FILT_D_HZ 5.0f // vertical velocity controller input filter for D # define POSCONTROL_ACC_Z_P 0.3f // vertical acceleration controller P gain default # define POSCONTROL_ACC_Z_I 1.0f // vertical acceleration controller I gain default # define POSCONTROL_ACC_Z_D 0.0f // vertical acceleration controller D gain default # define POSCONTROL_ACC_Z_IMAX 800 // vertical acceleration controller IMAX gain default # define POSCONTROL_ACC_Z_FILT_HZ 10.0f // vertical acceleration controller input filter default # define POSCONTROL_ACC_Z_DT 0.02f // vertical acceleration controller dt default # define POSCONTROL_POS_XY_P 1.0f // horizontal position controller P gain default # define POSCONTROL_VEL_XY_P 1.4f // horizontal velocity controller P gain default # define POSCONTROL_VEL_XY_I 0.7f // horizontal velocity controller I gain default # define POSCONTROL_VEL_XY_D 0.35f // horizontal velocity controller D gain default # define POSCONTROL_VEL_XY_IMAX 1000.0f // horizontal velocity controller IMAX gain default # define POSCONTROL_VEL_XY_FILT_HZ 5.0f // horizontal velocity controller input filter # define POSCONTROL_VEL_XY_FILT_D_HZ 5.0f // horizontal velocity controller input filter for D #elif APM_BUILD_TYPE(APM_BUILD_ArduSub) // default gains for Sub # define POSCONTROL_POS_Z_P 3.0f // vertical position controller P gain default # define POSCONTROL_VEL_Z_P 8.0f // vertical velocity controller P gain default # define POSCONTROL_VEL_Z_IMAX 1000.0f // vertical velocity controller IMAX gain default # define POSCONTROL_VEL_Z_FILT_HZ 5.0f // vertical velocity controller input filter # define POSCONTROL_VEL_Z_FILT_D_HZ 5.0f // vertical velocity controller input filter for D # define POSCONTROL_ACC_Z_P 0.5f // vertical acceleration controller P gain default # define POSCONTROL_ACC_Z_I 0.1f // vertical acceleration controller I gain default # define POSCONTROL_ACC_Z_D 0.0f // vertical acceleration controller D gain default # define POSCONTROL_ACC_Z_IMAX 100 // vertical acceleration controller IMAX gain default # define POSCONTROL_ACC_Z_FILT_HZ 20.0f // vertical acceleration controller input filter default # define POSCONTROL_ACC_Z_DT 0.0025f // vertical acceleration controller dt default # define POSCONTROL_POS_XY_P 1.0f // horizontal position controller P gain default # define POSCONTROL_VEL_XY_P 1.0f // horizontal velocity controller P gain default # define POSCONTROL_VEL_XY_I 0.5f // horizontal velocity controller I gain default # define POSCONTROL_VEL_XY_D 0.0f // horizontal velocity controller D gain default # define POSCONTROL_VEL_XY_IMAX 1000.0f // horizontal velocity controller IMAX gain default # define POSCONTROL_VEL_XY_FILT_HZ 5.0f // horizontal velocity controller input filter # define POSCONTROL_VEL_XY_FILT_D_HZ 5.0f // horizontal velocity controller input filter for D #else // default gains for Copter / TradHeli # define POSCONTROL_POS_Z_P 1.0f // vertical position controller P gain default # define POSCONTROL_VEL_Z_P 5.0f // vertical velocity controller P gain default # define POSCONTROL_VEL_Z_IMAX 1000.0f // vertical velocity controller IMAX gain default # define POSCONTROL_VEL_Z_FILT_HZ 5.0f // vertical velocity controller input filter # define POSCONTROL_VEL_Z_FILT_D_HZ 5.0f // vertical velocity controller input filter for D # define POSCONTROL_ACC_Z_P 0.5f // vertical acceleration controller P gain default # define POSCONTROL_ACC_Z_I 1.0f // vertical acceleration controller I gain default # define POSCONTROL_ACC_Z_D 0.0f // vertical acceleration controller D gain default # define POSCONTROL_ACC_Z_IMAX 800 // vertical acceleration controller IMAX gain default # define POSCONTROL_ACC_Z_FILT_HZ 20.0f // vertical acceleration controller input filter default # define POSCONTROL_ACC_Z_DT 0.0025f // vertical acceleration controller dt default # define POSCONTROL_POS_XY_P 1.0f // horizontal position controller P gain default # define POSCONTROL_VEL_XY_P 2.0f // horizontal velocity controller P gain default # define POSCONTROL_VEL_XY_I 1.0f // horizontal velocity controller I gain default # define POSCONTROL_VEL_XY_D 0.5f // horizontal velocity controller D gain default # define POSCONTROL_VEL_XY_IMAX 1000.0f // horizontal velocity controller IMAX gain default # define POSCONTROL_VEL_XY_FILT_HZ 5.0f // horizontal velocity controller input filter # define POSCONTROL_VEL_XY_FILT_D_HZ 5.0f // horizontal velocity controller input filter for D #endif // vibration compensation gains #define POSCONTROL_VIBE_COMP_P_GAIN 0.250f #define POSCONTROL_VIBE_COMP_I_GAIN 0.125f const AP_Param::GroupInfo AC_PosControl::var_info[] = { // 0 was used for HOVER // @Param: _ACC_XY_FILT // @DisplayName: XY Acceleration filter cutoff frequency // @Description: Lower values will slow the response of the navigation controller and reduce twitchiness // @Units: Hz // @Range: 0.5 5 // @Increment: 0.1 // @User: Advanced // @Param: _POSZ_P // @DisplayName: Position (vertical) controller P gain // @Description: Position (vertical) controller P gain. Converts the difference between the desired altitude and actual altitude into a climb or descent rate which is passed to the throttle rate controller // @Range: 1.000 3.000 // @User: Standard AP_SUBGROUPINFO(_p_pos_z, "_POSZ_", 2, AC_PosControl, AC_P_1D), // @Param: _VELZ_P // @DisplayName: Velocity (vertical) controller P gain // @Description: Velocity (vertical) controller P gain. Converts the difference between desired vertical speed and actual speed into a desired acceleration that is passed to the throttle acceleration controller // @Range: 1.000 8.000 // @User: Standard // @Param: _VELZ_I // @DisplayName: Velocity (vertical) controller I gain // @Description: Velocity (vertical) controller I gain. Corrects long-term difference in desired velocity to a target acceleration // @Range: 0.02 1.00 // @Increment: 0.01 // @User: Advanced // @Param: _VELZ_IMAX // @DisplayName: Velocity (vertical) controller I gain maximum // @Description: Velocity (vertical) controller I gain maximum. Constrains the target acceleration that the I gain will output // @Range: 1.000 8.000 // @User: Standard // @Param: _VELZ_D // @DisplayName: Velocity (vertical) controller D gain // @Description: Velocity (vertical) controller D gain. Corrects short-term changes in velocity // @Range: 0.00 1.00 // @Increment: 0.001 // @User: Advanced // @Param: _VELZ_FF // @DisplayName: Velocity (vertical) controller Feed Forward gain // @Description: Velocity (vertical) controller Feed Forward gain. Produces an output that is proportional to the magnitude of the target // @Range: 0 1 // @Increment: 0.01 // @User: Advanced // @Param: _VELZ_FLTE // @DisplayName: Velocity (vertical) error filter // @Description: Velocity (vertical) error filter. This filter (in Hz) is applied to the input for P and I terms // @Range: 0 100 // @Units: Hz // @User: Advanced // @Param: _VELZ_FLTD // @DisplayName: Velocity (vertical) input filter for D term // @Description: Velocity (vertical) input filter for D term. This filter (in Hz) is applied to the input for D terms // @Range: 0 100 // @Units: Hz // @User: Advanced AP_SUBGROUPINFO(_pid_vel_z, "_VELZ_", 3, AC_PosControl, AC_PID_Basic), // @Param: _ACCZ_P // @DisplayName: Acceleration (vertical) controller P gain // @Description: Acceleration (vertical) controller P gain. Converts the difference between desired vertical acceleration and actual acceleration into a motor output // @Range: 0.200 1.500 // @Increment: 0.05 // @User: Standard // @Param: _ACCZ_I // @DisplayName: Acceleration (vertical) controller I gain // @Description: Acceleration (vertical) controller I gain. Corrects long-term difference in desired vertical acceleration and actual acceleration // @Range: 0.000 3.000 // @User: Standard // @Param: _ACCZ_IMAX // @DisplayName: Acceleration (vertical) controller I gain maximum // @Description: Acceleration (vertical) controller I gain maximum. Constrains the maximum pwm that the I term will generate // @Range: 0 1000 // @Units: d% // @User: Standard // @Param: _ACCZ_D // @DisplayName: Acceleration (vertical) controller D gain // @Description: Acceleration (vertical) controller D gain. Compensates for short-term change in desired vertical acceleration vs actual acceleration // @Range: 0.000 0.400 // @User: Standard // @Param: _ACCZ_FF // @DisplayName: Acceleration (vertical) controller feed forward // @Description: Acceleration (vertical) controller feed forward // @Range: 0 0.5 // @Increment: 0.001 // @User: Standard // @Param: _ACCZ_FLTT // @DisplayName: Acceleration (vertical) controller target frequency in Hz // @Description: Acceleration (vertical) controller target frequency in Hz // @Range: 1 50 // @Increment: 1 // @Units: Hz // @User: Standard // @Param: _ACCZ_FLTE // @DisplayName: Acceleration (vertical) controller error frequency in Hz // @Description: Acceleration (vertical) controller error frequency in Hz // @Range: 1 100 // @Increment: 1 // @Units: Hz // @User: Standard // @Param: _ACCZ_FLTD // @DisplayName: Acceleration (vertical) controller derivative frequency in Hz // @Description: Acceleration (vertical) controller derivative frequency in Hz // @Range: 1 100 // @Increment: 1 // @Units: Hz // @User: Standard // @Param: _ACCZ_SMAX // @DisplayName: Accel (vertical) slew rate limit // @Description: Sets an upper limit on the slew rate produced by the combined P and D gains. If the amplitude of the control action produced by the rate feedback exceeds this value, then the D+P gain is reduced to respect the limit. This limits the amplitude of high frequency oscillations caused by an excessive gain. The limit should be set to no more than 25% of the actuators maximum slew rate to allow for load effects. Note: The gain will not be reduced to less than 10% of the nominal value. A value of zero will disable this feature. // @Range: 0 200 // @Increment: 0.5 // @User: Advanced AP_SUBGROUPINFO(_pid_accel_z, "_ACCZ_", 4, AC_PosControl, AC_PID), // @Param: _POSXY_P // @DisplayName: Position (horizontal) controller P gain // @Description: Position controller P gain. Converts the distance (in the latitude direction) to the target location into a desired speed which is then passed to the loiter latitude rate controller // @Range: 0.500 2.000 // @User: Standard AP_SUBGROUPINFO(_p_pos_xy, "_POSXY_", 5, AC_PosControl, AC_P_2D), // @Param: _VELXY_P // @DisplayName: Velocity (horizontal) P gain // @Description: Velocity (horizontal) P gain. Converts the difference between desired and actual velocity to a target acceleration // @Range: 0.1 6.0 // @Increment: 0.1 // @User: Advanced // @Param: _VELXY_I // @DisplayName: Velocity (horizontal) I gain // @Description: Velocity (horizontal) I gain. Corrects long-term difference between desired and actual velocity to a target acceleration // @Range: 0.02 1.00 // @Increment: 0.01 // @User: Advanced // @Param: _VELXY_D // @DisplayName: Velocity (horizontal) D gain // @Description: Velocity (horizontal) D gain. Corrects short-term changes in velocity // @Range: 0.00 1.00 // @Increment: 0.001 // @User: Advanced // @Param: _VELXY_IMAX // @DisplayName: Velocity (horizontal) integrator maximum // @Description: Velocity (horizontal) integrator maximum. Constrains the target acceleration that the I gain will output // @Range: 0 4500 // @Increment: 10 // @Units: cm/s/s // @User: Advanced // @Param: _VELXY_FLTE // @DisplayName: Velocity (horizontal) input filter // @Description: Velocity (horizontal) input filter. This filter (in Hz) is applied to the input for P and I terms // @Range: 0 100 // @Units: Hz // @User: Advanced // @Param: _VELXY_FLTD // @DisplayName: Velocity (horizontal) input filter // @Description: Velocity (horizontal) input filter. This filter (in Hz) is applied to the input for D term // @Range: 0 100 // @Units: Hz // @User: Advanced // @Param: _VELXY_FF // @DisplayName: Velocity (horizontal) feed forward gain // @Description: Velocity (horizontal) feed forward gain. Converts the difference between desired velocity to a target acceleration // @Range: 0 6 // @Increment: 0.01 // @User: Advanced AP_SUBGROUPINFO(_pid_vel_xy, "_VELXY_", 6, AC_PosControl, AC_PID_2D), // @Param: _ANGLE_MAX // @DisplayName: Position Control Angle Max // @Description: Maximum lean angle autopilot can request. Set to zero to use ANGLE_MAX parameter value // @Units: deg // @Range: 0 45 // @Increment: 1 // @User: Advanced AP_GROUPINFO("_ANGLE_MAX", 7, AC_PosControl, _lean_angle_max, 0.0f), // IDs 8,9 used for _TC_XY and _TC_Z in beta release candidate // @Param: _JERK_XY // @DisplayName: Jerk limit for the horizontal kinematic input shaping // @Description: Jerk limit of the horizontal kinematic path generation used to determine how quickly the aircraft varies the acceleration target // @Units: m/s/s/s // @Range: 1 20 // @Increment: 1 // @User: Advanced AP_GROUPINFO("_JERK_XY", 10, AC_PosControl, _shaping_jerk_xy, POSCONTROL_JERK_XY), // @Param: _JERK_Z // @DisplayName: Jerk limit for the vertical kinematic input shaping // @Description: Jerk limit of the vertical kinematic path generation used to determine how quickly the aircraft varies the acceleration target // @Units: m/s/s/s // @Range: 5 50 // @Increment: 1 // @User: Advanced AP_GROUPINFO("_JERK_Z", 11, AC_PosControl, _shaping_jerk_z, POSCONTROL_JERK_Z), AP_GROUPEND }; // Default constructor. // Note that the Vector/Matrix constructors already implicitly zero // their values. // AC_PosControl::AC_PosControl(AP_AHRS_View& ahrs, const AP_InertialNav& inav, const AP_Motors& motors, AC_AttitudeControl& attitude_control, float dt) : _ahrs(ahrs), _inav(inav), _motors(motors), _attitude_control(attitude_control), _p_pos_z(POSCONTROL_POS_Z_P, dt), _pid_vel_z(POSCONTROL_VEL_Z_P, 0.0f, 0.0f, 0.0f, POSCONTROL_VEL_Z_IMAX, POSCONTROL_VEL_Z_FILT_HZ, POSCONTROL_VEL_Z_FILT_D_HZ, dt), _pid_accel_z(POSCONTROL_ACC_Z_P, POSCONTROL_ACC_Z_I, POSCONTROL_ACC_Z_D, 0.0f, POSCONTROL_ACC_Z_IMAX, 0.0f, POSCONTROL_ACC_Z_FILT_HZ, 0.0f, dt), _p_pos_xy(POSCONTROL_POS_XY_P, dt), _pid_vel_xy(POSCONTROL_VEL_XY_P, POSCONTROL_VEL_XY_I, POSCONTROL_VEL_XY_D, 0.0f, POSCONTROL_VEL_XY_IMAX, POSCONTROL_VEL_XY_FILT_HZ, POSCONTROL_VEL_XY_FILT_D_HZ, dt), _dt(dt), _vel_max_down_cms(POSCONTROL_SPEED_DOWN), _vel_max_up_cms(POSCONTROL_SPEED_UP), _vel_max_xy_cms(POSCONTROL_SPEED), _accel_max_z_cmss(POSCONTROL_ACCEL_Z), _accel_max_xy_cmss(POSCONTROL_ACCEL_XY), _jerk_max_xy_cmsss(POSCONTROL_JERK_XY * 100.0), _jerk_max_z_cmsss(POSCONTROL_JERK_Z * 100.0) { AP_Param::setup_object_defaults(this, var_info); } /// /// 3D position shaper /// /// input_pos_xyz - calculate a jerk limited path from the current position, velocity and acceleration to an input position. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The kinematic path is constrained by the maximum jerk parameter and the velocity and acceleration limits set using the function set_max_speed_accel_xy. /// The jerk limit defines the acceleration error decay in the kinematic path as the system approaches constant acceleration. /// The jerk limit also defines the time taken to achieve the maximum acceleration. /// The function alters the input velocity to be the velocity that the system could reach zero acceleration in the minimum time. void AC_PosControl::input_pos_xyz(const Vector3p& pos, float pos_offset_z, float pos_offset_z_buffer) { // Terrain following velocity scalar must be calculated before we remove the position offset const float offset_z_scaler = pos_offset_z_scaler(pos_offset_z, pos_offset_z_buffer); // remove terrain offsets for flat earth assumption _pos_target.z -= _pos_offset_z; _vel_desired.z -= _vel_offset_z; _accel_desired.z -= _accel_offset_z; // calculated increased maximum acceleration and jerk if over speed float accel_max_z_cmss = _accel_max_z_cmss * calculate_overspeed_gain(); float jerk_max_z_cmsss = _jerk_max_z_cmsss * calculate_overspeed_gain(); update_pos_vel_accel_xy(_pos_target.xy(), _vel_desired.xy(), _accel_desired.xy(), _dt, _limit_vector.xy(), _p_pos_xy.get_error(), _pid_vel_xy.get_error()); // adjust desired altitude if motors have not hit their limits update_pos_vel_accel(_pos_target.z, _vel_desired.z, _accel_desired.z, _dt, _limit_vector.z, _p_pos_z.get_error(), _pid_vel_z.get_error()); // calculate the horizontal and vertical velocity limits to travel directly to the destination defined by pos float vel_max_xy_cms = 0.0f; float vel_max_z_cms = 0.0f; Vector3f dest_vector = (pos - _pos_target).tofloat(); if (is_positive(dest_vector.length_squared()) ) { dest_vector.normalize(); float dest_vector_xy_length = dest_vector.xy().length(); float vel_max_cms = kinematic_limit(dest_vector, _vel_max_xy_cms, _vel_max_up_cms, _vel_max_down_cms); vel_max_xy_cms = vel_max_cms * dest_vector_xy_length; vel_max_z_cms = fabsf(vel_max_cms * dest_vector.z); } // reduce speed if we are reaching the edge of our vertical buffer vel_max_xy_cms *= offset_z_scaler; Vector2f vel; Vector2f accel; shape_pos_vel_accel_xy(pos.xy(), vel, accel, _pos_target.xy(), _vel_desired.xy(), _accel_desired.xy(), vel_max_xy_cms, _accel_max_xy_cmss, _jerk_max_xy_cmsss, _dt, false); float posz = pos.z; shape_pos_vel_accel(posz, 0, 0, _pos_target.z, _vel_desired.z, _accel_desired.z, -vel_max_z_cms, vel_max_z_cms, -constrain_float(accel_max_z_cmss, 0.0f, 750.0f), accel_max_z_cmss, jerk_max_z_cmsss, _dt, false); // update the vertical position, velocity and acceleration offsets update_pos_offset_z(pos_offset_z); // add terrain offsets _pos_target.z += _pos_offset_z; _vel_desired.z += _vel_offset_z; _accel_desired.z += _accel_offset_z; } /// pos_offset_z_scaler - calculates a multiplier used to reduce the horizontal velocity to allow the z position controller to stay within the provided buffer range float AC_PosControl::pos_offset_z_scaler(float pos_offset_z, float pos_offset_z_buffer) const { if (is_zero(pos_offset_z_buffer)) { return 1.0; } float pos_offset_error_z = _inav.get_position_z_up_cm() - (_pos_target.z - _pos_offset_z + pos_offset_z); return constrain_float((1.0 - (fabsf(pos_offset_error_z) - 0.5 * pos_offset_z_buffer) / (0.5 * pos_offset_z_buffer)), 0.01, 1.0); } /// /// Lateral position controller /// /// set_max_speed_accel_xy - set the maximum horizontal speed in cm/s and acceleration in cm/s/s /// This function only needs to be called if using the kinematic shaping. /// This can be done at any time as changes in these parameters are handled smoothly /// by the kinematic shaping. void AC_PosControl::set_max_speed_accel_xy(float speed_cms, float accel_cmss) { _vel_max_xy_cms = speed_cms; _accel_max_xy_cmss = accel_cmss; // ensure the horizontal jerk is less than the vehicle is capable of const float jerk_max_cmsss = MIN(_attitude_control.get_ang_vel_roll_max_rads(), _attitude_control.get_ang_vel_pitch_max_rads()) * GRAVITY_MSS * 100.0; const float snap_max_cmssss = MIN(_attitude_control.get_accel_roll_max_radss(), _attitude_control.get_accel_pitch_max_radss()) * GRAVITY_MSS * 100.0; // get specified jerk limit _jerk_max_xy_cmsss = _shaping_jerk_xy * 100.0; // limit maximum jerk based on maximum angular rate if (is_positive(jerk_max_cmsss) && _attitude_control.get_bf_feedforward()) { _jerk_max_xy_cmsss = MIN(_jerk_max_xy_cmsss, jerk_max_cmsss); } // limit maximum jerk to maximum possible average jerk based on angular acceleration if (is_positive(snap_max_cmssss) && _attitude_control.get_bf_feedforward()) { _jerk_max_xy_cmsss = MIN(0.5 * safe_sqrt(_accel_max_xy_cmss * snap_max_cmssss), _jerk_max_xy_cmsss); } } /// set_max_speed_accel_xy - set the position controller correction velocity and acceleration limit /// This should be done only during initialisation to avoid discontinuities void AC_PosControl::set_correction_speed_accel_xy(float speed_cms, float accel_cmss) { _p_pos_xy.set_limits(speed_cms, accel_cmss, 0.0f); } /// init_xy_controller_stopping_point - initialise the position controller to the stopping point with zero velocity and acceleration. /// This function should be used when the expected kinematic path assumes a stationary initial condition but does not specify a specific starting position. /// The starting position can be retrieved by getting the position target using get_pos_target_cm() after calling this function. void AC_PosControl::init_xy_controller_stopping_point() { init_xy_controller(); get_stopping_point_xy_cm(_pos_target.xy()); _vel_desired.xy().zero(); _accel_desired.xy().zero(); _pid_vel_xy.set_integrator(_accel_target); } // relax_velocity_controller_xy - initialise the position controller to the current position and velocity with decaying acceleration. /// This function decays the output acceleration by 95% every half second to achieve a smooth transition to zero requested acceleration. void AC_PosControl::relax_velocity_controller_xy() { init_xy_controller(); // decay resultant acceleration and therefore current attitude target to zero float decay = 1.0 - _dt / (_dt + POSCONTROL_RELAX_TC); _accel_target.xy() *= decay; _pid_vel_xy.set_integrator(_accel_target - _accel_desired); } /// reduce response for landing void AC_PosControl::soften_for_landing_xy() { // decay position error to zero _pos_target.xy() += (_inav.get_position_xy_cm().topostype() - _pos_target.xy()) * (_dt / (_dt + POSCONTROL_RELAX_TC)); // Prevent I term build up in xy velocity controller. // Note that this flag is reset on each loop in update_xy_controller() set_externally_limited_xy(); } /// init_xy_controller - initialise the position controller to the current position, velocity, acceleration and attitude. /// This function is the default initialisation for any position control that provides position, velocity and acceleration. void AC_PosControl::init_xy_controller() { // set roll, pitch lean angle targets to current attitude const Vector3f &att_target_euler_cd = _attitude_control.get_att_target_euler_cd(); _roll_target = att_target_euler_cd.x; _pitch_target = att_target_euler_cd.y; _yaw_target = att_target_euler_cd.z; // todo: this should be thrust vector heading, not yaw. _yaw_rate_target = 0.0f; _angle_max_override_cd = 0.0; _pos_target.xy() = _inav.get_position_xy_cm().topostype(); const Vector2f &curr_vel = _inav.get_velocity_xy_cms(); _vel_desired.xy() = curr_vel; _vel_target.xy() = curr_vel; // Set desired accel to zero because raw acceleration is prone to noise _accel_desired.xy().zero(); lean_angles_to_accel_xy(_accel_target.x, _accel_target.y); // limit acceleration using maximum lean angles float angle_max = MIN(_attitude_control.get_althold_lean_angle_max_cd(), get_lean_angle_max_cd()); float accel_max = angle_to_accel(angle_max * 0.01) * 100.0; _accel_target.xy().limit_length(accel_max); // initialise I terms from lean angles _pid_vel_xy.reset_filter(); // initialise the I term to _accel_target - _accel_desired // _accel_desired is zero and can be removed from the equation _pid_vel_xy.set_integrator(_accel_target); // initialise ekf xy reset handler init_ekf_xy_reset(); // initialise z_controller time out _last_update_xy_us = AP_HAL::micros64(); } /// input_accel_xy - calculate a jerk limited path from the current position, velocity and acceleration to an input acceleration. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The kinematic path is constrained by the maximum acceleration and jerk set using the function set_max_speed_accel_xy. /// The jerk limit defines the acceleration error decay in the kinematic path as the system approaches constant acceleration. /// The jerk limit also defines the time taken to achieve the maximum acceleration. void AC_PosControl::input_accel_xy(const Vector3f& accel) { // check for ekf xy position reset handle_ekf_xy_reset(); update_pos_vel_accel_xy(_pos_target.xy(), _vel_desired.xy(), _accel_desired.xy(), _dt, _limit_vector.xy(), _p_pos_xy.get_error(), _pid_vel_xy.get_error()); shape_accel_xy(accel, _accel_desired, _jerk_max_xy_cmsss, _dt); } /// input_vel_accel_xy - calculate a jerk limited path from the current position, velocity and acceleration to an input velocity and acceleration. /// The vel is projected forwards in time based on a time step of dt and acceleration accel. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The kinematic path is constrained by the maximum acceleration and jerk set using the function set_max_speed_accel_xy. /// The parameter limit_output specifies if the velocity and acceleration limits are applied to the sum of commanded and correction values or just correction. void AC_PosControl::input_vel_accel_xy(Vector2f& vel, const Vector2f& accel, bool limit_output) { update_pos_vel_accel_xy(_pos_target.xy(), _vel_desired.xy(), _accel_desired.xy(), _dt, _limit_vector.xy(), _p_pos_xy.get_error(), _pid_vel_xy.get_error()); shape_vel_accel_xy(vel, accel, _vel_desired.xy(), _accel_desired.xy(), _accel_max_xy_cmss, _jerk_max_xy_cmsss, _dt, limit_output); update_vel_accel_xy(vel, accel, _dt, Vector2f(), Vector2f()); } /// input_pos_vel_accel_xy - calculate a jerk limited path from the current position, velocity and acceleration to an input position velocity and acceleration. /// The pos and vel are projected forwards in time based on a time step of dt and acceleration accel. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The function alters the pos and vel to be the kinematic path based on accel /// The parameter limit_output specifies if the velocity and acceleration limits are applied to the sum of commanded and correction values or just correction. void AC_PosControl::input_pos_vel_accel_xy(Vector2p& pos, Vector2f& vel, const Vector2f& accel, bool limit_output) { update_pos_vel_accel_xy(_pos_target.xy(), _vel_desired.xy(), _accel_desired.xy(), _dt, _limit_vector.xy(), _p_pos_xy.get_error(), _pid_vel_xy.get_error()); shape_pos_vel_accel_xy(pos, vel, accel, _pos_target.xy(), _vel_desired.xy(), _accel_desired.xy(), _vel_max_xy_cms, _accel_max_xy_cmss, _jerk_max_xy_cmsss, _dt, limit_output); update_pos_vel_accel_xy(pos, vel, accel, _dt, Vector2f(), Vector2f(), Vector2f()); } /// stop_pos_xy_stabilisation - sets the target to the current position to remove any position corrections from the system void AC_PosControl::stop_pos_xy_stabilisation() { _pos_target.xy() = _inav.get_position_xy_cm().topostype(); } /// stop_vel_xy_stabilisation - sets the target to the current position and velocity to the current velocity to remove any position and velocity corrections from the system void AC_PosControl::stop_vel_xy_stabilisation() { _pos_target.xy() = _inav.get_position_xy_cm().topostype(); const Vector2f &curr_vel = _inav.get_velocity_xy_cms(); _vel_desired.xy() = curr_vel; // with zero position error _vel_target = _vel_desired _vel_target.xy() = curr_vel; // initialise I terms from lean angles _pid_vel_xy.reset_filter(); _pid_vel_xy.reset_I(); } // is_active_xy - returns true if the xy position controller has been run in the previous 5 loop times bool AC_PosControl::is_active_xy() const { return ((AP_HAL::micros64() - _last_update_xy_us) <= _dt * 5000000.0); } /// update_xy_controller - runs the horizontal position controller correcting position, velocity and acceleration errors. /// Position and velocity errors are converted to velocity and acceleration targets using PID objects /// Desired velocity and accelerations are added to these corrections as they are calculated /// Kinematically consistent target position and desired velocity and accelerations should be provided before calling this function void AC_PosControl::update_xy_controller() { // check for ekf xy position reset handle_ekf_xy_reset(); // Check for position control time out if (!is_active_xy()) { init_xy_controller(); if (has_good_timing()) { // call internal error because initialisation has not been done INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control); } } _last_update_xy_us = AP_HAL::micros64(); float ahrsGndSpdLimit, ahrsControlScaleXY; AP::ahrs().getControlLimits(ahrsGndSpdLimit, ahrsControlScaleXY); // Position Controller const Vector3f &curr_pos = _inav.get_position_neu_cm(); Vector2f vel_target = _p_pos_xy.update_all(_pos_target.x, _pos_target.y, curr_pos); // add velocity feed-forward scaled to compensate for optical flow measurement induced EKF noise vel_target *= ahrsControlScaleXY; _vel_target.xy() = vel_target; _vel_target.xy() += _vel_desired.xy(); // Velocity Controller const Vector2f &curr_vel = _inav.get_velocity_xy_cms(); Vector2f accel_target = _pid_vel_xy.update_all(_vel_target.xy(), curr_vel, _limit_vector.xy()); // acceleration to correct for velocity error and scale PID output to compensate for optical flow measurement induced EKF noise accel_target *= ahrsControlScaleXY; // pass the correction acceleration to the target acceleration output _accel_target.xy() = accel_target; // Add feed forward into the target acceleration output _accel_target.xy() += _accel_desired.xy(); // Acceleration Controller // limit acceleration using maximum lean angles float angle_max = MIN(_attitude_control.get_althold_lean_angle_max_cd(), get_lean_angle_max_cd()); float accel_max = angle_to_accel(angle_max * 0.01) * 100; // Define the limit vector before we constrain _accel_target _limit_vector.xy() = _accel_target.xy(); if (!limit_accel_xy(_vel_desired.xy(), _accel_target.xy(), accel_max)) { // _accel_target was not limited so we can zero the xy limit vector _limit_vector.xy().zero(); } // update angle targets that will be passed to stabilize controller accel_to_lean_angles(_accel_target.x, _accel_target.y, _roll_target, _pitch_target); calculate_yaw_and_rate_yaw(); } /// /// Vertical position controller /// /// set_max_speed_accel_z - set the maximum vertical speed in cm/s and acceleration in cm/s/s /// speed_down can be positive or negative but will always be interpreted as a descent speed. /// This function only needs to be called if using the kinematic shaping. /// This can be done at any time as changes in these parameters are handled smoothly /// by the kinematic shaping. void AC_PosControl::set_max_speed_accel_z(float speed_down, float speed_up, float accel_cmss) { // ensure speed_down is always negative speed_down = -fabsf(speed_down); // sanity check and update if (is_negative(speed_down)) { _vel_max_down_cms = speed_down; } if (is_positive(speed_up)) { _vel_max_up_cms = speed_up; } if (is_positive(accel_cmss)) { _accel_max_z_cmss = accel_cmss; } // ensure the vertical Jerk is not limited by the filters in the Z accel PID object _jerk_max_z_cmsss = _shaping_jerk_z * 100.0; if (is_positive(_pid_accel_z.filt_T_hz())) { _jerk_max_z_cmsss = MIN(_jerk_max_z_cmsss, MIN(GRAVITY_MSS * 100.0, _accel_max_z_cmss) * (M_2PI * _pid_accel_z.filt_T_hz()) / 5.0); } if (is_positive(_pid_accel_z.filt_E_hz())) { _jerk_max_z_cmsss = MIN(_jerk_max_z_cmsss, MIN(GRAVITY_MSS * 100.0, _accel_max_z_cmss) * (M_2PI * _pid_accel_z.filt_E_hz()) / 5.0); } } /// set_correction_speed_accel_z - set the position controller correction velocity and acceleration limit /// speed_down can be positive or negative but will always be interpreted as a descent speed. /// This should be done only during initialisation to avoid discontinuities void AC_PosControl::set_correction_speed_accel_z(float speed_down, float speed_up, float accel_cmss) { // define maximum position error and maximum first and second differential limits _p_pos_z.set_limits(-fabsf(speed_down), speed_up, accel_cmss, 0.0f); } /// init_z_controller - initialise the position controller to the current position, velocity, acceleration and attitude. /// This function is the default initialisation for any position control that provides position, velocity and acceleration. /// This function does not allow any negative velocity or acceleration void AC_PosControl::init_z_controller_no_descent() { // Initialise the position controller to the current throttle, position, velocity and acceleration. init_z_controller(); // remove all descent if present _vel_desired.z = MAX(0.0, _vel_desired.z); _vel_target.z = MAX(0.0, _vel_target.z); _accel_desired.z = MAX(0.0, _accel_desired.z); _accel_target.z = MAX(0.0, _accel_target.z); } /// init_z_controller_stopping_point - initialise the position controller to the stopping point with zero velocity and acceleration. /// This function should be used when the expected kinematic path assumes a stationary initial condition but does not specify a specific starting position. /// The starting position can be retrieved by getting the position target using get_pos_target_cm() after calling this function. void AC_PosControl::init_z_controller_stopping_point() { // Initialise the position controller to the current throttle, position, velocity and acceleration. init_z_controller(); get_stopping_point_z_cm(_pos_target.z); _vel_desired.z = 0.0f; _accel_desired.z = 0.0f; } // relax_z_controller - initialise the position controller to the current position and velocity with decaying acceleration. /// This function decays the output acceleration by 95% every half second to achieve a smooth transition to zero requested acceleration. void AC_PosControl::relax_z_controller(float throttle_setting) { // Initialise the position controller to the current position, velocity and acceleration. init_z_controller(); // init_z_controller has set the accel PID I term to generate the current throttle set point // Use relax_integrator to decay the throttle set point to throttle_setting _pid_accel_z.relax_integrator((throttle_setting - _motors.get_throttle_hover()) * 1000.0f, POSCONTROL_RELAX_TC); } /// init_z_controller - initialise the position controller to the current position, velocity, acceleration and attitude. /// This function is the default initialisation for any position control that provides position, velocity and acceleration. /// This function is private and contains all the shared z axis initialisation functions void AC_PosControl::init_z_controller() { _pos_target.z = _inav.get_position_z_up_cm(); const float curr_vel_z = _inav.get_velocity_z_up_cms(); _vel_desired.z = curr_vel_z; // with zero position error _vel_target = _vel_desired _vel_target.z = curr_vel_z; // Reset I term of velocity PID _pid_vel_z.reset_filter(); _pid_vel_z.set_integrator(0.0f); _accel_desired.z = constrain_float(get_z_accel_cmss(), -_accel_max_z_cmss, _accel_max_z_cmss); // with zero position error _accel_target = _accel_desired _accel_target.z = _accel_desired.z; _pid_accel_z.reset_filter(); // initialise vertical offsets _pos_offset_target_z = 0.0; _pos_offset_z = 0.0; _vel_offset_z = 0.0; _accel_offset_z = 0.0; // Set accel PID I term based on the current throttle // Remove the expected P term due to _accel_desired.z being constrained to _accel_max_z_cmss // Remove the expected FF term due to non-zero _accel_target.z _pid_accel_z.set_integrator((_attitude_control.get_throttle_in() - _motors.get_throttle_hover()) * 1000.0f - _pid_accel_z.kP() * (_accel_target.z - get_z_accel_cmss()) - _pid_accel_z.ff() * _accel_target.z); // initialise ekf z reset handler init_ekf_z_reset(); // initialise z_controller time out _last_update_z_us = AP_HAL::micros64(); } /// input_vel_accel_z - calculate a jerk limited path from the current position, velocity and acceleration to an input velocity and acceleration. /// The vel is projected forwards in time based on a time step of dt and acceleration accel. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The function alters the vel to be the kinematic path based on accel void AC_PosControl::input_accel_z(float accel) { // calculated increased maximum jerk if over speed float jerk_max_z_cmsss = _jerk_max_z_cmsss * calculate_overspeed_gain(); // adjust desired alt if motors have not hit their limits update_pos_vel_accel(_pos_target.z, _vel_desired.z, _accel_desired.z, _dt, _limit_vector.z, _p_pos_z.get_error(), _pid_vel_z.get_error()); shape_accel(accel, _accel_desired.z, jerk_max_z_cmsss, _dt); } /// input_accel_z - calculate a jerk limited path from the current position, velocity and acceleration to an input acceleration. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The kinematic path is constrained by the maximum acceleration and jerk set using the function set_max_speed_accel_z. /// The parameter limit_output specifies if the velocity and acceleration limits are applied to the sum of commanded and correction values or just correction. void AC_PosControl::input_vel_accel_z(float &vel, float accel, bool ignore_descent_limit, bool limit_output) { if (ignore_descent_limit) { // turn off limits in the negative z direction _limit_vector.z = MAX(_limit_vector.z, 0.0f); } // calculated increased maximum acceleration and jerk if over speed float accel_max_z_cmss = _accel_max_z_cmss * calculate_overspeed_gain(); float jerk_max_z_cmsss = _jerk_max_z_cmsss * calculate_overspeed_gain(); // adjust desired alt if motors have not hit their limits update_pos_vel_accel(_pos_target.z, _vel_desired.z, _accel_desired.z, _dt, _limit_vector.z, _p_pos_z.get_error(), _pid_vel_z.get_error()); shape_vel_accel(vel, accel, _vel_desired.z, _accel_desired.z, -constrain_float(accel_max_z_cmss, 0.0f, 750.0f), accel_max_z_cmss, jerk_max_z_cmsss, _dt, limit_output); update_vel_accel(vel, accel, _dt, 0.0, 0.0); } /// set_pos_target_z_from_climb_rate_cm - adjusts target up or down using a commanded climb rate in cm/s /// using the default position control kinematic path. /// The zero target altitude is varied to follow pos_offset_z void AC_PosControl::set_pos_target_z_from_climb_rate_cm(float vel) { // remove terrain offsets for flat earth assumption _pos_target.z -= _pos_offset_z; _vel_desired.z -= _vel_offset_z; _accel_desired.z -= _accel_offset_z; float vel_temp = vel; input_vel_accel_z(vel_temp, 0, false); // update the vertical position, velocity and acceleration offsets update_pos_offset_z(_pos_offset_target_z); // add terrain offsets _pos_target.z += _pos_offset_z; _vel_desired.z += _vel_offset_z; _accel_desired.z += _accel_offset_z; } /// land_at_climb_rate_cm - adjusts target up or down using a commanded climb rate in cm/s /// using the default position control kinematic path. /// ignore_descent_limit turns off output saturation handling to aid in landing detection. ignore_descent_limit should be false unless landing. void AC_PosControl::land_at_climb_rate_cm(float vel, bool ignore_descent_limit) { input_vel_accel_z(vel, 0, ignore_descent_limit); } /// input_pos_vel_accel_z - calculate a jerk limited path from the current position, velocity and acceleration to an input position velocity and acceleration. /// The pos and vel are projected forwards in time based on a time step of dt and acceleration accel. /// The function takes the current position, velocity, and acceleration and calculates the required jerk limited adjustment to the acceleration for the next time dt. /// The function alters the pos and vel to be the kinematic path based on accel /// The parameter limit_output specifies if the velocity and acceleration limits are applied to the sum of commanded and correction values or just correction. void AC_PosControl::input_pos_vel_accel_z(float &pos, float &vel, float accel, bool limit_output) { // calculated increased maximum acceleration and jerk if over speed float accel_max_z_cmss = _accel_max_z_cmss * calculate_overspeed_gain(); float jerk_max_z_cmsss = _jerk_max_z_cmsss * calculate_overspeed_gain(); // adjust desired altitude if motors have not hit their limits update_pos_vel_accel(_pos_target.z, _vel_desired.z, _accel_desired.z, _dt, _limit_vector.z, _p_pos_z.get_error(), _pid_vel_z.get_error()); shape_pos_vel_accel(pos, vel, accel, _pos_target.z, _vel_desired.z, _accel_desired.z, _vel_max_down_cms, _vel_max_up_cms, -constrain_float(accel_max_z_cmss, 0.0f, 750.0f), accel_max_z_cmss, jerk_max_z_cmsss, _dt, limit_output); postype_t posp = pos; update_pos_vel_accel(posp, vel, accel, _dt, 0.0, 0.0, 0.0); pos = posp; } /// set_alt_target_with_slew - adjusts target up or down using a commanded altitude in cm /// using the default position control kinematic path. void AC_PosControl::set_alt_target_with_slew(float pos) { float zero = 0; input_pos_vel_accel_z(pos, zero, 0); } /// update_pos_offset_z - updates the vertical offsets used by terrain following void AC_PosControl::update_pos_offset_z(float pos_offset_z) { postype_t p_offset_z = _pos_offset_z; update_pos_vel_accel(p_offset_z, _vel_offset_z, _accel_offset_z, _dt, MIN(_limit_vector.z, 0.0f), _p_pos_z.get_error(), _pid_vel_z.get_error()); _pos_offset_z = p_offset_z; // input shape the terrain offset shape_pos_vel_accel(pos_offset_z, 0.0f, 0.0f, _pos_offset_z, _vel_offset_z, _accel_offset_z, get_max_speed_down_cms(), get_max_speed_up_cms(), -get_max_accel_z_cmss(), get_max_accel_z_cmss(), _jerk_max_z_cmsss, _dt, false); } // is_active_z - returns true if the z position controller has been run in the previous 5 loop times bool AC_PosControl::is_active_z() const { return ((AP_HAL::micros64() - _last_update_z_us) <= _dt * 5000000.0); } /// update_z_controller - runs the vertical position controller correcting position, velocity and acceleration errors. /// Position and velocity errors are converted to velocity and acceleration targets using PID objects /// Desired velocity and accelerations are added to these corrections as they are calculated /// Kinematically consistent target position and desired velocity and accelerations should be provided before calling this function void AC_PosControl::update_z_controller() { // check for ekf z-axis position reset handle_ekf_z_reset(); // Check for z_controller time out if (!is_active_z()) { init_z_controller(); if (has_good_timing()) { // call internal error because initialisation has not been done INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control); } } _last_update_z_us = AP_HAL::micros64(); // calculate the target velocity correction float pos_target_zf = _pos_target.z; _vel_target.z = _p_pos_z.update_all(pos_target_zf, _inav.get_position_z_up_cm()); _vel_target.z *= AP::ahrs().getControlScaleZ(); _pos_target.z = pos_target_zf; // add feed forward component _vel_target.z += _vel_desired.z; // Velocity Controller const float curr_vel_z = _inav.get_velocity_z_up_cms(); _accel_target.z = _pid_vel_z.update_all(_vel_target.z, curr_vel_z, _motors.limit.throttle_lower, _motors.limit.throttle_upper); _accel_target.z *= AP::ahrs().getControlScaleZ(); // add feed forward component _accel_target.z += _accel_desired.z; // Acceleration Controller // Calculate vertical acceleration const float z_accel_meas = get_z_accel_cmss(); // ensure imax is always large enough to overpower hover throttle if (_motors.get_throttle_hover() * 1000.0f > _pid_accel_z.imax()) { _pid_accel_z.imax(_motors.get_throttle_hover() * 1000.0f); } float thr_out; if (_vibe_comp_enabled) { thr_out = get_throttle_with_vibration_override(); } else { thr_out = _pid_accel_z.update_all(_accel_target.z, z_accel_meas, (_motors.limit.throttle_lower || _motors.limit.throttle_upper)) * 0.001f; thr_out += _pid_accel_z.get_ff() * 0.001f; } thr_out += _motors.get_throttle_hover(); // Actuator commands // send throttle to attitude controller with angle boost _attitude_control.set_throttle_out(thr_out, true, POSCONTROL_THROTTLE_CUTOFF_FREQ_HZ); // Check for vertical controller health // _speed_down_cms is checked to be non-zero when set float error_ratio = _pid_vel_z.get_error() / _vel_max_down_cms; _vel_z_control_ratio += _dt * 0.1f * (0.5 - error_ratio); _vel_z_control_ratio = constrain_float(_vel_z_control_ratio, 0.0f, 2.0f); // set vertical component of the limit vector if (_motors.limit.throttle_upper) { _limit_vector.z = 1.0f; } else if (_motors.limit.throttle_lower) { _limit_vector.z = -1.0f; } else { _limit_vector.z = 0.0f; } } /// /// Accessors /// /// get_lean_angle_max_cd - returns the maximum lean angle the autopilot may request float AC_PosControl::get_lean_angle_max_cd() const { if (is_positive(_angle_max_override_cd)) { return _angle_max_override_cd; } if (!is_positive(_lean_angle_max)) { return _attitude_control.lean_angle_max_cd(); } return _lean_angle_max * 100.0f; } /// set position, velocity and acceleration targets void AC_PosControl::set_pos_vel_accel(const Vector3p& pos, const Vector3f& vel, const Vector3f& accel) { _pos_target = pos; _vel_desired = vel; _accel_desired = accel; } /// set position, velocity and acceleration targets void AC_PosControl::set_pos_vel_accel_xy(const Vector2p& pos, const Vector2f& vel, const Vector2f& accel) { _pos_target.xy() = pos; _vel_desired.xy() = vel; _accel_desired.xy() = accel; } // get_lean_angles_to_accel - convert roll, pitch lean target angles to lat/lon frame accelerations in cm/s/s Vector3f AC_PosControl::lean_angles_to_accel(const Vector3f& att_target_euler) const { // rotate our roll, pitch angles into lat/lon frame const float sin_roll = sinf(att_target_euler.x); const float cos_roll = cosf(att_target_euler.x); const float sin_pitch = sinf(att_target_euler.y); const float cos_pitch = cosf(att_target_euler.y); const float sin_yaw = sinf(att_target_euler.z); const float cos_yaw = cosf(att_target_euler.z); return Vector3f{ (GRAVITY_MSS * 100) * (-cos_yaw * sin_pitch * cos_roll - sin_yaw * sin_roll) / MAX(cos_roll * cos_pitch, 0.1f), (GRAVITY_MSS * 100) * (-sin_yaw * sin_pitch * cos_roll + cos_yaw * sin_roll) / MAX(cos_roll * cos_pitch, 0.1f), (GRAVITY_MSS * 100) }; } // returns the NED target acceleration vector for attitude control Vector3f AC_PosControl::get_thrust_vector() const { Vector3f accel_target = get_accel_target_cmss(); accel_target.z = -GRAVITY_MSS * 100.0f; return accel_target; } /// get_stopping_point_xy_cm - calculates stopping point in NEU cm based on current position, velocity, vehicle acceleration /// function does not change the z axis void AC_PosControl::get_stopping_point_xy_cm(Vector2p &stopping_point) const { stopping_point = _inav.get_position_xy_cm().topostype(); float kP = _p_pos_xy.kP(); Vector2f curr_vel = _inav.get_velocity_xy_cms(); // calculate current velocity float vel_total = curr_vel.length(); if (!is_positive(vel_total)) { return; } const float stopping_dist = stopping_distance(constrain_float(vel_total, 0.0, _vel_max_xy_cms), kP, _accel_max_xy_cmss); if (!is_positive(stopping_dist)) { return; } // convert the stopping distance into a stopping point using velocity vector const float t = stopping_dist / vel_total; stopping_point += (curr_vel * t).topostype(); } /// get_stopping_point_z_cm - calculates stopping point in NEU cm based on current position, velocity, vehicle acceleration void AC_PosControl::get_stopping_point_z_cm(postype_t &stopping_point) const { const float curr_pos_z = _inav.get_position_z_up_cm(); // avoid divide by zero by using current position if kP is very low or acceleration is zero if (!is_positive(_p_pos_z.kP()) || !is_positive(_accel_max_z_cmss)) { stopping_point = curr_pos_z; return; } stopping_point = curr_pos_z + constrain_float(stopping_distance(_inav.get_velocity_z_up_cms(), _p_pos_z.kP(), _accel_max_z_cmss), - POSCONTROL_STOPPING_DIST_DOWN_MAX, POSCONTROL_STOPPING_DIST_UP_MAX); } /// get_bearing_to_target_cd - get bearing to target position in centi-degrees int32_t AC_PosControl::get_bearing_to_target_cd() const { return get_bearing_cd(_inav.get_position_xy_cm(), _pos_target.tofloat().xy()); } /// /// System methods /// // get throttle using vibration-resistant calculation (uses feed forward with manually calculated gain) float AC_PosControl::get_throttle_with_vibration_override() { const float thr_per_accelz_cmss = _motors.get_throttle_hover() / (GRAVITY_MSS * 100.0f); // during vibration compensation use feed forward with manually calculated gain // ToDo: clear pid_info P, I and D terms for logging if (!(_motors.limit.throttle_lower || _motors.limit.throttle_upper) || ((is_positive(_pid_accel_z.get_i()) && is_negative(_pid_vel_z.get_error())) || (is_negative(_pid_accel_z.get_i()) && is_positive(_pid_vel_z.get_error())))) { _pid_accel_z.set_integrator(_pid_accel_z.get_i() + _dt * thr_per_accelz_cmss * 1000.0f * _pid_vel_z.get_error() * _pid_vel_z.kP() * POSCONTROL_VIBE_COMP_I_GAIN); } return POSCONTROL_VIBE_COMP_P_GAIN * thr_per_accelz_cmss * _accel_target.z + _pid_accel_z.get_i() * 0.001f; } /// standby_xyz_reset - resets I terms and removes position error /// This function will let Loiter and Alt Hold continue to operate /// in the event that the flight controller is in control of the /// aircraft when in standby. void AC_PosControl::standby_xyz_reset() { // Set _pid_accel_z integrator to zero. _pid_accel_z.set_integrator(0.0f); // Set the target position to the current pos. _pos_target = _inav.get_position_neu_cm().topostype(); // Set _pid_vel_xy integrator and derivative to zero. _pid_vel_xy.reset_filter(); // initialise ekf xy reset handler init_ekf_xy_reset(); } // write PSC and/or PSCZ logs void AC_PosControl::write_log() { if (is_active_xy()) { float accel_x, accel_y; lean_angles_to_accel_xy(accel_x, accel_y); AP::logger().Write_PSCN(get_pos_target_cm().x, _inav.get_position_neu_cm().x, get_vel_desired_cms().x, get_vel_target_cms().x, _inav.get_velocity_neu_cms().x, _accel_desired.x, get_accel_target_cmss().x, accel_x); AP::logger().Write_PSCE(get_pos_target_cm().y, _inav.get_position_neu_cm().y, get_vel_desired_cms().y, get_vel_target_cms().y, _inav.get_velocity_neu_cms().y, _accel_desired.y, get_accel_target_cmss().y, accel_y); } if (is_active_z()) { AP::logger().Write_PSCD(-get_pos_target_cm().z, -_inav.get_position_z_up_cm(), -get_vel_desired_cms().z, -get_vel_target_cms().z, -_inav.get_velocity_z_up_cms(), -_accel_desired.z, -get_accel_target_cmss().z, -get_z_accel_cmss()); } } /// crosstrack_error - returns horizontal error to the closest point to the current track float AC_PosControl::crosstrack_error() const { const Vector2f pos_error = _inav.get_position_xy_cm() - (_pos_target.xy()).tofloat(); if (is_zero(_vel_desired.xy().length_squared())) { // crosstrack is the horizontal distance to target when stationary return pos_error.length(); } else { // crosstrack is the horizontal distance to the closest point to the current track const Vector2f vel_unit = _vel_desired.xy().normalized(); const float dot_error = pos_error * vel_unit; // todo: remove MAX of zero when safe_sqrt fixed return safe_sqrt(MAX(pos_error.length_squared() - sq(dot_error), 0.0)); } } /// /// private methods /// // get_lean_angles_to_accel - convert roll, pitch lean angles to NE frame accelerations in cm/s/s void AC_PosControl::accel_to_lean_angles(float accel_x_cmss, float accel_y_cmss, float& roll_target, float& pitch_target) const { // rotate accelerations into body forward-right frame const float accel_forward = accel_x_cmss * _ahrs.cos_yaw() + accel_y_cmss * _ahrs.sin_yaw(); const float accel_right = -accel_x_cmss * _ahrs.sin_yaw() + accel_y_cmss * _ahrs.cos_yaw(); // update angle targets that will be passed to stabilize controller pitch_target = accel_to_angle(-accel_forward * 0.01) * 100; float cos_pitch_target = cosf(pitch_target * M_PI / 18000.0f); roll_target = accel_to_angle((accel_right * cos_pitch_target)*0.01) * 100; } // lean_angles_to_accel_xy - convert roll, pitch lean target angles to NE frame accelerations in cm/s/s // todo: this should be based on thrust vector attitude control void AC_PosControl::lean_angles_to_accel_xy(float& accel_x_cmss, float& accel_y_cmss) const { // rotate our roll, pitch angles into lat/lon frame Vector3f att_target_euler = _attitude_control.get_att_target_euler_rad(); att_target_euler.z = _ahrs.yaw; Vector3f accel_cmss = lean_angles_to_accel(att_target_euler); accel_x_cmss = accel_cmss.x; accel_y_cmss = accel_cmss.y; } // calculate_yaw_and_rate_yaw - update the calculated the vehicle yaw and rate of yaw. bool AC_PosControl::calculate_yaw_and_rate_yaw() { // Calculate the turn rate float turn_rate = 0.0f; const float vel_desired_xy_len = _vel_desired.xy().length(); if (is_positive(vel_desired_xy_len)) { const float accel_forward = (_accel_desired.x * _vel_desired.x + _accel_desired.y * _vel_desired.y) / vel_desired_xy_len; const Vector2f accel_turn = _accel_desired.xy() - _vel_desired.xy() * accel_forward / vel_desired_xy_len; const float accel_turn_xy_len = accel_turn.length(); turn_rate = accel_turn_xy_len / vel_desired_xy_len; if ((accel_turn.y * _vel_desired.x - accel_turn.x * _vel_desired.y) < 0.0) { turn_rate = -turn_rate; } } // update the target yaw if velocity is greater than 5% _vel_max_xy_cms if (vel_desired_xy_len > _vel_max_xy_cms * 0.05f) { _yaw_target = degrees(_vel_desired.xy().angle()) * 100.0f; _yaw_rate_target = turn_rate * degrees(100.0f); return true; } return false; } // calculate_overspeed_gain - calculated increased maximum acceleration and jerk if over speed condition is detected float AC_PosControl::calculate_overspeed_gain() { if (_vel_desired.z < _vel_max_down_cms && !is_zero(_vel_max_down_cms)) { return POSCONTROL_OVERSPEED_GAIN_Z * _vel_desired.z / _vel_max_down_cms; } if (_vel_desired.z > _vel_max_up_cms && !is_zero(_vel_max_up_cms)) { return POSCONTROL_OVERSPEED_GAIN_Z * _vel_desired.z / _vel_max_up_cms; } return 1.0; } /// initialise ekf xy position reset check void AC_PosControl::init_ekf_xy_reset() { Vector2f pos_shift; _ekf_xy_reset_ms = _ahrs.getLastPosNorthEastReset(pos_shift); } /// handle_ekf_xy_reset - check for ekf position reset and adjust loiter or brake target position void AC_PosControl::handle_ekf_xy_reset() { // check for position shift Vector2f pos_shift; uint32_t reset_ms = _ahrs.getLastPosNorthEastReset(pos_shift); if (reset_ms != _ekf_xy_reset_ms) { _pos_target.xy() = (_inav.get_position_xy_cm() + _p_pos_xy.get_error()).topostype(); _vel_target.xy() = _inav.get_velocity_xy_cms() + _pid_vel_xy.get_error(); _ekf_xy_reset_ms = reset_ms; } } /// initialise ekf z axis reset check void AC_PosControl::init_ekf_z_reset() { float alt_shift; _ekf_z_reset_ms = _ahrs.getLastPosDownReset(alt_shift); } /// handle_ekf_z_reset - check for ekf position reset and adjust loiter or brake target position void AC_PosControl::handle_ekf_z_reset() { // check for position shift float alt_shift; uint32_t reset_ms = _ahrs.getLastPosDownReset(alt_shift); if (reset_ms != 0 && reset_ms != _ekf_z_reset_ms) { _pos_target.z = _inav.get_position_z_up_cm() + _p_pos_z.get_error(); _vel_target.z = _inav.get_velocity_z_up_cms() + _pid_vel_z.get_error(); _ekf_z_reset_ms = reset_ms; } } bool AC_PosControl::pre_arm_checks(const char *param_prefix, char *failure_msg, const uint8_t failure_msg_len) { if (!is_positive(get_pos_xy_p().kP())) { hal.util->snprintf(failure_msg, failure_msg_len, "%s_POSXY_P must be > 0", param_prefix); return false; } if (!is_positive(get_pos_z_p().kP())) { hal.util->snprintf(failure_msg, failure_msg_len, "%s_POSZ_P must be > 0", param_prefix); return false; } if (!is_positive(get_vel_z_pid().kP())) { hal.util->snprintf(failure_msg, failure_msg_len, "%s_VELZ_P must be > 0", param_prefix); return false; } if (!is_positive(get_accel_z_pid().kP())) { hal.util->snprintf(failure_msg, failure_msg_len, "%s_ACCZ_P must be > 0", param_prefix); return false; } if (!is_positive(get_accel_z_pid().kI())) { hal.util->snprintf(failure_msg, failure_msg_len, "%s_ACCZ_I must be > 0", param_prefix); return false; } return true; } // return true if on a real vehicle or SITL with lock-step scheduling bool AC_PosControl::has_good_timing(void) const { #if CONFIG_HAL_BOARD == HAL_BOARD_SITL auto *sitl = AP::sitl(); if (sitl) { return sitl->state.is_lock_step_scheduled; } #endif // real boards are assumed to have good timing return true; }