mirror of https://github.com/ArduPilot/ardupilot
1225 lines
49 KiB
C++
1225 lines
49 KiB
C++
#include <AP_HAL/AP_HAL.h>
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#include "AC_PosControl.h"
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#include <AP_Math/AP_Math.h>
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#include <DataFlash/DataFlash.h>
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extern const AP_HAL::HAL& hal;
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#if APM_BUILD_TYPE(APM_BUILD_ArduPlane)
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// default gains for Plane
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# define POSCONTROL_POS_Z_P 1.0f // vertical position controller P gain default
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# define POSCONTROL_VEL_Z_P 5.0f // vertical velocity controller P gain default
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# define POSCONTROL_ACC_Z_P 0.3f // vertical acceleration controller P gain default
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# define POSCONTROL_ACC_Z_I 1.0f // vertical acceleration controller I gain default
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# define POSCONTROL_ACC_Z_D 0.0f // vertical acceleration controller D gain default
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# define POSCONTROL_ACC_Z_IMAX 800 // vertical acceleration controller IMAX gain default
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# define POSCONTROL_ACC_Z_FILT_HZ 10.0f // vertical acceleration controller input filter default
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# define POSCONTROL_ACC_Z_DT 0.02f // vertical acceleration controller dt default
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# define POSCONTROL_POS_XY_P 1.0f // horizontal position controller P gain default
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# define POSCONTROL_VEL_XY_P 1.4f // horizontal velocity controller P gain default
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# define POSCONTROL_VEL_XY_I 0.7f // horizontal velocity controller I gain default
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# define POSCONTROL_VEL_XY_D 0.35f // horizontal velocity controller D gain default
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# define POSCONTROL_VEL_XY_IMAX 1000.0f // horizontal velocity controller IMAX gain default
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# define POSCONTROL_VEL_XY_FILT_HZ 5.0f // horizontal velocity controller input filter
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# define POSCONTROL_VEL_XY_FILT_D_HZ 5.0f // horizontal velocity controller input filter for D
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#elif APM_BUILD_TYPE(APM_BUILD_ArduSub)
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// default gains for Sub
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# define POSCONTROL_POS_Z_P 3.0f // vertical position controller P gain default
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# define POSCONTROL_VEL_Z_P 8.0f // vertical velocity controller P gain default
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# define POSCONTROL_ACC_Z_P 0.5f // vertical acceleration controller P gain default
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# define POSCONTROL_ACC_Z_I 0.1f // vertical acceleration controller I gain default
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# define POSCONTROL_ACC_Z_D 0.0f // vertical acceleration controller D gain default
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# define POSCONTROL_ACC_Z_IMAX 100 // vertical acceleration controller IMAX gain default
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# define POSCONTROL_ACC_Z_FILT_HZ 20.0f // vertical acceleration controller input filter default
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# define POSCONTROL_ACC_Z_DT 0.0025f // vertical acceleration controller dt default
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# define POSCONTROL_POS_XY_P 1.0f // horizontal position controller P gain default
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# define POSCONTROL_VEL_XY_P 1.0f // horizontal velocity controller P gain default
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# define POSCONTROL_VEL_XY_I 0.5f // horizontal velocity controller I gain default
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# define POSCONTROL_VEL_XY_D 0.0f // horizontal velocity controller D gain default
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# define POSCONTROL_VEL_XY_IMAX 1000.0f // horizontal velocity controller IMAX gain default
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# define POSCONTROL_VEL_XY_FILT_HZ 5.0f // horizontal velocity controller input filter
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# define POSCONTROL_VEL_XY_FILT_D_HZ 5.0f // horizontal velocity controller input filter for D
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#else
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// default gains for Copter / TradHeli
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# define POSCONTROL_POS_Z_P 1.0f // vertical position controller P gain default
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# define POSCONTROL_VEL_Z_P 5.0f // vertical velocity controller P gain default
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# define POSCONTROL_ACC_Z_P 0.5f // vertical acceleration controller P gain default
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# define POSCONTROL_ACC_Z_I 1.0f // vertical acceleration controller I gain default
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# define POSCONTROL_ACC_Z_D 0.0f // vertical acceleration controller D gain default
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# define POSCONTROL_ACC_Z_IMAX 800 // vertical acceleration controller IMAX gain default
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# define POSCONTROL_ACC_Z_FILT_HZ 20.0f // vertical acceleration controller input filter default
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# define POSCONTROL_ACC_Z_DT 0.0025f // vertical acceleration controller dt default
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# define POSCONTROL_POS_XY_P 1.0f // horizontal position controller P gain default
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# define POSCONTROL_VEL_XY_P 2.0f // horizontal velocity controller P gain default
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# define POSCONTROL_VEL_XY_I 1.0f // horizontal velocity controller I gain default
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# define POSCONTROL_VEL_XY_D 0.5f // horizontal velocity controller D gain default
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# define POSCONTROL_VEL_XY_IMAX 1000.0f // horizontal velocity controller IMAX gain default
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# define POSCONTROL_VEL_XY_FILT_HZ 5.0f // horizontal velocity controller input filter
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# define POSCONTROL_VEL_XY_FILT_D_HZ 5.0f // horizontal velocity controller input filter for D
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#endif
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const AP_Param::GroupInfo AC_PosControl::var_info[] = {
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// 0 was used for HOVER
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// @Param: _ACC_XY_FILT
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// @DisplayName: XY Acceleration filter cutoff frequency
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// @Description: Lower values will slow the response of the navigation controller and reduce twitchiness
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// @Units: Hz
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// @Range: 0.5 5
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// @Increment: 0.1
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// @User: Advanced
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AP_GROUPINFO("_ACC_XY_FILT", 1, AC_PosControl, _accel_xy_filt_hz, POSCONTROL_ACCEL_FILTER_HZ),
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// @Param: _POSZ_P
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// @DisplayName: Position (vertical) controller P gain
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// @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
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// @Range: 1.000 3.000
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// @User: Standard
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AP_SUBGROUPINFO(_p_pos_z, "_POSZ_", 2, AC_PosControl, AC_P),
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// @Param: _VELZ_P
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// @DisplayName: Velocity (vertical) controller P gain
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// @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
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// @Range: 1.000 8.000
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// @User: Standard
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AP_SUBGROUPINFO(_p_vel_z, "_VELZ_", 3, AC_PosControl, AC_P),
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// @Param: _ACCZ_P
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// @DisplayName: Acceleration (vertical) controller P gain
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// @Description: Acceleration (vertical) controller P gain. Converts the difference between desired vertical acceleration and actual acceleration into a motor output
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// @Range: 0.500 1.500
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// @Increment: 0.05
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// @User: Standard
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// @Param: _ACCZ_I
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// @DisplayName: Acceleration (vertical) controller I gain
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// @Description: Acceleration (vertical) controller I gain. Corrects long-term difference in desired vertical acceleration and actual acceleration
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// @Range: 0.000 3.000
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// @User: Standard
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// @Param: _ACCZ_IMAX
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// @DisplayName: Acceleration (vertical) controller I gain maximum
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// @Description: Acceleration (vertical) controller I gain maximum. Constrains the maximum pwm that the I term will generate
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// @Range: 0 1000
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// @Units: d%
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// @User: Standard
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// @Param: _ACCZ_D
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// @DisplayName: Acceleration (vertical) controller D gain
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// @Description: Acceleration (vertical) controller D gain. Compensates for short-term change in desired vertical acceleration vs actual acceleration
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// @Range: 0.000 0.400
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// @User: Standard
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// @Param: _ACCZ_FILT
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// @DisplayName: Acceleration (vertical) controller filter
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// @Description: Filter applied to acceleration to reduce noise. Lower values reduce noise but add delay.
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// @Range: 1.000 100.000
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// @Units: Hz
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// @User: Standard
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AP_SUBGROUPINFO(_pid_accel_z, "_ACCZ_", 4, AC_PosControl, AC_PID),
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// @Param: _POSXY_P
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// @DisplayName: Position (horizonal) controller P gain
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// @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
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// @Range: 0.500 2.000
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// @User: Standard
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AP_SUBGROUPINFO(_p_pos_xy, "_POSXY_", 5, AC_PosControl, AC_P),
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// @Param: _VELXY_P
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// @DisplayName: Velocity (horizontal) P gain
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// @Description: Velocity (horizontal) P gain. Converts the difference between desired velocity to a target acceleration
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// @Range: 0.1 6.0
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// @Increment: 0.1
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// @User: Advanced
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// @Param: _VELXY_I
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// @DisplayName: Velocity (horizontal) I gain
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// @Description: Velocity (horizontal) I gain. Corrects long-term difference in desired velocity to a target acceleration
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// @Range: 0.02 1.00
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// @Increment: 0.01
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// @User: Advanced
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// @Param: _VELXY_D
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// @DisplayName: Velocity (horizontal) D gain
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// @Description: Velocity (horizontal) D gain. Corrects short-term changes in velocity
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// @Range: 0.00 1.00
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// @Increment: 0.001
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// @User: Advanced
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// @Param: _VELXY_IMAX
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// @DisplayName: Velocity (horizontal) integrator maximum
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// @Description: Velocity (horizontal) integrator maximum. Constrains the target acceleration that the I gain will output
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// @Range: 0 4500
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// @Increment: 10
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// @Units: cm/s/s
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// @User: Advanced
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// @Param: _VELXY_FILT
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// @DisplayName: Velocity (horizontal) input filter
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// @Description: Velocity (horizontal) input filter. This filter (in hz) is applied to the input for P and I terms
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// @Range: 0 100
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// @Units: Hz
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// @User: Advanced
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// @Param: _VELXY_D_FILT
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// @DisplayName: Velocity (horizontal) input filter
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// @Description: Velocity (horizontal) input filter. This filter (in hz) is applied to the input for P and I terms
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// @Range: 0 100
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// @Units: Hz
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// @User: Advanced
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AP_SUBGROUPINFO(_pid_vel_xy, "_VELXY_", 6, AC_PosControl, AC_PID_2D),
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// @Param: _ANGLE_MAX
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// @DisplayName: Position Control Angle Max
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// @Description: Maximum lean angle autopilot can request. Set to zero to use ANGLE_MAX parameter value
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// @Units: deg
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// @Range: 0 45
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// @Increment: 1
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// @User: Advanced
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AP_GROUPINFO("_ANGLE_MAX", 7, AC_PosControl, _lean_angle_max, 0.0f),
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AP_GROUPEND
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};
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// Default constructor.
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// Note that the Vector/Matrix constructors already implicitly zero
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// their values.
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//
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AC_PosControl::AC_PosControl(const AP_AHRS_View& ahrs, const AP_InertialNav& inav,
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const AP_Motors& motors, AC_AttitudeControl& attitude_control) :
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_ahrs(ahrs),
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_inav(inav),
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_motors(motors),
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_attitude_control(attitude_control),
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_p_pos_z(POSCONTROL_POS_Z_P),
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_p_vel_z(POSCONTROL_VEL_Z_P),
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_pid_accel_z(POSCONTROL_ACC_Z_P, POSCONTROL_ACC_Z_I, POSCONTROL_ACC_Z_D, POSCONTROL_ACC_Z_IMAX, POSCONTROL_ACC_Z_FILT_HZ, POSCONTROL_ACC_Z_DT),
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_p_pos_xy(POSCONTROL_POS_XY_P),
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_pid_vel_xy(POSCONTROL_VEL_XY_P, POSCONTROL_VEL_XY_I, POSCONTROL_VEL_XY_D, POSCONTROL_VEL_XY_IMAX, POSCONTROL_VEL_XY_FILT_HZ, POSCONTROL_VEL_XY_FILT_D_HZ, POSCONTROL_DT_50HZ),
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_dt(POSCONTROL_DT_400HZ),
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_last_update_xy_ms(0),
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_last_update_z_ms(0),
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_speed_down_cms(POSCONTROL_SPEED_DOWN),
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_speed_up_cms(POSCONTROL_SPEED_UP),
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_speed_cms(POSCONTROL_SPEED),
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_accel_z_cms(POSCONTROL_ACCEL_Z),
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_accel_last_z_cms(0.0f),
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_accel_cms(POSCONTROL_ACCEL_XY),
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_leash(POSCONTROL_LEASH_LENGTH_MIN),
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_leash_down_z(POSCONTROL_LEASH_LENGTH_MIN),
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_leash_up_z(POSCONTROL_LEASH_LENGTH_MIN),
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_roll_target(0.0f),
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_pitch_target(0.0f),
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_distance_to_target(0.0f),
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_accel_target_filter(POSCONTROL_ACCEL_FILTER_HZ)
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{
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AP_Param::setup_object_defaults(this, var_info);
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// initialise flags
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_flags.recalc_leash_z = true;
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_flags.recalc_leash_xy = true;
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_flags.reset_desired_vel_to_pos = true;
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_flags.reset_accel_to_lean_xy = true;
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_flags.reset_rate_to_accel_z = true;
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_flags.reset_accel_to_throttle = true;
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_flags.freeze_ff_z = true;
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_flags.use_desvel_ff_z = true;
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_limit.pos_up = true;
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_limit.pos_down = true;
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_limit.vel_up = true;
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_limit.vel_down = true;
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_limit.accel_xy = true;
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}
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///
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/// z-axis position controller
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///
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/// set_dt - sets time delta in seconds for all controllers (i.e. 100hz = 0.01, 400hz = 0.0025)
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void AC_PosControl::set_dt(float delta_sec)
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{
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_dt = delta_sec;
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// update PID controller dt
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_pid_accel_z.set_dt(_dt);
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_pid_vel_xy.set_dt(_dt);
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// update rate z-axis velocity error and accel error filters
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_vel_error_filter.set_cutoff_frequency(POSCONTROL_VEL_ERROR_CUTOFF_FREQ);
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}
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/// set_speed_z - sets maximum climb and descent rates
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/// To-Do: call this in the main code as part of flight mode initialisation
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/// calc_leash_length_z should be called afterwards
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/// speed_down should be a negative number
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void AC_PosControl::set_speed_z(float speed_down, float speed_up)
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{
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// ensure speed_down is always negative
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speed_down = -fabsf(speed_down);
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if ((fabsf(_speed_down_cms-speed_down) > 1.0f) || (fabsf(_speed_up_cms-speed_up) > 1.0f)) {
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_speed_down_cms = speed_down;
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_speed_up_cms = speed_up;
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_flags.recalc_leash_z = true;
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calc_leash_length_z();
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}
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}
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/// set_accel_z - set vertical acceleration in cm/s/s
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void AC_PosControl::set_accel_z(float accel_cmss)
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{
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if (fabsf(_accel_z_cms-accel_cmss) > 1.0f) {
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_accel_z_cms = accel_cmss;
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_flags.recalc_leash_z = true;
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calc_leash_length_z();
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}
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}
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/// set_alt_target_with_slew - adjusts target towards a final altitude target
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/// should be called continuously (with dt set to be the expected time between calls)
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/// actual position target will be moved no faster than the speed_down and speed_up
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/// target will also be stopped if the motors hit their limits or leash length is exceeded
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void AC_PosControl::set_alt_target_with_slew(float alt_cm, float dt)
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{
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float alt_change = alt_cm-_pos_target.z;
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// do not use z-axis desired velocity feed forward
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_flags.use_desvel_ff_z = false;
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// adjust desired alt if motors have not hit their limits
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if ((alt_change<0 && !_motors.limit.throttle_lower) || (alt_change>0 && !_motors.limit.throttle_upper)) {
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if (!is_zero(dt)) {
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float climb_rate_cms = constrain_float(alt_change/dt, _speed_down_cms, _speed_up_cms);
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_pos_target.z += climb_rate_cms*dt;
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_vel_desired.z = climb_rate_cms; // recorded for reporting purposes
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}
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}
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// do not let target get too far from current altitude
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float curr_alt = _inav.get_altitude();
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_pos_target.z = constrain_float(_pos_target.z,curr_alt-_leash_down_z,curr_alt+_leash_up_z);
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}
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/// set_alt_target_from_climb_rate - adjusts target up or down using a climb rate in cm/s
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/// should be called continuously (with dt set to be the expected time between calls)
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/// actual position target will be moved no faster than the speed_down and speed_up
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/// target will also be stopped if the motors hit their limits or leash length is exceeded
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void AC_PosControl::set_alt_target_from_climb_rate(float climb_rate_cms, float dt, bool force_descend)
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{
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// adjust desired alt if motors have not hit their limits
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// To-Do: add check of _limit.pos_down?
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if ((climb_rate_cms<0 && (!_motors.limit.throttle_lower || force_descend)) || (climb_rate_cms>0 && !_motors.limit.throttle_upper && !_limit.pos_up)) {
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_pos_target.z += climb_rate_cms * dt;
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}
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// do not use z-axis desired velocity feed forward
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// vel_desired set to desired climb rate for reporting and land-detector
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_flags.use_desvel_ff_z = false;
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_vel_desired.z = climb_rate_cms;
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}
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/// set_alt_target_from_climb_rate_ff - adjusts target up or down using a climb rate in cm/s using feed-forward
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/// should be called continuously (with dt set to be the expected time between calls)
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/// actual position target will be moved no faster than the speed_down and speed_up
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/// target will also be stopped if the motors hit their limits or leash length is exceeded
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/// set force_descend to true during landing to allow target to move low enough to slow the motors
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void AC_PosControl::set_alt_target_from_climb_rate_ff(float climb_rate_cms, float dt, bool force_descend)
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{
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// calculated increased maximum acceleration if over speed
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float accel_z_cms = _accel_z_cms;
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if (_vel_desired.z < _speed_down_cms && !is_zero(_speed_down_cms)) {
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accel_z_cms *= POSCONTROL_OVERSPEED_GAIN_Z * _vel_desired.z / _speed_down_cms;
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}
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if (_vel_desired.z > _speed_up_cms && !is_zero(_speed_up_cms)) {
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accel_z_cms *= POSCONTROL_OVERSPEED_GAIN_Z * _vel_desired.z / _speed_up_cms;
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}
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accel_z_cms = constrain_float(accel_z_cms, 0.0f, 750.0f);
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// jerk_z is calculated to reach full acceleration in 1000ms.
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float jerk_z = accel_z_cms * POSCONTROL_JERK_RATIO;
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float accel_z_max = MIN(accel_z_cms, safe_sqrt(2.0f*fabsf(_vel_desired.z - climb_rate_cms)*jerk_z));
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_accel_last_z_cms += jerk_z * dt;
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_accel_last_z_cms = MIN(accel_z_max, _accel_last_z_cms);
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float vel_change_limit = _accel_last_z_cms * dt;
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_vel_desired.z = constrain_float(climb_rate_cms, _vel_desired.z-vel_change_limit, _vel_desired.z+vel_change_limit);
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_flags.use_desvel_ff_z = true;
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// adjust desired alt if motors have not hit their limits
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// To-Do: add check of _limit.pos_down?
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if ((_vel_desired.z<0 && (!_motors.limit.throttle_lower || force_descend)) || (_vel_desired.z>0 && !_motors.limit.throttle_upper && !_limit.pos_up)) {
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_pos_target.z += _vel_desired.z * dt;
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}
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}
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/// add_takeoff_climb_rate - adjusts alt target up or down using a climb rate in cm/s
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/// should be called continuously (with dt set to be the expected time between calls)
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/// almost no checks are performed on the input
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void AC_PosControl::add_takeoff_climb_rate(float climb_rate_cms, float dt)
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{
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_pos_target.z += climb_rate_cms * dt;
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}
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/// shift altitude target (positive means move altitude up)
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void AC_PosControl::shift_alt_target(float z_cm)
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{
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_pos_target.z += z_cm;
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// freeze feedforward to avoid jump
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if (!is_zero(z_cm)) {
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freeze_ff_z();
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}
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}
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/// relax_alt_hold_controllers - set all desired and targets to measured
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void AC_PosControl::relax_alt_hold_controllers(float throttle_setting)
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{
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_pos_target.z = _inav.get_altitude();
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_vel_desired.z = 0.0f;
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_flags.use_desvel_ff_z = false;
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_vel_target.z = _inav.get_velocity_z();
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_vel_last.z = _inav.get_velocity_z();
|
|
_accel_desired.z = 0.0f;
|
|
_accel_last_z_cms = 0.0f;
|
|
_accel_target.z = -(_ahrs.get_accel_ef_blended().z + GRAVITY_MSS) * 100.0f;
|
|
_flags.reset_accel_to_throttle = true;
|
|
_pid_accel_z.set_integrator((throttle_setting-_motors.get_throttle_hover())*1000.0f);
|
|
}
|
|
|
|
// get_alt_error - returns altitude error in cm
|
|
float AC_PosControl::get_alt_error() const
|
|
{
|
|
return (_pos_target.z - _inav.get_altitude());
|
|
}
|
|
|
|
/// set_target_to_stopping_point_z - returns reasonable stopping altitude in cm above home
|
|
void AC_PosControl::set_target_to_stopping_point_z()
|
|
{
|
|
// check if z leash needs to be recalculated
|
|
calc_leash_length_z();
|
|
|
|
get_stopping_point_z(_pos_target);
|
|
}
|
|
|
|
/// get_stopping_point_z - calculates stopping point based on current position, velocity, vehicle acceleration
|
|
void AC_PosControl::get_stopping_point_z(Vector3f& stopping_point) const
|
|
{
|
|
const float curr_pos_z = _inav.get_altitude();
|
|
float curr_vel_z = _inav.get_velocity_z();
|
|
|
|
float linear_distance; // half the distance we swap between linear and sqrt and the distance we offset sqrt
|
|
float linear_velocity; // the velocity we swap between linear and sqrt
|
|
|
|
// if position controller is active add current velocity error to avoid sudden jump in acceleration
|
|
if (is_active_z()) {
|
|
curr_vel_z += _vel_error.z;
|
|
if (_flags.use_desvel_ff_z) {
|
|
curr_vel_z -= _vel_desired.z;
|
|
}
|
|
}
|
|
|
|
// avoid divide by zero by using current position if kP is very low or acceleration is zero
|
|
if (_p_pos_z.kP() <= 0.0f || _accel_z_cms <= 0.0f) {
|
|
stopping_point.z = curr_pos_z;
|
|
return;
|
|
}
|
|
|
|
// calculate the velocity at which we switch from calculating the stopping point using a linear function to a sqrt function
|
|
linear_velocity = _accel_z_cms/_p_pos_z.kP();
|
|
|
|
if (fabsf(curr_vel_z) < linear_velocity) {
|
|
// if our current velocity is below the cross-over point we use a linear function
|
|
stopping_point.z = curr_pos_z + curr_vel_z/_p_pos_z.kP();
|
|
} else {
|
|
linear_distance = _accel_z_cms/(2.0f*_p_pos_z.kP()*_p_pos_z.kP());
|
|
if (curr_vel_z > 0){
|
|
stopping_point.z = curr_pos_z + (linear_distance + curr_vel_z*curr_vel_z/(2.0f*_accel_z_cms));
|
|
} else {
|
|
stopping_point.z = curr_pos_z - (linear_distance + curr_vel_z*curr_vel_z/(2.0f*_accel_z_cms));
|
|
}
|
|
}
|
|
stopping_point.z = constrain_float(stopping_point.z, curr_pos_z - POSCONTROL_STOPPING_DIST_DOWN_MAX, curr_pos_z + POSCONTROL_STOPPING_DIST_UP_MAX);
|
|
}
|
|
|
|
/// init_takeoff - initialises target altitude if we are taking off
|
|
void AC_PosControl::init_takeoff()
|
|
{
|
|
const Vector3f& curr_pos = _inav.get_position();
|
|
|
|
_pos_target.z = curr_pos.z;
|
|
|
|
// freeze feedforward to avoid jump
|
|
freeze_ff_z();
|
|
|
|
// shift difference between last motor out and hover throttle into accelerometer I
|
|
_pid_accel_z.set_integrator((_motors.get_throttle()-_motors.get_throttle_hover())*1000.0f);
|
|
|
|
// initialise ekf reset handler
|
|
init_ekf_z_reset();
|
|
}
|
|
|
|
// is_active_z - returns true if the z-axis position controller has been run very recently
|
|
bool AC_PosControl::is_active_z() const
|
|
{
|
|
return ((AP_HAL::millis() - _last_update_z_ms) <= POSCONTROL_ACTIVE_TIMEOUT_MS);
|
|
}
|
|
|
|
/// update_z_controller - fly to altitude in cm above home
|
|
void AC_PosControl::update_z_controller()
|
|
{
|
|
// check time since last cast
|
|
uint32_t now = AP_HAL::millis();
|
|
if (now - _last_update_z_ms > POSCONTROL_ACTIVE_TIMEOUT_MS) {
|
|
_flags.reset_rate_to_accel_z = true;
|
|
_flags.reset_accel_to_throttle = true;
|
|
}
|
|
_last_update_z_ms = now;
|
|
|
|
// check for ekf altitude reset
|
|
check_for_ekf_z_reset();
|
|
|
|
// check if leash lengths need to be recalculated
|
|
calc_leash_length_z();
|
|
|
|
// call z-axis position controller
|
|
run_z_controller();
|
|
}
|
|
|
|
/// calc_leash_length - calculates the vertical leash lengths from maximum speed, acceleration
|
|
/// called by update_z_controller if z-axis speed or accelerations are changed
|
|
void AC_PosControl::calc_leash_length_z()
|
|
{
|
|
if (_flags.recalc_leash_z) {
|
|
_leash_up_z = calc_leash_length(_speed_up_cms, _accel_z_cms, _p_pos_z.kP());
|
|
_leash_down_z = calc_leash_length(-_speed_down_cms, _accel_z_cms, _p_pos_z.kP());
|
|
_flags.recalc_leash_z = false;
|
|
}
|
|
}
|
|
|
|
// run position control for Z axis
|
|
// target altitude should be set with one of these functions: set_alt_target, set_target_to_stopping_point_z, init_takeoff
|
|
// calculates desired rate in earth-frame z axis and passes to rate controller
|
|
// vel_up_max, vel_down_max should have already been set before calling this method
|
|
void AC_PosControl::run_z_controller()
|
|
{
|
|
float curr_alt = _inav.get_altitude();
|
|
|
|
// clear position limit flags
|
|
_limit.pos_up = false;
|
|
_limit.pos_down = false;
|
|
|
|
// calculate altitude error
|
|
_pos_error.z = _pos_target.z - curr_alt;
|
|
|
|
// do not let target altitude get too far from current altitude
|
|
if (_pos_error.z > _leash_up_z) {
|
|
_pos_target.z = curr_alt + _leash_up_z;
|
|
_pos_error.z = _leash_up_z;
|
|
_limit.pos_up = true;
|
|
}
|
|
if (_pos_error.z < -_leash_down_z) {
|
|
_pos_target.z = curr_alt - _leash_down_z;
|
|
_pos_error.z = -_leash_down_z;
|
|
_limit.pos_down = true;
|
|
}
|
|
|
|
// calculate _vel_target.z using from _pos_error.z using sqrt controller
|
|
_vel_target.z = AC_AttitudeControl::sqrt_controller(_pos_error.z, _p_pos_z.kP(), _accel_z_cms, _dt);
|
|
|
|
// check speed limits
|
|
// To-Do: check these speed limits here or in the pos->rate controller
|
|
_limit.vel_up = false;
|
|
_limit.vel_down = false;
|
|
if (_vel_target.z < _speed_down_cms) {
|
|
_vel_target.z = _speed_down_cms;
|
|
_limit.vel_down = true;
|
|
}
|
|
if (_vel_target.z > _speed_up_cms) {
|
|
_vel_target.z = _speed_up_cms;
|
|
_limit.vel_up = true;
|
|
}
|
|
|
|
// add feed forward component
|
|
if (_flags.use_desvel_ff_z) {
|
|
_vel_target.z += _vel_desired.z;
|
|
}
|
|
|
|
// the following section calculates acceleration required to achieve the velocity target
|
|
|
|
const Vector3f& curr_vel = _inav.get_velocity();
|
|
|
|
// TODO: remove velocity derivative calculation
|
|
// reset last velocity target to current target
|
|
if (_flags.reset_rate_to_accel_z) {
|
|
_vel_last.z = _vel_target.z;
|
|
}
|
|
|
|
// feed forward desired acceleration calculation
|
|
if (_dt > 0.0f) {
|
|
if (!_flags.freeze_ff_z) {
|
|
_accel_desired.z = (_vel_target.z - _vel_last.z)/_dt;
|
|
} else {
|
|
// stop the feed forward being calculated during a known discontinuity
|
|
_flags.freeze_ff_z = false;
|
|
}
|
|
} else {
|
|
_accel_desired.z = 0.0f;
|
|
}
|
|
|
|
// store this iteration's velocities for the next iteration
|
|
_vel_last.z = _vel_target.z;
|
|
|
|
// reset velocity error and filter if this controller has just been engaged
|
|
if (_flags.reset_rate_to_accel_z) {
|
|
// Reset Filter
|
|
_vel_error.z = 0;
|
|
_vel_error_filter.reset(0);
|
|
_flags.reset_rate_to_accel_z = false;
|
|
} else {
|
|
// calculate rate error and filter with cut off frequency of 2 Hz
|
|
_vel_error.z = _vel_error_filter.apply(_vel_target.z - curr_vel.z, _dt);
|
|
}
|
|
|
|
_accel_target.z = _p_vel_z.get_p(_vel_error.z);
|
|
|
|
_accel_target.z += _accel_desired.z;
|
|
|
|
|
|
// the following section calculates a desired throttle needed to achieve the acceleration target
|
|
float z_accel_meas; // actual acceleration
|
|
float p,i,d; // used to capture pid values for logging
|
|
|
|
// Calculate Earth Frame Z acceleration
|
|
z_accel_meas = -(_ahrs.get_accel_ef_blended().z + GRAVITY_MSS) * 100.0f;
|
|
|
|
// reset target altitude if this controller has just been engaged
|
|
if (_flags.reset_accel_to_throttle) {
|
|
// Reset Filter
|
|
_accel_error.z = 0;
|
|
_flags.reset_accel_to_throttle = false;
|
|
} else {
|
|
// calculate accel error
|
|
_accel_error.z = _accel_target.z - z_accel_meas;
|
|
}
|
|
|
|
// set input to PID
|
|
_pid_accel_z.set_input_filter_all(_accel_error.z);
|
|
_pid_accel_z.set_desired_rate(_accel_target.z);
|
|
|
|
// separately calculate p, i, d values for logging
|
|
p = _pid_accel_z.get_p();
|
|
|
|
// get i term
|
|
i = _pid_accel_z.get_integrator();
|
|
|
|
// 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);
|
|
}
|
|
|
|
// update i term as long as we haven't breached the limits or the I term will certainly reduce
|
|
// To-Do: should this be replaced with limits check from attitude_controller?
|
|
if ((!_motors.limit.throttle_lower && !_motors.limit.throttle_upper) || (i>0&&_accel_error.z<0) || (i<0&&_accel_error.z>0)) {
|
|
i = _pid_accel_z.get_i();
|
|
}
|
|
|
|
// get d term
|
|
d = _pid_accel_z.get_d();
|
|
|
|
float thr_out = (p+i+d)*0.001f +_motors.get_throttle_hover();
|
|
|
|
// send throttle to attitude controller with angle boost
|
|
_attitude_control.set_throttle_out(thr_out, true, POSCONTROL_THROTTLE_CUTOFF_FREQ);
|
|
}
|
|
|
|
///
|
|
/// lateral position controller
|
|
///
|
|
|
|
/// set_accel_xy - set horizontal acceleration in cm/s/s
|
|
void AC_PosControl::set_accel_xy(float accel_cmss)
|
|
{
|
|
if (fabsf(_accel_cms-accel_cmss) > 1.0f) {
|
|
_accel_cms = accel_cmss;
|
|
_flags.recalc_leash_xy = true;
|
|
calc_leash_length_xy();
|
|
}
|
|
}
|
|
|
|
/// set_speed_xy - set horizontal speed maximum in cm/s
|
|
void AC_PosControl::set_speed_xy(float speed_cms)
|
|
{
|
|
if (fabsf(_speed_cms-speed_cms) > 1.0f) {
|
|
_speed_cms = speed_cms;
|
|
_flags.recalc_leash_xy = true;
|
|
calc_leash_length_xy();
|
|
}
|
|
}
|
|
|
|
/// set_pos_target in cm from home
|
|
void AC_PosControl::set_pos_target(const Vector3f& position)
|
|
{
|
|
_pos_target = position;
|
|
|
|
_flags.use_desvel_ff_z = false;
|
|
_vel_desired.z = 0.0f;
|
|
// initialise roll and pitch to current roll and pitch. This avoids a twitch between when the target is set and the pos controller is first run
|
|
// To-Do: this initialisation of roll and pitch targets needs to go somewhere between when pos-control is initialised and when it completes it's first cycle
|
|
//_roll_target = constrain_int32(_ahrs.roll_sensor,-_attitude_control.lean_angle_max(),_attitude_control.lean_angle_max());
|
|
//_pitch_target = constrain_int32(_ahrs.pitch_sensor,-_attitude_control.lean_angle_max(),_attitude_control.lean_angle_max());
|
|
}
|
|
|
|
/// set_xy_target in cm from home
|
|
void AC_PosControl::set_xy_target(float x, float y)
|
|
{
|
|
_pos_target.x = x;
|
|
_pos_target.y = y;
|
|
}
|
|
|
|
/// shift position target target in x, y axis
|
|
void AC_PosControl::shift_pos_xy_target(float x_cm, float y_cm)
|
|
{
|
|
// move pos controller target
|
|
_pos_target.x += x_cm;
|
|
_pos_target.y += y_cm;
|
|
}
|
|
|
|
/// set_target_to_stopping_point_xy - sets horizontal target to reasonable stopping position in cm from home
|
|
void AC_PosControl::set_target_to_stopping_point_xy()
|
|
{
|
|
// check if xy leash needs to be recalculated
|
|
calc_leash_length_xy();
|
|
|
|
get_stopping_point_xy(_pos_target);
|
|
}
|
|
|
|
/// get_stopping_point_xy - calculates stopping point based on current position, velocity, vehicle acceleration
|
|
/// distance_max allows limiting distance to stopping point
|
|
/// results placed in stopping_position vector
|
|
/// set_accel_xy() should be called before this method to set vehicle acceleration
|
|
/// set_leash_length() should have been called before this method
|
|
void AC_PosControl::get_stopping_point_xy(Vector3f &stopping_point) const
|
|
{
|
|
const Vector3f curr_pos = _inav.get_position();
|
|
Vector3f curr_vel = _inav.get_velocity();
|
|
float linear_distance; // the distance at which we swap from a linear to sqrt response
|
|
float linear_velocity; // the velocity above which we swap from a linear to sqrt response
|
|
float stopping_dist; // the distance within the vehicle can stop
|
|
float kP = _p_pos_xy.kP();
|
|
|
|
// add velocity error to current velocity
|
|
if (is_active_xy()) {
|
|
curr_vel.x += _vel_error.x;
|
|
curr_vel.y += _vel_error.y;
|
|
}
|
|
|
|
// calculate current velocity
|
|
float vel_total = norm(curr_vel.x, curr_vel.y);
|
|
|
|
// avoid divide by zero by using current position if the velocity is below 10cm/s, kP is very low or acceleration is zero
|
|
if (kP <= 0.0f || _accel_cms <= 0.0f || is_zero(vel_total)) {
|
|
stopping_point.x = curr_pos.x;
|
|
stopping_point.y = curr_pos.y;
|
|
return;
|
|
}
|
|
|
|
// calculate point at which velocity switches from linear to sqrt
|
|
linear_velocity = _accel_cms/kP;
|
|
|
|
// calculate distance within which we can stop
|
|
if (vel_total < linear_velocity) {
|
|
stopping_dist = vel_total/kP;
|
|
} else {
|
|
linear_distance = _accel_cms/(2.0f*kP*kP);
|
|
stopping_dist = linear_distance + (vel_total*vel_total)/(2.0f*_accel_cms);
|
|
}
|
|
|
|
// constrain stopping distance
|
|
stopping_dist = constrain_float(stopping_dist, 0, _leash);
|
|
|
|
// convert the stopping distance into a stopping point using velocity vector
|
|
stopping_point.x = curr_pos.x + (stopping_dist * curr_vel.x / vel_total);
|
|
stopping_point.y = curr_pos.y + (stopping_dist * curr_vel.y / vel_total);
|
|
}
|
|
|
|
/// get_distance_to_target - get horizontal distance to target position in cm
|
|
float AC_PosControl::get_distance_to_target() const
|
|
{
|
|
return _distance_to_target;
|
|
}
|
|
|
|
/// get_bearing_to_target - get bearing to target position in centi-degrees
|
|
int32_t AC_PosControl::get_bearing_to_target() const
|
|
{
|
|
return get_bearing_cd(_inav.get_position(), _pos_target);
|
|
}
|
|
|
|
// is_active_xy - returns true if the xy position controller has been run very recently
|
|
bool AC_PosControl::is_active_xy() const
|
|
{
|
|
return ((AP_HAL::millis() - _last_update_xy_ms) <= POSCONTROL_ACTIVE_TIMEOUT_MS);
|
|
}
|
|
|
|
/// 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_zero(_lean_angle_max)) {
|
|
return _attitude_control.lean_angle_max();
|
|
}
|
|
return _lean_angle_max * 100.0f;
|
|
}
|
|
|
|
/// init_xy_controller - initialise the xy controller
|
|
/// this should be called after setting the position target and the desired velocity and acceleration
|
|
/// sets target roll angle, pitch angle and I terms based on vehicle current lean angles
|
|
/// should be called once whenever significant changes to the position target are made
|
|
/// this does not update the xy target
|
|
void AC_PosControl::init_xy_controller()
|
|
{
|
|
// set roll, pitch lean angle targets to current attitude
|
|
// todo: this should probably be based on the desired attitude not the current attitude
|
|
_roll_target = _ahrs.roll_sensor;
|
|
_pitch_target = _ahrs.pitch_sensor;
|
|
|
|
// initialise I terms from lean angles
|
|
_pid_vel_xy.reset_filter();
|
|
lean_angles_to_accel(_accel_target.x, _accel_target.y);
|
|
_pid_vel_xy.set_integrator(_accel_target-_accel_desired);
|
|
|
|
// flag reset required in rate to accel step
|
|
_flags.reset_desired_vel_to_pos = true;
|
|
_flags.reset_accel_to_lean_xy = true;
|
|
|
|
// initialise ekf xy reset handler
|
|
init_ekf_xy_reset();
|
|
}
|
|
|
|
/// update_xy_controller - run the horizontal position controller - should be called at 100hz or higher
|
|
void AC_PosControl::update_xy_controller(float ekfNavVelGainScaler)
|
|
{
|
|
// compute dt
|
|
uint32_t now = AP_HAL::millis();
|
|
float dt = (now - _last_update_xy_ms)*0.001f;
|
|
|
|
// sanity check dt
|
|
if (dt >= POSCONTROL_ACTIVE_TIMEOUT_MS*1.0e-3f) {
|
|
dt = 0.0f;
|
|
}
|
|
|
|
// check for ekf xy position reset
|
|
check_for_ekf_xy_reset();
|
|
|
|
// check if xy leash needs to be recalculated
|
|
calc_leash_length_xy();
|
|
|
|
// translate any adjustments from pilot to loiter target
|
|
desired_vel_to_pos(dt);
|
|
|
|
// run horizontal position controller
|
|
run_xy_controller(dt, ekfNavVelGainScaler);
|
|
|
|
// update xy update time
|
|
_last_update_xy_ms = now;
|
|
}
|
|
|
|
float AC_PosControl::time_since_last_xy_update() const
|
|
{
|
|
uint32_t now = AP_HAL::millis();
|
|
return (now - _last_update_xy_ms)*0.001f;
|
|
}
|
|
|
|
// write log to dataflash
|
|
void AC_PosControl::write_log()
|
|
{
|
|
const Vector3f &pos_target = get_pos_target();
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const Vector3f &vel_target = get_vel_target();
|
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const Vector3f &accel_target = get_accel_target();
|
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const Vector3f &position = _inav.get_position();
|
|
const Vector3f &velocity = _inav.get_velocity();
|
|
float accel_x, accel_y;
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|
lean_angles_to_accel(accel_x, accel_y);
|
|
|
|
DataFlash_Class::instance()->Log_Write("PSC", "TimeUS,TPX,TPY,PX,PY,TVX,TVY,VX,VY,TAX,TAY,AX,AY",
|
|
"smmmmnnnnoooo", "FBBBBBBBBBBBB", "Qffffffffffff",
|
|
AP_HAL::micros64(),
|
|
(double)pos_target.x,
|
|
(double)pos_target.y,
|
|
(double)position.x,
|
|
(double)position.y,
|
|
(double)vel_target.x,
|
|
(double)vel_target.y,
|
|
(double)velocity.x,
|
|
(double)velocity.y,
|
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(double)accel_target.x,
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(double)accel_target.y,
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(double)accel_x,
|
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(double)accel_y);
|
|
}
|
|
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/// init_vel_controller_xyz - initialise the velocity controller - should be called once before the caller attempts to use the controller
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|
void AC_PosControl::init_vel_controller_xyz()
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|
{
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// set roll, pitch lean angle targets to current attitude
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_roll_target = _ahrs.roll_sensor;
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_pitch_target = _ahrs.pitch_sensor;
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|
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_pid_vel_xy.reset_filter();
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lean_angles_to_accel(_accel_target.x, _accel_target.y);
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_pid_vel_xy.set_integrator(_accel_target);
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|
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|
// flag reset required in rate to accel step
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_flags.reset_desired_vel_to_pos = true;
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_flags.reset_accel_to_lean_xy = true;
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|
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// set target position
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const Vector3f& curr_pos = _inav.get_position();
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set_xy_target(curr_pos.x, curr_pos.y);
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set_alt_target(curr_pos.z);
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|
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// move current vehicle velocity into feed forward velocity
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const Vector3f& curr_vel = _inav.get_velocity();
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set_desired_velocity(curr_vel);
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// set vehicle acceleration to zero
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set_desired_accel_xy(0.0f,0.0f);
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|
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// initialise ekf reset handlers
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init_ekf_xy_reset();
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init_ekf_z_reset();
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}
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|
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/// update_velocity_controller_xy - run the velocity controller - should be called at 100hz or higher
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/// velocity targets should we set using set_desired_velocity_xy() method
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/// callers should use get_roll() and get_pitch() methods and sent to the attitude controller
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/// throttle targets will be sent directly to the motors
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void AC_PosControl::update_vel_controller_xy(float ekfNavVelGainScaler)
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{
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// capture time since last iteration
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uint32_t now = AP_HAL::millis();
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float dt = (now - _last_update_xy_ms)*0.001f;
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|
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// sanity check dt
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if (dt >= 0.2f) {
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dt = 0.0f;
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}
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|
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// check for ekf xy position reset
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check_for_ekf_xy_reset();
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|
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// check if xy leash needs to be recalculated
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calc_leash_length_xy();
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|
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// apply desired velocity request to position target
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// TODO: this will need to be removed and added to the calling function.
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desired_vel_to_pos(dt);
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|
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// run position controller
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run_xy_controller(dt, ekfNavVelGainScaler);
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|
|
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// update xy update time
|
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_last_update_xy_ms = now;
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|
}
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|
|
|
|
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/// update_velocity_controller_xyz - run the velocity controller - should be called at 100hz or higher
|
|
/// velocity targets should we set using set_desired_velocity_xyz() method
|
|
/// callers should use get_roll() and get_pitch() methods and sent to the attitude controller
|
|
/// throttle targets will be sent directly to the motors
|
|
void AC_PosControl::update_vel_controller_xyz(float ekfNavVelGainScaler)
|
|
{
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|
update_vel_controller_xy(ekfNavVelGainScaler);
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|
|
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// update altitude target
|
|
set_alt_target_from_climb_rate_ff(_vel_desired.z, _dt, false);
|
|
|
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// run z-axis position controller
|
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update_z_controller();
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}
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|
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float AC_PosControl::get_horizontal_error() const
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|
{
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|
return norm(_pos_error.x, _pos_error.y);
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}
|
|
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///
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|
/// private methods
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|
///
|
|
|
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/// calc_leash_length - calculates the horizontal leash length given a maximum speed, acceleration
|
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/// should be called whenever the speed, acceleration or position kP is modified
|
|
void AC_PosControl::calc_leash_length_xy()
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|
{
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|
// todo: remove _flags.recalc_leash_xy or don't call this function after each variable change.
|
|
if (_flags.recalc_leash_xy) {
|
|
_leash = calc_leash_length(_speed_cms, _accel_cms, _p_pos_xy.kP());
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|
_flags.recalc_leash_xy = false;
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|
}
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|
}
|
|
|
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/// move velocity target using desired acceleration
|
|
void AC_PosControl::desired_accel_to_vel(float nav_dt)
|
|
{
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|
// range check nav_dt
|
|
if (nav_dt < 0) {
|
|
return;
|
|
}
|
|
|
|
// update target velocity
|
|
if (_flags.reset_desired_vel_to_pos) {
|
|
_flags.reset_desired_vel_to_pos = false;
|
|
} else {
|
|
_vel_desired.x += _accel_desired.x * nav_dt;
|
|
_vel_desired.y += _accel_desired.y * nav_dt;
|
|
}
|
|
}
|
|
|
|
/// desired_vel_to_pos - move position target using desired velocities
|
|
void AC_PosControl::desired_vel_to_pos(float nav_dt)
|
|
{
|
|
// range check nav_dt
|
|
if( nav_dt < 0 ) {
|
|
return;
|
|
}
|
|
|
|
// update target position
|
|
if (_flags.reset_desired_vel_to_pos) {
|
|
_flags.reset_desired_vel_to_pos = false;
|
|
} else {
|
|
_pos_target.x += _vel_desired.x * nav_dt;
|
|
_pos_target.y += _vel_desired.y * nav_dt;
|
|
}
|
|
}
|
|
|
|
/// run horizontal position controller correcting position and velocity
|
|
/// converts position (_pos_target) to target velocity (_vel_target)
|
|
/// desired velocity (_vel_desired) is combined into final target velocity
|
|
/// converts desired velocities in lat/lon directions to accelerations in lat/lon frame
|
|
/// converts desired accelerations provided in lat/lon frame to roll/pitch angles
|
|
void AC_PosControl::run_xy_controller(float dt, float ekfNavVelGainScaler)
|
|
{
|
|
Vector3f curr_pos = _inav.get_position();
|
|
float kP = ekfNavVelGainScaler * _p_pos_xy.kP(); // scale gains to compensate for noisy optical flow measurement in the EKF
|
|
|
|
// avoid divide by zero
|
|
if (kP <= 0.0f) {
|
|
_vel_target.x = 0.0f;
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|
_vel_target.y = 0.0f;
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|
}else{
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|
// calculate distance error
|
|
_pos_error.x = _pos_target.x - curr_pos.x;
|
|
_pos_error.y = _pos_target.y - curr_pos.y;
|
|
|
|
// Constrain _pos_error and target position
|
|
// Constrain the maximum length of _vel_target to the maximum position correction velocity
|
|
// TODO: replace the leash length with a user definable maximum position correction
|
|
if (limit_vector_length(_pos_error.x, _pos_error.y, _leash))
|
|
{
|
|
_pos_target.x = curr_pos.x + _pos_error.x;
|
|
_pos_target.y = curr_pos.y + _pos_error.y;
|
|
}
|
|
_distance_to_target = norm(_pos_error.x, _pos_error.y);
|
|
|
|
_vel_target = sqrt_controller(_pos_error, kP, _accel_cms);
|
|
}
|
|
|
|
// add velocity feed-forward
|
|
_vel_target.x += _vel_desired.x;
|
|
_vel_target.y += _vel_desired.y;
|
|
|
|
// the following section converts desired velocities in lat/lon directions to accelerations in lat/lon frame
|
|
|
|
Vector2f accel_target, vel_xy_p, vel_xy_i, vel_xy_d;
|
|
|
|
// check if vehicle velocity is being overridden
|
|
if (_flags.vehicle_horiz_vel_override) {
|
|
_flags.vehicle_horiz_vel_override = false;
|
|
} else {
|
|
_vehicle_horiz_vel.x = _inav.get_velocity().x;
|
|
_vehicle_horiz_vel.y = _inav.get_velocity().y;
|
|
}
|
|
|
|
// calculate velocity error
|
|
_vel_error.x = _vel_target.x - _vehicle_horiz_vel.x;
|
|
_vel_error.y = _vel_target.y - _vehicle_horiz_vel.y;
|
|
// TODO: constrain velocity error and velocity target
|
|
|
|
// call pi controller
|
|
_pid_vel_xy.set_input(_vel_error);
|
|
|
|
// get p
|
|
vel_xy_p = _pid_vel_xy.get_p();
|
|
|
|
// update i term if we have not hit the accel or throttle limits OR the i term will reduce
|
|
// TODO: move limit handling into the PI and PID controller
|
|
if (!_limit.accel_xy && !_motors.limit.throttle_upper) {
|
|
vel_xy_i = _pid_vel_xy.get_i();
|
|
} else {
|
|
vel_xy_i = _pid_vel_xy.get_i_shrink();
|
|
}
|
|
|
|
// get d
|
|
vel_xy_d = _pid_vel_xy.get_d();
|
|
|
|
// acceleration to correct for velocity error and scale PID output to compensate for optical flow measurement induced EKF noise
|
|
accel_target.x = (vel_xy_p.x + vel_xy_i.x + vel_xy_d.x) * ekfNavVelGainScaler;
|
|
accel_target.y = (vel_xy_p.y + vel_xy_i.y + vel_xy_d.y) * ekfNavVelGainScaler;
|
|
|
|
// reset accel to current desired acceleration
|
|
if (_flags.reset_accel_to_lean_xy) {
|
|
_accel_target_filter.reset(Vector2f(accel_target.x, accel_target.y));
|
|
_flags.reset_accel_to_lean_xy = false;
|
|
}
|
|
|
|
// filter correction acceleration
|
|
_accel_target_filter.set_cutoff_frequency(MIN(_accel_xy_filt_hz, 5.0f*ekfNavVelGainScaler));
|
|
_accel_target_filter.apply(accel_target, dt);
|
|
|
|
// pass the correction acceleration to the target acceleration output
|
|
_accel_target.x = _accel_target_filter.get().x;
|
|
_accel_target.y = _accel_target_filter.get().y;
|
|
|
|
// Add feed forward into the target acceleration output
|
|
_accel_target.x += _accel_desired.x;
|
|
_accel_target.y += _accel_desired.y;
|
|
|
|
// the following section converts desired accelerations provided in lat/lon frame to roll/pitch angles
|
|
|
|
// limit acceleration using maximum lean angles
|
|
float angle_max = MIN(_attitude_control.get_althold_lean_angle_max(), get_lean_angle_max_cd());
|
|
float accel_max = MIN(GRAVITY_MSS * 100.0f * tanf(ToRad(angle_max * 0.01f)), POSCONTROL_ACCEL_XY_MAX);
|
|
_limit.accel_xy = limit_vector_length(_accel_target.x, _accel_target.y, accel_max);
|
|
|
|
// update angle targets that will be passed to stabilize controller
|
|
accel_to_lean_angles(_accel_target.x, _accel_target.y, _roll_target, _pitch_target);
|
|
}
|
|
|
|
// get_lean_angles_to_accel - convert roll, pitch lean angles to lat/lon 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
|
|
{
|
|
float accel_right, accel_forward;
|
|
|
|
// rotate accelerations into body forward-right frame
|
|
// todo: this should probably be based on the desired heading not the current heading
|
|
accel_forward = accel_x_cmss*_ahrs.cos_yaw() + accel_y_cmss*_ahrs.sin_yaw();
|
|
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 = atanf(-accel_forward/(GRAVITY_MSS * 100.0f))*(18000.0f/M_PI);
|
|
float cos_pitch_target = cosf(pitch_target*M_PI/18000.0f);
|
|
roll_target = atanf(accel_right*cos_pitch_target/(GRAVITY_MSS * 100.0f))*(18000.0f/M_PI);
|
|
}
|
|
|
|
// get_lean_angles_to_accel - convert roll, pitch lean angles to lat/lon frame accelerations in cm/s/s
|
|
void AC_PosControl::lean_angles_to_accel(float& accel_x_cmss, float& accel_y_cmss) const
|
|
{
|
|
// rotate our roll, pitch angles into lat/lon frame
|
|
// todo: this should probably be based on the desired attitude not the current attitude
|
|
accel_x_cmss = (GRAVITY_MSS * 100) * (-_ahrs.cos_yaw() * _ahrs.sin_pitch() * _ahrs.cos_roll() - _ahrs.sin_yaw() * _ahrs.sin_roll()) / MAX(_ahrs.cos_roll()*_ahrs.cos_pitch(), 0.5f);
|
|
accel_y_cmss = (GRAVITY_MSS * 100) * (-_ahrs.sin_yaw() * _ahrs.sin_pitch() * _ahrs.cos_roll() + _ahrs.cos_yaw() * _ahrs.sin_roll()) / MAX(_ahrs.cos_roll()*_ahrs.cos_pitch(), 0.5f);
|
|
}
|
|
|
|
/// calc_leash_length - calculates the horizontal leash length given a maximum speed, acceleration and position kP gain
|
|
float AC_PosControl::calc_leash_length(float speed_cms, float accel_cms, float kP) const
|
|
{
|
|
float leash_length;
|
|
|
|
// sanity check acceleration and avoid divide by zero
|
|
if (accel_cms <= 0.0f) {
|
|
accel_cms = POSCONTROL_ACCELERATION_MIN;
|
|
}
|
|
|
|
// avoid divide by zero
|
|
if (kP <= 0.0f) {
|
|
return POSCONTROL_LEASH_LENGTH_MIN;
|
|
}
|
|
|
|
// calculate leash length
|
|
if(speed_cms <= accel_cms / kP) {
|
|
// linear leash length based on speed close in
|
|
leash_length = speed_cms / kP;
|
|
}else{
|
|
// leash length grows at sqrt of speed further out
|
|
leash_length = (accel_cms / (2.0f*kP*kP)) + (speed_cms*speed_cms / (2.0f*accel_cms));
|
|
}
|
|
|
|
// ensure leash is at least 1m long
|
|
if( leash_length < POSCONTROL_LEASH_LENGTH_MIN ) {
|
|
leash_length = POSCONTROL_LEASH_LENGTH_MIN;
|
|
}
|
|
|
|
return leash_length;
|
|
}
|
|
|
|
/// initialise ekf xy position reset check
|
|
void AC_PosControl::init_ekf_xy_reset()
|
|
{
|
|
Vector2f pos_shift;
|
|
_ekf_xy_reset_ms = _ahrs.getLastPosNorthEastReset(pos_shift);
|
|
}
|
|
|
|
/// check for ekf position reset and adjust loiter or brake target position
|
|
void AC_PosControl::check_for_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) {
|
|
shift_pos_xy_target(pos_shift.x * 100.0f, pos_shift.y * 100.0f);
|
|
_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);
|
|
}
|
|
|
|
/// check for ekf position reset and adjust loiter or brake target position
|
|
void AC_PosControl::check_for_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) {
|
|
shift_alt_target(-alt_shift * 100.0f);
|
|
_ekf_z_reset_ms = reset_ms;
|
|
}
|
|
}
|
|
|
|
|
|
/// limit vector to a given length, returns true if vector was limited
|
|
bool AC_PosControl::limit_vector_length(float& vector_x, float& vector_y, float max_length)
|
|
{
|
|
float vector_length = norm(vector_x, vector_y);
|
|
if ((vector_length > max_length) && is_positive(vector_length)) {
|
|
vector_x *= (max_length / vector_length);
|
|
vector_y *= (max_length / vector_length);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
|
|
/// Proportional controller with piecewise sqrt sections to constrain second derivative
|
|
Vector3f AC_PosControl::sqrt_controller(const Vector3f& error, float p, float second_ord_lim)
|
|
{
|
|
if (second_ord_lim < 0.0f || is_zero(second_ord_lim) || is_zero(p)) {
|
|
return Vector3f(error.x*p, error.y*p, error.z);
|
|
}
|
|
|
|
float linear_dist = second_ord_lim/sq(p);
|
|
float error_length = norm(error.x, error.y);
|
|
if (error_length > linear_dist) {
|
|
float first_order_scale = safe_sqrt(2.0f*second_ord_lim*(error_length-(linear_dist * 0.5f)))/error_length;
|
|
return Vector3f(error.x*first_order_scale, error.y*first_order_scale, error.z);
|
|
} else {
|
|
return Vector3f(error.x*p, error.y*p, error.z);
|
|
}
|
|
}
|