mirror of https://github.com/ArduPilot/ardupilot
1145 lines
57 KiB
C++
1145 lines
57 KiB
C++
#include "AC_AttitudeControl.h"
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#include <AP_HAL/AP_HAL.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 AC_ATTITUDE_CONTROL_INPUT_TC_DEFAULT 0.2f // Soft
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#else
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// default gains for Copter and Sub
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# define AC_ATTITUDE_CONTROL_INPUT_TC_DEFAULT 0.15f // Medium
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#endif
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AC_AttitudeControl *AC_AttitudeControl::_singleton;
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// table of user settable parameters
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const AP_Param::GroupInfo AC_AttitudeControl::var_info[] = {
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// 0, 1 were RATE_RP_MAX, RATE_Y_MAX
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// @Param: SLEW_YAW
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// @DisplayName: Yaw target slew rate
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// @Description: Maximum rate the yaw target can be updated in Loiter, RTL, Auto flight modes
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// @Units: cdeg/s
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// @Range: 500 18000
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// @Increment: 100
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// @User: Advanced
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AP_GROUPINFO("SLEW_YAW", 2, AC_AttitudeControl, _slew_yaw, AC_ATTITUDE_CONTROL_SLEW_YAW_DEFAULT_CDS),
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// 3 was for ACCEL_RP_MAX
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// @Param: ACCEL_Y_MAX
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// @DisplayName: Acceleration Max for Yaw
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// @Description: Maximum acceleration in yaw axis
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// @Units: cdeg/s/s
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// @Range: 0 72000
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// @Values: 0:Disabled, 9000:VerySlow, 18000:Slow, 36000:Medium, 54000:Fast
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// @Increment: 1000
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// @User: Advanced
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AP_GROUPINFO("ACCEL_Y_MAX", 4, AC_AttitudeControl, _accel_yaw_max, AC_ATTITUDE_CONTROL_ACCEL_Y_MAX_DEFAULT_CDSS),
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// @Param: RATE_FF_ENAB
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// @DisplayName: Rate Feedforward Enable
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// @Description: Controls whether body-frame rate feedfoward is enabled or disabled
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// @Values: 0:Disabled, 1:Enabled
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// @User: Advanced
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AP_GROUPINFO("RATE_FF_ENAB", 5, AC_AttitudeControl, _rate_bf_ff_enabled, AC_ATTITUDE_CONTROL_RATE_BF_FF_DEFAULT),
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// @Param: ACCEL_R_MAX
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// @DisplayName: Acceleration Max for Roll
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// @Description: Maximum acceleration in roll axis
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// @Units: cdeg/s/s
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// @Range: 0 180000
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// @Increment: 1000
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// @Values: 0:Disabled, 30000:VerySlow, 72000:Slow, 108000:Medium, 162000:Fast
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// @User: Advanced
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AP_GROUPINFO("ACCEL_R_MAX", 6, AC_AttitudeControl, _accel_roll_max, AC_ATTITUDE_CONTROL_ACCEL_RP_MAX_DEFAULT_CDSS),
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// @Param: ACCEL_P_MAX
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// @DisplayName: Acceleration Max for Pitch
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// @Description: Maximum acceleration in pitch axis
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// @Units: cdeg/s/s
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// @Range: 0 180000
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// @Increment: 1000
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// @Values: 0:Disabled, 30000:VerySlow, 72000:Slow, 108000:Medium, 162000:Fast
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// @User: Advanced
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AP_GROUPINFO("ACCEL_P_MAX", 7, AC_AttitudeControl, _accel_pitch_max, AC_ATTITUDE_CONTROL_ACCEL_RP_MAX_DEFAULT_CDSS),
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// IDs 8,9,10,11 RESERVED (in use on Solo)
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// @Param: ANGLE_BOOST
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// @DisplayName: Angle Boost
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// @Description: Angle Boost increases output throttle as the vehicle leans to reduce loss of altitude
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// @Values: 0:Disabled, 1:Enabled
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// @User: Advanced
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AP_GROUPINFO("ANGLE_BOOST", 12, AC_AttitudeControl, _angle_boost_enabled, 1),
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// @Param: ANG_RLL_P
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// @DisplayName: Roll axis angle controller P gain
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// @Description: Roll axis angle controller P gain. Converts the error between the desired roll angle and actual angle to a desired roll rate
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// @Range: 3.000 12.000
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// @Range{Sub}: 0.0 12.000
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// @User: Standard
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AP_SUBGROUPINFO(_p_angle_roll, "ANG_RLL_", 13, AC_AttitudeControl, AC_P),
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// @Param: ANG_PIT_P
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// @DisplayName: Pitch axis angle controller P gain
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// @Description: Pitch axis angle controller P gain. Converts the error between the desired pitch angle and actual angle to a desired pitch rate
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// @Range: 3.000 12.000
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// @Range{Sub}: 0.0 12.000
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// @User: Standard
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AP_SUBGROUPINFO(_p_angle_pitch, "ANG_PIT_", 14, AC_AttitudeControl, AC_P),
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// @Param: ANG_YAW_P
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// @DisplayName: Yaw axis angle controller P gain
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// @Description: Yaw axis angle controller P gain. Converts the error between the desired yaw angle and actual angle to a desired yaw rate
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// @Range: 3.000 12.000
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// @Range{Sub}: 0.0 6.000
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// @User: Standard
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AP_SUBGROUPINFO(_p_angle_yaw, "ANG_YAW_", 15, AC_AttitudeControl, AC_P),
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// @Param: ANG_LIM_TC
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// @DisplayName: Angle Limit (to maintain altitude) Time Constant
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// @Description: Angle Limit (to maintain altitude) Time Constant
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// @Range: 0.5 10.0
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// @User: Advanced
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AP_GROUPINFO("ANG_LIM_TC", 16, AC_AttitudeControl, _angle_limit_tc, AC_ATTITUDE_CONTROL_ANGLE_LIMIT_TC_DEFAULT),
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// @Param: RATE_R_MAX
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// @DisplayName: Angular Velocity Max for Roll
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// @Description: Maximum angular velocity in roll axis
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// @Units: deg/s
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// @Range: 0 1080
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// @Increment: 1
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// @Values: 0:Disabled, 60:Slow, 180:Medium, 360:Fast
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// @User: Advanced
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AP_GROUPINFO("RATE_R_MAX", 17, AC_AttitudeControl, _ang_vel_roll_max, 0.0f),
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// @Param: RATE_P_MAX
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// @DisplayName: Angular Velocity Max for Pitch
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// @Description: Maximum angular velocity in pitch axis
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// @Units: deg/s
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// @Range: 0 1080
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// @Increment: 1
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// @Values: 0:Disabled, 60:Slow, 180:Medium, 360:Fast
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// @User: Advanced
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AP_GROUPINFO("RATE_P_MAX", 18, AC_AttitudeControl, _ang_vel_pitch_max, 0.0f),
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// @Param: RATE_Y_MAX
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// @DisplayName: Angular Velocity Max for Yaw
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// @Description: Maximum angular velocity in yaw axis
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// @Units: deg/s
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// @Range: 0 1080
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// @Increment: 1
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// @Values: 0:Disabled, 60:Slow, 180:Medium, 360:Fast
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// @User: Advanced
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AP_GROUPINFO("RATE_Y_MAX", 19, AC_AttitudeControl, _ang_vel_yaw_max, 0.0f),
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// @Param: INPUT_TC
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// @DisplayName: Attitude control input time constant
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// @Description: Attitude control input time constant. Low numbers lead to sharper response, higher numbers to softer response
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// @Units: s
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// @Range: 0 1
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// @Increment: 0.01
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// @Values: 0.5:Very Soft, 0.2:Soft, 0.15:Medium, 0.1:Crisp, 0.05:Very Crisp
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// @User: Standard
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AP_GROUPINFO("INPUT_TC", 20, AC_AttitudeControl, _input_tc, AC_ATTITUDE_CONTROL_INPUT_TC_DEFAULT),
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AP_GROUPEND
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};
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// get the slew yaw rate limit in deg/s
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float AC_AttitudeControl::get_slew_yaw_max_degs() const
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{
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if (!is_positive(_ang_vel_yaw_max)) {
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return _slew_yaw * 0.01;
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}
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return MIN(_ang_vel_yaw_max, _slew_yaw * 0.01);
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}
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// Ensure attitude controller have zero errors to relax rate controller output
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void AC_AttitudeControl::relax_attitude_controllers()
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{
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// Initialize the attitude variables to the current attitude
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_ahrs.get_quat_body_to_ned(_attitude_target);
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_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
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_attitude_ang_error.initialise();
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// Initialize the angular rate variables to the current rate
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_ang_vel_target = _ahrs.get_gyro();
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ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
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_ang_vel_body = _ahrs.get_gyro();
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// Initialize remaining variables
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_thrust_error_angle = 0.0f;
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// Reset the PID filters
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get_rate_roll_pid().reset_filter();
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get_rate_pitch_pid().reset_filter();
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get_rate_yaw_pid().reset_filter();
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// Reset the I terms
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reset_rate_controller_I_terms();
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}
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void AC_AttitudeControl::reset_rate_controller_I_terms()
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{
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get_rate_roll_pid().reset_I();
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get_rate_pitch_pid().reset_I();
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get_rate_yaw_pid().reset_I();
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}
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// reset rate controller I terms smoothly to zero in 0.5 seconds
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void AC_AttitudeControl::reset_rate_controller_I_terms_smoothly()
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{
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get_rate_roll_pid().relax_integrator(0.0, AC_ATTITUDE_RATE_RELAX_TC);
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get_rate_pitch_pid().relax_integrator(0.0, AC_ATTITUDE_RATE_RELAX_TC);
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get_rate_yaw_pid().relax_integrator(0.0, AC_ATTITUDE_RATE_RELAX_TC);
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}
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// The attitude controller works around the concept of the desired attitude, target attitude
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// and measured attitude. The desired attitude is the attitude input into the attitude controller
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// that expresses where the higher level code would like the aircraft to move to. The target attitude is moved
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// to the desired attitude with jerk, acceleration, and velocity limits. The target angular velocities are fed
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// directly into the rate controllers. The angular error between the measured attitude and the target attitude is
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// fed into the angle controller and the output of the angle controller summed at the input of the rate controllers.
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// By feeding the target angular velocity directly into the rate controllers the measured and target attitudes
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// remain very close together.
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//
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// All input functions below follow the same procedure
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// 1. define the desired attitude the aircraft should attempt to achieve using the input variables
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// 2. using the desired attitude and input variables, define the target angular velocity so that it should
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// move the target attitude towards the desired attitude
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// 3. if _rate_bf_ff_enabled is not being used then make the target attitude
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// and target angular velocities equal to the desired attitude and desired angular velocities.
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// 4. ensure _attitude_target, _euler_angle_target, _euler_rate_target and
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// _ang_vel_target have been defined. This ensures input modes can be changed without discontinuity.
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// 5. attitude_controller_run_quat is then run to pass the target angular velocities to the rate controllers and
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// integrate them into the target attitude. Any errors between the target attitude and the measured attitude are
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// corrected by first correcting the thrust vector until the angle between the target thrust vector measured
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// trust vector drops below 2*AC_ATTITUDE_THRUST_ERROR_ANGLE. At this point the heading is also corrected.
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// Command a Quaternion attitude with feedforward and smoothing
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// attitude_desired_quat: is updated on each time_step (_dt) by the integral of the angular velocity
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void AC_AttitudeControl::input_quaternion(Quaternion& attitude_desired_quat, Vector3f ang_vel_target)
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{
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Quaternion attitude_error_quat = _attitude_target.inverse() * attitude_desired_quat;
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Vector3f attitude_error_angle;
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attitude_error_quat.to_axis_angle(attitude_error_angle);
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// Limit the angular velocity
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ang_vel_limit(ang_vel_target, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), radians(_ang_vel_yaw_max));
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if (_rate_bf_ff_enabled) {
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// When acceleration limiting and feedforward are enabled, the sqrt controller is used to compute an euler
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// angular velocity that will cause the euler angle to smoothly stop at the input angle with limited deceleration
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// and an exponential decay specified by _input_tc at the end.
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_ang_vel_target.x = input_shaping_angle(wrap_PI(attitude_error_angle.x), _input_tc, get_accel_roll_max_radss(), _ang_vel_target.x, ang_vel_target.x, radians(_ang_vel_roll_max), _dt);
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_ang_vel_target.y = input_shaping_angle(wrap_PI(attitude_error_angle.y), _input_tc, get_accel_pitch_max_radss(), _ang_vel_target.y, ang_vel_target.y, radians(_ang_vel_pitch_max), _dt);
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_ang_vel_target.z = input_shaping_angle(wrap_PI(attitude_error_angle.z), _input_tc, get_accel_yaw_max_radss(), _ang_vel_target.z, ang_vel_target.z, radians(_ang_vel_yaw_max), _dt);
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} else {
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_attitude_target = attitude_desired_quat;
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_ang_vel_target = ang_vel_target;
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}
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// calculate the attitude target euler angles
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_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
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// Convert body-frame angular velocity into euler angle derivative of desired attitude
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ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
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// rotate target and normalize
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Quaternion attitude_desired_update;
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attitude_desired_update.from_axis_angle(ang_vel_target * _dt);
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attitude_desired_quat = attitude_desired_quat * attitude_desired_update;
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attitude_desired_quat.normalize();
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// Call quaternion attitude controller
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attitude_controller_run_quat();
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}
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// Command an euler roll and pitch angle and an euler yaw rate with angular velocity feedforward and smoothing
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void AC_AttitudeControl::input_euler_angle_roll_pitch_euler_rate_yaw(float euler_roll_angle_cd, float euler_pitch_angle_cd, float euler_yaw_rate_cds)
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{
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// Convert from centidegrees on public interface to radians
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float euler_roll_angle = radians(euler_roll_angle_cd * 0.01f);
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float euler_pitch_angle = radians(euler_pitch_angle_cd * 0.01f);
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float euler_yaw_rate = radians(euler_yaw_rate_cds * 0.01f);
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// calculate the attitude target euler angles
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_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
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// Add roll trim to compensate tail rotor thrust in heli (will return zero on multirotors)
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euler_roll_angle += get_roll_trim_rad();
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if (_rate_bf_ff_enabled) {
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// translate the roll pitch and yaw acceleration limits to the euler axis
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const Vector3f euler_accel = euler_accel_limit(_euler_angle_target, Vector3f{get_accel_roll_max_radss(), get_accel_pitch_max_radss(), get_accel_yaw_max_radss()});
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// When acceleration limiting and feedforward are enabled, the sqrt controller is used to compute an euler
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// angular velocity that will cause the euler angle to smoothly stop at the input angle with limited deceleration
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// and an exponential decay specified by smoothing_gain at the end.
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_euler_rate_target.x = input_shaping_angle(wrap_PI(euler_roll_angle - _euler_angle_target.x), _input_tc, euler_accel.x, _euler_rate_target.x, _dt);
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_euler_rate_target.y = input_shaping_angle(wrap_PI(euler_pitch_angle - _euler_angle_target.y), _input_tc, euler_accel.y, _euler_rate_target.y, _dt);
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// When yaw acceleration limiting is enabled, the yaw input shaper constrains angular acceleration about the yaw axis, slewing
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// the output rate towards the input rate.
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_euler_rate_target.z = input_shaping_ang_vel(_euler_rate_target.z, euler_yaw_rate, euler_accel.z, _dt);
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// Convert euler angle derivative of desired attitude into a body-frame angular velocity vector for feedforward
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euler_rate_to_ang_vel(_euler_angle_target, _euler_rate_target, _ang_vel_target);
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// Limit the angular velocity
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ang_vel_limit(_ang_vel_target, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), radians(_ang_vel_yaw_max));
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// Convert body-frame angular velocity into euler angle derivative of desired attitude
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ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
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} else {
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// When feedforward is not enabled, the target euler angle is input into the target and the feedforward rate is zeroed.
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_euler_angle_target.x = euler_roll_angle;
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_euler_angle_target.y = euler_pitch_angle;
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_euler_angle_target.z += euler_yaw_rate * _dt;
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// Compute quaternion target attitude
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_attitude_target.from_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
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// Set rate feedforward requests to zero
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_euler_rate_target.zero();
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_ang_vel_target.zero();
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}
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// Call quaternion attitude controller
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attitude_controller_run_quat();
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}
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// Command an euler roll, pitch and yaw angle with angular velocity feedforward and smoothing
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void AC_AttitudeControl::input_euler_angle_roll_pitch_yaw(float euler_roll_angle_cd, float euler_pitch_angle_cd, float euler_yaw_angle_cd, bool slew_yaw)
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{
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// Convert from centidegrees on public interface to radians
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float euler_roll_angle = radians(euler_roll_angle_cd * 0.01f);
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float euler_pitch_angle = radians(euler_pitch_angle_cd * 0.01f);
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float euler_yaw_angle = radians(euler_yaw_angle_cd * 0.01f);
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// calculate the attitude target euler angles
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_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
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// Add roll trim to compensate tail rotor thrust in heli (will return zero on multirotors)
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euler_roll_angle += get_roll_trim_rad();
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const float slew_yaw_max_rads = get_slew_yaw_max_rads();
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if (_rate_bf_ff_enabled) {
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// translate the roll pitch and yaw acceleration limits to the euler axis
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const Vector3f euler_accel = euler_accel_limit(_euler_angle_target, Vector3f{get_accel_roll_max_radss(), get_accel_pitch_max_radss(), get_accel_yaw_max_radss()});
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// When acceleration limiting and feedforward are enabled, the sqrt controller is used to compute an euler
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// angular velocity that will cause the euler angle to smoothly stop at the input angle with limited deceleration
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// and an exponential decay specified by _input_tc at the end.
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_euler_rate_target.x = input_shaping_angle(wrap_PI(euler_roll_angle - _euler_angle_target.x), _input_tc, euler_accel.x, _euler_rate_target.x, _dt);
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_euler_rate_target.y = input_shaping_angle(wrap_PI(euler_pitch_angle - _euler_angle_target.y), _input_tc, euler_accel.y, _euler_rate_target.y, _dt);
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_euler_rate_target.z = input_shaping_angle(wrap_PI(euler_yaw_angle - _euler_angle_target.z), _input_tc, euler_accel.z, _euler_rate_target.z, _dt);
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if (slew_yaw) {
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_euler_rate_target.z = constrain_float(_euler_rate_target.z, -slew_yaw_max_rads, slew_yaw_max_rads);
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}
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// Convert euler angle derivative of desired attitude into a body-frame angular velocity vector for feedforward
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euler_rate_to_ang_vel(_euler_angle_target, _euler_rate_target, _ang_vel_target);
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// Limit the angular velocity
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ang_vel_limit(_ang_vel_target, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), radians(_ang_vel_yaw_max));
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// Convert body-frame angular velocity into euler angle derivative of desired attitude
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ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
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} else {
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// When feedforward is not enabled, the target euler angle is input into the target and the feedforward rate is zeroed.
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_euler_angle_target.x = euler_roll_angle;
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_euler_angle_target.y = euler_pitch_angle;
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if (slew_yaw) {
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// Compute constrained angle error
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float angle_error = constrain_float(wrap_PI(euler_yaw_angle - _euler_angle_target.z), -slew_yaw_max_rads * _dt, slew_yaw_max_rads * _dt);
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// Update attitude target from constrained angle error
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_euler_angle_target.z = wrap_PI(angle_error + _euler_angle_target.z);
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} else {
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_euler_angle_target.z = euler_yaw_angle;
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}
|
|
// Compute quaternion target attitude
|
|
_attitude_target.from_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
// Set rate feedforward requests to zero
|
|
_euler_rate_target.zero();
|
|
_ang_vel_target.zero();
|
|
}
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
// Command an euler roll, pitch, and yaw rate with angular velocity feedforward and smoothing
|
|
void AC_AttitudeControl::input_euler_rate_roll_pitch_yaw(float euler_roll_rate_cds, float euler_pitch_rate_cds, float euler_yaw_rate_cds)
|
|
{
|
|
// Convert from centidegrees on public interface to radians
|
|
float euler_roll_rate = radians(euler_roll_rate_cds * 0.01f);
|
|
float euler_pitch_rate = radians(euler_pitch_rate_cds * 0.01f);
|
|
float euler_yaw_rate = radians(euler_yaw_rate_cds * 0.01f);
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// translate the roll pitch and yaw acceleration limits to the euler axis
|
|
const Vector3f euler_accel = euler_accel_limit(_euler_angle_target, Vector3f{get_accel_roll_max_radss(), get_accel_pitch_max_radss(), get_accel_yaw_max_radss()});
|
|
|
|
// When acceleration limiting is enabled, the input shaper constrains angular acceleration, slewing
|
|
// the output rate towards the input rate.
|
|
_euler_rate_target.x = input_shaping_ang_vel(_euler_rate_target.x, euler_roll_rate, euler_accel.x, _dt);
|
|
_euler_rate_target.y = input_shaping_ang_vel(_euler_rate_target.y, euler_pitch_rate, euler_accel.y, _dt);
|
|
_euler_rate_target.z = input_shaping_ang_vel(_euler_rate_target.z, euler_yaw_rate, euler_accel.z, _dt);
|
|
|
|
// Convert euler angle derivative of desired attitude into a body-frame angular velocity vector for feedforward
|
|
euler_rate_to_ang_vel(_euler_angle_target, _euler_rate_target, _ang_vel_target);
|
|
} else {
|
|
// When feedforward is not enabled, the target euler angle is input into the target and the feedforward rate is zeroed.
|
|
// Pitch angle is restricted to +- 85.0 degrees to avoid gimbal lock discontinuities.
|
|
_euler_angle_target.x = wrap_PI(_euler_angle_target.x + euler_roll_rate * _dt);
|
|
_euler_angle_target.y = constrain_float(_euler_angle_target.y + euler_pitch_rate * _dt, radians(-85.0f), radians(85.0f));
|
|
_euler_angle_target.z = wrap_2PI(_euler_angle_target.z + euler_yaw_rate * _dt);
|
|
|
|
// Set rate feedforward requests to zero
|
|
_euler_rate_target.zero();
|
|
_ang_vel_target.zero();
|
|
|
|
// Compute quaternion target attitude
|
|
_attitude_target.from_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
}
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
// Command an angular velocity with angular velocity feedforward and smoothing
|
|
void AC_AttitudeControl::input_rate_bf_roll_pitch_yaw(float roll_rate_bf_cds, float pitch_rate_bf_cds, float yaw_rate_bf_cds)
|
|
{
|
|
// Convert from centidegrees on public interface to radians
|
|
float roll_rate_rads = radians(roll_rate_bf_cds * 0.01f);
|
|
float pitch_rate_rads = radians(pitch_rate_bf_cds * 0.01f);
|
|
float yaw_rate_rads = radians(yaw_rate_bf_cds * 0.01f);
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// Compute acceleration-limited body frame rates
|
|
// When acceleration limiting is enabled, the input shaper constrains angular acceleration about the axis, slewing
|
|
// the output rate towards the input rate.
|
|
_ang_vel_target.x = input_shaping_ang_vel(_ang_vel_target.x, roll_rate_rads, get_accel_roll_max_radss(), _dt);
|
|
_ang_vel_target.y = input_shaping_ang_vel(_ang_vel_target.y, pitch_rate_rads, get_accel_pitch_max_radss(), _dt);
|
|
_ang_vel_target.z = input_shaping_ang_vel(_ang_vel_target.z, yaw_rate_rads, get_accel_yaw_max_radss(), _dt);
|
|
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
|
|
} else {
|
|
// When feedforward is not enabled, the quaternion is calculated and is input into the target and the feedforward rate is zeroed.
|
|
Quaternion attitude_target_update;
|
|
attitude_target_update.from_axis_angle(Vector3f{roll_rate_rads * _dt, pitch_rate_rads * _dt, yaw_rate_rads * _dt});
|
|
_attitude_target = _attitude_target * attitude_target_update;
|
|
_attitude_target.normalize();
|
|
|
|
// Set rate feedforward requests to zero
|
|
_euler_rate_target.zero();
|
|
_ang_vel_target.zero();
|
|
}
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
// Command an angular velocity with angular velocity smoothing using rate loops only with no attitude loop stabilization
|
|
void AC_AttitudeControl::input_rate_bf_roll_pitch_yaw_2(float roll_rate_bf_cds, float pitch_rate_bf_cds, float yaw_rate_bf_cds)
|
|
{
|
|
// Convert from centidegrees on public interface to radians
|
|
float roll_rate_rads = radians(roll_rate_bf_cds * 0.01f);
|
|
float pitch_rate_rads = radians(pitch_rate_bf_cds * 0.01f);
|
|
float yaw_rate_rads = radians(yaw_rate_bf_cds * 0.01f);
|
|
|
|
// Compute acceleration-limited body frame rates
|
|
// When acceleration limiting is enabled, the input shaper constrains angular acceleration about the axis, slewing
|
|
// the output rate towards the input rate.
|
|
_ang_vel_target.x = input_shaping_ang_vel(_ang_vel_target.x, roll_rate_rads, get_accel_roll_max_radss(), _dt);
|
|
_ang_vel_target.y = input_shaping_ang_vel(_ang_vel_target.y, pitch_rate_rads, get_accel_pitch_max_radss(), _dt);
|
|
_ang_vel_target.z = input_shaping_ang_vel(_ang_vel_target.z, yaw_rate_rads, get_accel_yaw_max_radss(), _dt);
|
|
|
|
// Update the unused targets attitude based on current attitude to condition mode change
|
|
_ahrs.get_quat_body_to_ned(_attitude_target);
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
|
|
_ang_vel_body = _ang_vel_target;
|
|
}
|
|
|
|
// Command an angular velocity with angular velocity smoothing using rate loops only with integrated rate error stabilization
|
|
void AC_AttitudeControl::input_rate_bf_roll_pitch_yaw_3(float roll_rate_bf_cds, float pitch_rate_bf_cds, float yaw_rate_bf_cds)
|
|
{
|
|
// Convert from centidegrees on public interface to radians
|
|
float roll_rate_rads = radians(roll_rate_bf_cds * 0.01f);
|
|
float pitch_rate_rads = radians(pitch_rate_bf_cds * 0.01f);
|
|
float yaw_rate_rads = radians(yaw_rate_bf_cds * 0.01f);
|
|
|
|
// Update attitude error
|
|
Vector3f attitude_error;
|
|
_attitude_ang_error.to_axis_angle(attitude_error);
|
|
|
|
Quaternion attitude_ang_error_update_quat;
|
|
// limit the integrated error angle
|
|
float err_mag = attitude_error.length();
|
|
if (err_mag > AC_ATTITUDE_THRUST_ERROR_ANGLE) {
|
|
attitude_error *= AC_ATTITUDE_THRUST_ERROR_ANGLE / err_mag;
|
|
_attitude_ang_error.from_axis_angle(attitude_error);
|
|
}
|
|
|
|
Vector3f gyro_latest = _ahrs.get_gyro_latest();
|
|
attitude_ang_error_update_quat.from_axis_angle(Vector3f{(_ang_vel_target.x-gyro_latest.x) * _dt, (_ang_vel_target.y-gyro_latest.y) * _dt, (_ang_vel_target.z-gyro_latest.z) * _dt});
|
|
_attitude_ang_error = attitude_ang_error_update_quat * _attitude_ang_error;
|
|
|
|
// Compute acceleration-limited body frame rates
|
|
// When acceleration limiting is enabled, the input shaper constrains angular acceleration about the axis, slewing
|
|
// the output rate towards the input rate.
|
|
_ang_vel_target.x = input_shaping_ang_vel(_ang_vel_target.x, roll_rate_rads, get_accel_roll_max_radss(), _dt);
|
|
_ang_vel_target.y = input_shaping_ang_vel(_ang_vel_target.y, pitch_rate_rads, get_accel_pitch_max_radss(), _dt);
|
|
_ang_vel_target.z = input_shaping_ang_vel(_ang_vel_target.z, yaw_rate_rads, get_accel_yaw_max_radss(), _dt);
|
|
|
|
// Retrieve quaternion body attitude
|
|
Quaternion attitude_body;
|
|
_ahrs.get_quat_body_to_ned(attitude_body);
|
|
|
|
// Update the unused targets attitude based on current attitude to condition mode change
|
|
_attitude_target = attitude_body * _attitude_ang_error;
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
|
|
|
|
// Compute the angular velocity target from the integrated rate error
|
|
_attitude_ang_error.to_axis_angle(attitude_error);
|
|
_ang_vel_body = update_ang_vel_target_from_att_error(attitude_error);
|
|
_ang_vel_body += _ang_vel_target;
|
|
|
|
// ensure Quaternions stay normalized
|
|
_attitude_ang_error.normalize();
|
|
}
|
|
|
|
// Command an angular step (i.e change) in body frame angle
|
|
// Used to command a step in angle without exciting the orthogonal axis during autotune
|
|
void AC_AttitudeControl::input_angle_step_bf_roll_pitch_yaw(float roll_angle_step_bf_cd, float pitch_angle_step_bf_cd, float yaw_angle_step_bf_cd)
|
|
{
|
|
// Convert from centidegrees on public interface to radians
|
|
float roll_step_rads = radians(roll_angle_step_bf_cd * 0.01f);
|
|
float pitch_step_rads = radians(pitch_angle_step_bf_cd * 0.01f);
|
|
float yaw_step_rads = radians(yaw_angle_step_bf_cd * 0.01f);
|
|
|
|
// rotate attitude target by desired step
|
|
Quaternion attitude_target_update;
|
|
attitude_target_update.from_axis_angle(Vector3f{roll_step_rads, pitch_step_rads, yaw_step_rads});
|
|
_attitude_target = _attitude_target * attitude_target_update;
|
|
_attitude_target.normalize();
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
// Set rate feedforward requests to zero
|
|
_euler_rate_target.zero();
|
|
_ang_vel_target.zero();
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
// Command a thrust vector and heading rate
|
|
void AC_AttitudeControl::input_thrust_vector_rate_heading(const Vector3f& thrust_vector, float heading_rate_cds)
|
|
{
|
|
// Convert from centidegrees on public interface to radians
|
|
const float heading_rate = radians(heading_rate_cds * 0.01f);
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
// convert thrust vector to a quaternion attitude
|
|
Quaternion thrust_vec_quat = attitude_from_thrust_vector(thrust_vector, 0.0f);
|
|
|
|
// calculate the angle error in x and y.
|
|
float thrust_vector_diff_angle;
|
|
Quaternion thrust_vec_correction_quat;
|
|
Vector3f attitude_error;
|
|
float returned_thrust_vector_angle;
|
|
thrust_vector_rotation_angles(thrust_vec_quat, _attitude_target, thrust_vec_correction_quat, attitude_error, returned_thrust_vector_angle, thrust_vector_diff_angle);
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// When yaw acceleration limiting is enabled, the yaw input shaper constrains angular acceleration about the yaw axis, slewing
|
|
// the output rate towards the input rate.
|
|
_ang_vel_target.x = input_shaping_angle(attitude_error.x, _input_tc, get_accel_roll_max_radss(), _ang_vel_target.x, _dt);
|
|
_ang_vel_target.y = input_shaping_angle(attitude_error.y, _input_tc, get_accel_pitch_max_radss(), _ang_vel_target.y, _dt);
|
|
|
|
// When yaw acceleration limiting is enabled, the yaw input shaper constrains angular acceleration about the yaw axis, slewing
|
|
// the output rate towards the input rate.
|
|
_ang_vel_target.z = input_shaping_ang_vel(_ang_vel_target.z, heading_rate, get_accel_yaw_max_radss(), _dt);
|
|
|
|
// Limit the angular velocity
|
|
ang_vel_limit(_ang_vel_target, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), get_slew_yaw_max_rads());
|
|
} else {
|
|
Quaternion yaw_quat;
|
|
yaw_quat.from_axis_angle(Vector3f{0.0f, 0.0f, heading_rate * _dt});
|
|
_attitude_target = _attitude_target * thrust_vec_correction_quat * yaw_quat;
|
|
|
|
// Set rate feedforward requests to zero
|
|
_euler_rate_target.zero();
|
|
_ang_vel_target.zero();
|
|
}
|
|
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
// Command a thrust vector, heading and heading rate
|
|
void AC_AttitudeControl::input_thrust_vector_heading(const Vector3f& thrust_vector, float heading_angle_cd, float heading_rate_cds)
|
|
{
|
|
// a zero _angle_vel_yaw_max means that setting is disabled
|
|
const float slew_yaw_max_rads = get_slew_yaw_max_rads();
|
|
|
|
// Convert from centidegrees on public interface to radians
|
|
float heading_rate = constrain_float(radians(heading_rate_cds * 0.01f), -slew_yaw_max_rads, slew_yaw_max_rads);
|
|
float heading_angle = radians(heading_angle_cd * 0.01f);
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
|
|
// convert thrust vector and heading to a quaternion attitude
|
|
const Quaternion desired_attitude_quat = attitude_from_thrust_vector(thrust_vector, heading_angle);
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// calculate the angle error in x and y.
|
|
Vector3f attitude_error;
|
|
float thrust_vector_diff_angle;
|
|
Quaternion thrust_vec_correction_quat;
|
|
float returned_thrust_vector_angle;
|
|
thrust_vector_rotation_angles(desired_attitude_quat, _attitude_target, thrust_vec_correction_quat, attitude_error, returned_thrust_vector_angle, thrust_vector_diff_angle);
|
|
|
|
// When yaw acceleration limiting is enabled, the yaw input shaper constrains angular acceleration about the yaw axis, slewing
|
|
// the output rate towards the input rate.
|
|
_ang_vel_target.x = input_shaping_angle(attitude_error.x, _input_tc, get_accel_roll_max_radss(), _ang_vel_target.x, _dt);
|
|
_ang_vel_target.y = input_shaping_angle(attitude_error.y, _input_tc, get_accel_pitch_max_radss(), _ang_vel_target.y, _dt);
|
|
_ang_vel_target.z = input_shaping_angle(attitude_error.z, _input_tc, get_accel_yaw_max_radss(), _ang_vel_target.z, heading_rate, slew_yaw_max_rads, _dt);
|
|
|
|
// Limit the angular velocity
|
|
ang_vel_limit(_ang_vel_target, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), slew_yaw_max_rads);
|
|
} else {
|
|
// set persisted quaternion target attitude
|
|
_attitude_target = desired_attitude_quat;
|
|
|
|
// Set rate feedforward requests to zero
|
|
_euler_rate_target.zero();
|
|
_ang_vel_target.zero();
|
|
}
|
|
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_euler_angle_target, _ang_vel_target, _euler_rate_target);
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
Quaternion AC_AttitudeControl::attitude_from_thrust_vector(Vector3f thrust_vector, float heading_angle) const
|
|
{
|
|
const Vector3f thrust_vector_up{0.0f, 0.0f, -1.0f};
|
|
|
|
if (is_zero(thrust_vector.length_squared())) {
|
|
thrust_vector = thrust_vector_up;
|
|
} else {
|
|
thrust_vector.normalize();
|
|
}
|
|
|
|
// the cross product of the desired and target thrust vector defines the rotation vector
|
|
Vector3f thrust_vec_cross = thrust_vector_up % thrust_vector;
|
|
|
|
// the dot product is used to calculate the angle between the target and desired thrust vectors
|
|
const float thrust_vector_angle = acosf(constrain_float(thrust_vector_up * thrust_vector, -1.0f, 1.0f));
|
|
|
|
// Normalize the thrust rotation vector
|
|
const float thrust_vector_length = thrust_vec_cross.length();
|
|
if (is_zero(thrust_vector_length) || is_zero(thrust_vector_angle)) {
|
|
thrust_vec_cross = thrust_vector_up;
|
|
} else {
|
|
thrust_vec_cross /= thrust_vector_length;
|
|
}
|
|
|
|
Quaternion thrust_vec_quat;
|
|
thrust_vec_quat.from_axis_angle(thrust_vec_cross, thrust_vector_angle);
|
|
Quaternion yaw_quat;
|
|
yaw_quat.from_axis_angle(Vector3f{0.0f, 0.0f, 1.0f}, heading_angle);
|
|
return thrust_vec_quat*yaw_quat;
|
|
}
|
|
|
|
// Calculates the body frame angular velocities to follow the target attitude
|
|
void AC_AttitudeControl::attitude_controller_run_quat()
|
|
{
|
|
// This represents a quaternion rotation in NED frame to the body
|
|
Quaternion attitude_body;
|
|
_ahrs.get_quat_body_to_ned(attitude_body);
|
|
|
|
// This vector represents the angular error to rotate the thrust vector using x and y and heading using z
|
|
Vector3f attitude_error;
|
|
thrust_heading_rotation_angles(_attitude_target, attitude_body, attitude_error, _thrust_angle, _thrust_error_angle);
|
|
|
|
// Compute the angular velocity corrections in the body frame from the attitude error
|
|
_ang_vel_body = update_ang_vel_target_from_att_error(attitude_error);
|
|
|
|
// ensure angular velocity does not go over configured limits
|
|
ang_vel_limit(_ang_vel_body, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), radians(_ang_vel_yaw_max));
|
|
|
|
// rotation from the target frame to the body frame
|
|
Quaternion rotation_target_to_body = attitude_body.inverse() * _attitude_target;
|
|
|
|
// target angle velocity vector in the body frame
|
|
Vector3f ang_vel_body_feedforward = rotation_target_to_body * _ang_vel_target;
|
|
|
|
// Correct the thrust vector and smoothly add feedforward and yaw input
|
|
_feedforward_scalar = 1.0f;
|
|
if (_thrust_error_angle > AC_ATTITUDE_THRUST_ERROR_ANGLE * 2.0f) {
|
|
_ang_vel_body.z = _ahrs.get_gyro().z;
|
|
} else if (_thrust_error_angle > AC_ATTITUDE_THRUST_ERROR_ANGLE) {
|
|
_feedforward_scalar = (1.0f - (_thrust_error_angle - AC_ATTITUDE_THRUST_ERROR_ANGLE) / AC_ATTITUDE_THRUST_ERROR_ANGLE);
|
|
_ang_vel_body.x += ang_vel_body_feedforward.x * _feedforward_scalar;
|
|
_ang_vel_body.y += ang_vel_body_feedforward.y * _feedforward_scalar;
|
|
_ang_vel_body.z += ang_vel_body_feedforward.z;
|
|
_ang_vel_body.z = _ahrs.get_gyro().z * (1.0 - _feedforward_scalar) + _ang_vel_body.z * _feedforward_scalar;
|
|
} else {
|
|
_ang_vel_body += ang_vel_body_feedforward;
|
|
}
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// rotate target and normalize
|
|
Quaternion attitude_target_update;
|
|
attitude_target_update.from_axis_angle(Vector3f{_ang_vel_target.x * _dt, _ang_vel_target.y * _dt, _ang_vel_target.z * _dt});
|
|
_attitude_target = _attitude_target * attitude_target_update;
|
|
_attitude_target.normalize();
|
|
}
|
|
|
|
// ensure Quaternion stay normalised
|
|
_attitude_target.normalize();
|
|
|
|
// Record error to handle EKF resets
|
|
_attitude_ang_error = attitude_body.inverse() * _attitude_target;
|
|
}
|
|
|
|
// thrust_heading_rotation_angles - calculates two ordered rotations to move the attitude_body quaternion to the attitude_target quaternion.
|
|
// The maximum error in the yaw axis is limited based on the angle yaw P value and acceleration.
|
|
void AC_AttitudeControl::thrust_heading_rotation_angles(Quaternion& attitude_target, const Quaternion& attitude_body, Vector3f& attitude_error, float& thrust_angle, float& thrust_error_angle) const
|
|
{
|
|
Quaternion thrust_vector_correction;
|
|
thrust_vector_rotation_angles(attitude_target, attitude_body, thrust_vector_correction, attitude_error, thrust_angle, thrust_error_angle);
|
|
|
|
// Todo: Limit roll an pitch error based on output saturation and maximum error.
|
|
|
|
// Limit Yaw Error based on maximum acceleration - Update to include output saturation and maximum error.
|
|
// Currently the limit is based on the maximum acceleration using the linear part of the SQRT controller.
|
|
// This should be updated to be based on an angle limit, saturation, or unlimited based on user defined parameters.
|
|
Quaternion yaw_vec_correction_quat;
|
|
if (!is_zero(_p_angle_yaw.kP()) && fabsf(attitude_error.z) > AC_ATTITUDE_ACCEL_Y_CONTROLLER_MAX_RADSS / _p_angle_yaw.kP()) {
|
|
attitude_error.z = constrain_float(wrap_PI(attitude_error.z), -AC_ATTITUDE_ACCEL_Y_CONTROLLER_MAX_RADSS / _p_angle_yaw.kP(), AC_ATTITUDE_ACCEL_Y_CONTROLLER_MAX_RADSS / _p_angle_yaw.kP());
|
|
yaw_vec_correction_quat.from_axis_angle(Vector3f{0.0f, 0.0f, attitude_error.z});
|
|
attitude_target = attitude_body * thrust_vector_correction * yaw_vec_correction_quat;
|
|
}
|
|
}
|
|
|
|
// thrust_vector_rotation_angles - calculates two ordered rotations to move the attitude_body quaternion to the attitude_target quaternion.
|
|
// The first rotation corrects the thrust vector and the second rotation corrects the heading vector.
|
|
void AC_AttitudeControl::thrust_vector_rotation_angles(const Quaternion& attitude_target, const Quaternion& attitude_body, Quaternion& thrust_vector_correction, Vector3f& attitude_error, float& thrust_angle, float& thrust_error_angle) const
|
|
{
|
|
// The direction of thrust is [0,0,-1] is any body-fixed frame, inc. body frame and target frame.
|
|
const Vector3f thrust_vector_up{0.0f, 0.0f, -1.0f};
|
|
|
|
// attitude_target and attitute_body are passive rotations from target / body frames to the NED frame
|
|
|
|
// Rotating [0,0,-1] by attitude_target expresses (gets a view of) the target thrust vector in the inertial frame
|
|
Vector3f att_target_thrust_vec = attitude_target * thrust_vector_up; // target thrust vector
|
|
|
|
// Rotating [0,0,-1] by attitude_target expresses (gets a view of) the current thrust vector in the inertial frame
|
|
Vector3f att_body_thrust_vec = attitude_body * thrust_vector_up; // current thrust vector
|
|
|
|
// the dot product is used to calculate the current lean angle for use of external functions
|
|
thrust_angle = acosf(constrain_float(thrust_vector_up * att_body_thrust_vec,-1.0f,1.0f));
|
|
|
|
// the cross product of the desired and target thrust vector defines the rotation vector
|
|
Vector3f thrust_vec_cross = att_body_thrust_vec % att_target_thrust_vec;
|
|
|
|
// the dot product is used to calculate the angle between the target and desired thrust vectors
|
|
thrust_error_angle = acosf(constrain_float(att_body_thrust_vec * att_target_thrust_vec, -1.0f, 1.0f));
|
|
|
|
// Normalize the thrust rotation vector
|
|
float thrust_vector_length = thrust_vec_cross.length();
|
|
if (is_zero(thrust_vector_length) || is_zero(thrust_error_angle)) {
|
|
thrust_vec_cross = thrust_vector_up;
|
|
} else {
|
|
thrust_vec_cross /= thrust_vector_length;
|
|
}
|
|
|
|
// thrust_vector_correction is defined relative to the body frame but its axis `thrust_vec_cross` was computed in
|
|
// the inertial frame. First rotate it by the inverse of attitude_body to express it back in the body frame
|
|
thrust_vec_cross = attitude_body.inverse() * thrust_vec_cross;
|
|
thrust_vector_correction.from_axis_angle(thrust_vec_cross, thrust_error_angle);
|
|
|
|
// calculate the angle error in x and y.
|
|
Vector3f rotation;
|
|
thrust_vector_correction.to_axis_angle(rotation);
|
|
attitude_error.x = rotation.x;
|
|
attitude_error.y = rotation.y;
|
|
|
|
// calculate the remaining rotation required after thrust vector is rotated transformed to the body frame
|
|
// heading_vector_correction
|
|
Quaternion heading_vec_correction_quat = thrust_vector_correction.inverse() * attitude_body.inverse() * attitude_target;
|
|
|
|
// calculate the angle error in z (x and y should be zero here).
|
|
heading_vec_correction_quat.to_axis_angle(rotation);
|
|
attitude_error.z = rotation.z;
|
|
}
|
|
|
|
// calculates the velocity correction from an angle error. The angular velocity has acceleration and
|
|
// deceleration limits including basic jerk limiting using _input_tc
|
|
float AC_AttitudeControl::input_shaping_angle(float error_angle, float input_tc, float accel_max, float target_ang_vel, float desired_ang_vel, float max_ang_vel, float dt)
|
|
{
|
|
// Calculate the velocity as error approaches zero with acceleration limited by accel_max_radss
|
|
desired_ang_vel += sqrt_controller(error_angle, 1.0f / MAX(input_tc, 0.01f), accel_max, dt);
|
|
if (is_positive(max_ang_vel)) {
|
|
desired_ang_vel = constrain_float(desired_ang_vel, -max_ang_vel, max_ang_vel);
|
|
}
|
|
|
|
// Acceleration is limited directly to smooth the beginning of the curve.
|
|
return input_shaping_ang_vel(target_ang_vel, desired_ang_vel, accel_max, dt);
|
|
}
|
|
|
|
// limits the acceleration and deceleration of a velocity request
|
|
float AC_AttitudeControl::input_shaping_ang_vel(float target_ang_vel, float desired_ang_vel, float accel_max, float dt)
|
|
{
|
|
// Acceleration is limited directly to smooth the beginning of the curve.
|
|
if (is_positive(accel_max)) {
|
|
float delta_ang_vel = accel_max * dt;
|
|
return constrain_float(desired_ang_vel, target_ang_vel - delta_ang_vel, target_ang_vel + delta_ang_vel);
|
|
} else {
|
|
return desired_ang_vel;
|
|
}
|
|
}
|
|
|
|
// calculates the expected angular velocity correction from an angle error based on the AC_AttitudeControl settings.
|
|
// This function can be used to predict the delay associated with angle requests.
|
|
void AC_AttitudeControl::input_shaping_rate_predictor(const Vector2f &error_angle, Vector2f& target_ang_vel, float dt) const
|
|
{
|
|
if (_rate_bf_ff_enabled) {
|
|
// translate the roll pitch and yaw acceleration limits to the euler axis
|
|
target_ang_vel.x = input_shaping_angle(wrap_PI(error_angle.x), _input_tc, get_accel_roll_max_radss(), target_ang_vel.x, dt);
|
|
target_ang_vel.y = input_shaping_angle(wrap_PI(error_angle.y), _input_tc, get_accel_pitch_max_radss(), target_ang_vel.y, dt);
|
|
} else {
|
|
target_ang_vel.x = _p_angle_roll.get_p(wrap_PI(error_angle.x));
|
|
target_ang_vel.y = _p_angle_pitch.get_p(wrap_PI(error_angle.y));
|
|
}
|
|
// Limit the angular velocity correction
|
|
Vector3f ang_vel(target_ang_vel.x, target_ang_vel.y, 0.0f);
|
|
ang_vel_limit(ang_vel, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), 0.0f);
|
|
|
|
target_ang_vel.x = ang_vel.x;
|
|
target_ang_vel.y = ang_vel.y;
|
|
}
|
|
|
|
// limits angular velocity
|
|
void AC_AttitudeControl::ang_vel_limit(Vector3f& euler_rad, float ang_vel_roll_max, float ang_vel_pitch_max, float ang_vel_yaw_max) const
|
|
{
|
|
if (is_zero(ang_vel_roll_max) || is_zero(ang_vel_pitch_max)) {
|
|
if (!is_zero(ang_vel_roll_max)) {
|
|
euler_rad.x = constrain_float(euler_rad.x, -ang_vel_roll_max, ang_vel_roll_max);
|
|
}
|
|
if (!is_zero(ang_vel_pitch_max)) {
|
|
euler_rad.y = constrain_float(euler_rad.y, -ang_vel_pitch_max, ang_vel_pitch_max);
|
|
}
|
|
} else {
|
|
Vector2f thrust_vector_ang_vel(euler_rad.x / ang_vel_roll_max, euler_rad.y / ang_vel_pitch_max);
|
|
float thrust_vector_length = thrust_vector_ang_vel.length();
|
|
if (thrust_vector_length > 1.0f) {
|
|
euler_rad.x = thrust_vector_ang_vel.x * ang_vel_roll_max / thrust_vector_length;
|
|
euler_rad.y = thrust_vector_ang_vel.y * ang_vel_pitch_max / thrust_vector_length;
|
|
}
|
|
}
|
|
if (!is_zero(ang_vel_yaw_max)) {
|
|
euler_rad.z = constrain_float(euler_rad.z, -ang_vel_yaw_max, ang_vel_yaw_max);
|
|
}
|
|
}
|
|
|
|
// translates body frame acceleration limits to the euler axis
|
|
Vector3f AC_AttitudeControl::euler_accel_limit(const Vector3f &euler_rad, const Vector3f &euler_accel)
|
|
{
|
|
float sin_phi = constrain_float(fabsf(sinf(euler_rad.x)), 0.1f, 1.0f);
|
|
float cos_phi = constrain_float(fabsf(cosf(euler_rad.x)), 0.1f, 1.0f);
|
|
float sin_theta = constrain_float(fabsf(sinf(euler_rad.y)), 0.1f, 1.0f);
|
|
|
|
Vector3f rot_accel;
|
|
if (is_zero(euler_accel.x) || is_zero(euler_accel.y) || is_zero(euler_accel.z) || is_negative(euler_accel.x) || is_negative(euler_accel.y) || is_negative(euler_accel.z)) {
|
|
rot_accel.x = euler_accel.x;
|
|
rot_accel.y = euler_accel.y;
|
|
rot_accel.z = euler_accel.z;
|
|
} else {
|
|
rot_accel.x = euler_accel.x;
|
|
rot_accel.y = MIN(euler_accel.y / cos_phi, euler_accel.z / sin_phi);
|
|
rot_accel.z = MIN(MIN(euler_accel.x / sin_theta, euler_accel.y / sin_phi), euler_accel.z / cos_phi);
|
|
}
|
|
return rot_accel;
|
|
}
|
|
|
|
// Sets attitude target to vehicle attitude and sets all rates to zero
|
|
// If reset_rate is false rates are not reset to allow the rate controllers to run
|
|
void AC_AttitudeControl::reset_target_and_rate(bool reset_rate)
|
|
{
|
|
// move attitude target to current attitude
|
|
_ahrs.get_quat_body_to_ned(_attitude_target);
|
|
|
|
if (reset_rate) {
|
|
// Convert euler angle derivative of desired attitude into a body-frame angular velocity vector for feedforward
|
|
_ang_vel_target.zero();
|
|
_euler_angle_target.zero();
|
|
}
|
|
}
|
|
|
|
// Sets yaw target to vehicle heading and sets yaw rate to zero
|
|
// If reset_rate is false rates are not reset to allow the rate controllers to run
|
|
void AC_AttitudeControl::reset_yaw_target_and_rate(bool reset_rate)
|
|
{
|
|
// move attitude target to current heading
|
|
float yaw_shift = _ahrs.yaw - _euler_angle_target.z;
|
|
Quaternion _attitude_target_update;
|
|
_attitude_target_update.from_axis_angle(Vector3f{0.0f, 0.0f, yaw_shift});
|
|
_attitude_target = _attitude_target_update * _attitude_target;
|
|
|
|
if (reset_rate) {
|
|
// set yaw rate to zero
|
|
_euler_rate_target.z = 0.0f;
|
|
|
|
// Convert euler angle derivative of desired attitude into a body-frame angular velocity vector for feedforward
|
|
euler_rate_to_ang_vel(_euler_angle_target, _euler_rate_target, _ang_vel_target);
|
|
}
|
|
}
|
|
|
|
// Shifts the target attitude to maintain the current error in the event of an EKF reset
|
|
void AC_AttitudeControl::inertial_frame_reset()
|
|
{
|
|
// Retrieve quaternion body attitude
|
|
Quaternion attitude_body;
|
|
_ahrs.get_quat_body_to_ned(attitude_body);
|
|
|
|
// Recalculate the target quaternion
|
|
_attitude_target = attitude_body * _attitude_ang_error;
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target.to_euler(_euler_angle_target.x, _euler_angle_target.y, _euler_angle_target.z);
|
|
}
|
|
|
|
// Convert a 321-intrinsic euler angle derivative to an angular velocity vector
|
|
void AC_AttitudeControl::euler_rate_to_ang_vel(const Vector3f& euler_rad, const Vector3f& euler_rate_rads, Vector3f& ang_vel_rads)
|
|
{
|
|
float sin_theta = sinf(euler_rad.y);
|
|
float cos_theta = cosf(euler_rad.y);
|
|
float sin_phi = sinf(euler_rad.x);
|
|
float cos_phi = cosf(euler_rad.x);
|
|
|
|
ang_vel_rads.x = euler_rate_rads.x - sin_theta * euler_rate_rads.z;
|
|
ang_vel_rads.y = cos_phi * euler_rate_rads.y + sin_phi * cos_theta * euler_rate_rads.z;
|
|
ang_vel_rads.z = -sin_phi * euler_rate_rads.y + cos_theta * cos_phi * euler_rate_rads.z;
|
|
}
|
|
|
|
// Convert an angular velocity vector to a 321-intrinsic euler angle derivative
|
|
// Returns false if the vehicle is pitched 90 degrees up or down
|
|
bool AC_AttitudeControl::ang_vel_to_euler_rate(const Vector3f& euler_rad, const Vector3f& ang_vel_rads, Vector3f& euler_rate_rads)
|
|
{
|
|
float sin_theta = sinf(euler_rad.y);
|
|
float cos_theta = cosf(euler_rad.y);
|
|
float sin_phi = sinf(euler_rad.x);
|
|
float cos_phi = cosf(euler_rad.x);
|
|
|
|
// When the vehicle pitches all the way up or all the way down, the euler angles become discontinuous. In this case, we just return false.
|
|
if (is_zero(cos_theta)) {
|
|
return false;
|
|
}
|
|
|
|
euler_rate_rads.x = ang_vel_rads.x + sin_phi * (sin_theta / cos_theta) * ang_vel_rads.y + cos_phi * (sin_theta / cos_theta) * ang_vel_rads.z;
|
|
euler_rate_rads.y = cos_phi * ang_vel_rads.y - sin_phi * ang_vel_rads.z;
|
|
euler_rate_rads.z = (sin_phi / cos_theta) * ang_vel_rads.y + (cos_phi / cos_theta) * ang_vel_rads.z;
|
|
return true;
|
|
}
|
|
|
|
// Update rate_target_ang_vel using attitude_error_rot_vec_rad
|
|
Vector3f AC_AttitudeControl::update_ang_vel_target_from_att_error(const Vector3f &attitude_error_rot_vec_rad)
|
|
{
|
|
Vector3f rate_target_ang_vel;
|
|
// Compute the roll angular velocity demand from the roll angle error
|
|
if (_use_sqrt_controller && !is_zero(get_accel_roll_max_radss())) {
|
|
rate_target_ang_vel.x = sqrt_controller(attitude_error_rot_vec_rad.x, _p_angle_roll.kP(), constrain_float(get_accel_roll_max_radss() / 2.0f, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MIN_RADSS, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MAX_RADSS), _dt);
|
|
} else {
|
|
rate_target_ang_vel.x = _p_angle_roll.kP() * attitude_error_rot_vec_rad.x;
|
|
}
|
|
|
|
// Compute the pitch angular velocity demand from the pitch angle error
|
|
if (_use_sqrt_controller && !is_zero(get_accel_pitch_max_radss())) {
|
|
rate_target_ang_vel.y = sqrt_controller(attitude_error_rot_vec_rad.y, _p_angle_pitch.kP(), constrain_float(get_accel_pitch_max_radss() / 2.0f, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MIN_RADSS, AC_ATTITUDE_ACCEL_RP_CONTROLLER_MAX_RADSS), _dt);
|
|
} else {
|
|
rate_target_ang_vel.y = _p_angle_pitch.kP() * attitude_error_rot_vec_rad.y;
|
|
}
|
|
|
|
// Compute the yaw angular velocity demand from the yaw angle error
|
|
if (_use_sqrt_controller && !is_zero(get_accel_yaw_max_radss())) {
|
|
rate_target_ang_vel.z = sqrt_controller(attitude_error_rot_vec_rad.z, _p_angle_yaw.kP(), constrain_float(get_accel_yaw_max_radss() / 2.0f, AC_ATTITUDE_ACCEL_Y_CONTROLLER_MIN_RADSS, AC_ATTITUDE_ACCEL_Y_CONTROLLER_MAX_RADSS), _dt);
|
|
} else {
|
|
rate_target_ang_vel.z = _p_angle_yaw.kP() * attitude_error_rot_vec_rad.z;
|
|
}
|
|
return rate_target_ang_vel;
|
|
}
|
|
|
|
// Enable or disable body-frame feed forward
|
|
void AC_AttitudeControl::accel_limiting(bool enable_limits)
|
|
{
|
|
if (enable_limits) {
|
|
// If enabling limits, reload from eeprom or set to defaults
|
|
if (is_zero(_accel_roll_max)) {
|
|
_accel_roll_max.load();
|
|
}
|
|
if (is_zero(_accel_pitch_max)) {
|
|
_accel_pitch_max.load();
|
|
}
|
|
if (is_zero(_accel_yaw_max)) {
|
|
_accel_yaw_max.load();
|
|
}
|
|
} else {
|
|
_accel_roll_max = 0.0f;
|
|
_accel_pitch_max = 0.0f;
|
|
_accel_yaw_max = 0.0f;
|
|
}
|
|
}
|
|
|
|
// Return tilt angle limit for pilot input that prioritises altitude hold over lean angle
|
|
float AC_AttitudeControl::get_althold_lean_angle_max_cd() const
|
|
{
|
|
// convert to centi-degrees for public interface
|
|
return MAX(ToDeg(_althold_lean_angle_max), AC_ATTITUDE_CONTROL_ANGLE_LIMIT_MIN) * 100.0f;
|
|
}
|
|
|
|
// Return roll rate step size in centidegrees/s that results in maximum output after 4 time steps
|
|
float AC_AttitudeControl::max_rate_step_bf_roll()
|
|
{
|
|
float alpha = MIN(get_rate_roll_pid().get_filt_E_alpha(), get_rate_roll_pid().get_filt_D_alpha());
|
|
float alpha_remaining = 1 - alpha;
|
|
// todo: When a thrust_max is available we should replace 0.5f with 0.5f * _motors.thrust_max
|
|
float throttle_hover = constrain_float(_motors.get_throttle_hover(), 0.1f, 0.5f);
|
|
float rate_max = 2.0f * throttle_hover * AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX / ((alpha_remaining * alpha_remaining * alpha_remaining * alpha * get_rate_roll_pid().kD()) / _dt + get_rate_roll_pid().kP());
|
|
if (is_positive(_ang_vel_roll_max)) {
|
|
rate_max = MIN(rate_max, get_ang_vel_roll_max_rads());
|
|
}
|
|
return rate_max;
|
|
}
|
|
|
|
// Return pitch rate step size in centidegrees/s that results in maximum output after 4 time steps
|
|
float AC_AttitudeControl::max_rate_step_bf_pitch()
|
|
{
|
|
float alpha = MIN(get_rate_pitch_pid().get_filt_E_alpha(), get_rate_pitch_pid().get_filt_D_alpha());
|
|
float alpha_remaining = 1 - alpha;
|
|
// todo: When a thrust_max is available we should replace 0.5f with 0.5f * _motors.thrust_max
|
|
float throttle_hover = constrain_float(_motors.get_throttle_hover(), 0.1f, 0.5f);
|
|
float rate_max = 2.0f * throttle_hover * AC_ATTITUDE_RATE_RP_CONTROLLER_OUT_MAX / ((alpha_remaining * alpha_remaining * alpha_remaining * alpha * get_rate_pitch_pid().kD()) / _dt + get_rate_pitch_pid().kP());
|
|
if (is_positive(_ang_vel_pitch_max)) {
|
|
rate_max = MIN(rate_max, get_ang_vel_pitch_max_rads());
|
|
}
|
|
return rate_max;
|
|
}
|
|
|
|
// Return yaw rate step size in centidegrees/s that results in maximum output after 4 time steps
|
|
float AC_AttitudeControl::max_rate_step_bf_yaw()
|
|
{
|
|
float alpha = MIN(get_rate_yaw_pid().get_filt_E_alpha(), get_rate_yaw_pid().get_filt_D_alpha());
|
|
float alpha_remaining = 1 - alpha;
|
|
// todo: When a thrust_max is available we should replace 0.5f with 0.5f * _motors.thrust_max
|
|
float throttle_hover = constrain_float(_motors.get_throttle_hover(), 0.1f, 0.5f);
|
|
float rate_max = 2.0f * throttle_hover * AC_ATTITUDE_RATE_YAW_CONTROLLER_OUT_MAX / ((alpha_remaining * alpha_remaining * alpha_remaining * alpha * get_rate_yaw_pid().kD()) / _dt + get_rate_yaw_pid().kP());
|
|
if (is_positive(_ang_vel_yaw_max)) {
|
|
rate_max = MIN(rate_max, get_ang_vel_yaw_max_rads());
|
|
}
|
|
return rate_max;
|
|
}
|
|
|
|
bool AC_AttitudeControl::pre_arm_checks(const char *param_prefix,
|
|
char *failure_msg,
|
|
const uint8_t failure_msg_len)
|
|
{
|
|
// validate AC_P members:
|
|
const struct {
|
|
const char *pid_name;
|
|
AC_P &p;
|
|
} ps[] = {
|
|
{ "ANG_PIT", get_angle_pitch_p() },
|
|
{ "ANG_RLL", get_angle_roll_p() },
|
|
{ "ANG_YAW", get_angle_yaw_p() }
|
|
};
|
|
for (uint8_t i=0; i<ARRAY_SIZE(ps); i++) {
|
|
// all AC_P's must have a positive P value:
|
|
if (!is_positive(ps[i].p.kP())) {
|
|
hal.util->snprintf(failure_msg, failure_msg_len, "%s_%s_P must be > 0", param_prefix, ps[i].pid_name);
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// validate AC_PID members:
|
|
const struct {
|
|
const char *pid_name;
|
|
AC_PID &pid;
|
|
} pids[] = {
|
|
{ "RAT_RLL", get_rate_roll_pid() },
|
|
{ "RAT_PIT", get_rate_pitch_pid() },
|
|
{ "RAT_YAW", get_rate_yaw_pid() },
|
|
};
|
|
for (uint8_t i=0; i<ARRAY_SIZE(pids); i++) {
|
|
// if the PID has a positive FF then we just ensure kP and
|
|
// kI aren't negative
|
|
AC_PID &pid = pids[i].pid;
|
|
const char *pid_name = pids[i].pid_name;
|
|
if (is_positive(pid.ff())) {
|
|
// kP and kI must be non-negative:
|
|
if (is_negative(pid.kP())) {
|
|
hal.util->snprintf(failure_msg, failure_msg_len, "%s_%s_P must be >= 0", param_prefix, pid_name);
|
|
return false;
|
|
}
|
|
if (is_negative(pid.kI())) {
|
|
hal.util->snprintf(failure_msg, failure_msg_len, "%s_%s_I must be >= 0", param_prefix, pid_name);
|
|
return false;
|
|
}
|
|
} else {
|
|
// kP and kI must be positive:
|
|
if (!is_positive(pid.kP())) {
|
|
hal.util->snprintf(failure_msg, failure_msg_len, "%s_%s_P must be > 0", param_prefix, pid_name);
|
|
return false;
|
|
}
|
|
if (!is_positive(pid.kI())) {
|
|
hal.util->snprintf(failure_msg, failure_msg_len, "%s_%s_I must be > 0", param_prefix, pid_name);
|
|
return false;
|
|
}
|
|
}
|
|
// never allow a negative D term (but zero is allowed)
|
|
if (is_negative(pid.kD())) {
|
|
hal.util->snprintf(failure_msg, failure_msg_len, "%s_%s_D must be >= 0", param_prefix, pid_name);
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
get the slew rate for roll, pitch and yaw, for oscillation
|
|
detection in lua scripts
|
|
*/
|
|
void AC_AttitudeControl::get_rpy_srate(float &roll_srate, float &pitch_srate, float &yaw_srate)
|
|
{
|
|
roll_srate = get_rate_roll_pid().get_pid_info().slew_rate;
|
|
pitch_srate = get_rate_pitch_pid().get_pid_info().slew_rate;
|
|
yaw_srate = get_rate_yaw_pid().get_pid_info().slew_rate;
|
|
}
|