mirror of https://github.com/ArduPilot/ardupilot
1072 lines
55 KiB
C++
1072 lines
55 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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// 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 6.000
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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, 360:Slow, 720:Medium, 1080: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, 360:Slow, 720:Medium, 1080: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, 360:Slow, 720:Medium, 1080: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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// 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_quat);
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_attitude_target_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.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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_attitude_target_ang_vel = _ahrs.get_gyro();
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ang_vel_to_euler_rate(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
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_rate_target_ang_vel = _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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// 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_quat, _attitude_target_euler_angle, _attitude_target_euler_rate and
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// _attitude_target_ang_vel 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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void AC_AttitudeControl::input_quaternion(Quaternion attitude_desired_quat)
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{
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// calculate the attitude target euler angles
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_attitude_target_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
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Quaternion attitude_error_quat = _attitude_target_quat.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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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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_attitude_target_ang_vel.x = input_shaping_angle(wrap_PI(attitude_error_angle.x), _input_tc, get_accel_roll_max_radss(), _attitude_target_ang_vel.x, _dt);
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_attitude_target_ang_vel.y = input_shaping_angle(wrap_PI(attitude_error_angle.y), _input_tc, get_accel_pitch_max_radss(), _attitude_target_ang_vel.y, _dt);
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_attitude_target_ang_vel.z = input_shaping_angle(wrap_PI(attitude_error_angle.z), _input_tc, get_accel_yaw_max_radss(), _attitude_target_ang_vel.z, _dt);
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// Limit the angular velocity
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ang_vel_limit(_attitude_target_ang_vel, 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(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
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} else {
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_attitude_target_quat = attitude_desired_quat;
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// Set rate feedforward requests to zero
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_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
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_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
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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 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_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.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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Vector3f euler_accel = euler_accel_limit(_attitude_target_euler_angle, 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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_attitude_target_euler_rate.x = input_shaping_angle(wrap_PI(euler_roll_angle - _attitude_target_euler_angle.x), _input_tc, euler_accel.x, _attitude_target_euler_rate.x, _dt);
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_attitude_target_euler_rate.y = input_shaping_angle(wrap_PI(euler_pitch_angle - _attitude_target_euler_angle.y), _input_tc, euler_accel.y, _attitude_target_euler_rate.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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_attitude_target_euler_rate.z = input_shaping_ang_vel(_attitude_target_euler_rate.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(_attitude_target_euler_angle, _attitude_target_euler_rate, _attitude_target_ang_vel);
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// Limit the angular velocity
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ang_vel_limit(_attitude_target_ang_vel, 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(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
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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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_attitude_target_euler_angle.x = euler_roll_angle;
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_attitude_target_euler_angle.y = euler_pitch_angle;
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_attitude_target_euler_angle.z += euler_yaw_rate * _dt;
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// Compute quaternion target attitude
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_attitude_target_quat.from_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
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// Set rate feedforward requests to zero
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_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
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_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
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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_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.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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Vector3f euler_accel = euler_accel_limit(_attitude_target_euler_angle, 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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_attitude_target_euler_rate.x = input_shaping_angle(wrap_PI(euler_roll_angle - _attitude_target_euler_angle.x), _input_tc, euler_accel.x, _attitude_target_euler_rate.x, _dt);
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_attitude_target_euler_rate.y = input_shaping_angle(wrap_PI(euler_pitch_angle - _attitude_target_euler_angle.y), _input_tc, euler_accel.y, _attitude_target_euler_rate.y, _dt);
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_attitude_target_euler_rate.z = input_shaping_angle(wrap_PI(euler_yaw_angle - _attitude_target_euler_angle.z), _input_tc, euler_accel.z, _attitude_target_euler_rate.z, _dt);
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if (slew_yaw) {
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_attitude_target_euler_rate.z = constrain_float(_attitude_target_euler_rate.z, -get_slew_yaw_rads(), get_slew_yaw_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(_attitude_target_euler_angle, _attitude_target_euler_rate, _attitude_target_ang_vel);
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// Limit the angular velocity
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ang_vel_limit(_attitude_target_ang_vel, 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(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
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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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_attitude_target_euler_angle.x = euler_roll_angle;
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_attitude_target_euler_angle.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 - _attitude_target_euler_angle.z), -get_slew_yaw_rads() * _dt, get_slew_yaw_rads() * _dt);
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// Update attitude target from constrained angle error
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_attitude_target_euler_angle.z = wrap_PI(angle_error + _attitude_target_euler_angle.z);
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} else {
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_attitude_target_euler_angle.z = euler_yaw_angle;
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}
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// Compute quaternion target attitude
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_attitude_target_quat.from_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
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// Set rate feedforward requests to zero
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_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
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_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
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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 euler yaw rate and pitch angle with roll angle specified in body frame
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// (used only by tailsitter quadplanes)
|
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// If plane_controls is true, swap the effects of roll and yaw as euler pitch approaches 90 degrees
|
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void AC_AttitudeControl::input_euler_rate_yaw_euler_angle_pitch_bf_roll(bool plane_controls, float body_roll_cd, float euler_pitch_cd, float euler_yaw_rate_cds)
|
|
{
|
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// Convert from centidegrees on public interface to radians
|
|
float euler_yaw_rate = radians(euler_yaw_rate_cds*0.01f);
|
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float euler_pitch = radians(constrain_float(euler_pitch_cd * 0.01f, -90.0f, 90.0f));
|
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float body_roll = radians(-body_roll_cd * 0.01f);
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const float cpitch = cosf(euler_pitch);
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const float spitch = fabsf(sinf(euler_pitch));
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|
|
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// Compute attitude error
|
|
Quaternion attitude_vehicle_quat;
|
|
Quaternion error_quat;
|
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attitude_vehicle_quat.from_rotation_matrix(_ahrs.get_rotation_body_to_ned());
|
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error_quat = attitude_vehicle_quat.inverse() * _attitude_target_quat;
|
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Vector3f att_error;
|
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error_quat.to_axis_angle(att_error);
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|
|
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// update heading
|
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float yaw_rate = euler_yaw_rate;
|
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if (plane_controls) {
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yaw_rate = (euler_yaw_rate * spitch) + (body_roll * cpitch);
|
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}
|
|
// limit yaw error
|
|
float yaw_error = fabsf(att_error.z);
|
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float error_ratio = yaw_error / M_PI_2;
|
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if (error_ratio > 1) {
|
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yaw_rate /= (error_ratio * error_ratio);
|
|
}
|
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_attitude_target_euler_angle.z = wrap_PI(_attitude_target_euler_angle.z + yaw_rate * _dt);
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|
|
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// init attitude target to desired euler yaw and pitch with zero roll
|
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_attitude_target_quat.from_euler(0, euler_pitch, _attitude_target_euler_angle.z);
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|
|
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// apply body-frame yaw/roll (this is roll/yaw for a tailsitter in forward flight)
|
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// rotate body_roll axis by |sin(pitch angle)|
|
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Quaternion bf_roll_Q;
|
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bf_roll_Q.from_axis_angle(Vector3f(0, 0, spitch * body_roll));
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|
|
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// rotate body_yaw axis by cos(pitch angle)
|
|
Quaternion bf_yaw_Q;
|
|
if (plane_controls) {
|
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bf_yaw_Q.from_axis_angle(Vector3f(cpitch, 0, 0), euler_yaw_rate);
|
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} else {
|
|
bf_yaw_Q.from_axis_angle(Vector3f(-cpitch * body_roll, 0, 0));
|
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}
|
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_attitude_target_quat = _attitude_target_quat * bf_roll_Q * bf_yaw_Q;
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|
|
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// _attitude_target_euler_angle roll and pitch: Note: roll/yaw will be indeterminate when pitch is near +/-90
|
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// These should be used only for logging target eulers, with the caveat noted above.
|
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// Also note that _attitude_target_quat.from_euler() should only be used in special circumstances
|
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// such as when attitude is specified directly in terms of Euler angles.
|
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// _attitude_target_euler_angle.x = _attitude_target_quat.get_euler_roll();
|
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// _attitude_target_euler_angle.y = euler_pitch;
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|
|
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// Set rate feedforward requests to zero
|
|
_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
|
|
_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
|
|
|
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// Compute attitude error
|
|
error_quat = attitude_vehicle_quat.inverse() * _attitude_target_quat;
|
|
error_quat.to_axis_angle(att_error);
|
|
|
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// Compute the angular velocity target from the attitude error
|
|
_rate_target_ang_vel = update_ang_vel_target_from_att_error(att_error);
|
|
}
|
|
|
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// 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_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// translate the roll pitch and yaw acceleration limits to the euler axis
|
|
Vector3f euler_accel = euler_accel_limit(_attitude_target_euler_angle, 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.
|
|
_attitude_target_euler_rate.x = input_shaping_ang_vel(_attitude_target_euler_rate.x, euler_roll_rate, euler_accel.x, _dt);
|
|
_attitude_target_euler_rate.y = input_shaping_ang_vel(_attitude_target_euler_rate.y, euler_pitch_rate, euler_accel.y, _dt);
|
|
_attitude_target_euler_rate.z = input_shaping_ang_vel(_attitude_target_euler_rate.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(_attitude_target_euler_angle, _attitude_target_euler_rate, _attitude_target_ang_vel);
|
|
} 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.
|
|
_attitude_target_euler_angle.x = wrap_PI(_attitude_target_euler_angle.x + euler_roll_rate * _dt);
|
|
_attitude_target_euler_angle.y = constrain_float(_attitude_target_euler_angle.y + euler_pitch_rate * _dt, radians(-85.0f), radians(85.0f));
|
|
_attitude_target_euler_angle.z = wrap_2PI(_attitude_target_euler_angle.z + euler_yaw_rate * _dt);
|
|
|
|
// Set rate feedforward requests to zero
|
|
_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
|
|
_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
|
|
|
|
// Compute quaternion target attitude
|
|
_attitude_target_quat.from_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.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_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.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.
|
|
_attitude_target_ang_vel.x = input_shaping_ang_vel(_attitude_target_ang_vel.x, roll_rate_rads, get_accel_roll_max_radss(), _dt);
|
|
_attitude_target_ang_vel.y = input_shaping_ang_vel(_attitude_target_ang_vel.y, pitch_rate_rads, get_accel_pitch_max_radss(), _dt);
|
|
_attitude_target_ang_vel.z = input_shaping_ang_vel(_attitude_target_ang_vel.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(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
|
|
} 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_quat;
|
|
attitude_target_update_quat.from_axis_angle(Vector3f(roll_rate_rads * _dt, pitch_rate_rads * _dt, yaw_rate_rads * _dt));
|
|
_attitude_target_quat = _attitude_target_quat * attitude_target_update_quat;
|
|
_attitude_target_quat.normalize();
|
|
|
|
// Set rate feedforward requests to zero
|
|
_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
|
|
_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
|
|
}
|
|
|
|
// 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.
|
|
_attitude_target_ang_vel.x = input_shaping_ang_vel(_attitude_target_ang_vel.x, roll_rate_rads, get_accel_roll_max_radss(), _dt);
|
|
_attitude_target_ang_vel.y = input_shaping_ang_vel(_attitude_target_ang_vel.y, pitch_rate_rads, get_accel_pitch_max_radss(), _dt);
|
|
_attitude_target_ang_vel.z = input_shaping_ang_vel(_attitude_target_ang_vel.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_quat);
|
|
_attitude_target_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
|
|
_rate_target_ang_vel = _attitude_target_ang_vel;
|
|
}
|
|
|
|
// 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_vector;
|
|
_attitude_ang_error.to_axis_angle(attitude_error_vector);
|
|
|
|
Quaternion attitude_ang_error_update_quat;
|
|
// limit the integrated error angle
|
|
float err_mag = attitude_error_vector.length();
|
|
if (err_mag > AC_ATTITUDE_THRUST_ERROR_ANGLE) {
|
|
attitude_error_vector *= AC_ATTITUDE_THRUST_ERROR_ANGLE / err_mag;
|
|
_attitude_ang_error.from_axis_angle(attitude_error_vector);
|
|
}
|
|
|
|
Vector3f gyro_latest = _ahrs.get_gyro_latest();
|
|
attitude_ang_error_update_quat.from_axis_angle(Vector3f((_attitude_target_ang_vel.x-gyro_latest.x) * _dt, (_attitude_target_ang_vel.y-gyro_latest.y) * _dt, (_attitude_target_ang_vel.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.
|
|
_attitude_target_ang_vel.x = input_shaping_ang_vel(_attitude_target_ang_vel.x, roll_rate_rads, get_accel_roll_max_radss(), _dt);
|
|
_attitude_target_ang_vel.y = input_shaping_ang_vel(_attitude_target_ang_vel.y, pitch_rate_rads, get_accel_pitch_max_radss(), _dt);
|
|
_attitude_target_ang_vel.z = input_shaping_ang_vel(_attitude_target_ang_vel.z, yaw_rate_rads, get_accel_yaw_max_radss(), _dt);
|
|
|
|
// Retrieve quaternion vehicle attitude
|
|
Quaternion attitude_vehicle_quat;
|
|
_ahrs.get_quat_body_to_ned(attitude_vehicle_quat);
|
|
|
|
// Update the unused targets attitude based on current attitude to condition mode change
|
|
_attitude_target_quat = attitude_vehicle_quat * _attitude_ang_error;
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
|
|
|
|
// Convert body-frame angular velocity into euler angle derivative of desired attitude
|
|
ang_vel_to_euler_rate(_attitude_target_euler_angle, _attitude_target_ang_vel, _attitude_target_euler_rate);
|
|
|
|
// Compute the angular velocity target from the integrated rate error
|
|
_attitude_ang_error.to_axis_angle(attitude_error_vector);
|
|
_rate_target_ang_vel = update_ang_vel_target_from_att_error(attitude_error_vector);
|
|
_rate_target_ang_vel += _attitude_target_ang_vel;
|
|
|
|
// 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_quat;
|
|
attitude_target_update_quat.from_axis_angle(Vector3f(roll_step_rads, pitch_step_rads, yaw_step_rads));
|
|
_attitude_target_quat = _attitude_target_quat * attitude_target_update_quat;
|
|
_attitude_target_quat.normalize();
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.z);
|
|
|
|
// Set rate feedforward requests to zero
|
|
_attitude_target_euler_rate = Vector3f(0.0f, 0.0f, 0.0f);
|
|
_attitude_target_ang_vel = Vector3f(0.0f, 0.0f, 0.0f);
|
|
|
|
// Call quaternion attitude controller
|
|
attitude_controller_run_quat();
|
|
}
|
|
|
|
// Calculates the body frame angular velocities to follow the target attitude
|
|
void AC_AttitudeControl::attitude_controller_run_quat()
|
|
{
|
|
// Retrieve quaternion vehicle attitude
|
|
Quaternion attitude_vehicle_quat;
|
|
_ahrs.get_quat_body_to_ned(attitude_vehicle_quat);
|
|
|
|
// Compute attitude error
|
|
Vector3f attitude_error_vector;
|
|
thrust_heading_rotation_angles(_attitude_target_quat, attitude_vehicle_quat, attitude_error_vector, _thrust_error_angle);
|
|
|
|
// Compute the angular velocity target from the attitude error
|
|
_rate_target_ang_vel = update_ang_vel_target_from_att_error(attitude_error_vector);
|
|
|
|
// Add feedforward term that attempts to ensure that roll and pitch errors rotate with the body frame rather than the reference frame.
|
|
// todo: this should probably be a matrix that couples yaw as well.
|
|
_rate_target_ang_vel.x += constrain_float(attitude_error_vector.y, -M_PI / 4, M_PI / 4) * _ahrs.get_gyro().z;
|
|
_rate_target_ang_vel.y += -constrain_float(attitude_error_vector.x, -M_PI / 4, M_PI / 4) * _ahrs.get_gyro().z;
|
|
|
|
ang_vel_limit(_rate_target_ang_vel, radians(_ang_vel_roll_max), radians(_ang_vel_pitch_max), radians(_ang_vel_yaw_max));
|
|
|
|
// Add the angular velocity feedforward, rotated into vehicle frame
|
|
Quaternion attitude_target_ang_vel_quat = Quaternion(0.0f, _attitude_target_ang_vel.x, _attitude_target_ang_vel.y, _attitude_target_ang_vel.z);
|
|
Quaternion to_to_from_quat = attitude_vehicle_quat.inverse() * _attitude_target_quat;
|
|
Quaternion desired_ang_vel_quat = to_to_from_quat.inverse() * attitude_target_ang_vel_quat * to_to_from_quat;
|
|
|
|
// 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) {
|
|
_rate_target_ang_vel.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);
|
|
_rate_target_ang_vel.x += desired_ang_vel_quat.q2 * _feedforward_scalar;
|
|
_rate_target_ang_vel.y += desired_ang_vel_quat.q3 * _feedforward_scalar;
|
|
_rate_target_ang_vel.z += desired_ang_vel_quat.q4;
|
|
_rate_target_ang_vel.z = _ahrs.get_gyro().z * (1.0 - _feedforward_scalar) + _rate_target_ang_vel.z * _feedforward_scalar;
|
|
} else {
|
|
_rate_target_ang_vel.x += desired_ang_vel_quat.q2;
|
|
_rate_target_ang_vel.y += desired_ang_vel_quat.q3;
|
|
_rate_target_ang_vel.z += desired_ang_vel_quat.q4;
|
|
}
|
|
|
|
if (_rate_bf_ff_enabled) {
|
|
// rotate target and normalize
|
|
Quaternion attitude_target_update_quat;
|
|
attitude_target_update_quat.from_axis_angle(Vector3f(_attitude_target_ang_vel.x * _dt, _attitude_target_ang_vel.y * _dt, _attitude_target_ang_vel.z * _dt));
|
|
_attitude_target_quat = _attitude_target_quat * attitude_target_update_quat;
|
|
_attitude_target_quat.normalize();
|
|
}
|
|
|
|
// ensure Quaternions stay normalized
|
|
_attitude_target_quat.normalize();
|
|
|
|
// Record error to handle EKF resets
|
|
_attitude_ang_error = attitude_vehicle_quat.inverse() * _attitude_target_quat;
|
|
}
|
|
|
|
// thrust_heading_rotation_angles - calculates two ordered rotations to move the att_from_quat quaternion to the att_to_quat quaternion.
|
|
// The first rotation corrects the thrust vector and the second rotation corrects the heading vector.
|
|
void AC_AttitudeControl::thrust_heading_rotation_angles(Quaternion& att_to_quat, const Quaternion& att_from_quat, Vector3f& att_diff_angle, float& thrust_vec_dot)
|
|
{
|
|
Matrix3f att_to_rot_matrix; // rotation from the target body frame to the inertial frame.
|
|
att_to_quat.rotation_matrix(att_to_rot_matrix);
|
|
Vector3f att_to_thrust_vec = att_to_rot_matrix * Vector3f(0.0f, 0.0f, 1.0f);
|
|
|
|
Matrix3f att_from_rot_matrix; // rotation from the current body frame to the inertial frame.
|
|
att_from_quat.rotation_matrix(att_from_rot_matrix);
|
|
Vector3f att_from_thrust_vec = att_from_rot_matrix * Vector3f(0.0f, 0.0f, 1.0f);
|
|
|
|
// the dot product is used to calculate the current lean angle for use of external functions
|
|
_thrust_angle = acosf(constrain_float(Vector3f(0.0f,0.0f,1.0f) * att_from_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_from_thrust_vec % att_to_thrust_vec;
|
|
|
|
// the dot product is used to calculate the angle between the target and desired thrust vectors
|
|
thrust_vec_dot = acosf(constrain_float(att_from_thrust_vec * att_to_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_vec_dot)) {
|
|
thrust_vec_cross = Vector3f(0, 0, 1);
|
|
thrust_vec_dot = 0.0f;
|
|
} else {
|
|
thrust_vec_cross /= thrust_vector_length;
|
|
}
|
|
Quaternion thrust_vec_correction_quat;
|
|
thrust_vec_correction_quat.from_axis_angle(thrust_vec_cross, thrust_vec_dot);
|
|
|
|
// Rotate thrust_vec_correction_quat to the att_from frame
|
|
thrust_vec_correction_quat = att_from_quat.inverse() * thrust_vec_correction_quat * att_from_quat;
|
|
|
|
// calculate the remaining rotation required after thrust vector is rotated transformed to the att_from frame
|
|
Quaternion yaw_vec_correction_quat = thrust_vec_correction_quat.inverse() * att_from_quat.inverse() * att_to_quat;
|
|
|
|
// calculate the angle error in x and y.
|
|
Vector3f rotation;
|
|
thrust_vec_correction_quat.to_axis_angle(rotation);
|
|
att_diff_angle.x = rotation.x;
|
|
att_diff_angle.y = rotation.y;
|
|
|
|
// calculate the angle error in z (x and y should be zero here).
|
|
yaw_vec_correction_quat.to_axis_angle(rotation);
|
|
att_diff_angle.z = rotation.z;
|
|
|
|
// 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.
|
|
if (!is_zero(_p_angle_yaw.kP()) && fabsf(att_diff_angle.z) > AC_ATTITUDE_ACCEL_Y_CONTROLLER_MAX_RADSS / _p_angle_yaw.kP()) {
|
|
att_diff_angle.z = constrain_float(wrap_PI(att_diff_angle.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, att_diff_angle.z));
|
|
att_to_quat = att_from_quat * thrust_vec_correction_quat * yaw_vec_correction_quat;
|
|
}
|
|
}
|
|
|
|
// 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 dt)
|
|
{
|
|
// Calculate the velocity as error approaches zero with acceleration limited by accel_max_radss
|
|
float desired_ang_vel = sqrt_controller(error_angle, 1.0f / MAX(input_tc, 0.01f), accel_max, dt);
|
|
|
|
// 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;
|
|
}
|
|
|
|
// Shifts earth frame yaw target by yaw_shift_cd. yaw_shift_cd should be in centidegrees and is added to the current target heading
|
|
void AC_AttitudeControl::shift_ef_yaw_target(float yaw_shift_cd)
|
|
{
|
|
float yaw_shift = radians(yaw_shift_cd * 0.01f);
|
|
Quaternion _attitude_target_update_quat;
|
|
_attitude_target_update_quat.from_axis_angle(Vector3f(0.0f, 0.0f, yaw_shift));
|
|
_attitude_target_quat = _attitude_target_update_quat * _attitude_target_quat;
|
|
}
|
|
|
|
// Shifts earth frame yaw target by yaw_shift_cd. yaw_shift_cd should be in centidegrees and is added to the current target heading
|
|
void AC_AttitudeControl::inertial_frame_reset()
|
|
{
|
|
// Retrieve quaternion vehicle attitude
|
|
Quaternion attitude_vehicle_quat;
|
|
_ahrs.get_quat_body_to_ned(attitude_vehicle_quat);
|
|
|
|
// Recalculate the target quaternion
|
|
_attitude_target_quat = attitude_vehicle_quat * _attitude_ang_error;
|
|
|
|
// calculate the attitude target euler angles
|
|
_attitude_target_quat.to_euler(_attitude_target_euler_angle.x, _attitude_target_euler_angle.y, _attitude_target_euler_angle.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) {
|
|
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;
|
|
}
|
|
// todo: Add Angular Velocity Limit
|
|
|
|
// Compute the pitch angular velocity demand from the pitch angle error
|
|
if (_use_sqrt_controller) {
|
|
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;
|
|
}
|
|
// todo: Add Angular Velocity Limit
|
|
|
|
// Compute the yaw angular velocity demand from the yaw angle error
|
|
if (_use_sqrt_controller) {
|
|
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;
|
|
}
|
|
// todo: Add Angular Velocity Limit
|
|
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() const
|
|
{
|
|
// convert to centi-degrees for public interface
|
|
return MAX(ToDeg(_althold_lean_angle_max), AC_ATTITUDE_CONTROL_ANGLE_LIMIT_MIN) * 100.0f;
|
|
}
|
|
|
|
// Proportional controller with piecewise sqrt sections to constrain second derivative
|
|
float AC_AttitudeControl::sqrt_controller(float error, float p, float second_ord_lim, float dt)
|
|
{
|
|
float correction_rate;
|
|
if (is_negative(second_ord_lim) || is_zero(second_ord_lim)) {
|
|
// second order limit is zero or negative.
|
|
correction_rate = error * p;
|
|
} else if (is_zero(p)) {
|
|
// P term is zero but we have a second order limit.
|
|
if (is_positive(error)) {
|
|
correction_rate = safe_sqrt(2.0f * second_ord_lim * (error));
|
|
} else if (is_negative(error)) {
|
|
correction_rate = -safe_sqrt(2.0f * second_ord_lim * (-error));
|
|
} else {
|
|
correction_rate = 0.0f;
|
|
}
|
|
} else {
|
|
// Both the P and second order limit have been defined.
|
|
float linear_dist = second_ord_lim / sq(p);
|
|
if (error > linear_dist) {
|
|
correction_rate = safe_sqrt(2.0f * second_ord_lim * (error - (linear_dist / 2.0f)));
|
|
} else if (error < -linear_dist) {
|
|
correction_rate = -safe_sqrt(2.0f * second_ord_lim * (-error - (linear_dist / 2.0f)));
|
|
} else {
|
|
correction_rate = error * p;
|
|
}
|
|
}
|
|
if (!is_zero(dt)) {
|
|
// this ensures we do not get small oscillations by over shooting the error correction in the last time step.
|
|
return constrain_float(correction_rate, -fabsf(error) / dt, fabsf(error) / dt);
|
|
} else {
|
|
return correction_rate;
|
|
}
|
|
}
|
|
|
|
// Inverse proportional controller with piecewise sqrt sections to constrain second derivative
|
|
float AC_AttitudeControl::stopping_point(float first_ord_mag, float p, float second_ord_lim)
|
|
{
|
|
if (is_positive(second_ord_lim) && !is_zero(second_ord_lim) && is_zero(p)) {
|
|
return (first_ord_mag * first_ord_mag) / (2.0f * second_ord_lim);
|
|
} else if ((is_negative(second_ord_lim) || is_zero(second_ord_lim)) && !is_zero(p)) {
|
|
return first_ord_mag / p;
|
|
} else if ((is_negative(second_ord_lim) || is_zero(second_ord_lim)) && is_zero(p)) {
|
|
return 0.0f;
|
|
}
|
|
|
|
// calculate the velocity at which we switch from calculating the stopping point using a linear function to a sqrt function
|
|
float linear_velocity = second_ord_lim / p;
|
|
|
|
if (fabsf(first_ord_mag) < linear_velocity) {
|
|
// if our current velocity is below the cross-over point we use a linear function
|
|
return first_ord_mag / p;
|
|
} else {
|
|
float linear_dist = second_ord_lim / sq(p);
|
|
float overshoot = (linear_dist * 0.5f) + sq(first_ord_mag) / (2.0f * second_ord_lim);
|
|
if (is_positive(first_ord_mag)) {
|
|
return overshoot;
|
|
} else {
|
|
return -overshoot;
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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);
|
|
return 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());
|
|
}
|
|
|
|
// 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);
|
|
return 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());
|
|
}
|
|
|
|
// 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);
|
|
return 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());
|
|
}
|
|
|
|
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;
|
|
}
|