ardupilot/libraries/APM_Control/AR_PosControl.cpp

420 lines
16 KiB
C++

/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "AR_PosControl.h"
#include <AP_HAL/AP_HAL.h>
#include <AP_Math/AP_Math.h>
#include <AP_AHRS/AP_AHRS.h>
#include <AP_Logger/AP_Logger.h>
#include <GCS_MAVLink/GCS.h>
#include <AC_Avoidance/AC_Avoid.h>
extern const AP_HAL::HAL& hal;
#define AR_POSCON_TIMEOUT_MS 100 // timeout after 0.1 sec
#define AR_POSCON_POS_P 0.2f // default position P gain
#define AR_POSCON_VEL_P 1.0f // default velocity P gain
#define AR_POSCON_VEL_I 0.0f // default velocity I gain
#define AR_POSCON_VEL_D 0.0f // default velocity D gain
#define AR_POSCON_VEL_FF 0.0f // default velocity FF gain
#define AR_POSCON_VEL_IMAX 1.0f // default velocity IMAX
#define AR_POSCON_VEL_FILT 5.0f // default velocity filter
#define AR_POSCON_VEL_FILT_D 5.0f // default velocity D term filter
#define AR_POSCON_DT 0.02f // default dt for PID controllers
const AP_Param::GroupInfo AR_PosControl::var_info[] = {
// @Param: _POS_P
// @DisplayName: Position controller P gain
// @Description: Position controller P gain. Converts the distance to the target location into a desired speed which is then passed to the loiter latitude rate controller
// @Range: 0.500 2.000
// @User: Standard
AP_SUBGROUPINFO(_p_pos, "_POS_", 1, AR_PosControl, AC_P_2D),
// @Param: _VEL_P
// @DisplayName: Velocity (horizontal) P gain
// @Description: Velocity (horizontal) P gain. Converts the difference between desired and actual velocity to a target acceleration
// @Range: 0.1 6.0
// @Increment: 0.1
// @User: Advanced
// @Param: _VEL_I
// @DisplayName: Velocity (horizontal) I gain
// @Description: Velocity (horizontal) I gain. Corrects long-term difference between desired and actual velocity to a target acceleration
// @Range: 0.02 1.00
// @Increment: 0.01
// @User: Advanced
// @Param: _VEL_D
// @DisplayName: Velocity (horizontal) D gain
// @Description: Velocity (horizontal) D gain. Corrects short-term changes in velocity
// @Range: 0.00 1.00
// @Increment: 0.001
// @User: Advanced
// @Param: _VEL_IMAX
// @DisplayName: Velocity (horizontal) integrator maximum
// @Description: Velocity (horizontal) integrator maximum. Constrains the target acceleration that the I gain will output
// @Range: 0 4500
// @Increment: 10
// @Units: cm/s/s
// @User: Advanced
// @Param: _VEL_FLTE
// @DisplayName: Velocity (horizontal) input filter
// @Description: Velocity (horizontal) input filter. This filter (in Hz) is applied to the input for P and I terms
// @Range: 0 100
// @Units: Hz
// @User: Advanced
// @Param: _VEL_FLTD
// @DisplayName: Velocity (horizontal) input filter
// @Description: Velocity (horizontal) input filter. This filter (in Hz) is applied to the input for D term
// @Range: 0 100
// @Units: Hz
// @User: Advanced
// @Param: _VEL_FF
// @DisplayName: Velocity (horizontal) feed forward gain
// @Description: Velocity (horizontal) feed forward gain. Converts the difference between desired velocity to a target acceleration
// @Range: 0 6
// @Increment: 0.01
// @User: Advanced
AP_SUBGROUPINFO(_pid_vel, "_VEL_", 2, AR_PosControl, AC_PID_2D),
AP_GROUPEND
};
AR_PosControl::AR_PosControl(AR_AttitudeControl& atc) :
_atc(atc),
_p_pos(AR_POSCON_POS_P),
_pid_vel(AR_POSCON_VEL_P, AR_POSCON_VEL_I, AR_POSCON_VEL_D, AR_POSCON_VEL_FF, AR_POSCON_VEL_IMAX, AR_POSCON_VEL_FILT, AR_POSCON_VEL_FILT_D)
{
AP_Param::setup_object_defaults(this, var_info);
}
// update navigation
void AR_PosControl::update(float dt)
{
// exit immediately if no current location, destination or disarmed
Vector2f curr_pos_NE;
Vector3f curr_vel_NED;
if (!hal.util->get_soft_armed() || !AP::ahrs().get_relative_position_NE_origin(curr_pos_NE) ||
!AP::ahrs().get_velocity_NED(curr_vel_NED)) {
_desired_speed = _atc.get_desired_speed_accel_limited(0.0f, dt);
_desired_lat_accel = 0.0f;
_desired_turn_rate_rads = 0.0f;
return;
}
// check for ekf xy position reset
handle_ekf_xy_reset();
// if no recent calls reset velocity controller
if (!is_active()) {
_pid_vel.reset_I();
_pid_vel.reset_filter();
}
_last_update_ms = AP_HAL::millis();
// calculate position error and convert to desired velocity
_vel_target.zero();
if (_pos_target_valid) {
Vector2p pos_target = _pos_target;
_vel_target = _p_pos.update_all(pos_target.x, pos_target.y, curr_pos_NE);
}
// calculation velocity error
if (_vel_desired_valid) {
// add target velocity to desired velocity from position error
_vel_target += _vel_desired;
}
// limit velocity to maximum speed
_vel_target.limit_length(get_speed_max());
// Limit the velocity to prevent fence violations
bool backing_up = false;
AC_Avoid *avoid = AP::ac_avoid();
if (avoid != nullptr) {
Vector3f vel_3d_cms{_vel_target.x * 100.0f, _vel_target.y * 100.0f, 0.0f};
const float accel_max_cmss = MIN(_accel_max, _lat_accel_max) * 100.0;
avoid->adjust_velocity(vel_3d_cms, backing_up, _p_pos.kP(), accel_max_cmss, _p_pos.kP(), accel_max_cmss, dt);
_vel_target.x = vel_3d_cms.x * 0.01;
_vel_target.y = vel_3d_cms.y * 0.01;
}
// calculate limit vector based on steering limits
Vector2f steering_limit_vec;
if (_atc.steering_limit_left()) {
steering_limit_vec = AP::ahrs().body_to_earth2D(Vector2f{0, _reversed ? 1.0f : -1.0f});
} else if (_atc.steering_limit_right()) {
steering_limit_vec = AP::ahrs().body_to_earth2D(Vector2f{0, _reversed ? -1.0f : 1.0f});
}
// calculate desired acceleration
_accel_target = _pid_vel.update_all(_vel_target, curr_vel_NED.xy(), dt, steering_limit_vec);
if (_accel_desired_valid) {
_accel_target += _accel_desired;
}
// velocity controller I-term zeroed in forward-back direction
const Vector2f lat_vec_ef = AP::ahrs().body_to_earth2D(Vector2f{0, 1});
const Vector2f vel_i = _pid_vel.get_i().projected(lat_vec_ef);
_pid_vel.set_integrator(vel_i);
// convert desired acceleration to desired forward-back speed, desired lateral speed and desired turn rate
// rotate acceleration into body frame using current heading
const Vector2f accel_target_FR = AP::ahrs().earth_to_body2D(_accel_target);
// calculate minimum turn speed which is the max speed the vehicle could turn through the corner
// given the vehicle's turn radius and half its max lateral acceleration
// todo: remove MAX of zero when safe_sqrt fixed
float turn_speed_min = MAX(safe_sqrt(_atc.get_turn_lat_accel_max() * 0.5 * _turn_radius), 0);
// rotate target velocity from earth-frame to body frame
const Vector2f vel_target_FR = AP::ahrs().earth_to_body2D(_vel_target);
// desired speed is normally the forward component (only) of the target velocity
// but we do not let it fall below the minimum turn speed unless the vehicle is slowing down
const float abs_des_speed_min = MIN(_vel_target.length(), turn_speed_min);
float des_speed;
if (_reversed != backing_up) {
// if reversed or backing up desired speed will be negative
des_speed = MIN(-abs_des_speed_min, vel_target_FR.x);
} else {
des_speed = MAX(abs_des_speed_min, vel_target_FR.x);
}
_desired_speed = _atc.get_desired_speed_accel_limited(des_speed, dt);
// calculate turn rate from desired lateral acceleration
_desired_lat_accel = accel_target_FR.y;
_desired_turn_rate_rads = _atc.get_turn_rate_from_lat_accel(_desired_lat_accel, _desired_speed);
}
// true if update has been called recently
bool AR_PosControl::is_active() const
{
return ((AP_HAL::millis() - _last_update_ms) < AR_POSCON_TIMEOUT_MS);
}
// set limits
void AR_PosControl::set_limits(float speed_max, float accel_max, float lat_accel_max, float jerk_max)
{
_speed_max = MAX(speed_max, 0);
_accel_max = MAX(accel_max, 0);
_lat_accel_max = MAX(lat_accel_max, 0);
_jerk_max = MAX(jerk_max, 0);
// set position P controller limits
_p_pos.set_limits(_speed_max, MIN(_accel_max, _lat_accel_max), _jerk_max);
}
// setter to allow vehicle code to provide turn related param values to this library (should be updated regularly)
void AR_PosControl::set_turn_params(float turn_radius, bool pivot_possible)
{
if (pivot_possible) {
_turn_radius = 0;
} else {
_turn_radius = turn_radius;
}
}
// initialise the position controller to the current position, velocity, acceleration and attitude
// this should be called before the input shaping methods are used
bool AR_PosControl::init()
{
// get current position and velocity from AHRS
Vector2f pos_NE;
Vector3f vel_NED;
if (!AP::ahrs().get_relative_position_NE_origin(pos_NE) || !AP::ahrs().get_velocity_NED(vel_NED)) {
return false;
}
// set target position to current position
_pos_target.x = pos_NE.x;
_pos_target.y = pos_NE.y;
// set target velocity and acceleration
_vel_desired = vel_NED.xy();
_vel_target.zero();
_accel_desired = AP::ahrs().get_accel_ef().xy();
_accel_target.zero();
// clear reversed setting
_reversed = false;
// initialise ekf xy reset handler
init_ekf_xy_reset();
return true;
}
// adjust position, velocity and acceleration targets smoothly using input shaping
// pos is the target position as an offset from the EKF origin (in meters)
// vel is the target velocity in m/s. accel is the target acceleration in m/s/s
// dt should be the update rate in seconds
// init should be called once before starting to use these methods
void AR_PosControl::input_pos_target(const Vector2p &pos, float dt)
{
Vector2f vel;
Vector2f accel;
input_pos_vel_accel_target(pos, vel, accel, dt);
}
// adjust position, velocity and acceleration targets smoothly using input shaping
// pos is the target position as an offset from the EKF origin (in meters)
// vel is the target velocity in m/s. accel is the target acceleration in m/s/s
// dt should be the update rate in seconds
// init should be called once before starting to use these methods
void AR_PosControl::input_pos_vel_target(const Vector2p &pos, const Vector2f &vel, float dt)
{
Vector2f accel;
input_pos_vel_accel_target(pos, vel, accel, dt);
}
// adjust position, velocity and acceleration targets smoothly using input shaping
// pos is the target position as an offset from the EKF origin (in meters)
// vel is the target velocity in m/s. accel is the target acceleration in m/s/s
// dt should be the update rate in seconds
// init should be called once before starting to use these methods
void AR_PosControl::input_pos_vel_accel_target(const Vector2p &pos, const Vector2f &vel, const Vector2f &accel, float dt)
{
// adjust target position, velocity and acceleration forward by dt
update_pos_vel_accel_xy(_pos_target, _vel_desired, _accel_desired, dt, Vector2f(), Vector2f(), Vector2f());
// call shape_pos_vel_accel_xy to pull target towards final destination
const float accel_max = MIN(_accel_max, _lat_accel_max);
shape_pos_vel_accel_xy(pos, vel, accel, _pos_target, _vel_desired, _accel_desired,
_speed_max, accel_max, _jerk_max, dt, false);
// set flags so update will consume target position, desired velocity and desired acceleration
_pos_target_valid = true;
_vel_desired_valid = true;
_accel_desired_valid = true;
}
// set target position, desired velocity and acceleration. These should be from an externally created path and are not "input shaped"
void AR_PosControl::set_pos_vel_accel_target(const Vector2p &pos, const Vector2f &vel, const Vector2f &accel)
{
_pos_target = pos;
_vel_desired = vel;
_accel_desired = accel;
_pos_target_valid = true;
_vel_desired_valid = true;
_accel_desired_valid = true;
}
// returns desired velocity vector (i.e. feed forward) in cm/s in lat and lon direction
Vector2f AR_PosControl::get_desired_velocity() const
{
if (_vel_desired_valid) {
return _vel_desired;
}
return Vector2f();
}
// return desired acceleration vector in m/s in lat and lon direction
Vector2f AR_PosControl::get_desired_accel() const
{
if (_accel_desired_valid) {
return _accel_desired;
}
return Vector2f();
}
/// get position error as a vector from the current position to the target position
Vector2p AR_PosControl::get_pos_error() const
{
// return zero error is not active or no position estimate
Vector2f curr_pos_NE;
if (!is_active() ||!AP::ahrs().get_relative_position_NE_origin(curr_pos_NE)) {
return Vector2p{};
}
// get current position
return (_pos_target - curr_pos_NE.topostype());
}
// write PSC logs
void AR_PosControl::write_log()
{
// exit immediately if not active
if (!is_active()) {
return;
}
// exit immediately if no position or velocity estimate
Vector3f curr_pos_NED;
Vector3f curr_vel_NED;
if (!AP::ahrs().get_relative_position_NED_origin(curr_pos_NED) || !AP::ahrs().get_velocity_NED(curr_vel_NED)) {
return;
}
// get acceleration
const Vector3f curr_accel_NED = AP::ahrs().get_accel_ef() * 100.0;
// convert position to required format
Vector2f pos_target_2d_cm = get_pos_target().tofloat() * 100.0;
AP::logger().Write_PSCN(pos_target_2d_cm.x, // position target
curr_pos_NED.x * 100.0, // position
_vel_desired.x * 100.0, // desired velocity
_vel_target.x * 100.0, // target velocity
curr_vel_NED.x * 100.0, // velocity
_accel_desired.x * 100.0, // desired accel
_accel_target.x * 100.0, // target accel
curr_accel_NED.x); // accel
AP::logger().Write_PSCE(pos_target_2d_cm.y, // position target
curr_pos_NED.y * 100.0, // position
_vel_desired.y * 100.0, // desired velocity
_vel_target.y * 100.0, // target velocity
curr_vel_NED.y * 100.0, // velocity
_accel_desired.y * 100.0, // desired accel
_accel_target.y * 100.0, // target accel
curr_accel_NED.y); // accel
}
/// initialise ekf xy position reset check
void AR_PosControl::init_ekf_xy_reset()
{
Vector2f pos_shift;
_ekf_xy_reset_ms = AP::ahrs().getLastPosNorthEastReset(pos_shift);
}
/// handle_ekf_xy_reset - check for ekf position reset and adjust loiter or brake target position
void AR_PosControl::handle_ekf_xy_reset()
{
// check for position shift
Vector2f pos_shift;
uint32_t reset_ms = AP::ahrs().getLastPosNorthEastReset(pos_shift);
if (reset_ms != _ekf_xy_reset_ms) {
Vector2f pos_NE;
if (!AP::ahrs().get_relative_position_NE_origin(pos_NE)) {
return;
}
_pos_target = (pos_NE + _p_pos.get_error()).topostype();
Vector3f vel_NED;
if (!AP::ahrs().get_velocity_NED(vel_NED)) {
return;
}
_vel_desired = vel_NED.xy() + _pid_vel.get_error();
_ekf_xy_reset_ms = reset_ms;
}
}