bizhang_-obav/src/modules/flight_mode_manager/tasks/Utility/StickAccelerationXY.cpp

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/**
 * @file StickAccelerationXY.cpp
 */

#include "StickAccelerationXY.hpp"

#include <ecl/geo/geo.h>
#include "Sticks.hpp"

using namespace matrix;

StickAccelerationXY::StickAccelerationXY(ModuleParams *parent) :
	ModuleParams(parent)
{
	_brake_boost_filter.reset(1.f);
	resetPosition();
}

void StickAccelerationXY::resetPosition()
{
	_position.setNaN();
}

void StickAccelerationXY::resetVelocity(const matrix::Vector2f &velocity)
{
	_velocity = velocity;
}

void StickAccelerationXY::resetAcceleration(const matrix::Vector2f &acceleration)
{
	_acceleration_slew_rate_x.setForcedValue(acceleration(0));
	_acceleration_slew_rate_x.setForcedValue(acceleration(1));
}

void StickAccelerationXY::generateSetpoints(Vector2f stick_xy, const float yaw, const float yaw_sp, const Vector3f &pos,
		const float dt)
{
	// maximum commanded acceleration and velocity
	Vector2f acceleration_scale(_param_mpc_acc_hor.get(), _param_mpc_acc_hor.get());
	Vector2f velocity_scale(_param_mpc_vel_manual.get(), _param_mpc_vel_manual.get());

	acceleration_scale *= 2.f; // because of drag the average aceleration is half

	// Map stick input to acceleration
	Sticks::limitStickUnitLengthXY(stick_xy);
	Sticks::rotateIntoHeadingFrameXY(stick_xy, yaw, yaw_sp);
	_acceleration = stick_xy.emult(acceleration_scale);
	applyFeasibilityLimit(_acceleration, dt);

	// Add drag to limit speed and brake again
	Vector2f drag = calculateDrag(acceleration_scale.edivide(velocity_scale), dt, stick_xy, _velocity);

	// Don't allow the drag to change the sign of the velocity, otherwise we might get into oscillations around 0, due
	// to discretization
	if (_acceleration.norm_squared() < FLT_EPSILON && _velocity.norm_squared() < drag.norm_squared() * dt * dt) {
		drag.setZero();
		_velocity.setZero();
	}

	_acceleration -= drag;

	applyTiltLimit(_acceleration);

	// Generate velocity setpoint by forward integrating commanded acceleration
	_velocity += _acceleration * dt;

	lockPosition(_velocity, pos, dt, _position);
}

void StickAccelerationXY::getSetpoints(Vector3f &pos_sp, Vector3f &vel_sp, Vector3f &acc_sp)
{
	pos_sp.xy() = _position;
	vel_sp.xy() = _velocity;
	acc_sp.xy() = _acceleration;
}

void StickAccelerationXY::applyFeasibilityLimit(Vector2f &acceleration, const float dt)
{
	// Apply jerk limit - acceleration slew rate
	_acceleration_slew_rate_x.setSlewRate(_param_mpc_jerk_max.get());
	_acceleration_slew_rate_y.setSlewRate(_param_mpc_jerk_max.get());
	acceleration(0) = _acceleration_slew_rate_x.update(acceleration(0), dt);
	acceleration(1) = _acceleration_slew_rate_y.update(acceleration(1), dt);
}

Vector2f StickAccelerationXY::calculateDrag(Vector2f drag_coefficient, const float dt, const Vector2f &stick_xy,
		const Vector2f &vel_sp)
{
	_brake_boost_filter.setParameters(dt, .8f);

	if (stick_xy.norm_squared() < FLT_EPSILON) {
		_brake_boost_filter.update(2.f);

	} else {
		_brake_boost_filter.update(1.f);
	}

	drag_coefficient *= _brake_boost_filter.getState();

	// increase drag with sqareroot function when velocity is lower than 1m/s
	const Vector2f velocity_with_sqrt_boost = vel_sp.unit_or_zero() * math::sqrt_linear(vel_sp.norm());
	return drag_coefficient.emult(velocity_with_sqrt_boost);
}

void StickAccelerationXY::applyTiltLimit(Vector2f &acceleration)
{
	// Check if acceleration would exceed the tilt limit
	const float acc = acceleration.length();
	const float acc_tilt_max = tanf(M_DEG_TO_RAD_F * _param_mpc_tiltmax_air.get()) * CONSTANTS_ONE_G;

	if (acc > acc_tilt_max) {
		acceleration *= acc_tilt_max / acc;
	}
}

void StickAccelerationXY::lockPosition(const Vector2f &vel_sp, const Vector3f &pos, const float dt, Vector2f &pos_sp)
{
	if (vel_sp.norm_squared() < FLT_EPSILON) {
		if (!PX4_ISFINITE(pos_sp(0))) {
			pos_sp = Vector2f(pos);
		}

	} else {
		pos_sp.setNaN();

	}
}