/****************************************************************************
 *
 *   Copyright (c) 2013-2020 Estimation and Control Library (ECL). All rights reserved.
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 *    distribution.
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 *    used to endorse or promote products derived from this software
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/**
 * @file ecl_pitch_controller.cpp
 * Implementation of a simple orthogonal pitch PID controller.
 *
 * Authors and acknowledgements in header.
 */

#include "ecl_pitch_controller.h"
#include <float.h>
#include <lib/geo/geo.h>
#include <mathlib/mathlib.h>

float ECL_PitchController::control_attitude(const float dt, const ECL_ControlData &ctl_data)
{
	/* Do not calculate control signal with bad inputs */
	if (!(PX4_ISFINITE(ctl_data.pitch_setpoint) &&
	      PX4_ISFINITE(ctl_data.roll) &&
	      PX4_ISFINITE(ctl_data.pitch) &&
	      PX4_ISFINITE(ctl_data.euler_yaw_rate_setpoint) &&
	      PX4_ISFINITE(ctl_data.airspeed))) {

		return _body_rate_setpoint;
	}

	/* Calculate the error */
	float pitch_error = ctl_data.pitch_setpoint - ctl_data.pitch;

	/*  Apply P controller: rate setpoint from current error and time constant */
	_euler_rate_setpoint =  pitch_error / _tc;

	/* Transform setpoint to body angular rates (jacobian) */
	const float pitch_body_rate_setpoint_raw = cosf(ctl_data.roll) * _euler_rate_setpoint +
			cosf(ctl_data.pitch) * sinf(ctl_data.roll) * ctl_data.euler_yaw_rate_setpoint;
	_body_rate_setpoint = math::constrain(pitch_body_rate_setpoint_raw, -_max_rate_neg, _max_rate);

	return _body_rate_setpoint;
}