DroneXControllerService.cpp

//    Copyright (C) 2017, ETH Zurich, D-ITET, Paul Beuchat, Angel Romero, Cyrill Burgener, Marco Mueller, Philipp Friedli
//
//    This file is part of D-FaLL-System.
//
//    D-FaLL-System 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.
//
//    D-FaLL-System 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 D-FaLL-System.  If not, see <http://www.gnu.org/licenses/>.
//
//
//    ----------------------------------------------------------------------------------
//    DDDD        FFFFF        L     L           SSSS  Y   Y   SSSS  TTTTT  EEEEE  M   M
//    D   D       F      aaa   L     L          S       Y Y   S        T    E      MM MM
//    D   D  ---  FFFF  a   a  L     L     ---   SSS     Y     SSS     T    EEE    M M M
//    D   D       F     a  aa  L     L              S    Y        S    T    E      M   M
//    DDDD        F      aa a  LLLL  LLLL       SSSS     Y    SSSS     T    EEEEE  M   M
//
//
//    DESCRIPTION:
//    Place for students to implement their controller
//
//    ----------------------------------------------------------------------------------





// INCLUDE THE HEADER
#include "nodes/DroneXControllerService.h"





//    ----------------------------------------------------------------------------------
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//    ----------------------------------------------------------------------------------




// REMINDER OF THE NAME OF USEFUL CLASS VARIABLE
// // > Mass of the Crazyflie quad-rotor, in [grams]
// float m_mass_CF_grams;
// // > Mass of the letters to be lifted, in [grams]
// float m_mass_E_grams;
// float m_mass_T_grams;
// float m_mass_H_grams;
// // > Total mass of the Crazyflie plus whatever it is carrying, in [grams]
// float m_mass_total_grams;
// // Thickness of the object at pick-up and put-down, in [meters]
// // > This should also account for extra height due to
// //   the surface where the object is
// float m_thickness_of_object_at_pickup;
// float m_thickness_of_object_at_putdown;
// // (x,y) coordinates of the pickup location
// std::vector<float> m_pickup_coordinates_xy(2);
// // (x,y) coordinates of the drop off location
// std::vector<float> m_dropoff_coordinates_xy_for_E(2);
// std::vector<float> m_dropoff_coordinates_xy_for_T(2);
// std::vector<float> m_dropoff_coordinates_xy_for_H(2);
// // Length of the string from the Crazyflie
// // to the end of the DroneX, in [meters]
// float m_dronex_string_length;
// // > The setpoints for (x,y,z) position and yaw angle, in that order
// float m_setpoint[4] = {0.0,0.0,0.4,0.0};
// float m_setpoint_for_controller[4] = {0.0,0.0,0.4,0.0};
// // > Small adjustments to the x-y setpoint
// float m_xAdjustment = 0.0f;
// float m_yAdjustment = 0.0f;
// // Boolean for whether to limit rate of change of the setpoint
// bool m_shouldSmoothSetpointChanges = true;
// // Max setpoint change per second
// float m_max_setpoint_change_per_second_horizontal;
// float m_max_setpoint_change_per_second_vertical;
// float m_max_setpoint_change_per_second_yaw_degrees;
// float m_max_setpoint_change_per_second_yaw_radians;
// // Frequency at which the controller is running
// float m_vicon_frequency;


// A FEW EXTRA COMMENTS ABOUT THE MOST IMPORTANT VARIABLES

// Variable name:    m_setpoint
// Description:
// This is a float array of length 4. It specifies a location
// in space where you want the drone to be. The 4 element are:
// >> m_setpoint[0]   The x-poistion in [meters]
// >> m_setpoint[1]   The y-poistion in [meters]
// >> m_setpoint[2]   The z-poistion in [meters]
// >> m_setpoint[3]   The yaw heading angle in [radians]


// Variable name:    m_setpoint_for_controller
// Description:
// Similar to the variable "m_setpoint" this is also float array
// of length 4 that specifies an (x,y,z,yaw) location. The
// difference it that this variable specifies the location where
// the low-level controller is guiding the drone to be.
// HINT: to make changes the "m_setpoint" variable, you can edit
// the function named "perControlCycleOperations" so that the
// "m_setpoint_for_controller" changes by a maximum amount at
// each cycle of the contoller



// THIS FUNCTION IS CALLED AT "m_vicon_frequency" HERTZ.
// IT CAN BE USED TO ADJUST THINGS IN "REAL TIME".
// For example, the equation:
// >> m_max_setpoint_change_per_second_horizontal / m_vicon_frequency
// will convert the "change per second" to a "change per cycle".

void perControlCycleOperations()
{
	if (m_shouldSmoothSetpointChanges)
	{
		for(int i = 0; i < 4; ++i)
		{
			float max_for_this_coordinate;
			// FILLE IN THE STATE INERTIAL ESTIMATE TO BE USED FOR CONTROL
			switch (i)
			{
				case 0:
					max_for_this_coordinate = m_max_setpoint_change_per_second_horizontal / m_vicon_frequency;
					break;
				case 1:
					max_for_this_coordinate = m_max_setpoint_change_per_second_horizontal / m_vicon_frequency;
					break;
				case 2:
					max_for_this_coordinate = m_max_setpoint_change_per_second_vertical / m_vicon_frequency;
					break;
				case 3:
					max_for_this_coordinate = m_max_setpoint_change_per_second_yaw_radians / m_vicon_frequency;
					break;
				// Handle the exception
				default:
					max_for_this_coordinate = 0.0f;
					break;
			}

			// Compute the difference in setpoint
			float setpoint_difference = m_setpoint[i] - m_setpoint_for_controller[i];

			// Clip the difference to the maximum
			if (setpoint_difference > max_for_this_coordinate)
			{
				setpoint_difference = max_for_this_coordinate;
			}
			else if (setpoint_difference < -max_for_this_coordinate)
			{
				setpoint_difference = -max_for_this_coordinate;
			}

			// Update the setpoint of the controller
			m_setpoint_for_controller[i] += setpoint_difference;
		}

	}
	else
	{
		m_setpoint_for_controller[0] = m_setpoint[0];
		m_setpoint_for_controller[1] = m_setpoint[1];
		m_setpoint_for_controller[2] = m_setpoint[2];
		m_setpoint_for_controller[3] = m_setpoint[3];
	}
}








void buttonPressed_take_off(){

	//if(flying_state == DRONEX_STATE_GROUND || flying_state == DRONEX_STATE_ON_MOTHERSHIP){
		ROS_INFO("[DRONEX CONTROLLER-DroneXControllerService] Taking off...");
		flying_state = DRONEX_STATE_TAKING_OFF;
	//}else{
	//	ROS_ERROR("Cannot change to DRONEX_STATE_TAKING_OFF");
	//}
}

void buttonPressed_land(){
	//if(flying_state == DRONEX_STATE_HOVER){
		ROS_INFO("[DRONEX CONTROLLER-DroneXControllerService] Start flight-sequence LA...");
		// OLD:flying_state = DRONEX_STATE_LAND_ON_MOTHERSHIP;
		// NEW: 
		flightSequence = 1;
}

void buttonPressed_abort(){
	ROS_INFO("[DRONEX CONTROLLER-DroneXControllerService] Abort Mission!");
	flying_state = DRONEX_STATE_LAND_ON_GROUND;
}

void buttonPressed_integrator_on(){
	ROS_INFO("[DRONEX CONTROLLER-DroneXControllerService] Turn ON integrator");
	integratorFlag = DRONEX_INTEGRATOR_ON;
}

void buttonPressed_integrator_off(){
	ROS_INFO("[DRONEX CONTROLLER-DroneXControllerService] Turn OFF integrator");
	integratorFlag = DRONEX_INTEGRATOR_OFF;
}

void buttonPressed_integrator_reset(){
	ROS_INFO("[DRONEX CONTROLLER-DroneXControllerService] RESET integrator to zero");
	integratorFlag = DRONEX_INTEGRATOR_RESET;
}








//    ------------------------------------------------------------------------------
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//
//     CCCC   OOO   N   N  TTTTT  RRRR    OOO   L           L       OOO    OOO   PPPP
//    C      O   O  NN  N    T    R   R  O   O  L           L      O   O  O   O  P   P
//    C      O   O  N N N    T    RRRR   O   O  L           L      O   O  O   O  PPPP
//    C      O   O  N  NN    T    R  R   O   O  L           L      O   O  O   O  P
//     CCCC   OOO   N   N    T    R   R   OOO   LLLLL       LLLLL   OOO    OOO   P
//    ----------------------------------------------------------------------------------

// This function is the callback that is linked to the "DroneXController" service that
// is advertised in the main function. This must have arguments that match the
// "input-output" behaviour defined in the "Controller.srv" file (located in the "srv"
// folder)
//
// The arument "request" is a structure provided to this service with the following two
// properties:
// request.ownCrazyflie
// This property is itself a structure of type "CrazyflieData",  which is defined in the
// file "CrazyflieData.msg", and has the following properties
// string crazyflieName
//     float64 x                         The x position of the Crazyflie [metres]
//     float64 y                         The y position of the Crazyflie [metres]
//     float64 z                         The z position of the Crazyflie [metres]
//     float64 roll                      The roll component of the intrinsic Euler angles [radians]
//     float64 pitch                     The pitch component of the intrinsic Euler angles [radians]
//     float64 yaw                       The yaw component of the intrinsic Euler angles [radians]
//     float64 acquiringTime #delta t    The time elapsed since the previous "CrazyflieData" was received [seconds]
//     bool occluded                     A boolean indicted whether the Crazyflie for visible at the time of this measurement
// The values in these properties are directly the measurement taken by the Vicon
// motion capture system of the Crazyflie that is to be controlled by this service
//
// request.otherCrazyflies
// This property is an array of "CrazyflieData" structures, what allows access to the
// Vicon measurements of other Crazyflies.
//
// The argument "response" is a structure that is expected to be filled in by this
// service by this function, it has only the following property
// response.ControlCommand
// This property is iteself a structure of type "ControlCommand", which is defined in
// the file "ControlCommand.msg", and has the following properties:
//     float32 roll                      The command sent to the Crazyflie for the body frame x-axis
//     float32 pitch                     The command sent to the Crazyflie for the body frame y-axis
//     float32 yaw                       The command sent to the Crazyflie for the body frame z-axis
//     uint16 motorCmd1                  The command sent to the Crazyflie for motor 1
//     uint16 motorCmd2                  The command sent to the Crazyflie for motor 1
//     uint16 motorCmd3                  The command sent to the Crazyflie for motor 1
//     uint16 motorCmd4                  The command sent to the Crazyflie for motor 1
//     uint8 onboardControllerType       The flag sent to the Crazyflie for indicating how to implement the command
//
// IMPORTANT NOTES FOR "onboardControllerType"  AND AXIS CONVENTIONS
// > The allowed values for "onboardControllerType" are in the "Defines" section at the
//   top of this file, they are:
//   CF_COMMAND_TYPE_MOTOR
//   CF_COMMAND_TYPE_RATE
//   CF_COMMAND_TYPE_ANGLE.
// > With CF_COMMAND_TYPE_RATE the ".roll", ".ptich", and ".yaw" properties of "response.ControlCommand"
//   specify the angular rate in [radians/second] that will be requested from the
//   PID controllers running in the Crazyflie 2.0 firmware.
// > With CF_COMMAND_TYPE_RATE the ".motorCmd1" to ".motorCmd4" properties of "response.ControlCommand"
//   are the baseline motor commands requested from the Crazyflie, with the adjustment
//   for body rates being added on top of this in the firmware (i.e., as per the code
//   of the "distribute_power" function provided in exercise sheet 2).
// > With CF_COMMAND_TYPE_RATE the axis convention for the roll, pitch, and yaw body rates returned
//   in "response.ControlCommand" should use right-hand coordinate axes with x-forward
//   and z-upwards (i.e., the positive z-axis is aligned with the direction of positive
//   thrust). To assist, teh following is an ASCII art of this convention:
//
// ASCII ART OF THE CRAZYFLIE 2.0 LAYOUT
//
//  > This is a top view,
//  > M1 to M4 stand for Motor 1 to Motor 4,
//  > "CW"  indicates that the motor rotates Clockwise,
//  > "CCW" indicates that the motor rotates Counter-Clockwise,
//  > By right-hand axis convention, the positive z-direction points our of the screen,
//  > This being a "top view" means tha the direction of positive thrust produced
//    by the propellers is also out of the screen.
//
//        ____                         ____
//       /    \                       /    \
//  (CW) | M4 |           x           | M1 | (CCW)
//       \____/\          ^          /\____/
//            \ \         |         / /
//             \ \        |        / /
//              \ \______ | ______/ /
//               \        |        /
//                |       |       |
//        y <-------------o       |
//                |               |
//               / _______________ \
//              / /               \ \
//             / /                 \ \
//        ____/ /                   \ \____
//       /    \/                     \/    \
// (CCW) | M3 |                       | M2 | (CW)
//       \____/                       \____/
//
//
//
// This function WILL NEED TO BE edited for successful completion of the PPS exercise
bool calculateControlOutput(Controller::Request &request, Controller::Response &response)
{

	// Keep track of time
	m_time_ticks++;
	m_time_seconds = float(m_time_ticks) / m_vicon_frequency;


	switch(flying_state){
		case DRONEX_STATE_APPROACH:
			{
				ROS_INFO("DRONEX_STATE_APPROACH");
			dronexSetpoint.x = request.otherCrazyflies[0].x;
			dronexSetpoint.y = request.otherCrazyflies[0].y;
			dronexSetpoint.z = request.otherCrazyflies[0].z + 0.2;
			//setpointCallback(dronexSetpoint);

		}
			break;
		case DRONEX_STATE_GROUND:
			//{
				ROS_INFO("DRONEX_STATE_GROUND");
			/*	std_msgs::Int32 flying_state_msg;
    			flying_state_msg.data = STATE_MOTORS_OFF;
				flyingStatePublisher.publish(flying_state_msg);
			return true;
			}*/
			break;

		case DRONEX_STATE_LAND_ON_GROUND:
			{
				//ROS_INFO_STREAM("DRONEX_STATE_LAND_ON_GROUND: Crazyflie z coordinate " << request.ownCrazyflie.z);
				//ROS_INFO_STREAM("DRONEX_STATE_LAND_ON_GROUND: Mothership z coordinate " << request.otherCrazyflies[0].z);

					dronexSetpoint.x = request.otherCrazyflies[0].x;	//set setpoint to droneX x y and z coordinates
					dronexSetpoint.y = request.otherCrazyflies[0].y;
					dronexSetpoint.z = request.otherCrazyflies[0].z+0.05;

			/*if(request.ownCrazyflie.z < request.otherCrazyflies[0].z+0.25){ // >0.1

				std_msgs::Int32 flying_state_msg;
    			flying_state_msg.data = STATE_MOTORS_OFF;

				//flyingStatePublisher.publish(flying_state_msg);

				ROS_INFO_STREAM("DRONEX_MOTORS_OFF..." << request.ownCrazyflie.z - request.otherCrazyflies[0].z);
				return true;
			}*/
			/*
			}else{
				//if(dronexSetpoint.z>=request.otherCrazyflies[0].z){
					float down_per_cycle = 0.003;
					if(dronexSetpoint.z < request.otherCrazyflies[0].z+0.5){
						down_per_cycle = 0.0005;
					}

					dronexSetpoint.z -= down_per_cycle;
				ROS_INFO_STREAM("DRONEX_L: z" << dronexSetpoint.z);
				//}else{

				//}
			}*/



			}
			break;

		case DRONEX_STATE_TAKING_OFF:
			{
			ROS_INFO_STREAM("DRONEX_STATE_TAKING_OFF");

			if(!savedStartCoordinates)
			{
				startCoordinateY = request.ownCrazyflie.x; // Nöd sicher öbs das brucht. Idee: Afangscoordinate abspeichere zum in Hover state z ende.
				startCoordinateX = request.ownCrazyflie.y;
				startCoordinateZ = request.ownCrazyflie.z;

				

				savedStartCoordinates = true;
				//setpointCallback(dronexSetpoint);
				}
			}

			dronexSetpoint.x = startCoordinateX;
				dronexSetpoint.y = startCoordinateY;
				dronexSetpoint.z = startCoordinateZ + 0.6;
				

			if((request.ownCrazyflie.z > startCoordinateZ + 0.6 - eps_height) || (request.ownCrazyflie.z < startCoordinateZ + 0.6 + eps_height)){
				tookOffFlag == true;
				// -> flyingState: Hover
			}

			break;
			
		} // END switch case

		
	

	if (flightSequence == 1){
			flying_state = DRONEX_TAKE_OFF;
			//ROS_INFO_STREAM("Flight sequence: Landing on mothership");
			if(tookOffFlag){
				flying_state = DRONEX_STATE_APPROACH;

				if(approachedFlag){
					flying_state = DRONEX_LAND;
				}

			}

	}

	setpointCallback(dronexSetpoint);

	/*dronexSetpoint.x = request.otherCrazyflies[0].x;
	dronexSetpoint.y = request.otherCrazyflies[0].y;
	dronexSetpoint.z = request.otherCrazyflies[0].z + 0.3*/

	//setpointCallback(dronexSetpoint);
	// CALL THE FUNCTION FOR PER CYLCE OPERATIONS

		perControlCycleOperations();

	// THIS IS THE START OF THE "OUTER" CONTROL LOOP
	// > i.e., this is the control loop run on this laptop
	// > this function is called at the frequency specified
	// > this function performs all estimation and control


	// PERFORM THE ESTIMATOR UPDATE FOR THE INTERIAL FRAME STATE
	// > After this function is complete the class variable
	//   "current_stateInertialEstimate" is updated and ready
	//   to be used for subsequent controller copmutations
	performEstimatorUpdate_forStateInterial(request);


	// CONVERT THE CURRENT INERTIAL FRAME STATE ESTIMATE, INTO
	// THE BODY FRAME ERROR REQUIRED BY THE CONTROLLER
	// > Define a local array to fill in with the body frame error
	float current_bodyFrameError[12];
	// > Call the function to perform the conversion
	convert_stateInertial_to_bodyFrameError(current_stateInertialEstimate,m_setpoint_for_controller,current_bodyFrameError);



	// CARRY OUT THE CONTROLLER COMPUTATIONS
	// Call the function that performs the control computations for this mode

	if((flying_state == DRONEX_STATE_LAND_ON_GROUND && (request.ownCrazyflie.z < 0.1 + request.otherCrazyflies[0].z)) || flying_state == DRONEX_STATE_GROUND){

		motorsOFF(response);

	}else{

		calculateControlOutput_viaLQRforRates(current_bodyFrameError,request,response);

	}


	// PUBLISH THE CURRENT X,Y,Z, AND YAW (if required)
	if (shouldPublishCurrent_xyz_yaw)
	{
		publish_current_xyz_yaw(request.ownCrazyflie.x,request.ownCrazyflie.y,request.ownCrazyflie.z,request.ownCrazyflie.yaw);
	}

	// PUBLISH THE DEBUG MESSAGE (if required)
	if (shouldPublishDebugMessage)
	{
		construct_and_publish_debug_message(request,response);
	}

	// RETURN "true" TO INDICATE THAT THE COMPUTATIONS WERE SUCCESSFUL
	return true;
}

// Set motors Output to 0
void motorsOFF(Controller::Response &response){
	response.controlOutput.motorCmd1 = 0;
	response.controlOutput.motorCmd2 = 0;
	response.controlOutput.motorCmd3 = 0;
	response.controlOutput.motorCmd4 = 0;

	// Specify that this controller is a rate controller
	// response.controlOutput.onboardControllerType = CF_COMMAND_TYPE_MOTOR;
	response.controlOutput.onboardControllerType = CF_COMMAND_TYPE_RATE;
	// response.controlOutput.onboardControllerType = CF_COMMAND_TYPE_ANGLE;
}



//    ------------------------------------------------------------------------------
//    EEEEE   SSSS  TTTTT  III  M   M    A    TTTTT  III   OOO   N   N
//    E      S        T     I   MM MM   A A     T     I   O   O  NN  N
//    EEE     SSS     T     I   M M M  A   A    T     I   O   O  N N N
//    E          S    T     I   M   M  AAAAA    T     I   O   O  N  NN
//    EEEEE  SSSS     T    III  M   M  A   A    T    III   OOO   N   N
//    ------------------------------------------------------------------------------
void performEstimatorUpdate_forStateInterial(Controller::Request &request)
{

	// PUT THE CURRENT MEASURED DATA INTO THE CLASS VARIABLE
	// > for (x,y,z) position
	current_xzy_rpy_measurement[0] = request.ownCrazyflie.x;
	current_xzy_rpy_measurement[1] = request.ownCrazyflie.y;
	current_xzy_rpy_measurement[2] = request.ownCrazyflie.z;
	// > for (roll,pitch,yaw) angles
	current_xzy_rpy_measurement[3] = request.ownCrazyflie.roll;
	current_xzy_rpy_measurement[4] = request.ownCrazyflie.pitch;
	current_xzy_rpy_measurement[5] = request.ownCrazyflie.yaw;


	// RUN THE FINITE DIFFERENCE ESTIMATOR
	performEstimatorUpdate_forStateInterial_viaFiniteDifference();


	// RUN THE POINT MASS KALMAN FILTER ESTIMATOR
	performEstimatorUpdate_forStateInterial_viaPointMassKalmanFilter();


	// FILLE IN THE STATE INERTIAL ESTIMATE TO BE USED FOR CONTROL
	switch (estimator_method)
	{
		// Estimator based on finte differences
		case ESTIMATOR_METHOD_FINITE_DIFFERENCE:
		{
			// Transfer the estimate
			for(int i = 0; i < 12; ++i)
			{
				current_stateInertialEstimate[i]  = stateInterialEstimate_viaFiniteDifference[i];
			}
			break;
		}
		// Estimator based on Point Mass Kalman Filter
		case ESTIMATOR_METHOD_POINT_MASS_PER_DIMENSION:
		{
			// Transfer the estimate
			for(int i = 0; i < 12; ++i)
			{
				current_stateInertialEstimate[i]  = stateInterialEstimate_viaPointMassKalmanFilter[i];
			}
			break;
		}
		// Handle the exception
		default:
		{
			// Display that the "estimator_method" was not recognised
			ROS_INFO_STREAM("[DRONEX CONTROLLER] ERROR: in the 'calculateControlOutput' function of the 'DroneXControllerService': the 'estimator_method' is not recognised.");
			// Transfer the finite difference estimate by default
			for(int i = 0; i < 12; ++i)
			{
				current_stateInertialEstimate[i]  = stateInterialEstimate_viaFiniteDifference[i];
			}
			break;
		}
	}


	// NOW THAT THE ESTIMATORS HAVE ALL BEEN RUN, PUT THE CURRENT
	// MEASURED DATA INTO THE CLASS VARIABLE FOR THE PREVIOUS
	// > for (x,y,z) position
	previous_xzy_rpy_measurement[0] = current_xzy_rpy_measurement[0];
	previous_xzy_rpy_measurement[1] = current_xzy_rpy_measurement[1];
	previous_xzy_rpy_measurement[2] = current_xzy_rpy_measurement[2];
	// > for (roll,pitch,yaw) angles
	previous_xzy_rpy_measurement[3] = current_xzy_rpy_measurement[3];
	previous_xzy_rpy_measurement[4] = current_xzy_rpy_measurement[4];
	previous_xzy_rpy_measurement[5] = current_xzy_rpy_measurement[5];
}



void performEstimatorUpdate_forStateInterial_viaFiniteDifference()
{
	// PUT IN THE CURRENT MEASUREMENT DIRECTLY
	// > for (x,y,z) position
	stateInterialEstimate_viaFiniteDifference[0]  = current_xzy_rpy_measurement[0];
	stateInterialEstimate_viaFiniteDifference[1]  = current_xzy_rpy_measurement[1];
	stateInterialEstimate_viaFiniteDifference[2]  = current_xzy_rpy_measurement[2];
	// > for (roll,pitch,yaw) angles
	stateInterialEstimate_viaFiniteDifference[6]  = current_xzy_rpy_measurement[3];
	stateInterialEstimate_viaFiniteDifference[7]  = current_xzy_rpy_measurement[4];
	stateInterialEstimate_viaFiniteDifference[8]  = current_xzy_rpy_measurement[5];

	// COMPUTE THE VELOCITIES VIA FINITE DIFFERENCE
	// > for (x,y,z) velocities
	stateInterialEstimate_viaFiniteDifference[3]  = (current_xzy_rpy_measurement[0] - previous_xzy_rpy_measurement[0]) * estimator_frequency;
	stateInterialEstimate_viaFiniteDifference[4]  = (current_xzy_rpy_measurement[1] - previous_xzy_rpy_measurement[1]) * estimator_frequency;
	stateInterialEstimate_viaFiniteDifference[5]  = (current_xzy_rpy_measurement[2] - previous_xzy_rpy_measurement[2]) * estimator_frequency;
	// > for (roll,pitch,yaw) velocities
	stateInterialEstimate_viaFiniteDifference[9]  = (current_xzy_rpy_measurement[3] - previous_xzy_rpy_measurement[3]) * estimator_frequency;
	stateInterialEstimate_viaFiniteDifference[10] = (current_xzy_rpy_measurement[4] - previous_xzy_rpy_measurement[4]) * estimator_frequency;
	stateInterialEstimate_viaFiniteDifference[11] = (current_xzy_rpy_measurement[5] - previous_xzy_rpy_measurement[5]) * estimator_frequency;
}



void performEstimatorUpdate_forStateInterial_viaPointMassKalmanFilter()
{
	// PERFORM THE KALMAN FILTER UPDATE STEP
	// > First take a copy of the estimator state
	float temp_PMKFstate[12];
	for(int i = 0; i < 12; ++i)
	{
		temp_PMKFstate[i]  = stateInterialEstimate_viaPointMassKalmanFilter[i];
	}
	// > Now perform update for:
	// > x position and velocity:
	stateInterialEstimate_viaPointMassKalmanFilter[0] = PMKF_Ahat_row1_for_positions[0]*temp_PMKFstate[0] + PMKF_Ahat_row1_for_positions[1]*temp_PMKFstate[3] + PMKF_Kinf_for_positions[0]*current_xzy_rpy_measurement[0];
	stateInterialEstimate_viaPointMassKalmanFilter[3] = PMKF_Ahat_row2_for_positions[0]*temp_PMKFstate[0] + PMKF_Ahat_row2_for_positions[1]*temp_PMKFstate[3] + PMKF_Kinf_for_positions[1]*current_xzy_rpy_measurement[0];
	// > y position and velocity:
	stateInterialEstimate_viaPointMassKalmanFilter[1] = PMKF_Ahat_row1_for_positions[0]*temp_PMKFstate[1] + PMKF_Ahat_row1_for_positions[1]*temp_PMKFstate[4] + PMKF_Kinf_for_positions[0]*current_xzy_rpy_measurement[1];
	stateInterialEstimate_viaPointMassKalmanFilter[4] = PMKF_Ahat_row2_for_positions[0]*temp_PMKFstate[1] + PMKF_Ahat_row2_for_positions[1]*temp_PMKFstate[4] + PMKF_Kinf_for_positions[1]*current_xzy_rpy_measurement[1];
	// > z position and velocity:
	stateInterialEstimate_viaPointMassKalmanFilter[2] = PMKF_Ahat_row1_for_positions[0]*temp_PMKFstate[2] + PMKF_Ahat_row1_for_positions[1]*temp_PMKFstate[5] + PMKF_Kinf_for_positions[0]*current_xzy_rpy_measurement[2];
	stateInterialEstimate_viaPointMassKalmanFilter[5] = PMKF_Ahat_row2_for_positions[0]*temp_PMKFstate[2] + PMKF_Ahat_row2_for_positions[1]*temp_PMKFstate[5] + PMKF_Kinf_for_positions[1]*current_xzy_rpy_measurement[2];

	// > roll  position and velocity:
	stateInterialEstimate_viaPointMassKalmanFilter[6]  = PMKF_Ahat_row1_for_angles[0]*temp_PMKFstate[6] + PMKF_Ahat_row1_for_angles[1]*temp_PMKFstate[9]  + PMKF_Kinf_for_angles[0]*current_xzy_rpy_measurement[3];
	stateInterialEstimate_viaPointMassKalmanFilter[9]  = PMKF_Ahat_row2_for_angles[0]*temp_PMKFstate[6] + PMKF_Ahat_row2_for_angles[1]*temp_PMKFstate[9]  + PMKF_Kinf_for_angles[1]*current_xzy_rpy_measurement[3];
	// > pitch position and velocity:
	stateInterialEstimate_viaPointMassKalmanFilter[7]  = PMKF_Ahat_row1_for_angles[0]*temp_PMKFstate[7] + PMKF_Ahat_row1_for_angles[1]*temp_PMKFstate[10] + PMKF_Kinf_for_angles[0]*current_xzy_rpy_measurement[4];
	stateInterialEstimate_viaPointMassKalmanFilter[10] = PMKF_Ahat_row2_for_angles[0]*temp_PMKFstate[7] + PMKF_Ahat_row2_for_angles[1]*temp_PMKFstate[10] + PMKF_Kinf_for_angles[1]*current_xzy_rpy_measurement[4];
	// > yaw   position and velocity:
	stateInterialEstimate_viaPointMassKalmanFilter[8]  = PMKF_Ahat_row1_for_angles[0]*temp_PMKFstate[8] + PMKF_Ahat_row1_for_angles[1]*temp_PMKFstate[11] + PMKF_Kinf_for_angles[0]*current_xzy_rpy_measurement[5];
	stateInterialEstimate_viaPointMassKalmanFilter[11] = PMKF_Ahat_row2_for_angles[0]*temp_PMKFstate[8] + PMKF_Ahat_row2_for_angles[1]*temp_PMKFstate[11] + PMKF_Kinf_for_angles[1]*current_xzy_rpy_measurement[5];
}





//    ----------------------------------------------------------------------------------
//    L       QQQ   RRRR
//    L      Q   Q  R   R
//    L      Q   Q  RRRR
//    L      Q  Q   R  R
//    LLLLL   QQ Q  R   R
//    ----------------------------------------------------------------------------------

void calculateControlOutput_viaLQRforRates(float stateErrorBody[12], Controller::Request &request, Controller::Response &response)
{
	// PERFORM THE "u=Kx" LQR CONTROLLER COMPUTATION

	// Instantiate the local variables for the following:
	// > body frame roll rate,
	// > body frame pitch rate,
	// > body frame yaw rate,
	// > total thrust adjustment.
	// These will be requested from the Crazyflie's on-baord "inner-loop" controller
	float rollRate_forResponse = 0;
	float pitchRate_forResponse = 0;
	float yawRate_forResponse = 0;
	float thrustAdjustment = 0;


	//integrator for x,y,z
	if(integratorFlag == DRONEX_INTEGRATOR_ON)
	{
		ROS_INFO_STREAM("DRONEX_INTEGRATOR_ON");
		for(int i=0; i < 3; i++)
		{
			integrator_var[i] += stateErrorBody[i]*(1.0/control_frequency);
		}
	}

	if(integratorFlag == DRONEX_INTEGRATOR_RESET)
	{
		for(int i=0; i < 3; i++)
		{
			integrator_var[i] = 0;
		}
	}

	for(int i=0; i < 3; i++)
	{
		stateErrorBody[i] += integrator_var[i] * gainIntegrator[i];
	}

	// Perform the "-Kx" LQR computation for the rates and thrust:
	for(int i = 0; i < 9; ++i)
	{
		// BODY FRAME Y CONTROLLER
		rollRate_forResponse  -= gainMatrixRollRate[i] * stateErrorBody[i];
		// BODY FRAME X CONTROLLER
		pitchRate_forResponse -= gainMatrixPitchRate[i] * stateErrorBody[i];
		// BODY FRAME YAW CONTROLLER
		yawRate_forResponse   -= gainMatrixYawRate[i] * stateErrorBody[i];
		// > ALITUDE CONTROLLER (i.e., z-controller):
		thrustAdjustment      -= gainMatrixThrust_NineStateVector[i] * stateErrorBody[i];
	}


	// UPDATE THE "RETURN" THE VARIABLE NAMED "response"

	// Put the computed rates and thrust into the "response" variable
	// > For roll, pitch, and yaw:
	response.controlOutput.roll  = rollRate_forResponse;
	response.controlOutput.pitch = pitchRate_forResponse;
	response.controlOutput.yaw   = yawRate_forResponse;
	// > For the thrust adjustment we must add the feed-forward thrust to counter-act gravity.
	// > NOTE: remember that the thrust is commanded per motor, so you sohuld
	//         consider whether the "thrustAdjustment" computed by your
	//         controller needed to be divided by 4 or not.
	thrustAdjustment = thrustAdjustment / 4.0;
	// > Compute the feed-forward force
	float feed_forward_thrust_per_motor = m_mass_total_grams * 9.81/(1000*4);
	// > Put in the per motor commands
	response.controlOutput.motorCmd1 = computeMotorPolyBackward(thrustAdjustment + feed_forward_thrust_per_motor);
	response.controlOutput.motorCmd2 = computeMotorPolyBackward(thrustAdjustment + feed_forward_thrust_per_motor);
	response.controlOutput.motorCmd3 = computeMotorPolyBackward(thrustAdjustment + feed_forward_thrust_per_motor);
	response.controlOutput.motorCmd4 = computeMotorPolyBackward(thrustAdjustment + feed_forward_thrust_per_motor);


	// Specify that this controller is a rate controller
	// response.controlOutput.onboardControllerType = CF_COMMAND_TYPE_MOTOR;
	response.controlOutput.onboardControllerType = CF_COMMAND_TYPE_RATE;
	// response.controlOutput.onboardControllerType = CF_COMMAND_TYPE_ANGLE;


	// An alternate debugging technique is to print out data directly to the
	// command line from which this node was launched.
	if (shouldDisplayDebugInfo)
	{
		// An example of "printing out" the data from the "request" argument to the
		// command line. This might be useful for debugging.
		ROS_INFO_STREAM("x-coordinate [m]: " << request.ownCrazyflie.x);
		ROS_INFO_STREAM("y-coordinate [m]: " << request.ownCrazyflie.y);
		ROS_INFO_STREAM("z-coordinate [m]: " << request.ownCrazyflie.z);
		ROS_INFO_STREAM("roll       [deg]: " << request.ownCrazyflie.roll);
		ROS_INFO_STREAM("pitch      [deg]: " << request.ownCrazyflie.pitch);
		ROS_INFO_STREAM("yaw        [deg]: " << request.ownCrazyflie.yaw);
		ROS_INFO_STREAM("Delta t      [s]: " << request.ownCrazyflie.acquiringTime);

		// An example of "printing out" the control actions computed.
		ROS_INFO_STREAM("thrustAdjustment = " << thrustAdjustment);
		ROS_INFO_STREAM("controlOutput.roll = " << response.controlOutput.roll);
		ROS_INFO_STREAM("controlOutput.pitch = " << response.controlOutput.pitch);
		ROS_INFO_STREAM("controlOutput.yaw = " << response.controlOutput.yaw);

		// An example of "printing out" the "thrust-to-command" conversion parameters.
		ROS_INFO_STREAM("motorPoly 0:" << motorPoly[0]);
		ROS_INFO_STREAM("motorPoly 0:" << motorPoly[1]);
		ROS_INFO_STREAM("motorPoly 0:" << motorPoly[2]);

		// An example of "printing out" the per motor 16-bit command computed.
		ROS_INFO_STREAM("controlOutput.cmd1 = " << response.controlOutput.motorCmd1);
		ROS_INFO_STREAM("controlOutput.cmd3 = " << response.controlOutput.motorCmd2);
		ROS_INFO_STREAM("controlOutput.cmd2 = " << response.controlOutput.motorCmd3);
		ROS_INFO_STREAM("controlOutput.cmd4 = " << response.controlOutput.motorCmd4);
	}
}



//  ***********************************************************
//  DDDD   EEEEE  BBBB   U   U   GGGG       M   M   SSSS   GGGG
//  D   D  E      B   B  U   U  G           MM MM  S      G
//  D   D  EEE    BBBB   U   U  G           M M M   SSS   G
//  D   D  E      B   B  U   U  G   G       M   M      S  G   G
//  DDDD   EEEEE  BBBB    UUU    GGGG       M   M  SSSS    GGGG

void construct_and_publish_debug_message(Controller::Request &request, Controller::Response &response)
{

    // DEBUGGING CODE:
    // As part of the D-FaLL-System we have defined a message type names"DebugMsg".
    // By fill this message with data and publishing it you can display the data in
    // real time using rpt plots. Instructions for using rqt plots can be found on
    // the wiki of the D-FaLL-System repository

	// Instantiate a local variable of type "DebugMsg", see the file "DebugMsg.msg"
	// (located in the "msg" folder) to see the full structure of this message.
	DebugMsg debugMsg;

	// Fill the debugging message with the data provided by Vicon
	debugMsg.vicon_x      = request.ownCrazyflie.x;
	debugMsg.vicon_y      = request.ownCrazyflie.y;
	debugMsg.vicon_z      = request.ownCrazyflie.z;
	debugMsg.vicon_roll   = request.ownCrazyflie.roll;
	debugMsg.vicon_pitch  = request.ownCrazyflie.pitch;
	debugMsg.vicon_yaw    = request.ownCrazyflie.yaw;

	// Fill in the debugging message with any other data you would like to display
	// in real time. For example, it might be useful to display the thrust
	// adjustment computed by the z-altitude controller.
	// The "DebugMsg" type has 10 properties from "value_1" to "value_10", all of
	// type "float64" that you can fill in with data you would like to plot in
	// real-time.
	// debugMsg.value_1 = thrustAdjustment;
	// ......................
	// debugMsg.value_10 = your_variable_name;

	// Publish the "debugMsg"
	debugPublisher.publish(debugMsg);
}


//    ------------------------------------------------------------------------------
//    RRRR    OOO   TTTTT    A    TTTTT  EEEEE       III  N   N  TTTTT   OOO
//    R   R  O   O    T     A A     T    E            I   NN  N    T    O   O
//    RRRR   O   O    T    A   A    T    EEE          I   N N N    T    O   O
//    R  R   O   O    T    AAAAA    T    E            I   N  NN    T    O   O
//    R   R   OOO     T    A   A    T    EEEEE       III  N   N    T     OOO
//
//    BBBB    OOO   DDDD   Y   Y       FFFFF  RRRR     A    M   M  EEEEE
//    B   B  O   O  D   D   Y Y        F      R   R   A A   MM MM  E
//    BBBB   O   O  D   D    Y         FFF    RRRR   A   A  M M M  EEE
//    B   B  O   O  D   D    Y         F      R  R   AAAAA  M   M  E
//    BBBB    OOO   DDDD     Y         F      R   R  A   A  M   M  EEEEE
//    ------------------------------------------------------------------------------

void convertIntoBodyFrame(float stateInertial[12], float (&stateBody)[12], float yaw_measured)
{
	if (shouldPerformConvertIntoBodyFrame)
	{
		float sinYaw = sin(yaw_measured);
    	float cosYaw = cos(yaw_measured);

    	// Fill in the (x,y,z) position estimates to be returned
	    stateBody[0] = stateInertial[0] * cosYaw  +  stateInertial[1] * sinYaw;
	    stateBody[1] = stateInertial[1] * cosYaw  -  stateInertial[0] * sinYaw;
	    stateBody[2] = stateInertial[2];

	    // Fill in the (x,y,z) velocity estimates to be returned
	    stateBody[3] = stateInertial[3] * cosYaw  +  stateInertial[4] * sinYaw;
	    stateBody[4] = stateInertial[4] * cosYaw  -  stateInertial[3] * sinYaw;
	    stateBody[5] = stateInertial[5];

	    // Fill in the (roll,pitch,yaw) estimates to be returned
	    stateBody[6] = stateInertial[6];
	    stateBody[7] = stateInertial[7];
	    stateBody[8] = stateInertial[8];

	    // Fill in the (roll,pitch,yaw) velocity estimates to be returned
	    stateBody[9]  = stateInertial[9];
	    stateBody[10] = stateInertial[10];
	    stateBody[11] = stateInertial[11];
	}
	else
	{
	    // Fill in the (x,y,z) position estimates to be returned
	    stateBody[0] = stateInertial[0];
	    stateBody[1] = stateInertial[1];
	    stateBody[2] = stateInertial[2];

	    // Fill in the (x,y,z) velocity estimates to be returned
	    stateBody[3] = stateInertial[3];
	    stateBody[4] = stateInertial[4];
	    stateBody[5] = stateInertial[5];

	    // Fill in the (roll,pitch,yaw) estimates to be returned
	    stateBody[6] = stateInertial[6];
	    stateBody[7] = stateInertial[7];
	    stateBody[8] = stateInertial[8];

	    // Fill in the (roll,pitch,yaw) velocity estimates to be returned
	    stateBody[9]  = stateInertial[9];
	    stateBody[10] = stateInertial[10];
	    stateBody[11] = stateInertial[11];
	}
}




void convert_stateInertial_to_bodyFrameError(float stateInertial[12], float setpoint[4], float (&bodyFrameError)[12])
{
	// Store the current YAW in a local variable
	float temp_stateInertial_yaw = stateInertial[8];

	// Adjust the INERTIAL (x,y,z) position for the setpoint
	stateInertial[0] = stateInertial[0] - setpoint[0] - m_xAdjustment;
	stateInertial[1] = stateInertial[1] - setpoint[1] - m_yAdjustment;
	stateInertial[2] = stateInertial[2] - setpoint[2];

	if (stateInertial[2] > 30.0f)
	{
		stateInertial[2] = 30.0f;
	}
	else if (stateInertial[2] < -30.0f)
	{
		stateInertial[2] = 30.0f;
	}

	// Fill in the yaw angle error
	// > This error should be "unwrapped" to be in the range
	//   ( -pi , pi )
	// > First, get the yaw error into a local variable
	float yawError = stateInertial[8] - setpoint[3];
	// > Second, "unwrap" the yaw error to the interval ( -pi , pi )
	while(yawError > PI) {yawError -= 2 * PI;}
	while(yawError < -PI) {yawError += 2 * PI;}
	// > Third, put the "yawError" into the "stateError" variable
	stateInertial[8] = yawError;


	if (yawError>(PI/6))
	{
		yawError = (PI/6);
	}
	else if (yawError<(-PI/6))
	{
		yawError = (-PI/6);
	}

	// CONVERSION INTO BODY FRAME
	// Conver the state erorr from the Inertial frame into the Body frame
	// > Note: the function "convertIntoBodyFrame" is implemented in this file
	//   and by default does not perform any conversion. The equations to convert
	//   the state error into the body frame should be implemented in that function
	//   for successful completion of the PPS exercise
	convertIntoBodyFrame(stateInertial, bodyFrameError, temp_stateInertial_yaw);
}




//    ------------------------------------------------------------------------------
//    N   N  EEEEE  W     W   TTTTT   OOO   N   N        CCCC  M   M  DDDD
//    NN  N  E      W     W     T    O   O  NN  N       C      MM MM  D   D
//    N N N  EEE    W     W     T    O   O  N N N  -->  C      M M M  D   D
//    N  NN  E       W W W      T    O   O  N  NN       C      M   M  D   D
//    N   N  EEEEE    W W       T     OOO   N   N        CCCC  M   M  DDDD
//
//     CCCC   OOO   N   N  V   V  EEEEE  RRRR    SSSS  III   OOO   N   N
//    C      O   O  NN  N  V   V  E      R   R  S       I   O   O  NN  N
//    C      O   O  N N N  V   V  EEE    RRRR    SSS    I   O   O  N N N
//    C      O   O  N  NN   V V   E      R  R       S   I   O   O  N  NN
//     CCCC   OOO   N   N    V    EEEEE  R   R  SSSS   III   OOO   N   N
//    ------------------------------------------------------------------------------

// This function DOES NOT NEED TO BE edited for successful completion of the PPS exercise
float computeMotorPolyBackward(float thrust)
{
	// Compute the 16-bit command signal that generates the "thrust" force
	float cmd = (-motorPoly[1] + sqrt(motorPoly[1] * motorPoly[1] - 4 * motorPoly[2] * (motorPoly[0] - thrust))) / (2 * motorPoly[2]);

	// Saturate the signal to be 0 or in the range [1000,65000]
	if (cmd < cmd_sixteenbit_min)
	{
		cmd = 0;
	}
	else if (cmd > cmd_sixteenbit_max)
	{
		cmd = cmd_sixteenbit_max;
	}

    return cmd;
}




//    ----------------------------------------------------------------------------------
//    N   N  EEEEE  W     W        SSSS  EEEEE  TTTTT  PPPP    OOO   III  N   N  TTTTT