TreppenRobo
first commit
Dependencies: PM2_Libary
Revision 43:057640e99f8e, committed 2022-05-22
- Comitter:
- lupomic
- Date:
- Sun May 22 10:10:17 2022 +0200
- Parent:
- 35:96ed18b1af94
- Parent:
- 42:ec3a88a24666
- Commit message:
- merge
Changed in this revision
--- a/main.cpp Wed Apr 13 07:11:14 2022 +0000
+++ b/main.cpp Sun May 22 10:10:17 2022 +0200
@@ -1,11 +1,21 @@
#include "mbed.h"
#include "PM2_Libary.h"
#include <cstdint>
-
-
+#include <cstdio>
+#include "math.h"
+//*******************************************************************************************************************************************************************
+// Defined Variables in mm coming from Hardware-team. Need to be updated
+const float wheel_diameter = 30.0f; // diameter of wheel with caterpillar to calculate mm per wheel turn (4)
+const float arm_length = 118.5; // lenght of arm from pivotpoint to pivotpoint (3)
+const float dist_arm_attach_distsensor = 20; // distance between pivot point arm on body to start distancesensor on top in horizontal (6)
+const float dist_distsensors = 200; // distance between the two distancesensors on top of Wall-E (9)
+const float dist_arm_ground = 51; // distance between pivotpoint arm and ground (5)
+const float dist_arm_attach_OK_griparea = 10.5 ; // Height of Grappler cutout to grapple Stair (8) (maybe add 1mm so gripper is a bit over the plate)
+const float dist_grappleratt_grappler_uk = 36.5; // distance between pivotpoint Grappler and bottom edge (?)
-// logical variable main task
-bool do_execute_main_task = false; // this variable will be toggled via the user button (blue button) to or not to execute the main task
+const float height_stairs = 100; // height to top of next stairstep in mm
+//***********************************************************************************************************************************************************
+// declaration of Input - Output pins
// user button on nucleo board
Timer user_button_timer; // create Timer object which we use to check if user button was pressed for a certain time (robust against signal bouncing)
@@ -13,37 +23,47 @@
void user_button_pressed_fcn(); // custom functions which gets executed when user button gets pressed and released, definition below
void user_button_released_fcn();
-// while loop gets executed every main_task_period_ms milliseconds
-int main_task_period_ms = 30; // define main task period time in ms e.g. 50 ms -> main task runns 20 times per second
-Timer main_task_timer; // create Timer object which we use to run the main task every main task period time in ms
+// Sharp GP2Y0A41SK0F, 4-40 cm IR Sensor
+// define variable to store measurement from infrared distancesensor in mm
+float ir_distance_mm_L;
+float ir_distance_mm_R;
+float ir_distance_mm_Lookdown_B;
+float ir_distance_mm_Lookdown_F;
-// Sharp GP2Y0A41SK0F, 4-40 cm IR Sensor
-float ir_distance_mV = 0.0f; // define variable to store measurement
-AnalogIn ir_analog_in(PC_2); // create AnalogIn object to read in infrared distance sensor, 0...3.3V are mapped to 0...1
+// create AnalogIn object to read in infrared distance sensor, 0...3.3V are mapped to 0...1
+AnalogIn ir_analog_in_Distance_L(PC_2);
+AnalogIn ir_analog_in_Lookdown_B(PC_5);
+AnalogIn ir_analog_in_Lookdown_F(PB_1);
+
+// Digital Inputs
+DigitalIn mechanical_button(PC_3);
-
-// 78:1, 100:1, ... Metal Gearmotor 20Dx44L mm 12V CB
DigitalOut enable_motors(PB_15); // create DigitalOut object to enable dc motors
float pwm_period_s = 0.00005f; // define pwm period time in seconds and create FastPWM objects to command dc motors
+
//motor pin declaration
-FastPWM pwm_M_right(PB_13);
-FastPWM pwm_M_left(PA_9);
-FastPWM pwm_M_arm(PA_10);
+FastPWM pwm_M_right (PB_13); //motor pin decalaration for wheels right side
+FastPWM pwm_M_left (PA_9); //motor pin decalaration for wheels left side
+FastPWM pwm_M_arm (PA_10); //motor pin decalaration for arm
//Encoder pin declaration
-EncoderCounter encoder_M_right(PA_6, PC_7); //encoder pin decalaration for wheels right side
-EncoderCounter encoder_M_left(PB_6, PB_7); //encoder pin decalaration for wheels left side
-EncoderCounter encoder_M_arm(PA_0, PA_1); //encoder pin decalaration for arm
+EncoderCounter encoder_M_right (PA_6, PC_7); //encoder pin decalaration for wheels right side
+EncoderCounter encoder_M_left (PB_6, PB_7); //encoder pin decalaration for wheels left side
+EncoderCounter encoder_M_arm (PA_0, PA_1); //encoder pin decalaration for arm
+//***********************************************************************************************************************************************************
+// Hardware controll Setup and functions (motors and sensors)
+
+
// create SpeedController and PositionController objects, default parametrization is for 78.125:1 gear box
-float max_voltage = 12.0f; // define maximum voltage of battery packs, adjust this to 6.0f V if you only use one batterypack
-float counts_per_turn_wheels = 2000.0f * 100.0f; // define counts per turn at gearbox end (counts/turn * gearratio) for wheels
-float counts_per_turn_arm = 2000.0f * 100.0f; // define counts per turn at gearbox end (counts/turn * gearratio) for arm
-float kn = 180.0f / 12.0f; // define motor constant in rpm per V
-float k_gear = 100.0f / 78.125f; // define additional ratio in case you are using a dc motor with a different gear box, e.g. 100:1
-float kp = 0.1f; // define custom kp, this is the default speed controller gain for gear box 78.125:1
+const float max_voltage = 12.0f; // define maximum voltage of battery packs, adjust this to 6.0f V if you only use one batterypack
+const float counts_per_turn_wheels = 20.0f * 78.125f;// define counts per turn at gearbox end (counts/turn * gearratio) for wheels
+const float counts_per_turn_arm = 20.0f * 78.125f * 19.0f; // define counts per turn at gearbox end (counts/turn * gearratio) for arm
+const float kn = 180.0f / 12.0f; // define motor constant in rpm per V
+const float k_gear = 100.0f / 78.125f; // define additional ratio in case you are using a dc motor with a different gear box, e.g. 100:1 (DC with 100:1 has 2'000 turns for 360°)
+const float kp = 0.1f; // define custom kp, this is the default speed controller gain for gear box 78.125:1
//motors for tracks
PositionController positionController_M_right(counts_per_turn_wheels * k_gear, kn / k_gear, kp * k_gear, max_voltage, pwm_M_right, encoder_M_right); // parameters adjusted to 100:1 gear, we need a different speed controller gain here
@@ -51,153 +71,378 @@
//Arm Motor
PositionController positionController_M_Arm(counts_per_turn_arm * k_gear, kn / k_gear, kp * k_gear, max_voltage, pwm_M_arm, encoder_M_arm); // parameters adjusted to 100:1 gear, we need a different speed controller gain here
-//float max_speed_rps = 0.5f; not sure if needed // define maximum speed that the position controller is changig the speed, has to be smaller or equal to kn * max_voltage
// PositionController positionController_M3(counts_per_turn, kn, max_voltage, pwm_M3, encoder_M3); // default 78.125:1 gear with default contoller parameters
//PositionController positionController_M3(counts_per_turn * k_gear, kn / k_gear, kp * k_gear, max_voltage, pwm_M3, encoder_M3); // parameters adjusted to 100:1 gear, we need a different speed controller gain here
+//***********************************************************************************************************************************************************
-// LSM9DS1 IMU, carefull: not all PES boards have an imu (chip shortage)
-// LSM9DS1 imu(PC_9, PA_8); // create LSM9DS1 comunication object, if you want to be able to use the imu you need to #include "LSM9DS1_i2c.h"
+//these variables represent relative position NOT absolut
+float startPos = -0.545; //from last lift up position to start position
+float liftPos = -0.555; //from start position to lift up position
-//Platzhalter Variabeln für die Positionierung
-float PositionStair = 0.2;
-float PositionBackOff = -0.5;
-float degArmStart = 0.5;
-float degArmLift = -0.5;
-int ToNextFunction = 0;
-float max_speed_rps = 0.5f;
+const float drive_straight_mm = 200.0;
+const float drive_back_mm = -20.0f;
+int ToNextFunction = 0; // current state of the system (which function is beeing executed)
+int state=0; //return value of functions
+float desired_pos;
+int nextStep=0;
+
+// definition variables for calculations
+const float pi = 2 * acos(0.0); // definiton of pi
+const float end_pos_lift_deg = 180 + asin((dist_arm_ground-(dist_grappleratt_grappler_uk))/arm_length) * 180 / pi; // calculates the degree which the arm has to have when lift_up has been executed.
+const float start_deg_arm = -asin((dist_arm_ground - dist_grappleratt_grappler_uk) / arm_length) * 180.0/pi ; //calculates the starting degree of the arm (gripper has to touch ground in frotn of Wall-E)
-int StartPosition(float deg){
+// definition of rotation speeds for motors 0 = none 1.0 = max.
+const float max_speed_rps_wheel = 0.8f; // define maximum speed that the position controller is changig the speed for the wheels, has to be smaller or equal to kn * max_voltage
+const float max_speed_rps_arm = 0.9f; // define maximum speed that the position controller is changig the speed for the arm, has to be smaller or equal to kn * max_voltage
- positionController_M_Arm.setDesiredRotation(deg);
-
- return NULL;
+// calculates the deg which the arm has to take to reach a certain height (the input height has to be the height of OK Gripper area)
+// PARAM: height_mm = height which OK Gripperarea has to reach.
+// RETURN: deg_arm = absolut Position in deg that the arm has to take.
+float calc_arm_deg_for_height(int height_mm)
+{
+ float height_arm = height_mm - (dist_arm_ground - dist_arm_attach_OK_griparea); // calculates the height which only the arm has to cover (- attachement height (arm to robot) etc.)
+ float deg_arm = asin(height_arm / arm_length) * 180.0/pi; // calculates the absolute degrees which the arm has to reach
+ return deg_arm;
}
-//Drives forward into the next step
-int Drive(float dist){
-float distance;
-
-distance=dist;
+//calculates the deg which the wheels have to turn in order to cover specified distance in mm
+//PARAM: distance = distance to drive in milimeter
+//RETURN: deg_wheel = degree which the motor has to turn in order to cover distance(mm)
+float wheel_dist_to_deg(float distance)
+{
+ float deg_wheel = (distance) / (wheel_diameter * pi) ;
+ return deg_wheel;
+}
- positionController_M_right.setDesiredRotation(distance,max_speed_rps);
- positionController_M_left.setDesiredRotation(distance,max_speed_rps);
+// increments the Motor for defined degree from the current one
+// PARAM: deg_to_turn = degree to turn the Motor
+// PARAM: current_rotation = the current rotation of the Motor (Motor.getRotation())
+// RETURN: new_turn_rotation = new Rotation value in rotations
+float turn_relative_deg(float deg_to_turn, float current_rotation)
+{
+ float new_turn_rotation = current_rotation + deg_to_turn;
+ return new_turn_rotation;
+}
+// sets the Motor to a specified degree in one rotation
+// PARAM: end_deg = new position of the arm in degree 0 <= value >=360
+// PARAM: current_rotation = the current rotation of the Motor (Motor.getRotation())
+// RETURN: new_partial_rotation = new deg value in rotations
+float turn_absolut_deg(float end_deg, float current_rotations)
+{
+ int full_rotations;
+ if(current_rotations > 0)
+ {
+ full_rotations = round(current_rotations - 0.5);
+ }
+ else if(current_rotations < 0)
+ {
+ full_rotations = round(current_rotations + 0.5);
+ }
+ else
+ {
+ full_rotations = 0;
+ }
+ float new_partial_rotation = full_rotations - start_deg_arm/360 + end_deg/360;
+ return new_partial_rotation;
+}
- return 0;
+//calculates position of arm when lift up has ended.
+//RETURN: end_deg = degree which the motor has to turn in order to reach end lift position.
+float calc_pos_end_lift()
+{
+ float end_deg;
+ end_deg = asin((dist_arm_ground-(dist_grappleratt_grappler_uk-dist_grappleratt_grappler_uk))/arm_length) + start_deg_arm;
+ end_deg = end_deg * 180 / pi;
+ return end_deg;
}
-//only turns the arm until the robot is on the next step
-//not yet clear if the motor controler function drives to a absolute poition or if it drives the given distance relative to the current position
-int LiftUp(float deg){
+//***********************************************************************************************************************************************************
+// important calculatet constant for Wall-E
+const double deg_up_from_horizon_to_stair = calc_arm_deg_for_height(height_stairs);
+
+// import functions from file mapping
+extern double powerx(double base, double pow2);
+extern double mapping (float adc_value_mV);
+
+//
+//simple check if there is an object in proximity
+//returns 0 if there is NO object present
+//returns 1 if there is an object present
+//returns 2 if the distance isn't in the expected range
- int8_t i = 0; //prov condition variable
-
- positionController_M_Arm.setDesiredRotation(deg);
-
-
- return 0;
+uint8_t nextStepDetection(double distanceCm,double setpointDistance){
+ double distance = distanceCm;
+ double setpoint = setpointDistance;
+ if(distance == 0){
+ return 10; //sensor value is outside the expected range
+ }
+ if((distance <= (setpoint + 2)) && (distance >= (setpoint - 2))){
+ return 3; //the distance to the next step is in ±1cm of the setpoint
+ }
+ if(distance < setpoint){
+ return 0; //the robot is to close to the step to rotate the arm unhindered
+ }
+ if(distance > setpoint){
+ return 1; //the robot is too far away from the next step
+ }
+ else{
+ return 2;
+ }
+
}
-//pow function is here so we dont have to use the math.h library
-//it takes 2 arguments the base can be any negative or positive floating point number the power has to be a hos to be an "integer" defined as a double
-double powerx(double base, double pow2){
- double result = -1;
- double power = pow2;
- double basis = base;
- result = 1;
- //handling negative exponents
- if(power<0){
- for(double i=1; i<=(power*(-1.0)); i++) {
- result *= basis;
- }
- result = 1.0/result;
+//simple check if there is an object in proximity
+//returns 0 if there is NO object present
+//returns 1 if there is an object present
+//returns 2 if the distance isn't in the expected range
+uint8_t StepDetection_down(float sensor)
+
+{
+ double d_valueMM = mapping(sensor*1.0e3f*3.3f);
+ if(d_valueMM >= 4) return 0;
+ else if( d_valueMM > 100 ) return 2;
+ else if((d_valueMM < 4)||(d_valueMM==0)) return 1;
+
+ else return 5;
+}
+
+// bring arm in starting position. Height of stairs.
+int set_arm_stair_height()
+
+{
+ float diff;
+ int gripper=nextStepDetection(ir_distance_mm_L, 2);
+
+ //first step to calculate desired position
+ if (desired_pos==0) {
+ desired_pos=turn_relative_deg(startPos, positionController_M_Arm.getRotation());
+ positionController_M_Arm.setDesiredRotation(desired_pos, 0.5); // command to turn motor to desired deg.
}
- //handling positive exponents
- else{
- for(double i=1; i<=power; i++){
- result *= basis;}}
+ // to check if the position controller is finished
+ diff =abs( desired_pos-(positionController_M_Arm.getRotation()));
- return result;
+ //prints for testing
+ printf("Set arm Position ARM (rot): %3.3f Desired:%3.3f State:%d ToNextfunction:%d Diff:%3.3f\n",
+ positionController_M_Arm.getRotation(), desired_pos, state, ToNextFunction, diff);
+
+ // stops the positioning, when the gripper is in proximity of the sensor
+ if (gripper==3){
+ desired_pos=turn_relative_deg(-0.01, positionController_M_Arm.getRotation() );
+ positionController_M_Arm.setDesiredRotation(desired_pos, 0.2);
}
-double mapping(float adc_value_mV){
- double distance = 0.0f; //distance in mm
- double infY =360 , supY = 2360; //Window for sensor values
- double voltage_mV = adc_value_mV;
- double p1 = -1.127*powerx(10,-14), p2 = 8.881*powerx(10,-11), p3 = -2.76*powerx(10,-7), p4 = 0.0004262, p5 = -0.3363, p6 = 120.1 ; //faktoren für polynomkurve -> von matlab exportiert
- if(voltage_mV > infY && voltage_mV < supY){
- distance = p1*powerx(voltage_mV,5) + p2*powerx(voltage_mV,4) + p3*powerx(voltage_mV,3) + p4*powerx(voltage_mV,2) + p5*voltage_mV + p6;
+ if((diff<0.008)&&gripper){
+ return 1;
}
- return (distance);
+ else {
+ return NULL;
+}
+}
+
+//Drives forward into the next step
+//Prameter:distance in milimeter
+int drive_straight(float distance)
+{
+ float diff_R;
+ float diff_L;
+
+// calculates the desired position
+if (desired_pos==0) {
+ desired_pos=wheel_dist_to_deg(distance);
+ float relativ_turns_rightmotor = turn_relative_deg(desired_pos, positionController_M_right.getRotation());
+ float relativ_turns_leftmotor = turn_relative_deg(desired_pos, positionController_M_left.getRotation());
}
+ positionController_M_right.setDesiredRotation(desired_pos, max_speed_rps_wheel);
+ positionController_M_left.setDesiredRotation(desired_pos, max_speed_rps_wheel);
+
+ // to check if the position controller are finished
+ diff_R= abs(desired_pos-(positionController_M_right.getRotation()));
+ diff_L= abs(desired_pos-(positionController_M_left.getRotation()));
+
+ //prints for testing
+ printf("Drive Straight Position Right(rot): %3.3f; Position Left (rot): %3.3f Desired: %3.3f Diff:%3.3f State:%d ToNextfunction:%d\n",
+ positionController_M_right.getRotation(),positionController_M_left.getRotation(),desired_pos,diff_L, state, ToNextFunction);
+
+
+ if ((diff_R<=0.02) && (diff_L<=0.02))
+ {
+ return 1;
+ }
+ else
+ {
+ return 0;
+ }
+}
+
+//turns the arm until the robot is on the next step
+int lift_up()
+{
+ float diff;
+
+ // calculates the desired position
+ if (desired_pos==0) {
+ desired_pos = turn_relative_deg(liftPos,positionController_M_Arm.getRotation());
+ }
+
+ positionController_M_Arm.setDesiredRotation(desired_pos, max_speed_rps_arm);
+
+ // to check if the position controller is finished
+ diff=abs(desired_pos-positionController_M_Arm.getRotation());
+
+ //prints for testing
+ printf("Lift Up: Position ARM (rot): %3.3f Desired:%3.3f State:%d ToNextfunction:%d\n",positionController_M_Arm.getRotation(),desired_pos, state, ToNextFunction);
+
+ if(diff<=0.03)
+ { return 1;
+ }
+ else
+ { return 0;
+ }
+
+}
+//***********************************************************************************************************************************************************
+
+// while loop gets executed every main_task_period_ms milliseconds
+int main_task_period_ms = 30; // define main task period time in ms e.g. 30 ms -> main task runns ~33,33 times per second
+Timer main_task_timer; // create Timer object which we use to run the main task every main task period time in ms
+//***********************************************************************************************************************************************************
+
int main(void)
{
// attach button fall and rise functions to user button object
-user_button.fall(&user_button_pressed_fcn);
-user_button.rise(&user_button_released_fcn);
-
-
-
- while (true){
- enable_motors = 1;
+ user_button.fall(&user_button_pressed_fcn);
+ user_button.rise(&user_button_released_fcn);
+ mechanical_button.mode(PullDown);
+
+ while (true)
+ {
- ir_distance_mV = 1.0e3f * ir_analog_in.read() * 3.3f;
+ ir_distance_mm_L= mapping(ir_analog_in_Distance_L.read()*1.0e3f * 3.3f);
+
+
+ if (ToNextFunction>=1||(mechanical_button.read()!=1)) {
+ enable_motors=1;
+ }
+
- // printf("test pow function 2 ^ 2 %lf\n",powerx(2,2));
- //printf("test mapping function %f\n", mapping(ir_distance_mV));
+ switch (ToNextFunction)
+ {
+
+ // case 0: For referencing the arm position
+ case 0: while (mechanical_button.read()!=1)
+ {
+ positionController_M_Arm.setDesiredRotation(-1,0.5);
+
+ }
+ if (mechanical_button){
+ positionController_M_Arm.setDesiredRotation(positionController_M_Arm.getRotation());
+
+ }
+ break;
- //printf("IR sensor (mV): %3.3f\n", ir_distance_mV);
+ // case 1:
+ case 1:
+ ToNextFunction +=1;
+ state=0;
+ break;
+
+ // case 2: drive too the stair
+ case 2: state=drive_straight(drive_straight_mm);
+
+ if (state==1){
+ ToNextFunction += 1;
+ state=0;
+ desired_pos=0;
+ }
+ break;
- switch (ToNextFunction) {
- case 1: StartPosition(degArmStart);
- printf("Case 1: Position ARM (rot): %3.3f\n",positionController_M_Arm.getRotation());
- // ToNextFunction+=1;
- break;
- case 2: Drive(PositionStair);
- printf("Case 2: Position Right(rot): %3.3f; Position Left (rot): %3.3f\n",
- positionController_M_right.getRotation(),positionController_M_left.getRotation());
- // ToNextFunction+=1;
+ // case 3: lift the roboer up
+ case 3: state=lift_up();
+
+ if (state==1){
+ ToNextFunction += 1;
+ state=0;
+ desired_pos=0;
+ }
break;
- case 3: LiftUp(degArmLift);
- // ToNextFunction+=1;
- printf("Case 3: Position ARM (rot): %3.3f\n",positionController_M_Arm.getRotation());
+
+ // case 4: detect if there is a next step
+ case 4: state=nextStepDetection(ir_distance_mm_L,4);
+ // if there is a next step, variable nextStep=1
+ if (state==3){
+ nextStep=1;
+ }
+
+
+ ToNextFunction +=1;
+ state=0;
+
+ printf("distance:%3.3f Output:%d NextStep:%d\n ", ir_distance_mm_L, nextStepDetection(ir_distance_mm_L,4), nextStep);
break;
- case 4: Drive(PositionBackOff);
- printf("Case 4: Position Right(rot): %3.3f; Position Left (rot): %3.3f\n",
- positionController_M_right.getRotation(),positionController_M_left.getRotation());
- // ToNextFunction+=1;
+
+ // case 5: Drive the roboter back until there is no step underneath the lookdown sensor
+ case 5:
+ state=drive_straight(drive_back_mm);
+
+ if (StepDetection_down(ir_analog_in_Lookdown_B) != 1)
+ {
+ ToNextFunction += 1;
+ state=0;
+ desired_pos=0;
+ positionController_M_left.setDesiredRotation(positionController_M_left.getRotation());
+ positionController_M_right.setDesiredRotation(positionController_M_right.getRotation());
+
+ }
break;
- case 5: LiftUp(degArmStart);
- printf("Case 5: Position ARM (rot): %3.3f\n",positionController_M_Arm.getRotation());
- // ToNextFunction = 0;
+
+ //case 6: bring arm back to starting positon
+ case 6:
+ state=set_arm_stair_height();
+ //if there is a next step, continue to climb up
+ if ((state==1) && (nextStep)){
+ ToNextFunction = 1;
+ state=0;
+ desired_pos=0;
+ nextStep=0;
+ }
+ //if there is no next step, stop
+ if ((state==1) && (nextStep!=1)) {
+ ToNextFunction=0;
+ state=0;
+ desired_pos=0;
+ nextStep=0;
+ }
break;
+
default: ;
}
-
-
-
}
- // read timer and make the main thread sleep for the remaining time span (non blocking)
- int main_task_elapsed_time_ms = std::chrono::duration_cast<std::chrono::milliseconds>(main_task_timer.elapsed_time()).count();
- thread_sleep_for(main_task_period_ms - main_task_elapsed_time_ms);
+ // read timer and make the main thread sleep for the remaining time span (non blocking)
+ int main_task_elapsed_time_ms = std::chrono::duration_cast<std::chrono::milliseconds>(main_task_timer.elapsed_time()).count();
+ thread_sleep_for(main_task_period_ms - main_task_elapsed_time_ms);
return 0;
}
+
void user_button_pressed_fcn()
{
user_button_timer.start();
user_button_timer.reset();
}
-void user_button_released_fcn() {
+void user_button_released_fcn()
+{
// read timer and toggle do_execute_main_task if the button was pressed longer than the below specified time
int user_button_elapsed_time_ms = std::chrono::duration_cast<std::chrono::milliseconds>(user_button_timer.elapsed_time()).count();
user_button_timer.stop();
- if (user_button_elapsed_time_ms > 200) {
- ToNextFunction += 1;}
- }
\ No newline at end of file
+ if (user_button_elapsed_time_ms > 200)
+ {
+ ToNextFunction =1;
+ }
+}
\ No newline at end of file