TreppenRobo / Mbed OS PrototypV2

Prototyp V2

Dependencies:   PM2_Libary

main.cpp@97:37550ebdee00, 2022-05-04 (annotated)

Committer:
lupomic
Date:
Wed May 04 10:21:11 2022 +0200
Revision:
97:37550ebdee00
Parent:
89:9c13036600ac
Child:
100:1287abe79a0f
updatet calculations

Who changed what in which revision?

UserRevisionLine numberNew contents of line
pmic 1:93d997d6b232 1 #include "mbed.h"
pmic 17:c19b471f05cb 2 #include "PM2_Libary.h"
lupomic 33:70ea029a69e8 3 #include <cstdint>
raomen 41:4a4978d1a578 4 #include <cstdio>
raomen 39:025d1bee1397 5 #include "math.h"
raomen 39:025d1bee1397 6 //*******************************************************************************************************************************************************************
raomen 39:025d1bee1397 7 // Defined Variables in mm coming from Hardware-team. Need to be updated
raomen 55:8cb262e56efb 8 const float wheel_diameter = 30; // diameter of wheel with caterpillar to calculate mm per wheel turn (4)
raomen 55:8cb262e56efb 9 const float arm_length = 118.5; // lenght of arm from pivotpoint to pivotpoint (3)
raomen 55:8cb262e56efb 10 const float dist_arm_attach_distsensor = 20; // distance between pivot point arm on body to start distancesensor on top in horizontal (6)
raomen 55:8cb262e56efb 11 const float dist_distsensors = 200; // distance between the two distancesensors on top of Wall-E (9)
raomen 55:8cb262e56efb 12 const float dist_arm_ground = 51; // distance between pivotpoint arm and ground (5)
lupomic 97:37550ebdee00 13 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)
lupomic 97:37550ebdee00 14 const float dist_grappleratt_grappler_uk = 36.5; // distance between pivotpoint Grappler and bottom edge (?)
lupomic 97:37550ebdee00 15 const float grip_area_depth =32.5;
raomen 41:4a4978d1a578 16
raomen 55:8cb262e56efb 17 const float height_stairs = 100; // height to top of next stairstep in mm
raomen 39:025d1bee1397 18 //***********************************************************************************************************************************************************
raomen 41:4a4978d1a578 19 // declaration of Input - Output pins
pmic 17:c19b471f05cb 20
pmic 24:86f1a63e35a0 21 // user button on nucleo board
pmic 24:86f1a63e35a0 22 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)
pmic 24:86f1a63e35a0 23 InterruptIn user_button(PC_13); // create InterruptIn interface object to evaluate user button falling and rising edge (no blocking code in ISR)
pmic 24:86f1a63e35a0 24 void user_button_pressed_fcn(); // custom functions which gets executed when user button gets pressed and released, definition below
pmic 24:86f1a63e35a0 25 void user_button_released_fcn();
pmic 6:e1fa1a2d7483 26
pmic 24:86f1a63e35a0 27 // Sharp GP2Y0A41SK0F, 4-40 cm IR Sensor
lupomic 97:37550ebdee00 28 // define variable to store measurement from infrared distancesensor in mm
lupomic 97:37550ebdee00 29 float ir_distance_mm_L;
lupomic 97:37550ebdee00 30 float ir_distance_mm_R;
lupomic 97:37550ebdee00 31
lupomic 97:37550ebdee00 32 AnalogIn ir_analog_in_Distance_L(PC_2);
lupomic 97:37550ebdee00 33 AnalogIn ir_analog_in_Distance_R(PC_3);
lupomic 97:37550ebdee00 34 AnalogIn ir_analog_in_Lookdown_B(PC_5);
lupomic 97:37550ebdee00 35 AnalogIn ir_analog_in_Lookdown_F(PB_1);
lupomic 97:37550ebdee00 36 // create AnalogIn object to read in infrared distance sensor, 0...3.3V are mapped to 0...1
pmic 6:e1fa1a2d7483 37
pmic 24:86f1a63e35a0 38 // 78:1, 100:1, ... Metal Gearmotor 20Dx44L mm 12V CB
pmic 24:86f1a63e35a0 39 DigitalOut enable_motors(PB_15); // create DigitalOut object to enable dc motors
pmic 24:86f1a63e35a0 40 float pwm_period_s = 0.00005f; // define pwm period time in seconds and create FastPWM objects to command dc motors
raomen 48:0ab6b1fd455f 41
lupomic 33:70ea029a69e8 42 //motor pin declaration
raomen 46:eba2263eb626 43 FastPWM pwm_M_right (PB_13); //motor pin decalaration for wheels right side
raomen 46:eba2263eb626 44 FastPWM pwm_M_left (PA_9); //motor pin decalaration for wheels left side
raomen 46:eba2263eb626 45 FastPWM pwm_M_arm (PA_10); //motor pin decalaration for arm
pmic 17:c19b471f05cb 46
lupomic 33:70ea029a69e8 47 //Encoder pin declaration
raomen 46:eba2263eb626 48 EncoderCounter encoder_M_right (PA_6, PC_7); //encoder pin decalaration for wheels right side
raomen 46:eba2263eb626 49 EncoderCounter encoder_M_left (PB_6, PB_7); //encoder pin decalaration for wheels left side
raomen 46:eba2263eb626 50 EncoderCounter encoder_M_arm (PA_0, PA_1); //encoder pin decalaration for arm
raomen 41:4a4978d1a578 51 //***********************************************************************************************************************************************************
raomen 43:7964411b4a6b 52 // Hardware controll Setup and functions (motors and sensors)
pmic 17:c19b471f05cb 53
pmic 30:1e8295770bc1 54 // create SpeedController and PositionController objects, default parametrization is for 78.125:1 gear box
raomen 55:8cb262e56efb 55 const float max_voltage = 12.0f; // define maximum voltage of battery packs, adjust this to 6.0f V if you only use one batterypack
raomen 55:8cb262e56efb 56 const float counts_per_turn_wheels = 20.0f * 78.125f; // define counts per turn at gearbox end (counts/turn * gearratio) for wheels
raomen 59:f6c3e42f16c7 57 const float counts_per_turn_arm = 20.0f * 78.125f * 20.0f; // define counts per turn at gearbox end (counts/turn * gearratio) for arm
raomen 55:8cb262e56efb 58 const float kn = 180.0f / 12.0f; // define motor constant in rpm per V
raomen 55:8cb262e56efb 59 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°)
raomen 55:8cb262e56efb 60 const float kp = 0.1f; // define custom kp, this is the default speed controller gain for gear box 78.125:1
raomen 46:eba2263eb626 61
lupomic 33:70ea029a69e8 62 //motors for tracks
lupomic 33:70ea029a69e8 63 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
lupomic 33:70ea029a69e8 64 PositionController positionController_M_left(counts_per_turn_wheels * k_gear, kn / k_gear, kp * k_gear, max_voltage, pwm_M_left, encoder_M_left); // parameters adjusted to 100:1 gear, we need a different speed controller gain here
lupomic 33:70ea029a69e8 65 //Arm Motor
lupomic 33:70ea029a69e8 66 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
pmic 17:c19b471f05cb 67
lupomic 33:70ea029a69e8 68 // PositionController positionController_M3(counts_per_turn, kn, max_voltage, pwm_M3, encoder_M3); // default 78.125:1 gear with default contoller parameters
lupomic 33:70ea029a69e8 69 //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
raomen 41:4a4978d1a578 70 //***********************************************************************************************************************************************************
raomen 80:4eae727a13b5 71 // calculations for basic movment and controll
raomen 41:4a4978d1a578 72
raomen 50:058dc65d0fa4 73 //placeholder variables for prototype testing
lupomic 97:37550ebdee00 74 const int drive_straight_mm = 200; // placeholder for testing drives amount forward
lupomic 97:37550ebdee00 75 const int drive_back_mm = -200; // placeholder for testing drives amount backwards
raomen 65:1ee1f319a199 76 int ToNextFunction = 0; // current state of the system (which function is beeing executed)
lupomic 33:70ea029a69e8 77
raomen 81:909670edc2a2 78 // definition variables for calculations
raomen 55:8cb262e56efb 79 const float pi = 2 * acos(0.0); // definiton of pi
lupomic 97:37550ebdee00 80 const float end_pos_lift_deg = 180 + asin((dist_arm_ground-(dist_grappleratt_grappler_uk-dist_arm_attach_OK_griparea))/arm_length) * 180 / pi; // calculates the degree which the arm has to have when lift_up has been executed.
raomen 81:909670edc2a2 81 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)
raomen 81:909670edc2a2 82
raomen 81:909670edc2a2 83 // definition of rotation speeds for motors 0 = none 1.0 = max.
raomen 66:b4e55e1eebfc 84 const float max_speed_rps_wheel = 0.5f; // define maximum speed that the position controller is changig the speed for the wheels, has to be smaller or equal to kn * max_voltage
raomen 55:8cb262e56efb 85 const float max_speed_rps_arm = 0.3f; // define maximum speed that the position controller is changig the speed for the arm, has to be smaller or equal to kn * max_voltage
raomen 65:1ee1f319a199 86
raomen 46:eba2263eb626 87 // 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)
raomen 74:d7569d530f6c 88 // PARAM: height_mm = height which OK Gripperarea has to reach.
raomen 74:d7569d530f6c 89 // RETURN: deg_arm = absolut Position in deg that the arm has to take.
raomen 65:1ee1f319a199 90 float calc_arm_deg_for_height(int height_mm)
raomen 40:e32c57763d92 91 {
lupomic 97:37550ebdee00 92 float height_arm = height_mm - (dist_arm_ground - dist_arm_attach_OK_griparea + dist_grappleratt_grappler_uk); // calculates the height which only the arm has to cover (- attachement height (arm to robot) etc.)
raomen 81:909670edc2a2 93 float deg_arm = asin(height_arm / arm_length) * 180.0/pi; // calculates the absolute degrees which the arm has to reach
raomen 51:7d165baaa646 94 return deg_arm;
raomen 40:e32c57763d92 95 }
raomen 38:c2663f7dcccb 96
raomen 46:eba2263eb626 97 //calculates the deg which the wheels have to turn in order to cover specified distance in mm
raomen 60:b2e9958f2298 98 //RETURN: deg_wheel = degree which the motor has to turn in order to cover distance(mm)
raomen 45:8050724fe19b 99 float wheel_dist_to_deg(int distance) // distance has to be in mm.
raomen 45:8050724fe19b 100 {
lupomic 97:37550ebdee00 101 float deg_wheel = distance/(wheel_diameter * pi) * 360 ;
raomen 45:8050724fe19b 102 return deg_wheel;
raomen 45:8050724fe19b 103 }
raomen 45:8050724fe19b 104
raomen 58:3cd93949a7d7 105 // increments the Motor for defined degree from the current one
raomen 58:3cd93949a7d7 106 // PARAM: deg_to_turn = degree to turn the Motor
raomen 80:4eae727a13b5 107 // PARAM: current_rotation = the current rotation of the Motor (Motor.getRotation())
raomen 80:4eae727a13b5 108 // RETURN: new_turn_rotation = new Rotation value in rotations
raomen 80:4eae727a13b5 109 float turn_relative_deg(float deg_to_turn, float current_rotation)
raomen 57:79732e5818d7 110 {
raomen 80:4eae727a13b5 111 float new_turn_rotation = current_rotation + deg_to_turn/360.0;
raomen 57:79732e5818d7 112 return new_turn_rotation;
raomen 57:79732e5818d7 113 }
raomen 57:79732e5818d7 114
raomen 80:4eae727a13b5 115 // sets the Motor to a specified degree in one rotation
raomen 80:4eae727a13b5 116 // PARAM: end_deg = new position of the arm in degree 0 <= value >=360
raomen 80:4eae727a13b5 117 // PARAM: current_rotation = the current rotation of the Motor (Motor.getRotation())
raomen 80:4eae727a13b5 118 // RETURN: new_partial_rotation = new deg value in rotations
raomen 80:4eae727a13b5 119 float turn_absolut_deg(float end_deg, float current_rotations)
raomen 80:4eae727a13b5 120 {
raomen 80:4eae727a13b5 121 int full_rotations;
raomen 80:4eae727a13b5 122 if(current_rotations > 0)
raomen 80:4eae727a13b5 123 {
raomen 80:4eae727a13b5 124 full_rotations = round(current_rotations - 0.5);
raomen 80:4eae727a13b5 125 }
raomen 80:4eae727a13b5 126 else if(current_rotations < 0)
raomen 80:4eae727a13b5 127 {
raomen 80:4eae727a13b5 128 full_rotations = round(current_rotations + 0.5);
raomen 80:4eae727a13b5 129 }
raomen 80:4eae727a13b5 130 else
raomen 80:4eae727a13b5 131 {
raomen 80:4eae727a13b5 132 full_rotations = 0;
raomen 80:4eae727a13b5 133 }
raomen 80:4eae727a13b5 134 float new_partial_rotation = full_rotations - start_deg_arm/360 + end_deg/360;
raomen 80:4eae727a13b5 135 return new_partial_rotation;
raomen 80:4eae727a13b5 136 }
lupomic 97:37550ebdee00 137
lupomic 97:37550ebdee00 138 float calc_pos_end_lift()
lupomic 97:37550ebdee00 139 {
lupomic 97:37550ebdee00 140 float end_deg;
lupomic 97:37550ebdee00 141 end_deg = asin((dist_arm_ground - (dist_grappleratt_grappler_uk - dist_arm_attach_OK_griparea)) / arm_length) + start_deg_arm;
lupomic 97:37550ebdee00 142 end_deg = end_deg * 180 / pi;
lupomic 97:37550ebdee00 143 return end_deg;
lupomic 97:37550ebdee00 144 }
lupomic 97:37550ebdee00 145
raomen 80:4eae727a13b5 146 //***********************************************************************************************************************************************************
raomen 81:909670edc2a2 147 // important calculatet constants for Wall-E
raomen 81:909670edc2a2 148 const double deg_up_from_horizon_to_stair = calc_arm_deg_for_height(height_stairs);
raomen 80:4eae727a13b5 149
raomen 80:4eae727a13b5 150 // import functions from file mapping
raomen 80:4eae727a13b5 151 extern double powerx(double base, double pow2);
raomen 80:4eae727a13b5 152 extern double mapping (float adc_value_mV);
raomen 75:3831b90a4ae0 153
raomen 75:3831b90a4ae0 154 //simple check if there is an object in proximity
raomen 75:3831b90a4ae0 155 //returns 0 if there is NO object present
raomen 75:3831b90a4ae0 156 //returns 1 if there is an object present
raomen 75:3831b90a4ae0 157 //returns 2 if the distance isn't in the expected range
raomen 80:4eae727a13b5 158 uint8_t StepDetection(double distance)
raomen 80:4eae727a13b5 159 {
raomen 75:3831b90a4ae0 160 double d_valueMM = distance;
raomen 79:368cbf09cf6a 161 if(d_valueMM >= 4) return 0;
raomen 79:368cbf09cf6a 162 else if(d_valueMM < 4) return 1;
raomen 79:368cbf09cf6a 163 else if(d_valueMM <= 0 || d_valueMM > 100 ) return 2;
raomen 79:368cbf09cf6a 164 else return 2;
raomen 75:3831b90a4ae0 165
raomen 75:3831b90a4ae0 166 }
raomen 58:3cd93949a7d7 167
raomen 46:eba2263eb626 168 // bring arm in starting position. Height of stairs.
raomen 68:e3fc5ed0bc0e 169 void set_arm_stair_height()
raomen 42:6e7ab1136354 170 {
raomen 81:909670edc2a2 171 float deg = deg_up_from_horizon_to_stair + start_deg_arm;
raomen 66:b4e55e1eebfc 172
lupomic 89:9c13036600ac 173
raomen 45:8050724fe19b 174 positionController_M_Arm.setDesiredRotation(deg / 360.0, max_speed_rps_arm); // command to turn motor to desired deg.
lupomic 89:9c13036600ac 175
raomen 42:6e7ab1136354 176 }
raomen 42:6e7ab1136354 177
raomen 55:8cb262e56efb 178 //Drives forward into the next step
raomen 55:8cb262e56efb 179 //Prameter:distance in milimeter
raomen 64:72b9efe62ece 180 void drive_straight(float distance)
raomen 40:e32c57763d92 181 {
raomen 46:eba2263eb626 182 float deg_to_turn = wheel_dist_to_deg(distance);
raomen 60:b2e9958f2298 183
raomen 60:b2e9958f2298 184 float relativ_turns_rightmotor = turn_relative_deg(deg_to_turn, positionController_M_right.getRotation());
raomen 60:b2e9958f2298 185 float relativ_turns_leftmotor = turn_relative_deg(deg_to_turn, positionController_M_left.getRotation());
raomen 66:b4e55e1eebfc 186
lupomic 89:9c13036600ac 187
raomen 60:b2e9958f2298 188 positionController_M_right.setDesiredRotation(relativ_turns_rightmotor, max_speed_rps_wheel);
raomen 64:72b9efe62ece 189 positionController_M_left.setDesiredRotation(relativ_turns_leftmotor, max_speed_rps_wheel);
lupomic 89:9c13036600ac 190
lupomic 33:70ea029a69e8 191 }
lupomic 33:70ea029a69e8 192
raomen 74:d7569d530f6c 193 //turns the arm until the robot is on the next step
raomen 64:72b9efe62ece 194 void lift_up()
raomen 40:e32c57763d92 195 {
raomen 81:909670edc2a2 196 float absolut_pos_arm = turn_absolut_deg(end_pos_lift_deg, positionController_M_Arm.getRotation()-1);
lupomic 97:37550ebdee00 197 float position_lift_end_deg = asin((-dist_arm_ground - (dist_grappleratt_grappler_uk - dist_arm_attach_OK_griparea)) / arm_length) - 90;
raomen 46:eba2263eb626 198
lupomic 89:9c13036600ac 199
lupomic 97:37550ebdee00 200 positionController_M_Arm.setDesiredRotation(position_lift_end_deg, max_speed_rps_arm);
lupomic 89:9c13036600ac 201
lupomic 33:70ea029a69e8 202 }
raomen 43:7964411b4a6b 203 //***********************************************************************************************************************************************************
raomen 38:c2663f7dcccb 204
raomen 80:4eae727a13b5 205 //Function which checks if sensors and motors have been wired correctly and the expectet results will happen. otherwise Wall-E will ???.
raomen 65:1ee1f319a199 206 void check_start()
raomen 43:7964411b4a6b 207 {
raomen 43:7964411b4a6b 208
raomen 43:7964411b4a6b 209 }
raomen 43:7964411b4a6b 210
raomen 41:4a4978d1a578 211 // while loop gets executed every main_task_period_ms milliseconds
raomen 41:4a4978d1a578 212 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
raomen 41:4a4978d1a578 213 Timer main_task_timer; // create Timer object which we use to run the main task every main task period time in ms
raomen 43:7964411b4a6b 214 //***********************************************************************************************************************************************************
raomen 39:025d1bee1397 215
lupomic 33:70ea029a69e8 216 int main(void)
pmic 23:26b3a25fc637 217 {
raomen 46:eba2263eb626 218 // attach button fall and rise functions to user button object
raomen 46:eba2263eb626 219 user_button.fall(&user_button_pressed_fcn);
raomen 46:eba2263eb626 220 user_button.rise(&user_button_released_fcn);
lupomic 34:9f779e91168e 221
raomen 40:e32c57763d92 222 while (true)
raomen 40:e32c57763d92 223 {
lupomic 89:9c13036600ac 224 if (ToNextFunction>=1){
lupomic 89:9c13036600ac 225
lupomic 89:9c13036600ac 226 enable_motors = 1;
lupomic 89:9c13036600ac 227 }
raomen 75:3831b90a4ae0 228
raomen 40:e32c57763d92 229 switch (ToNextFunction)
raomen 40:e32c57763d92 230 {
raomen 46:eba2263eb626 231
raomen 45:8050724fe19b 232 case 1:
raomen 68:e3fc5ed0bc0e 233 set_arm_stair_height();
raomen 46:eba2263eb626 234 printf("Case 1: Position ARM (rot): %3.3f\n",positionController_M_Arm.getRotation());
raomen 46:eba2263eb626 235 break;
raomen 46:eba2263eb626 236
raomen 45:8050724fe19b 237 case 2:
raomen 80:4eae727a13b5 238 drive_straight(drive_straight_mm);
raomen 45:8050724fe19b 239 printf("Case 2: Position Right(rot): %3.3f; Position Left (rot): %3.3f\n",
raomen 46:eba2263eb626 240 positionController_M_right.getRotation(),positionController_M_left.getRotation());
raomen 46:eba2263eb626 241 break;
raomen 46:eba2263eb626 242
raomen 45:8050724fe19b 243 case 3:
raomen 46:eba2263eb626 244 lift_up();
raomen 46:eba2263eb626 245 printf("Case 3: Position ARM (rot): %3.3f\n",positionController_M_Arm.getRotation());
raomen 46:eba2263eb626 246 break;
raomen 46:eba2263eb626 247
raomen 45:8050724fe19b 248 case 4:
raomen 46:eba2263eb626 249 drive_straight(drive_back_mm);
lupomic 34:9f779e91168e 250 printf("Case 4: Position Right(rot): %3.3f; Position Left (rot): %3.3f\n",
raomen 46:eba2263eb626 251 positionController_M_right.getRotation(),positionController_M_left.getRotation());
raomen 65:1ee1f319a199 252 ToNextFunction = 0;
raomen 46:eba2263eb626 253 break;
raomen 46:eba2263eb626 254
raomen 46:eba2263eb626 255 default: ;
lupomic 33:70ea029a69e8 256 }
lupomic 33:70ea029a69e8 257 }
raomen 80:4eae727a13b5 258 // read timer and make the main thread sleep for the remaining time span (non blocking)
raomen 80:4eae727a13b5 259 int main_task_elapsed_time_ms = std::chrono::duration_cast<std::chrono::milliseconds>(main_task_timer.elapsed_time()).count();
raomen 80:4eae727a13b5 260 thread_sleep_for(main_task_period_ms - main_task_elapsed_time_ms);
raomen 80:4eae727a13b5 261 return 0;
pmic 1:93d997d6b232 262 }
pmic 6:e1fa1a2d7483 263
lupomic 33:70ea029a69e8 264
pmic 24:86f1a63e35a0 265 void user_button_pressed_fcn()
pmic 25:ea1d6e27c895 266 {
pmic 26:28693b369945 267 user_button_timer.start();
pmic 6:e1fa1a2d7483 268 user_button_timer.reset();
pmic 6:e1fa1a2d7483 269 }
pmic 6:e1fa1a2d7483 270
raomen 43:7964411b4a6b 271 void user_button_released_fcn()
raomen 43:7964411b4a6b 272 {
pmic 24:86f1a63e35a0 273 // read timer and toggle do_execute_main_task if the button was pressed longer than the below specified time
pmic 24:86f1a63e35a0 274 int user_button_elapsed_time_ms = std::chrono::duration_cast<std::chrono::milliseconds>(user_button_timer.elapsed_time()).count();
pmic 6:e1fa1a2d7483 275 user_button_timer.stop();
raomen 43:7964411b4a6b 276 if (user_button_elapsed_time_ms > 200)
raomen 43:7964411b4a6b 277 {
raomen 43:7964411b4a6b 278 ToNextFunction += 1;
raomen 43:7964411b4a6b 279 }
raomen 43:7964411b4a6b 280 }