Balancing_Robot_2 - First trial

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Lakshmanan Gopalakrishnan / Mbed 2 deprecated Balancing_Robot_2

First trial

Dependencies: MPU6050 Motor ledControl2 mbed

Fork of BalancingRobotPS3 by Kristian Lauszus

BalancingRobot.cpp@1:01295228342f, 2012-02-14 (annotated)

Committer:: Lauszus
Date:: Tue Feb 14 18:31:05 2012 +0000
Revision:: 1:01295228342f
Parent:: 0:f5c02b620688
Child:: 2:caec5534774d

Who changed what in which revision?

User	Revision	Line number	New contents of line
Lauszus	1:01295228342f	1	/*
Lauszus	1:01295228342f	2	* The code is released under the GNU General Public License.
Lauszus	1:01295228342f	3	* Developed by Kristian Lauszus
Lauszus	1:01295228342f	4	* This is the algorithm for my balancing robot/segway.
Lauszus	1:01295228342f	5	* It is controlled by a PS3 Controller via bluetooth.
Lauszus	1:01295228342f	6	* The remote control code can be found at my other github repository: https://github.com/TKJElectronics/BalancingRobot
Lauszus	1:01295228342f	7	* For details, see http://blog.tkjelectronics.dk
Lauszus	1:01295228342f	8	*/
Lauszus	1:01295228342f	9
Lauszus	0:f5c02b620688	10	#include "BalancingRobot.h"
Lauszus	0:f5c02b620688	11
Lauszus	0:f5c02b620688	12	/* Serial communication */
Lauszus	0:f5c02b620688	13	Serial xbee(p13,p14); // For wireless debugging
Lauszus	0:f5c02b620688	14	Serial ps3(p9,p10); // For remote control
Lauszus	0:f5c02b620688	15	Serial debug(USBTX, USBRX); // USB
Lauszus	0:f5c02b620688	16
Lauszus	0:f5c02b620688	17	/* Timer instance */
Lauszus	0:f5c02b620688	18	Timer t;
Lauszus	0:f5c02b620688	19
Lauszus	0:f5c02b620688	20	int main() {
Lauszus	0:f5c02b620688	21	xbee.baud(115200);
Lauszus	0:f5c02b620688	22	ps3.baud(115200);
Lauszus	0:f5c02b620688	23	debug.baud(115200);
Lauszus	0:f5c02b620688	24
Lauszus	0:f5c02b620688	25	leftPWM.period(0.00005); //The motor driver can handle pwm values up to 20kHz (1/20000=0.00005)
Lauszus	0:f5c02b620688	26	rightPWM.period(0.00005);
Lauszus	0:f5c02b620688	27
Lauszus	0:f5c02b620688	28	calibrateSensors(); // Calibrate the gyro and accelerometer relative to ground
Lauszus	0:f5c02b620688	29
Lauszus	0:f5c02b620688	30	xbee.printf("Initialized\n");
Lauszus	0:f5c02b620688	31
Lauszus	0:f5c02b620688	32	// Start timing
Lauszus	0:f5c02b620688	33	t.start();
Lauszus	0:f5c02b620688	34	loopStartTime = t.read_us();
Lauszus	0:f5c02b620688	35	timer = loopStartTime;
Lauszus	0:f5c02b620688	36
Lauszus	0:f5c02b620688	37	while (1) {
Lauszus	0:f5c02b620688	38	// See my guide for more info about calculation the angles and the Kalman filter: http://arduino.cc/forum/index.php/topic,58048.0.html
Lauszus	0:f5c02b620688	39	accYangle = getAccY();
Lauszus	0:f5c02b620688	40	gyroYrate = getGyroYrate();
Lauszus	0:f5c02b620688	41
Lauszus	0:f5c02b620688	42	pitch = kalman(accYangle, gyroYrate, t.read_us() - timer); // calculate the angle using a Kalman filter
Lauszus	0:f5c02b620688	43	timer = t.read_us();
Lauszus	0:f5c02b620688	44
Lauszus	0:f5c02b620688	45	if (ps3.readable()) // Check if there's any incoming data
Lauszus	0:f5c02b620688	46	receiveSerial();
Lauszus	0:f5c02b620688	47
Lauszus	0:f5c02b620688	48	//debug.printf("Pitch: %f, accYangle: %f\n",pitch,accYangle);
Lauszus	0:f5c02b620688	49
Lauszus	1:01295228342f	50	if (pitch < 75 \|\| pitch > 105) // Stop if falling or laying down
Lauszus	0:f5c02b620688	51	stopAndReset();
Lauszus	0:f5c02b620688	52	else
Lauszus	0:f5c02b620688	53	PID(targetAngle);
Lauszus	0:f5c02b620688	54
Lauszus	0:f5c02b620688	55	/* Used a time fixed loop */
Lauszus	0:f5c02b620688	56	lastLoopUsefulTime = t.read_us() - loopStartTime;
Lauszus	0:f5c02b620688	57	if (lastLoopUsefulTime < STD_LOOP_TIME)
Lauszus	0:f5c02b620688	58	wait_us(STD_LOOP_TIME - lastLoopUsefulTime);
Lauszus	0:f5c02b620688	59	lastLoopTime = t.read_us() - loopStartTime; // only used for debugging
Lauszus	0:f5c02b620688	60	loopStartTime = t.read_us();
Lauszus	0:f5c02b620688	61
Lauszus	0:f5c02b620688	62	//debug.printf("%i,%i\n",lastLoopUsefulTime,lastLoopTime);
Lauszus	0:f5c02b620688	63	}
Lauszus	0:f5c02b620688	64	}
Lauszus	0:f5c02b620688	65	void stopAndReset() {
Lauszus	0:f5c02b620688	66	stop(both);
Lauszus	0:f5c02b620688	67	lastError = 0;
Lauszus	0:f5c02b620688	68	iTerm = 0;
Lauszus	0:f5c02b620688	69	}
Lauszus	0:f5c02b620688	70	void receiveSerial() {
Lauszus	0:f5c02b620688	71	char input[16]; // The serial buffer is only 16 characters, so the data has to be split up
Lauszus	1:01295228342f	72	int i = 0;
Lauszus	0:f5c02b620688	73	while (ps3.readable()) {
Lauszus	1:01295228342f	74	input[i] = ps3.getc();
Lauszus	1:01295228342f	75	if(input[i] == ';')
Lauszus	1:01295228342f	76	break;
Lauszus	1:01295228342f	77	i++;
Lauszus	1:01295228342f	78	}
Lauszus	0:f5c02b620688	79	//debug.printf("Input: %s\n",input);
Lauszus	0:f5c02b620688	80
Lauszus	0:f5c02b620688	81	/* For remote control */
Lauszus	0:f5c02b620688	82	if (input[0] == 'F') { // Forward
Lauszus	0:f5c02b620688	83	steerForward = true;
Lauszus	0:f5c02b620688	84	steerBackward = false;
Lauszus	0:f5c02b620688	85	steerLeft = false;
Lauszus	0:f5c02b620688	86	steerRotateLeft = false;
Lauszus	0:f5c02b620688	87	steerRight = false;
Lauszus	0:f5c02b620688	88	steerRotateRight = false;
Lauszus	0:f5c02b620688	89	} else if (input[0] == 'B') { // Backward
Lauszus	0:f5c02b620688	90	steerForward = false;
Lauszus	0:f5c02b620688	91	steerBackward = true;
Lauszus	0:f5c02b620688	92	steerLeft = false;
Lauszus	0:f5c02b620688	93	steerRotateLeft = false;
Lauszus	0:f5c02b620688	94	steerRight = false;
Lauszus	0:f5c02b620688	95	steerRotateRight = false;
Lauszus	0:f5c02b620688	96	} else if (input[0] == 'L') { // Left
Lauszus	0:f5c02b620688	97	if (input[1] == 'R') { // Left Rotate
Lauszus	0:f5c02b620688	98	steerLeft = false;
Lauszus	0:f5c02b620688	99	steerRotateLeft = true;
Lauszus	0:f5c02b620688	100	} else {
Lauszus	0:f5c02b620688	101	steerLeft = true;
Lauszus	0:f5c02b620688	102	steerRotateLeft = false;
Lauszus	0:f5c02b620688	103	}
Lauszus	0:f5c02b620688	104	steerForward = false;
Lauszus	0:f5c02b620688	105	steerBackward = false;
Lauszus	0:f5c02b620688	106	steerRight = false;
Lauszus	0:f5c02b620688	107	steerRotateRight = false;
Lauszus	0:f5c02b620688	108	} else if (input[0] == 'R') { // Right
Lauszus	0:f5c02b620688	109	if (input[1] == 'R') { // Right Rotate
Lauszus	0:f5c02b620688	110	steerRight = false;
Lauszus	0:f5c02b620688	111	steerRotateRight = true;
Lauszus	0:f5c02b620688	112	} else {
Lauszus	0:f5c02b620688	113	steerRight = true;
Lauszus	0:f5c02b620688	114	steerRotateRight = false;
Lauszus	0:f5c02b620688	115	}
Lauszus	0:f5c02b620688	116	steerForward = false;
Lauszus	0:f5c02b620688	117	steerBackward = false;
Lauszus	0:f5c02b620688	118	steerLeft = false;
Lauszus	0:f5c02b620688	119	steerRotateLeft = false;
Lauszus	0:f5c02b620688	120	} else if (input[0] == 'S') { // Stop
Lauszus	0:f5c02b620688	121	steerForward = false;
Lauszus	0:f5c02b620688	122	steerBackward = false;
Lauszus	0:f5c02b620688	123	steerLeft = false;
Lauszus	0:f5c02b620688	124	steerRotateLeft = false;
Lauszus	0:f5c02b620688	125	steerRight = false;
Lauszus	0:f5c02b620688	126	steerRotateRight = false;
Lauszus	0:f5c02b620688	127	}
Lauszus	0:f5c02b620688	128
Lauszus	0:f5c02b620688	129	else if (input[0] == 'T') { // Set the target angle
Lauszus	0:f5c02b620688	130	strtok(input, ","); // Ignore 'T'
Lauszus	1:01295228342f	131	targetAngle = atof(strtok(NULL, ";")); // read until the end and then convert from string to double
Lauszus	0:f5c02b620688	132	if (targetAngle < 75 \|\| targetAngle > 105) // The serial communication sometimes behaves weird
Lauszus	1:01295228342f	133	targetAngle = lastTargetAngle;
Lauszus	1:01295228342f	134	lastTargetAngle = targetAngle;
Lauszus	0:f5c02b620688	135	xbee.printf("%f\n",targetAngle); // Print targetAngle for debugging
Lauszus	0:f5c02b620688	136	} else if (input[0] == 'A') { // Abort
Lauszus	0:f5c02b620688	137	stopAndReset();
Lauszus	0:f5c02b620688	138	while (ps3.getc() != 'C'); // Wait until continue is send
Lauszus	0:f5c02b620688	139	}
Lauszus	0:f5c02b620688	140	}
Lauszus	0:f5c02b620688	141	void PID(double restAngle) {
Lauszus	0:f5c02b620688	142	if (steerForward)
Lauszus	1:01295228342f	143	restAngle -= 1.5;
Lauszus	0:f5c02b620688	144	else if (steerBackward)
Lauszus	1:01295228342f	145	restAngle += 1.5;
Lauszus	0:f5c02b620688	146
Lauszus	0:f5c02b620688	147	double error = (restAngle - pitch)/100;
Lauszus	0:f5c02b620688	148	double pTerm = Kp * error;
Lauszus	0:f5c02b620688	149	iTerm += Ki * error;
Lauszus	0:f5c02b620688	150	double dTerm = Kd * (error - lastError);
Lauszus	0:f5c02b620688	151	lastError = error;
Lauszus	0:f5c02b620688	152
Lauszus	0:f5c02b620688	153	double PIDValue = pTerm + iTerm + dTerm;
Lauszus	0:f5c02b620688	154
Lauszus	0:f5c02b620688	155	//debug.printf("Pitch: %5.2f\tPIDValue: %5.2f\tpTerm: %5.2f\tiTerm: %5.2f\tdTerm: %5.2f\tKp: %5.2f\tKi: %5.2f\tKd: %5.2f\n",pitch,PIDValue,pTerm,iTerm,dTerm,Kp,Ki,Kd);
Lauszus	0:f5c02b620688	156
Lauszus	0:f5c02b620688	157	double PIDLeft;
Lauszus	0:f5c02b620688	158	double PIDRight;
Lauszus	0:f5c02b620688	159	if (steerLeft) {
Lauszus	0:f5c02b620688	160	PIDLeft = PIDValue-(0.1);
Lauszus	0:f5c02b620688	161	PIDRight = PIDValue+(0.1);
Lauszus	0:f5c02b620688	162	} else if (steerRotateLeft) {
Lauszus	0:f5c02b620688	163	PIDLeft = PIDValue-(0.2);
Lauszus	0:f5c02b620688	164	PIDRight = PIDValue+(0.2);
Lauszus	0:f5c02b620688	165	} else if (steerRight) {
Lauszus	0:f5c02b620688	166	PIDLeft = PIDValue-(-0.1);
Lauszus	0:f5c02b620688	167	PIDRight = PIDValue+(-0.1);
Lauszus	0:f5c02b620688	168	} else if (steerRotateRight) {
Lauszus	0:f5c02b620688	169	PIDLeft = PIDValue-(-0.2);
Lauszus	0:f5c02b620688	170	PIDRight = PIDValue+(-0.2);
Lauszus	0:f5c02b620688	171	} else {
Lauszus	0:f5c02b620688	172	PIDLeft = PIDValue;
Lauszus	0:f5c02b620688	173	PIDRight = PIDValue;
Lauszus	0:f5c02b620688	174	}
Lauszus	0:f5c02b620688	175	PIDLeft *= 0.9; // compensate for difference in the motors
Lauszus	0:f5c02b620688	176
Lauszus	0:f5c02b620688	177	//Set PWM Values
Lauszus	0:f5c02b620688	178	if (PIDLeft >= 0)
Lauszus	0:f5c02b620688	179	move(left, forward, PIDLeft);
Lauszus	0:f5c02b620688	180	else
Lauszus	0:f5c02b620688	181	move(left, backward, PIDLeft * -1);
Lauszus	0:f5c02b620688	182	if (PIDRight >= 0)
Lauszus	0:f5c02b620688	183	move(right, forward, PIDRight);
Lauszus	0:f5c02b620688	184	else
Lauszus	0:f5c02b620688	185	move(right, backward, PIDRight * -1);
Lauszus	0:f5c02b620688	186	}
Lauszus	0:f5c02b620688	187	double kalman(double newAngle, double newRate, double dtime) {
Lauszus	0:f5c02b620688	188	// KasBot V2 - Kalman filter module - http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1284738418 - http://www.x-firm.com/?page_id=145
Lauszus	0:f5c02b620688	189	// with slightly modifications by Kristian Lauszus
Lauszus	0:f5c02b620688	190	dt = dtime / 1000000; // Convert from microseconds to seconds
Lauszus	0:f5c02b620688	191
Lauszus	0:f5c02b620688	192	// Discrete Kalman filter time update equations - Time Update ("Predict")
Lauszus	0:f5c02b620688	193	// Update xhat - Project the state ahead
Lauszus	0:f5c02b620688	194	angle += dt * (newRate - bias);
Lauszus	0:f5c02b620688	195
Lauszus	0:f5c02b620688	196	// Update estimation error covariance - Project the error covariance ahead
Lauszus	0:f5c02b620688	197	P_00 += -dt * (P_10 + P_01) + Q_angle * dt;
Lauszus	0:f5c02b620688	198	P_01 += -dt * P_11;
Lauszus	0:f5c02b620688	199	P_10 += -dt * P_11;
Lauszus	0:f5c02b620688	200	P_11 += +Q_gyro * dt;
Lauszus	0:f5c02b620688	201
Lauszus	0:f5c02b620688	202	// Discrete Kalman filter measurement update equations - Measurement Update ("Correct")
Lauszus	0:f5c02b620688	203	// Calculate Kalman gain - Compute the Kalman gain
Lauszus	0:f5c02b620688	204	S = P_00 + R_angle;
Lauszus	0:f5c02b620688	205	K_0 = P_00 / S;
Lauszus	0:f5c02b620688	206	K_1 = P_10 / S;
Lauszus	0:f5c02b620688	207
Lauszus	0:f5c02b620688	208	// Calculate angle and resting rate - Update estimate with measurement zk
Lauszus	0:f5c02b620688	209	y = newAngle - angle;
Lauszus	0:f5c02b620688	210	angle += K_0 * y;
Lauszus	0:f5c02b620688	211	bias += K_1 * y;
Lauszus	0:f5c02b620688	212
Lauszus	0:f5c02b620688	213	// Calculate estimation error covariance - Update the error covariance
Lauszus	0:f5c02b620688	214	P_00 -= K_0 * P_00;
Lauszus	0:f5c02b620688	215	P_01 -= K_0 * P_01;
Lauszus	0:f5c02b620688	216	P_10 -= K_1 * P_00;
Lauszus	0:f5c02b620688	217	P_11 -= K_1 * P_01;
Lauszus	0:f5c02b620688	218
Lauszus	0:f5c02b620688	219	return angle;
Lauszus	0:f5c02b620688	220	}
Lauszus	0:f5c02b620688	221	double getGyroYrate() {
Lauszus	0:f5c02b620688	222	// (gyroAdc-gyroZero)/Sensitivity (In quids) - Sensitivity = 0.00333/3.3*4095=4.132227273
Lauszus	0:f5c02b620688	223	double gyroRate = -(((gyroY.read()*4095) - zeroValues[0]) / 4.132227273);
Lauszus	0:f5c02b620688	224	return gyroRate;
Lauszus	0:f5c02b620688	225	}
Lauszus	0:f5c02b620688	226	double getAccY() {
Lauszus	0:f5c02b620688	227	// (accAdc-accZero)/Sensitivity (In quids) - Sensitivity = 0.33/3.3*4095=409.5
Lauszus	0:f5c02b620688	228	double accXval = ((accX.read()*4095) - zeroValues[1]) / 409.5;
Lauszus	0:f5c02b620688	229	double accYval = ((accY.read()*4095) - zeroValues[2]) / 409.5;
Lauszus	0:f5c02b620688	230	accYval--;//-1g when lying down
Lauszus	0:f5c02b620688	231	double accZval = ((accZ.read()*4095) - zeroValues[3]) / 409.5;
Lauszus	0:f5c02b620688	232
Lauszus	0:f5c02b620688	233	double R = sqrt(pow(accXval, 2) + pow(accYval, 2) + pow(accZval, 2)); // Calculate the force vector
Lauszus	0:f5c02b620688	234	double angleY = acos(accYval / R) * RAD_TO_DEG;
Lauszus	0:f5c02b620688	235
Lauszus	0:f5c02b620688	236	return angleY;
Lauszus	0:f5c02b620688	237	}
Lauszus	0:f5c02b620688	238	void calibrateSensors() {
Lauszus	0:f5c02b620688	239	onboardLED1 = 1;
Lauszus	0:f5c02b620688	240	onboardLED2 = 1;
Lauszus	0:f5c02b620688	241	onboardLED3 = 1;
Lauszus	0:f5c02b620688	242	onboardLED4 = 1;
Lauszus	0:f5c02b620688	243
Lauszus	0:f5c02b620688	244	double adc[4];
Lauszus	0:f5c02b620688	245	for (uint8_t i = 0; i < 100; i++) { // Take the average of 100 readings
Lauszus	0:f5c02b620688	246	adc[0] += gyroY.read()*4095;
Lauszus	0:f5c02b620688	247	adc[1] += accX.read()*4095;
Lauszus	0:f5c02b620688	248	adc[2] += accY.read()*4095;
Lauszus	0:f5c02b620688	249	adc[3] += accZ.read()*4095;
Lauszus	0:f5c02b620688	250	wait_ms(10);
Lauszus	0:f5c02b620688	251	}
Lauszus	0:f5c02b620688	252	zeroValues[0] = adc[0] / 100; // Gyro X-axis
Lauszus	0:f5c02b620688	253	zeroValues[1] = adc[1] / 100; // Accelerometer X-axis
Lauszus	0:f5c02b620688	254	zeroValues[2] = adc[2] / 100; // Accelerometer Y-axis
Lauszus	0:f5c02b620688	255	zeroValues[3] = adc[3] / 100; // Accelerometer Z-axis
Lauszus	0:f5c02b620688	256
Lauszus	0:f5c02b620688	257	onboardLED1 = 0;
Lauszus	0:f5c02b620688	258	onboardLED2 = 0;
Lauszus	0:f5c02b620688	259	onboardLED3 = 0;
Lauszus	0:f5c02b620688	260	onboardLED4 = 0;
Lauszus	0:f5c02b620688	261	}
Lauszus	0:f5c02b620688	262	void move(Motor motor, Direction direction, float speed) { // speed is a value in percentage (0.0f to 1.0f)
Lauszus	0:f5c02b620688	263	if (motor == right) {
Lauszus	0:f5c02b620688	264	leftPWM = speed;
Lauszus	0:f5c02b620688	265	if (direction == forward) {
Lauszus	0:f5c02b620688	266	leftA = 0;
Lauszus	0:f5c02b620688	267	leftB = 1;
Lauszus	0:f5c02b620688	268	} else if (direction == backward) {
Lauszus	0:f5c02b620688	269	leftA = 1;
Lauszus	0:f5c02b620688	270	leftB = 0;
Lauszus	0:f5c02b620688	271	}
Lauszus	0:f5c02b620688	272	} else if (motor == left) {
Lauszus	0:f5c02b620688	273	rightPWM = speed;
Lauszus	0:f5c02b620688	274	if (direction == forward) {
Lauszus	0:f5c02b620688	275	rightA = 0;
Lauszus	0:f5c02b620688	276	rightB = 1;
Lauszus	0:f5c02b620688	277	} else if (direction == backward) {
Lauszus	0:f5c02b620688	278	rightA = 1;
Lauszus	0:f5c02b620688	279	rightB = 0;
Lauszus	0:f5c02b620688	280	}
Lauszus	0:f5c02b620688	281	} else if (motor == both) {
Lauszus	0:f5c02b620688	282	leftPWM = speed;
Lauszus	0:f5c02b620688	283	rightPWM = speed;
Lauszus	0:f5c02b620688	284	if (direction == forward) {
Lauszus	0:f5c02b620688	285	leftA = 0;
Lauszus	0:f5c02b620688	286	leftB = 1;
Lauszus	0:f5c02b620688	287
Lauszus	0:f5c02b620688	288	rightA = 0;
Lauszus	0:f5c02b620688	289	rightB = 1;
Lauszus	0:f5c02b620688	290	} else if (direction == backward) {
Lauszus	0:f5c02b620688	291	leftA = 1;
Lauszus	0:f5c02b620688	292	leftB = 0;
Lauszus	0:f5c02b620688	293
Lauszus	0:f5c02b620688	294	rightA = 1;
Lauszus	0:f5c02b620688	295	rightB = 0;
Lauszus	0:f5c02b620688	296	}
Lauszus	0:f5c02b620688	297	}
Lauszus	0:f5c02b620688	298	}
Lauszus	0:f5c02b620688	299	void stop(Motor motor) {
Lauszus	0:f5c02b620688	300	if (motor == left) {
Lauszus	0:f5c02b620688	301	leftPWM = 1;
Lauszus	0:f5c02b620688	302	leftA = 1;
Lauszus	0:f5c02b620688	303	leftB = 1;
Lauszus	0:f5c02b620688	304	} else if (motor == right) {
Lauszus	0:f5c02b620688	305	rightPWM = 1;
Lauszus	0:f5c02b620688	306	rightA = 1;
Lauszus	0:f5c02b620688	307	rightB = 1;
Lauszus	0:f5c02b620688	308	} else if (motor == both) {
Lauszus	0:f5c02b620688	309	leftPWM = 1;
Lauszus	0:f5c02b620688	310	leftA = 1;
Lauszus	0:f5c02b620688	311	leftB = 1;
Lauszus	0:f5c02b620688	312
Lauszus	0:f5c02b620688	313	rightPWM = 1;
Lauszus	0:f5c02b620688	314	rightA = 1;
Lauszus	0:f5c02b620688	315	rightB = 1;
Lauszus	0:f5c02b620688	316	}
Lauszus	0:f5c02b620688	317	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	25 Aug 2016
Imports:	10
Forks:	0
Commits:	11
Dependents:	0
Dependencies:	4
Followers:	1

BalancingRobot.cpp@1:01295228342f, 2012-02-14 (annotated)

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