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Puck.js v 2.1 a not turning on

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  • •

    I've just converted the Madgwick code:

    // Based on https://github.com/arduino-libraries/MadgwickAHRS/blob/master/src/MadgwickAHRS.cpp
const sampleFreqDef =  26.0;          // sample frequency in Hz
const betaDef       =  0.1;            // 2 * proportional gain


//============================================================================================
// Functions
function invSqrt(x) { return 1/Math.sqrt(x); }

//-------------------------------------------------------------------------------------------
// AHRS algorithm update

class Madgwick {
  /*
    contains:
    
    roll, pitch, yaw (in radians)
  */
  constructor() {
    this.beta = betaDef;
    this.q0 = 1.0;
    this.q1 = 0.0;
    this.q2 = 0.0;
    this.q3 = 0.0;
    this.invSampleFreq = 1.0 / sampleFreqDef;
    this.anglesComputed = 0;
  }

 update(gx, gy, gz, ax, ay, az, mx, my, mz) {
	var recipNorm;
	var s0, s1, s2, s3;
	var qDot1, qDot2, qDot3, qDot4;
	var hx, hy;
	var _2q0mx, _2q0my, _2q0mz, _2q1mx, _2bx, _2bz, _4bx, _4bz, _2q0, _2q1, _2q2, _2q3, _2q0q2, _2q2q3, q0q0, q0q1, q0q2, q0q3, q1q1, q1q2, q1q3, q2q2, q2q3, q3q3;

	// Use IMU algorithm if magnetometer measurement invalid (avoids NaN in magnetometer normalisation)
	if((mx == 0) && (my == 0) && (mz == 0)) {
		this.updateIMU(gx, gy, gz, ax, ay, az);
		return;
	}
   
  var q0 = this.q0, q1 = this.q1, q2 = this.q2, q3 = this.q3;

	// Convert gyroscope degrees/sec to radians/sec
	gx *= 0.0174533;
	gy *= 0.0174533;
	gz *= 0.0174533;

	// Rate of change of quaternion from gyroscope
	qDot1 = 0.5 * (-q1 * gx - q2 * gy - q3 * gz);
	qDot2 = 0.5 * (q0 * gx + q2 * gz - q3 * gy);
	qDot3 = 0.5 * (q0 * gy - q1 * gz + q3 * gx);
	qDot4 = 0.5 * (q0 * gz + q1 * gy - q2 * gx);

	// Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
	if(!((ax == 0.0) && (ay == 0.0) && (az == 0.0))) {

		// Normalise accelerometer measurement
		recipNorm = invSqrt(ax * ax + ay * ay + az * az);
		ax *= recipNorm;
		ay *= recipNorm;
		az *= recipNorm;

		// Normalise magnetometer measurement
		recipNorm = invSqrt(mx * mx + my * my + mz * mz);
		mx *= recipNorm;
		my *= recipNorm;
		mz *= recipNorm;

		// Auxiliary variables to avoid repeated arithmetic
		_2q0mx = 2 * q0 * mx;
		_2q0my = 2 * q0 * my;
		_2q0mz = 2 * q0 * mz;
		_2q1mx = 2 * q1 * mx;
		_2q0 = 2 * q0;
		_2q1 = 2 * q1;
		_2q2 = 2 * q2;
		_2q3 = 2 * q3;
		_2q0q2 = 2 * q0 * q2;
		_2q2q3 = 2 * q2 * q3;
		q0q0 = q0 * q0;
		q0q1 = q0 * q1;
		q0q2 = q0 * q2;
		q0q3 = q0 * q3;
		q1q1 = q1 * q1;
		q1q2 = q1 * q2;
		q1q3 = q1 * q3;
		q2q2 = q2 * q2;
		q2q3 = q2 * q3;
		q3q3 = q3 * q3;

		// Reference direction of Earth's magnetic field
		hx = mx * q0q0 - _2q0my * q3 + _2q0mz * q2 + mx * q1q1 + _2q1 * my * q2 + _2q1 * mz * q3 - mx * q2q2 - mx * q3q3;
		hy = _2q0mx * q3 + my * q0q0 - _2q0mz * q1 + _2q1mx * q2 - my * q1q1 + my * q2q2 + _2q2 * mz * q3 - my * q3q3;
		_2bx = Math.sqrt(hx * hx + hy * hy);
		_2bz = -_2q0mx * q2 + _2q0my * q1 + mz * q0q0 + _2q1mx * q3 - mz * q1q1 + _2q2 * my * q3 - mz * q2q2 + mz * q3q3;
		_4bx = 2 * _2bx;
		_4bz = 2 * _2bz;

		// Gradient decent algorithm corrective step
		s0 = -_2q2 * (2 * q1q3 - _2q0q2 - ax) + _2q1 * (2 * q0q1 + _2q2q3 - ay) - _2bz * q2 * (_2bx * (0.5 - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) + (-_2bx * q3 + _2bz * q1) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) + _2bx * q2 * (_2bx * (q0q2 + q1q3) + _2bz * (0.5 - q1q1 - q2q2) - mz);
		s1 = _2q3 * (2 * q1q3 - _2q0q2 - ax) + _2q0 * (2 * q0q1 + _2q2q3 - ay) - 4 * q1 * (1 - 2 * q1q1 - 2 * q2q2 - az) + _2bz * q3 * (_2bx * (0.5 - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) + (_2bx * q2 + _2bz * q0) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) + (_2bx * q3 - _4bz * q1) * (_2bx * (q0q2 + q1q3) + _2bz * (0.5 - q1q1 - q2q2) - mz);
		s2 = -_2q0 * (2 * q1q3 - _2q0q2 - ax) + _2q3 * (2 * q0q1 + _2q2q3 - ay) - 4 * q2 * (1 - 2 * q1q1 - 2 * q2q2 - az) + (-_4bx * q2 - _2bz * q0) * (_2bx * (0.5 - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) + (_2bx * q1 + _2bz * q3) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) + (_2bx * q0 - _4bz * q2) * (_2bx * (q0q2 + q1q3) + _2bz * (0.5 - q1q1 - q2q2) - mz);
		s3 = _2q1 * (2 * q1q3 - _2q0q2 - ax) + _2q2 * (2 * q0q1 + _2q2q3 - ay) + (-_4bx * q3 + _2bz * q1) * (_2bx * (0.5 - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) + (-_2bx * q0 + _2bz * q2) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) + _2bx * q1 * (_2bx * (q0q2 + q1q3) + _2bz * (0.5 - q1q1 - q2q2) - mz);
		recipNorm = invSqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
		s0 *= recipNorm;
		s1 *= recipNorm;
		s2 *= recipNorm;
		s3 *= recipNorm;

		// Apply feedback step
		qDot1 -= this.beta * s0;
		qDot2 -= this.beta * s1;
		qDot3 -= this.beta * s2;
		qDot4 -= this.beta * s3;
	}

	// Integrate rate of change of quaternion to yield quaternion
	q0 += qDot1 * this.invSampleFreq;
	q1 += qDot2 * this.invSampleFreq;
	q2 += qDot3 * this.invSampleFreq;
	q3 += qDot4 * this.invSampleFreq;

	// Normalise quaternion
	recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
	this.q0 = q0 * recipNorm;
	this.q1 = q1 * recipNorm;
	this.q2 = q2 * recipNorm;
	this.q3 = q3 * recipNorm;
	anglesComputed = 0;
}

//-------------------------------------------------------------------------------------------
// IMU algorithm update

updateIMU(gx, gy, gz, ax, ay, az) {
	var recipNorm;
	var s0, s1, s2, s3;
	var qDot1, qDot2, qDot3, qDot4;
	var _2q0, _2q1, _2q2, _2q3, _4q0, _4q1, _4q2 ,_8q1, _8q2, q0q0, q1q1, q2q2, q3q3;
  var q0 = this.q0, q1 = this.q1, q2 = this.q2, q3 = this.q3;

	// Convert gyroscope degrees/sec to radians/sec
	gx *= 0.0174533;
	gy *= 0.0174533;
	gz *= 0.0174533;

	// Rate of change of quaternion from gyroscope
	qDot1 = 0.5 * (-q1 * gx - q2 * gy - q3 * gz);
	qDot2 = 0.5 * (q0 * gx + q2 * gz - q3 * gy);
	qDot3 = 0.5 * (q0 * gy - q1 * gz + q3 * gx);
	qDot4 = 0.5 * (q0 * gz + q1 * gy - q2 * gx);

	// Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
	if(!((ax == 0) && (ay == 0) && (az == 0))) {

		// Normalise accelerometer measurement
		recipNorm = invSqrt(ax * ax + ay * ay + az * az);
		ax *= recipNorm;
		ay *= recipNorm;
		az *= recipNorm;

		// Auxiliary variables to avoid repeated arithmetic
		_2q0 = 2 * q0;
		_2q1 = 2 * q1;
		_2q2 = 2 * q2;
		_2q3 = 2 * q3;
		_4q0 = 4 * q0;
		_4q1 = 4 * q1;
		_4q2 = 4 * q2;
		_8q1 = 8 * q1;
		_8q2 = 8 * q2;
		q0q0 = q0 * q0;
		q1q1 = q1 * q1;
		q2q2 = q2 * q2;
		q3q3 = q3 * q3;

		// Gradient decent algorithm corrective step
		s0 = _4q0 * q2q2 + _2q2 * ax + _4q0 * q1q1 - _2q1 * ay;
		s1 = _4q1 * q3q3 - _2q3 * ax + 4 * q0q0 * q1 - _2q0 * ay - _4q1 + _8q1 * q1q1 + _8q1 * q2q2 + _4q1 * az;
		s2 = 4 * q0q0 * q2 + _2q0 * ax + _4q2 * q3q3 - _2q3 * ay - _4q2 + _8q2 * q1q1 + _8q2 * q2q2 + _4q2 * az;
		s3 = 4 * q1q1 * q3 - _2q1 * ax + 4 * q2q2 * q3 - _2q2 * ay;
		recipNorm = invSqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
		s0 *= recipNorm;
		s1 *= recipNorm;
		s2 *= recipNorm;
		s3 *= recipNorm;

		// Apply feedback step
		qDot1 -= this.beta * s0;
		qDot2 -= this.beta * s1;
		qDot3 -= this.beta * s2;
		qDot4 -= this.beta * s3;
	}

	// Integrate rate of change of quaternion to yield quaternion
	q0 += qDot1 * this.invSampleFreq;
	q1 += qDot2 * this.invSampleFreq;
	q2 += qDot3 * this.invSampleFreq;
	q3 += qDot4 * this.invSampleFreq;

	// Normalise quaternion
	recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
	this.q0 = q0 * recipNorm;
	this.q1 = q1 * recipNorm;
	this.q2 = q2 * recipNorm;
	this.q3 = q3 * recipNorm;
	anglesComputed = 0;
}

//-------------------------------------------------------------------------------------------
// Fast inverse square-root
// See: http://en.wikipedia.org/wiki/Fast_inverse_square_root

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

computeAngles() {
  var q0 = this.q0, q1 = this.q1, q2 = this.q2, q3 = this.q3;
	this.roll = Math.atan2(q0*q1 + q2*q3, 0.5 - q1*q1 - q2*q2);
	this.pitch = Math.asin(-2 * (q1*q3 - q0*q2));
	this.yaw = Math.atan2(q1*q2 + q0*q3, 0.5 - q2*q2 - q3*q3);
	this.anglesComputed = 1;
}
}


var m = new Madgwick();
var mag = {x:0,y:0,z:0};
Puck.magOn(40);
Puck.on('mag', function(xyz) {
  mag = xyz;
});
Puck.on('accel', function(a) {
  m.update( 
    a.gyro.x/134, a.gyro.y/134, a.gyro.z/134,
    a.acc.x/8192, a.acc.y/8192, a.acc.z/8192,
    mag.x, mag.y, mag.z );
  m.computeAngles();
});
Puck.accelOn(sampleFreqDef);

// Check m.roll, m.yaw, m.pitch (in radians)

    If this works ok I'm very happy to turn it into a library.

    It seems to work well here - if anything it's just a shame that there's no absolute position measurement built in here - but the actual roll/pitch/yaw looks like it works ok

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